CN121195140A

CN121195140A - Series overheat control for dehumidification systems

Info

Publication number: CN121195140A
Application number: CN202480034822.3A
Authority: CN
Inventors: S·E·斯隆; 余为众; S·S·丁格尔; T·R·德蒙特; G·M·洛朗; T·S·奥布赖恩
Original assignee: Therma Stor LLC
Current assignee: Therma Stor LLC
Priority date: 2023-04-24
Filing date: 2024-04-19
Publication date: 2025-12-23
Also published as: WO2024226400A1; AU2024260680A1; MX2025012530A; EP4702287A1

Abstract

A dehumidification system includes a main evaporator, a main condenser, a secondary evaporator, a secondary condenser, a superheat control evaporator, and a regulating valve. The superheat control evaporator is connected in series with the secondary evaporator and configured to receive inlet airflow and output a first airflow to the secondary evaporator. The secondary evaporator receives the first airflow and outputs a second airflow to the main evaporator. The main evaporator receives the second airflow and outputs a third airflow to the secondary condenser. The secondary condenser receives the third airflow and outputs a fourth airflow to the main condenser. The main condenser outputs a ventable airflow. Depending on the operating mode, the regulating valve directs the refrigerant flow to either the secondary condenser or the main evaporator.

Description

In-line superheat control for dehumidification systems

Technical Field

The present invention relates generally to dehumidification and more particularly to a dehumidifier having a secondary evaporator and condenser coil.

Background

In some cases, it is desirable to reduce the air humidity within the structure. For example, in fire and flood remediation applications, it may be desirable to quickly remove water from damaged structural areas. To achieve this, one or more portable dehumidifiers may be placed within the structure to direct dry air toward the area damaged by the water. However, current dehumidifiers have proven to be inefficient in various respects.

Disclosure of Invention

In accordance with embodiments of the present disclosure, disadvantages and problems associated with previous systems may be reduced or eliminated.

In certain embodiments, a dehumidification system includes a primary metering device, a secondary metering device, and a superheat control evaporator. The superheat-controlled evaporator is operable to receive the refrigerant flow from the main evaporator and to receive an inlet air flow and to output a first air flow, the first air flow comprising air that is cooler than the inlet air flow, the first air flow being generated by transferring heat from the inlet air flow to the refrigerant flow as the inlet air flow passes through the superheat-controlled evaporator. The dehumidification system also includes a secondary evaporator disposed downstream of and in series with the superheat control evaporator relative to the air flow. The secondary evaporator is operable to receive the flow of refrigerant from the primary metering device, and to receive a first air flow and to output a second air flow, the second air flow comprising air that is cooler than the first air flow, the second air flow being generated by transferring heat from the first air flow to the flow of refrigerant as the first air flow passes through the secondary evaporator. The dehumidification system also includes a primary evaporator operable to receive the refrigerant flow from the first modulation valve, and to receive the second air flow and to output a third air flow comprising air cooler than the second air flow, the third air flow being generated by transferring heat from the second air flow to the refrigerant flow as the second air flow passes through the primary evaporator. The dehumidification system also includes a secondary condenser operable to receive the refrigerant flow from the first modulation valve, receive the third gas flow, and output a fourth gas flow.

The dehumidification system also includes a first modulation valve operable to receive a flow of refrigerant from the secondary evaporator. During the first mode of operation, the first modulating valve is operable to direct the flow of refrigerant to the secondary condenser. During the second mode of operation, the first modulating valve is operable to direct a flow of refrigerant to the primary evaporator, wherein the flow of refrigerant bypasses the secondary condenser. The dehumidification system is also configured to operate in a third mode of operation, wherein the first modulation valve is operable to direct a portion of the refrigerant flow to the secondary condenser and a remaining portion of the refrigerant flow to the primary evaporator. The dehumidification system also includes a compressor operable to receive the refrigerant flow from the superheat control evaporator and discharge the refrigerant flow at a higher pressure than the refrigerant flow received at the compressor. The dehumidification system also includes a main condenser operable to receive a flow of refrigerant discharged from the compressor. The main condenser is also operable to output a dischargeable gas stream in response to receiving the refrigerant stream from the compressor.

In certain embodiments, a dehumidification system includes a primary metering device, a secondary metering device, and a superheat control evaporator. The superheat-controlled evaporator is operable to receive a flow of refrigerant from the main evaporator, and to receive a first inlet airflow comprising air that is cooler than the first inlet airflow and to output a first airflow generated by transferring heat from the first inlet airflow to the flow of refrigerant as the first inlet airflow passes through the superheat-controlled evaporator. The dehumidification system also includes a secondary evaporator disposed in parallel with the superheat control evaporator. The secondary evaporator is operable to receive the refrigerant flow from the primary metering device, and to receive a second inlet air flow and to output a second air flow, the second air flow comprising air that is cooler than the second inlet air flow, the second air flow being generated by transferring heat from the second inlet air flow to the refrigerant flow as the second inlet air flow passes through the secondary evaporator. The dehumidification system also includes a primary evaporator operable to receive the refrigerant flow from the first modulation valve, to receive both the first and second airflows, and to output a third airflows comprising air cooler than both the first and second airflows, the third airflows being generated by transferring heat from the first and second airflows to the refrigerant flow as both the first and second airflows pass through the primary evaporator. The dehumidification system also includes a secondary condenser operable to receive the refrigerant flow from the first modulation valve, receive the third gas flow, and output a fourth gas flow.

In certain embodiments, a dehumidification system includes a primary metering device, a secondary metering device, and a mixing coil unit. The mixing coil unit is operable to receive an inlet air flow and output a first air flow, the first air flow comprising air that is cooler than the first inlet air flow, the first air flow being generated by transferring heat from the inlet air flow to refrigerant flows within the superheat control evaporator and the secondary evaporator as the inlet air flow passes through both the superheat control evaporator and the secondary evaporator. The hybrid coil unit includes a superheat controlled evaporator and a secondary evaporator. The superheat control evaporator is operable to receive refrigerant flow from the primary evaporator, and the secondary evaporator is operable to receive refrigerant flow from the primary metering device. The dehumidification system also includes a primary evaporator operable to receive the refrigerant flow from the first modulation valve and to receive the first air flow and output a second air flow comprising air cooler than the first air flow, the second air flow being generated by transferring heat from the first air flow to the refrigerant flow as the first air flow passes through the primary evaporator. The dehumidification system also includes a secondary condenser operable to receive the refrigerant flow from the first modulation valve, receive the second gas flow, and output a third gas flow.

Certain embodiments of the present disclosure may provide one or more technical advantages. Advantages of these embodiments include modulating the ratio of sensible to latent heat. For example, adjusting the ratio of sensible to latent heat may further reduce the temperature of the surrounding gas stream or increase the amount of water removed from the gas stream. The secondary condenser may be isolated in that the air flow does not recover energy via the refrigerant flowing through the secondary condenser, thereby providing an air cooling operation rather than dehumidification. Further, the modulation is based on controlling the superheat of one or more evaporator coils of the dehumidification system. The addition of another evaporator coil upstream of the main evaporator allows for faster and more efficient control of the operation of the dehumidification system. For example, providing increased superheat control may prevent cooling of the air stream that has been determined to be at a controlled or set temperature.

In other examples, certain embodiments include two evaporators, two condensers, and two metering devices employing a closed refrigeration loop. This configuration allows a portion of the refrigerant within the system to evaporate and condense twice in one refrigeration cycle, thereby increasing the capacity of the compressor over typical systems without adding any additional energy source to the compressor. This in turn increases the overall efficiency of the system by providing more dehumidification per kilowatt of energy used. The lower humidity of the output gas stream may allow for increased drying potential, which may be beneficial in certain applications (e.g., fire and flood recovery).

Some embodiments of the present disclosure may include some, all, or none of the above advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.

Drawings

For a more complete understanding of the present invention, and the features and advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates an exemplary split system for reducing air humidity within a structure in accordance with certain embodiments;

FIG. 2 illustrates an exemplary portable system for reducing air humidity within a structure in accordance with certain embodiments;

FIGS. 3 and 4 illustrate example dehumidification systems that may be used by the systems of FIGS. 1 and 2 to reduce air humidity within a structure, in accordance with certain embodiments;

FIG. 5 illustrates an example dehumidification method that may be used by the systems of FIGS. 1 and 2 to reduce air humidity within a structure, in accordance with certain embodiments;

FIGS. 6A and 6B illustrate an exemplary air conditioning and dehumidification system in accordance with certain embodiments;

FIG. 7 illustrates an example condenser system for the systems described herein, according to some embodiments;

FIGS. 8A, 8B, and 8C illustrate exemplary air conditioning and dehumidification systems in accordance with certain embodiments;

Fig. 9 and 10 illustrate examples of a single coil set for the systems described herein, according to certain embodiments;

11, 12, 13, and 14 illustrate examples of a primary evaporator including three loops for the systems described herein, according to certain embodiments;

FIGS. 15A and 15B illustrate an exemplary dehumidification system with a liquid cooled condenser in accordance with certain embodiments, and

16A, 16B, 16C, and 16D illustrate an exemplary dehumidification system with a modulation valve in accordance with certain embodiments.

17A, 17B, and 17C illustrate an exemplary dehumidification system with a superheat controlled evaporator in accordance with certain embodiments.

Detailed Description

In some cases, it is desirable to reduce the air humidity within the structure. For example, in fire and flood remediation applications, it may be desirable to remove water from a damaged structure by placing one or more portable dehumidifiers within the structure. As another example, in areas experiencing high humidity level weather, or in buildings requiring low humidity levels (e.g., libraries), it may be desirable to install a dehumidification unit within the central air conditioning system. Furthermore, in some commercial applications it may be desirable to maintain a desired humidity level. However, current dehumidifiers have proven to be deficient or inefficient in various respects.

To address the inefficiency and other problems of current dehumidification systems, the disclosed embodiments provide a dehumidification system that includes a secondary evaporator and a secondary condenser that causes a portion of the refrigerant within the multi-stage system to evaporate and condense twice in one refrigeration cycle. This increases compressor capacity over typical systems without adding any additional energy source to the compressor. This in turn increases the overall efficiency of the system by providing more dehumidification per kilowatt of energy.

FIG. 1 illustrates an exemplary dehumidification system 100 for supplying dehumidified air 106 to a structure 102, in accordance with certain embodiments. The dehumidification system 100 includes an evaporator system 104 located within a structure 102. The structure 102 may include all or a portion of a building or other suitable enclosed space, such as an apartment building, hotel, office space, commercial building, or private home (e.g., a house). The evaporator system 104 receives the inlet air 101 from inside the structure 102, reduces moisture in the received inlet air 101, and supplies dehumidified air 106 back to the structure 102. The evaporator system 104 may distribute the dehumidified air 106 throughout the structure 102 via air ducts, as shown.

In general, the dehumidification system 100 is a split system in which the evaporator system 104 is coupled to a remote condenser system 108 located outside of the structure 102. The remote condenser system 108 may include a condenser unit 112 and a compressor unit 114 that facilitate the function of the evaporator system 104 by processing a refrigerant flow as part of a refrigeration cycle. The refrigerant flow may include any suitable cooling material, such as R410a refrigerant. In certain embodiments, the compressor unit 114 may receive a flow of refrigerant vapor from the evaporator system 104 via a refrigerant line 116. The compressor unit 114 may pressurize the refrigerant flow, thereby increasing the temperature of the refrigerant. The speed of the compressor may be adjusted to achieve desired operating characteristics. The condenser unit 112 may receive the pressurized flow of refrigerant vapor from the compressor unit 114 and cool the pressurized refrigerant by facilitating heat transfer from the refrigerant to ambient air outside of the structure 102. In certain embodiments, the remote condenser system 108 may utilize a heat exchanger (such as a microchannel heat exchanger) to remove heat from the refrigerant stream. Remote condenser system 108 may include a fan that draws ambient air from outside structure 102 for cooling the refrigerant flow. In certain embodiments, the speed of the fan is adjusted to achieve desired operating characteristics. For example, an illustrative embodiment of an exemplary condenser system (described in further detail below) is shown in fig. 7.

The refrigerant flow, after being cooled and condensed to a liquid by the condenser unit 112, may proceed to the evaporator system 104 through a refrigerant line 118. In certain embodiments, the refrigerant stream may be received by an expansion device (described in further detail below) that reduces the pressure of the refrigerant stream, thereby reducing the temperature of the refrigerant stream. An evaporator unit (described in further detail below) of the evaporator system 104 may receive the refrigerant flow from the expansion device and use the refrigerant flow to dehumidify and cool the incoming gas stream. The refrigerant flow may then flow back to the remote condenser system 108 and repeat the cycle.

In certain embodiments, the evaporator system 104 may be installed in series with an air mover. The air mover may include a fan that blows air from one location to another. The air mover may facilitate distribution of air exiting the evaporator system 104 to various portions of the structure 102. The air mover and evaporator system 104 can have a separate return air inlet from which air is drawn. In certain embodiments, air exiting the evaporator system 104 may be mixed with air generated by another component (e.g., an air conditioner) and blown through an air duct by an air mover. In other embodiments, the evaporator system 104 may perform both cooling and dehumidification, and thus may be used without a conventional air conditioner.

Although particular embodiments of the dehumidification system 100 are illustrated and described primarily, the present disclosure contemplates any suitable embodiments of the dehumidification system 100 according to particular needs. Furthermore, while the various components of the dehumidification system 100 have been depicted as being located in particular locations, the present disclosure contemplates locating the components in any suitable locations according to particular needs.

Fig. 2 illustrates an exemplary portable dehumidification system 200 for reducing air humidity within a structure 102 in accordance with certain embodiments of the present disclosure. The dehumidification system 200 may be positioned anywhere within the structure 102 to direct the dehumidified air 106 toward an area that needs to be dehumidified (e.g., an area damaged by water). Generally, the dehumidification system 200 receives the inlet airflow 101, removes moisture from the inlet airflow 101, and discharges dehumidified air 106 back into the structure 102. In certain embodiments, the structure 102 includes a space that is subject to water damage (e.g., due to a flood or fire). To repair a water damaged structure 102, one or more dehumidification systems 200 may be strategically positioned within the structure 102 to quickly reduce the air humidity within the structure 102 and thereby dry the water damaged portion of the structure 102.

Although a particular embodiment of portable dehumidification system 200 is illustrated and described primarily, the present disclosure contemplates any suitable embodiment of portable dehumidification system 200 according to particular needs. Further, while the various components of the portable dehumidification system 200 have been depicted as being located at particular locations within the structure 102, the present disclosure contemplates positioning the components at any suitable locations according to particular needs.

Fig. 3 and 4 illustrate an exemplary dehumidification system 300 that may be used by the dehumidification system 100 and portable dehumidification system 200 of fig. 1 and 2 to reduce air humidity within the structure 102. The dehumidification system 300 includes a main evaporator 310, a main condenser 330, a secondary evaporator 340, a secondary condenser 320, a compressor 360, a main metering device 380, a secondary metering device 390, and a fan 370. In some embodiments, the dehumidification system 300 may also include a subcooling coil 350. In certain embodiments, subcooling coil 350 and main condenser 330 are combined into a single coil. As shown, a flow of refrigerant 305 is circulated through the dehumidification system 300. Generally, the dehumidification system 300 receives the inlet airflow 101, removes moisture from the inlet airflow 101, and discharges dehumidified air 106. The refrigeration cycle utilizing the flow of refrigerant 305 removes moisture from the inlet air 101. However, by including the secondary evaporator 340 and the secondary condenser 320, the dehumidification system 300 causes at least a portion of the flow of refrigerant 305 to evaporate and condense twice in a single refrigeration cycle. This increases the cooling capacity over typical systems without adding any additional energy to the compressor, thereby increasing the overall dehumidification efficiency of the system.

In general, the dehumidification system 300 attempts to match the saturation temperature of the secondary evaporator 340 with the saturation temperature of the secondary condenser 320. The saturation temperature of the secondary evaporator 340 and secondary condenser 320 is generally controlled according to the following equation (temperature of the inlet air 101 + temperature of the second air stream 315)/2. Since the saturation temperature of the secondary evaporator 340 is lower than the inlet air 101, evaporation occurs in the secondary evaporator 340. Since the saturation temperature of the secondary condenser 320 is higher than the second air stream 315, condensation occurs in the secondary condenser 320. The amount of refrigerant 305 evaporated in the secondary evaporator 340 is substantially equal to the amount of refrigerant 305 condensed in the secondary condenser 320.

The primary evaporator 310 receives a flow of refrigerant 305 from the secondary metering device 390 and outputs the flow of refrigerant 305 to the compressor 360. The primary evaporator 310 can be any type of coil (e.g., finned tubes, microchannels, etc.). The primary evaporator 310 receives the first air stream 345 from the secondary evaporator 340 and outputs the second air stream 315 to the secondary condenser 320. Typically, the temperature of the second air stream 315 is lower than the temperature of the first air stream 345. To cool the incoming first gas stream 345, the primary evaporator 310 transfers heat from the first gas stream 345 to the flow of refrigerant 305, thereby causing the flow of refrigerant 305 to at least partially evaporate from a liquid to a gas. Heat transfer from the first air stream 345 to the flow of refrigerant 305 also removes water from the first air stream 345.

The secondary condenser 320 receives the flow of refrigerant 305 from the secondary evaporator 340 and outputs the flow of refrigerant 305 to the secondary metering device 390. The secondary condenser 320 may be any type of coil (e.g., finned tubes, microchannels, etc.). The secondary condenser 320 receives the second air flow 315 from the primary evaporator 310 and outputs a third air flow 325. The third air stream 325 is typically warmer and drier (i.e., the dew point is the same but the relative humidity is lower) than the second air stream 315. The secondary condenser 320 generates a third gas flow 325 by transferring heat from the flow of refrigerant 305 to the second gas flow 315, thereby condensing the flow of refrigerant 305 at least partially from a gas to a liquid.

The main condenser 330 receives a flow of refrigerant 305 from the compressor 360 and outputs the flow of refrigerant 305 to the main metering device 380 or the subcooling coil 350. The main condenser 330 may be any type of coil (e.g., finned tubes, microchannels, etc.). The main condenser 330 receives the third air flow 325 or the fourth air flow 355 and outputs dehumidified air 106. The dehumidified air 106 is typically warmer and drier (i.e., lower relative humidity) than the third airflow 325 and the fourth airflow 355. The main condenser 330 generates dehumidified air 106 by transferring heat from the flow of refrigerant 305, thereby condensing the flow of refrigerant 305 at least partially from a gas to a liquid. In some embodiments, the main condenser 330 fully condenses the flow of refrigerant 305 to a liquid (i.e., 100% liquid). In other embodiments, the main condenser 330 partially condenses the flow of refrigerant 305 into a liquid (i.e., less than 100% liquid). In some embodiments, as shown in FIG. 4, a portion of main condenser 330 receives a separate air stream in addition to air stream 101. For example, the rightmost edge of the main condenser 330 of fig. 4 extends beyond or protrudes beyond the rightmost edges of the secondary evaporator 340, the main evaporator 310, the secondary condenser 320, and the subcooling coil 350. The protruding portion of main condenser 330 may receive additional separate streams.

The secondary evaporator 340 receives the flow of refrigerant 305 from the primary metering device 380 and outputs the flow of refrigerant 305 to the secondary condenser 320. The secondary evaporator 340 can be any type of coil (e.g., finned tubes, microchannels, etc.). The secondary evaporator 340 receives the inlet air 101 and outputs a first air stream 345 to the primary evaporator 310. Typically, the temperature of the first air stream 345 is lower than the temperature of the inlet air 101. To cool the incoming inlet air 101, the secondary evaporator 340 transfers heat from the inlet air 101 to the flow of refrigerant 305, thereby evaporating the flow of refrigerant 305 at least partially from a liquid to a gas.

Subcooling coil 350 is an optional component of dehumidification system 300 that subcools liquid refrigerant 305 as liquid refrigerant 305 exits main condenser 330. This in turn supplies the main metering device 380 with liquid refrigerant 30 degrees (or more) lower than before entering the subcooling coil 350. For example, if the flow of refrigerant 305 into the subcooling coil 350 is 340 psig/105F/60% steam, the flow of refrigerant 305 upon exiting the subcooling coil 350 may be 340 psig/80F/0% steam. The subcooled refrigerant 305 has a greater enthalpy factor and a greater density, which results in a reduction in the cycle time and frequency of the evaporation cycle of the flow of refrigerant 305. This results in a more efficient dehumidification system 300 and less energy being used. Embodiments of the dehumidification system 300 may or may not include a subcooling coil 350. For example, embodiments of the dehumidification system 300 having a microchannel condenser 330 or 320 for use in the portable dehumidification system 200 may include a subcooling coil 350, while embodiments of the dehumidification system 300 using other types of condensers 330 or 320 may not include a subcooling coil 350. As another example, a dehumidification system 300 used in a split system (such as dehumidification system 100) may not include a subcooling coil 350.

The compressor 360 pressurizes the flow of refrigerant 305, thereby increasing the temperature of the refrigerant 305. For example, if the flow of refrigerant 305 into compressor 360 is 128 psig/52F/100% steam, the flow of refrigerant 305 upon exiting compressor 360 may be 340 psig/150F/100% steam. The compressor 360 receives a flow of refrigerant 305 from the main evaporator 310 and supplies a flow of pressurized refrigerant 305 to the main condenser 330.

The fan 370 may include any suitable component operable to draw the inlet air 101 into the dehumidification system 300 and through the secondary evaporator 340, the primary evaporator 310, the secondary condenser 320, the subcooling coil 350, and the primary condenser 330. The fan 370 may be any type of air mover (e.g., an axial fan, a forward-tilted impeller, a backward-tilted impeller, etc.). For example, the fan 370 may be a retroverted impeller located near the main condenser 330, as shown in FIG. 3. Although the fan 370 is depicted in fig. 3 as being located near the main condenser 330, it should be understood that the fan 370 may be located at any location along the airflow path of the dehumidification system 300. For example, fan 370 may be located in the airflow path of any of airflows 101, 345, 315, 325, 355, or 106. Further, the dehumidification system 300 may include one or more additional fans located within any one or more of these airflow paths.

The primary metering device 380 and the secondary metering device 390 are any suitable type of metering/expansion devices. In some embodiments, the primary metering device 380 is a thermostatic expansion valve (TXV) and the secondary metering device 390 is a fixed orifice device (or vice versa). In certain embodiments, metering devices 380 and 390 remove pressure from the flow of refrigerant 305 to allow expansion in evaporators 310 and 340 or change state from liquid to vapor. The temperature of the high pressure liquid (or mostly liquid) refrigerant entering metering devices 380 and 390 is higher than the temperature of liquid refrigerant 305 exiting metering devices 380 and 390. For example, if the flow of refrigerant 305 into the primary metering device 380 is 340 psig/80F/0% steam, the flow of refrigerant 305 may be 196 psig/68F/5% steam as it exits the primary metering device 380. As another example, if the flow of refrigerant 305 into the secondary metering device 390 is 196 psig/68F/4% steam, the flow of refrigerant 305 may be 128 psig/44F/14% steam as it exits the secondary metering device 390.

Refrigerant 305 may be any suitable refrigerant, such as R410a. In general, the dehumidification system 300 employs a closed refrigeration loop of refrigerant 305 flowing from a compressor 360 through a main condenser 330, (optional) subcooling coil 350, a main metering device 380, a secondary evaporator 340, a secondary condenser 320, a secondary metering device 390, and a main evaporator 310. The compressor 360 pressurizes the flow of refrigerant 305, thereby increasing the temperature of the refrigerant 305. The main condenser 330 and the secondary condenser 320 may include any suitable heat exchanger, with the main condenser 330 and the secondary condenser 320 cooling the flow of pressurized refrigerant 305 by facilitating heat transfer from the flow of refrigerant 305 to the respective streams (i.e., the fourth stream 355 and the second stream 315) flowing through the main condenser 330 and the secondary condenser 320. The flow of cooled refrigerant 305 exiting the main condenser 330 and the secondary condenser 320 may enter respective expansion devices (i.e., the main metering device 380 and the secondary metering device 390) operable to reduce the pressure of the flow of refrigerant 305, thereby reducing the temperature of the flow of refrigerant 305. The primary and secondary evaporators 310, 340 may include any suitable heat exchanger, with the primary and secondary evaporators 310, 340 receiving a flow of refrigerant 305 from the secondary metering device 390 and the primary metering device 380, respectively. The primary evaporator 310 and the secondary evaporator 340 facilitate heat transfer from the respective streams flowing through them (i.e., the inlet air 101 and the first stream 345) to the stream of refrigerant 305. The flow of refrigerant 305 after leaving the main evaporator 310 flows back to the compressor 360 and repeats the cycle.

In certain embodiments, the refrigeration loop described above may be configured such that the evaporators 310 and 340 operate in a flooded condition. In other words, the flow of refrigerant 305 may enter the evaporators 310 and 340 in a liquid state, and a portion of the flow of refrigerant 305 remains in a liquid state upon exiting the evaporators 310 and 340. Accordingly, a phase change of the flow of refrigerant 305 (as heat is transferred to the flow of refrigerant 305, the liquid changes to vapor) occurs across the evaporators 310 and 340, resulting in an almost constant pressure and temperature across the entire evaporators 310 and 340 (and thus, increased cooling capacity).

In operation of an exemplary embodiment of the dehumidification system 300, inlet air 101 may be drawn into the dehumidification system 300 by a fan 370. The inlet air 101 passes through the secondary evaporator 340 where heat is transferred from the inlet air 101 to the cold flow of refrigerant 305 through the secondary evaporator 340. As a result, the inlet air 101 may be cooled. For example, if the inlet air 101 is 80°f/60% humidity, the secondary evaporator 340 may output a first air stream 345 of 70°f/84% humidity. This may cause the flow of refrigerant 305 to partially evaporate within the secondary evaporator 340. For example, if the flow of refrigerant 305 into the secondary evaporator 340 is 196 psig/68°f/5% steam, the flow of refrigerant 305 upon exiting the secondary evaporator 340 may be 196 psig/68°f/38% steam.

The cooled inlet air 101 exits the secondary evaporator 340 as a first air stream 345 and enters the primary evaporator 310. Similar to the secondary evaporator 340, the primary evaporator 310 transfers heat from the first air stream 345 to the flow of cold refrigerant 305 through the primary evaporator 310. As a result, the first gas stream 345 may be cooled to or below its dew point temperature, resulting in condensation of water vapor in the first gas stream 345 (thereby reducing the absolute humidity of the first gas stream 345). For example, if the first air stream 345 is 70°f/84% humidity, the main evaporator 310 may output a second air stream 315 of 54°f/98% humidity. This may result in the flow of refrigerant 305 partially or completely evaporating within the main evaporator 310. For example, if the flow of refrigerant 305 into the main evaporator 310 is 128 psig/44°f/14% steam, the flow of refrigerant 305 out of the main evaporator 310 may be 128 psig/52°f/100% steam. In certain embodiments, liquid condensate from the first gas stream 345 may be collected in a drain pan connected to a condensate reservoir, as shown in fig. 4. Further, the condensate reservoir may include a condensate pump that continuously or at periodic time intervals moves collected condensate from the dehumidification system 300 (e.g., via a drain hose) to a suitable drain or storage location.

The cooled first air stream 345 exits the primary evaporator 310 as a second air stream 315 and enters the secondary condenser 320. The secondary condenser 320 facilitates heat transfer from the flow of hot refrigerant 305 through the secondary condenser 320 to the second airflow 315. This will reheat the second air stream 315, thereby reducing the relative humidity of the second air stream 315. For example, if the second air flow 315 is 54°f/98% humidity, the secondary condenser 320 may output a third air flow 325 of 65°f/68% humidity. This may result in the flow of refrigerant 305 partially or fully condensing within secondary condenser 320. For example, if the flow of refrigerant 305 into secondary condenser 320 is 196 psig/68F/38% steam, then the flow of refrigerant 305 out of secondary condenser 320 may be 196 psig/68F/4% steam.

In some embodiments, the dehumidified second air stream 315 exits the secondary condenser 320 as a third air stream 325 and enters the main condenser 330. The main condenser 330 facilitates heat transfer from the flow of hot refrigerant 305 through the main condenser 330 to the third air stream 325. This further heats the third airflow 325, thereby further reducing the relative humidity of the third airflow 325. For example, if the third airflow 325 is 65°f/68% humidity, the secondary condenser 320 may output 102°f/19% humidity dehumidified air 106. This may result in the flow of refrigerant 305 partially or fully condensing within main condenser 330. For example, if the flow of refrigerant 305 into main condenser 330 is 340 psig/150F/100% steam, then the flow of refrigerant 305 may be 340 psig/105F/60% steam as it exits main condenser 330.

As described above, some embodiments of the dehumidification system 300 may include a subcooling coil 350 in the air stream between the secondary condenser 320 and the main condenser 330. The subcooling coil 350 facilitates heat transfer from the flow of hot refrigerant 305 through the subcooling coil 350 to the third air flow 325. This further heats the third airflow 325, thereby further reducing the relative humidity of the third airflow 325. For example, if the third air flow 325 is 65°f/68% humidity, the subcooling coil 350 may output a fourth air flow 355 of 81°f/37% humidity. This may result in the flow of refrigerant 305 partially or fully condensing within the subcooling coil 350. For example, if the flow of refrigerant 305 into the subcooling coil 350 is 340 psig/150F/60% steam, then the flow of refrigerant 305 may be 340 psig/80F/0% steam as it exits the subcooling coil 350.

Some embodiments of the dehumidification system 300 may include a controller, which may include one or more computer systems located at one or more locations. Each computer system may include any suitable input device (e.g., keyboard, touch screen, mouse, or other device that can accept information), output device, mass storage medium, or other suitable means for receiving, processing, storing, and transmitting data. Both the input device and the output device may include fixed or removable storage media such as a computer disk, CD-ROM, or other suitable media to receive input from a user and provide output to the user. Each computer system may include a personal computer, a workstation, a network computer, a self-service terminal, a wireless data port, a Personal Data Assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. In short, the controller may comprise any suitable combination of software, firmware, and hardware.

The controller may additionally include one or more processing modules. Each processing module may include one or more microprocessors, controllers, or any other suitable computing devices or resources, and may operate alone or in conjunction with other components of the dehumidification system 300 to provide some or all of the functionality described herein. The controller may also include (or be communicatively coupled to via wireless or wired communications) a computer memory. The memory may include any memory or database module and may take the form of volatile or nonvolatile memory including, but not limited to, magnetic media, optical media, random Access Memory (RAM), read Only Memory (ROM), removable media, or any other suitable local or remote memory component.

Although particular embodiments of the dehumidification system 300 are illustrated and described primarily, the present disclosure contemplates any suitable embodiments of the dehumidification system 300 according to particular needs. Further, while the various components of the dehumidification system 300 have been depicted as being positioned in particular locations and relative to one another, the present disclosure contemplates positioning the components in any suitable locations according to particular needs.

Fig. 5 illustrates an exemplary dehumidification method 500 that may be used by the dehumidification system 100 and portable dehumidification system 200 of fig. 1 and 2 to reduce air humidity within the structure 102. The method 500 may begin at step 510, where a secondary evaporator receives an inlet airflow and outputs a first airflow. In some embodiments, the secondary evaporator is a secondary evaporator 340. In some embodiments, the inlet airflow is inlet air 101 and the first airflow is first airflow 345. In some embodiments, the secondary evaporator of step 510 receives the refrigerant flow from a primary metering device (such as primary metering device 380) and supplies the refrigerant flow (in a changed state) to a secondary condenser (such as secondary condenser 320). In some embodiments, the refrigerant flow of method 500 is the flow of refrigerant 305 described above.

In step 520, the primary evaporator receives the first air flow of step 510 and outputs a second air flow. In some embodiments, the primary evaporator is primary evaporator 310 and the second air flow is secondary air flow 315. In some embodiments, the primary evaporator of step 520 receives the refrigerant flow from a secondary metering device (such as secondary metering device 390) and supplies the refrigerant flow (in a changed state) to a compressor (such as compressor 360).

In step 530, the secondary condenser receives the second air stream of step 520 and outputs a third air stream. In some embodiments, the secondary condenser is a secondary condenser 320 and the third airflow is a third airflow 325. In some embodiments, the secondary condenser of step 530 receives the refrigerant flow from the secondary evaporator of step 510 and supplies the refrigerant flow (in a changed state) to a secondary metering device (such as secondary metering device 390).

In step 540, the main condenser receives the third air stream of step 530 and outputs a dehumidified air stream. In some embodiments, the main condenser is main condenser 330 and the dehumidified airflow is dehumidified air 106. In some embodiments, the main condenser of step 540 receives the refrigerant flow from the compressor of step 520 and supplies the refrigerant flow (in a changed state) to the main metering device of step 510. In an alternative embodiment, the main condenser of step 540 supplies the refrigerant stream (in an altered state) to a subcooling coil (such as subcooling coil 350), which in turn supplies the refrigerant stream (in an altered state) to the main metering device of step 510.

In step 550, the compressor receives the refrigerant flow from the main evaporator of step 520 and provides the refrigerant flow (in a modified state) to the main condenser of step 540. After step 550, the method 500 may end.

Particular embodiments may repeat one or more steps of method 500 of fig. 5, where appropriate. Although this disclosure describes and illustrates particular steps of the method of fig. 5 as occurring in a particular order, this disclosure contemplates any suitable steps of the method of fig. 5 occurring in any suitable order. Furthermore, while this disclosure describes and illustrates that an exemplary dehumidification method for reducing air humidity within a structure includes particular steps of the method of fig. 5, this disclosure contemplates any suitable method for reducing air humidity within a structure including any suitable steps, which may include all, some, or none of the steps of the method of fig. 5, where appropriate. Furthermore, although this disclosure describes and illustrates particular components, devices, or systems performing particular steps of the method of fig. 5, this disclosure contemplates any suitable combination of any suitable components, devices, or systems performing any suitable steps of the method of fig. 5.

While the exemplary method of fig. 5 is described above in connection with the dehumidification system 300 of fig. 3a plurality of times, it should be appreciated that any of the dehumidification systems described herein may be used to perform the same or similar methods, including the dehumidification systems 600 and 800 of fig. 6A-6B and 8 (described below). Furthermore, it should be understood that with respect to the exemplary method of fig. 5, references to an evaporator or condenser may refer to an evaporator portion or condenser portion of a single coil assembly that is operable to perform the functions of these components, for example, as described above with respect to the examples of fig. 9 and 10.

Fig. 6A and 6B illustrate an exemplary air conditioning and dehumidification system 600 that may be used in accordance with the split dehumidification system 100 of fig. 1 to reduce air humidity within the structure 102. The dehumidification system 600 includes a dehumidification unit 602 (typically located indoors) and a condenser system 604 (e.g., the condenser system 108 of fig. 1). As shown in fig. 6A, the dehumidification unit 602 includes a primary evaporator 610, a secondary evaporator 640, a secondary condenser 620, a primary metering device 680, a secondary metering device 690, and a first fan 670, while the condenser system 604 includes a primary condenser 630, a compressor 660, an optional subcooling coil 650, and a second fan 695. In the embodiment shown in fig. 6B, the compressor 660 may be disposed within the dehumidification unit 602 instead of within the condenser system 604.

Referring to both fig. 6A and 6B, as shown, a flow of refrigerant 605 is circulated through the dehumidification system 600. In general, the dehumidification unit 602 receives the inlet air flow 601, removes water from the inlet air flow 601, and discharges dehumidified air 625 into a conditioned space. Water is removed from the inlet air 601 using a refrigeration cycle of the refrigerant 605 flow. The manner in which the refrigerant 605 in fig. 6A and 6B flows through the system 600 is similar to the manner in which the refrigerant 305 flows through the dehumidification system 300 of fig. 3. However, as described herein, the path of the airflow through system 600 is different than the path of the airflow through system 300. However, by including the secondary evaporator 640 and the secondary condenser 620, the dehumidification system 600 causes at least a portion of the flow of refrigerant 605 to evaporate and condense twice in a single refrigeration cycle. This increases the refrigeration capacity compared to typical systems without adding any additional energy source to the compressor, thereby increasing the overall efficiency of the system.

The split configuration of the system 600 including the dehumidification unit 602 and the condenser system 604 allows heat from the cooling and dehumidification process to be released to the outside or unregulated space (e.g., outside of the space being dehumidified). This allows the dehumidification system 600 to have a similar footprint as a typical central air conditioning system or heat pump. In general, the temperature of the third air stream 625 output from the system 600 to the conditioned space is significantly reduced compared to the temperature of the air stream 106 output from the system 300 of fig. 3. Thus, the configuration of the system 600 allows for providing dehumidified air to a conditioned space at a reduced temperature. Thus, the system 600 may perform the functions of both a dehumidifier (dehumidifying air) and a central air conditioner (cooling air).

In general, the dehumidification system 600 attempts to match the saturation temperature of the secondary evaporator 640 to the saturation temperature of the secondary condenser 620. The saturation temperature of the secondary evaporator 640 and secondary condenser 620 is generally controlled according to the following formula (temperature of the inlet air 601 + temperature of the second air stream 615)/2. Since the saturation temperature of the secondary evaporator 640 is lower than the inlet air 601, evaporation occurs in the secondary evaporator 640. Since the saturation temperature of the secondary condenser 620 is higher than the second airflow 615, condensation occurs in the secondary condenser 620. The amount of refrigerant 605 evaporated in the secondary evaporator 640 is substantially equal to the amount of refrigerant 605 condensed in the secondary condenser 620.

The primary evaporator 610 receives the flow of refrigerant 605 from the secondary metering device 690 and outputs the flow of refrigerant 605 to the compressor 660. The primary evaporator 610 can be any type of coil (e.g., finned tubes, microchannels, etc.). The primary evaporator 610 receives the first air stream 645 from the secondary evaporator 640 and outputs the second air stream 615 to the secondary condenser 620. Typically, the temperature of the second air stream 615 is lower than the temperature of the first air stream 645. To cool the incoming first gas stream 645, the primary evaporator 610 transfers heat from the first gas stream 645 to the flow of refrigerant 605, thereby evaporating the flow of refrigerant 605 at least partially from a liquid to a gas. Heat transfer from the first air stream 645 to the flow of refrigerant 605 also removes water from the first air stream 645.

The secondary condenser 620 receives the flow of refrigerant 605 from the secondary evaporator 640 and outputs the flow of refrigerant 605 to the secondary metering device 690. The secondary condenser 620 may be any type of coil (e.g., finned tubes, microchannels, etc.). The secondary condenser 620 receives the second airflow 615 from the primary evaporator 610 and outputs a third airflow 625. The third air stream 625 is typically warmer and drier (i.e., the dew point is the same but the relative humidity is lower) than the second air stream 615. The secondary condenser 620 generates a third gas stream 625 by transferring heat from the flow of refrigerant 605 to the second gas stream 615, thereby condensing the flow of refrigerant 605 at least partially from a gas to a liquid. As described above, the third air flow 625 is output into the conditioned space. In other embodiments (e.g., as shown in fig. 8A and 8B), the third air stream 625 may first pass through and/or over the subcooling coil 650 and then be output into the conditioned space at a further reduced relative humidity.

As shown in fig. 6A, refrigerant 605 flows to the outdoor or unregulated space to the compressor 660 of the condenser system 604. Alternatively, the refrigerant 605 may continue to flow to the compressor 660 within the dehumidification unit 602 and then out the outdoor or to an unregulated space, as can be seen in fig. 6B. In fig. 6A and 6B, compressor 660 pressurizes the flow of refrigerant 605, thereby increasing the temperature of refrigerant 605. For example, if the flow of refrigerant 605 into compressor 660 is 128 psig/52F/100% steam, then the flow of refrigerant 605 may be 340 psig/150F/100% steam as it exits compressor 660. The compressor 660 receives a flow of refrigerant 605 from the main evaporator 610 and supplies the flow of pressurized refrigerant 605 to the main condenser 630.

The main condenser 630 receives the flow of refrigerant 605 from the compressor 660 and outputs the flow of refrigerant 605 to the subcooling coil 650. The main condenser 630 may be any type of coil (e.g., finned tubes, microchannels, etc.). The main condenser 630 and the subcooling coil 650 receive the first outdoor air stream 606 and output a second outdoor air stream 608. The second outdoor airflow 608 is typically warmer (i.e., has a lower relative humidity) than the first outdoor airflow 606. The main condenser 630 transfers heat from the flow of refrigerant 605, thereby condensing the flow of refrigerant 605 at least partially from a gas to a liquid. In some embodiments, main condenser 630 condenses the flow of refrigerant 605 completely to a liquid (i.e., 100% liquid). In other embodiments, the main condenser 630 partially condenses the flow of refrigerant 605 into a liquid (i.e., less than 100% liquid).

Subcooling coil 650 is an optional component of dehumidification system 600, and subcooling coil 650 subcools liquid refrigerant 605 as liquid refrigerant 605 leaves main condenser 630. This in turn provides the main metering device 680 with 30 degrees (or more) lower liquid refrigerant than before entering the subcooling coil 650. For example, if the flow of refrigerant 605 into subcooling coil 650 is 340 psig/105F/60% steam, then the flow of refrigerant 605 out of subcooling coil 650 may be 340 psig/80F/0% steam. The subcooled refrigerant 605 has a greater enthalpy factor and a greater density, which increases the energy transfer between the gas stream and the evaporator, thereby removing more latent heat from the refrigerant 605. This further makes the dehumidification system 600 more efficient and uses less energy. Embodiments of the dehumidification system 600 may or may not include a subcooling coil 650.

In certain embodiments, subcooling coil 650 and main condenser 630 are combined into a single coil. Such a single coil includes suitable circuits for the flows of air streams 606 and 608 and refrigerant 605. Fig. 7 shows an illustrative example of a condenser system 604 that includes a single coil condenser and a subcooling coil. The single unit coil includes an inner tube 710 corresponding to the condenser and an outer tube 705 corresponding to the subcooling coil. The refrigerant may be directed through the inner tube 710 before flowing through the outer tube 705. In the illustrative example shown in fig. 7, the air flow is drawn through a single unit coil and exhausted upward by a fan 695. However, it should be understood that the condenser system of other embodiments may include a condenser, a compressor, an optional subcooling coil, and a fan having other configurations known in the art.

The secondary evaporator 640 receives the flow of refrigerant 605 from the primary metering device 680 and outputs the flow of refrigerant 605 to the secondary condenser 620. The secondary evaporator 640 may be any type of coil (e.g., finned tubes, microchannels, etc.). The secondary evaporator 640 receives the inlet air 601 and outputs a first air stream 645 to the primary evaporator 610. Typically, the temperature of the first air stream 645 is lower than the temperature of the inlet air 601. To cool the incoming inlet air 601, the secondary evaporator 640 transfers heat from the inlet air 601 to the flow of refrigerant 605, thereby evaporating the flow of refrigerant 605 at least partially from a liquid to a gas.

The fan 670 may include any suitable components operable to draw inlet air 601 into the dehumidification unit 602 and through the secondary evaporator 640, the primary evaporator 610, and the secondary condenser 620. Fan 670 may be any type of air mover (e.g., an axial fan, a forward-tilted impeller, a backward-tilted impeller, etc.). For example, the fan 670 may be a retroverted impeller located near the secondary condenser 620.

Although the fan 670 is depicted in fig. 6A and 6B as being located near the condenser 620, it should be understood that the fan 670 may be located at any location along the airflow path of the dehumidification unit 602. For example, the fan 670 may be located in the airflow path of any of the airflows 601, 645, 615, or 625. Furthermore, the dehumidification unit 602 may include one or more additional fans located within any one or more of these airflow paths. Similarly, while fan 695 of condenser system 604 is depicted in fig. 6A and 6B as being located above main condenser 630, it should be appreciated that fan 695 may be located anywhere (e.g., above, below, beside) with respect to condenser 630 and subcooling coil 650, so long as fan 695 is suitably positioned and configured to facilitate flow of air stream 606 toward main condenser 630 and subcooling coil 650.

The airflow rate generated by fan 670 may be different from the airflow rate generated by fan 695. For example, the flow rate of the air stream 606 generated by the fan 695 may be higher than the flow rate of the air stream 601 generated by the fan 670. This difference in flow rates may provide several advantages to the dehumidification system described herein. For example, the large airflow generated by the fan 695 may improve heat transfer at the subcooling coil 650 and the main condenser 630 of the condenser system 604. Typically, the second fan 695 generates an airflow rate that is about 2 to 5 times the airflow rate generated by the first fan 670. For example, the air flow rate generated by the first fan 670 may be about 200 to 400 cubic feet per minute (cfm). For example, the second fan 695 may generate an airflow rate of approximately 900 to 1200 cubic feet per minute (cfm).

The primary metering device 680 and the secondary metering device 690 are any suitable type of metering/expansion devices. In some embodiments, the primary metering device 680 is a thermostatic expansion valve (TXV) and the secondary metering device 690 is a fixed orifice device (or vice versa). In certain embodiments, metering devices 680 and 690 remove pressure from the flow of refrigerant 605 to allow the refrigerant to expand in evaporators 610 and 640 or change state from a liquid to a vapor. The temperature of the high pressure liquid (or mostly liquid) refrigerant entering metering devices 680 and 690 is higher than the temperature of liquid refrigerant 605 exiting metering devices 680 and 690. For example, if the flow of refrigerant 605 into the primary metering device 680 is 340 psig/80F/0% steam, the flow of refrigerant 605 out of the primary metering device 680 may be 196 psig/68F/5% steam. As another example, if the flow of refrigerant 605 into the secondary metering device 690 is 196 psig/68F/4% steam, the flow of refrigerant 605 may be 128 psig/44F/14% steam as it exits the secondary metering device 690.

In certain embodiments, the secondary metering device 690 operates in a substantially open state (referred to herein as a "fully open" state) such that the pressure of the refrigerant 605 entering the metering device 690 is substantially the same as the pressure of the refrigerant 605 exiting the metering device 605. For example, the pressure of the refrigerant 605 may be 80%, 90%, 95%, 99%, or up to 100% of the pressure of the refrigerant 605 entering the metering device 690. The primary metering device 680 is the primary source of pressure drop in the dehumidification system 600 when the secondary metering device 690 is in a "fully open" state. In this configuration, as the airflow 615 passes through the secondary condenser 620, the airflow 615 is not significantly heated, and the secondary evaporator 640, the primary evaporator 610, and the secondary condenser 620 effectively act as a single evaporator. Although less water may be removed from the air stream 601 when the secondary metering device 690 is operating in the "fully open" state, the air stream 606 will be output to the conditioned space at a lower temperature than when the secondary metering device 690 is not in the "fully open" state. This configuration corresponds to a relatively high Sensible Heat Ratio (SHR) mode of operation such that the dehumidification system 600 may produce a cold air stream 625 having similar characteristics to the air stream produced by the central air conditioner. If the rate of the air flow 601 increases to a threshold (e.g., by increasing the speed of the fan 670 or one or more other fans of the dehumidification system 600), the dehumidification system 600 may be sensible cooled without removing water from the air flow 601.

Refrigerant 605 may be any suitable refrigerant, such as R410a. In general, the dehumidification system 600 employs a closed refrigeration loop of refrigerant 605, with the refrigerant 605 passing from the compressor 660 through a main condenser 630, (optionally) a subcooling coil 650, a main metering device 680, a secondary evaporator 640, a secondary condenser 620, a secondary metering device 690, and a main evaporator 610. The compressor 660 pressurizes the flow of refrigerant 605, thereby increasing the temperature of the refrigerant 605. The main condenser 630 and the secondary condenser 620 may include any suitable heat exchanger, with the main condenser 630 and the secondary condenser 620 cooling the flow of pressurized refrigerant 605 by facilitating heat transfer from the flow of refrigerant 605 to the respective streams (i.e., the first outdoor stream 606 and the second stream 615) passing through them. The cooled flow of refrigerant 605 exiting the main condenser 630 and the secondary condenser 620 may enter respective expansion devices (i.e., a main metering device 680 and a secondary metering device 690) that are operable to reduce the pressure of the flow of refrigerant 605, thereby reducing the temperature of the flow of refrigerant 605. The primary evaporator 610 and the secondary evaporator 640 may include any suitable heat exchanger, with the primary evaporator 610 and the secondary evaporator 640 receiving the flow of refrigerant 605 from the secondary metering device 690 and the primary metering device 680, respectively. The primary evaporator 610 and the secondary evaporator 640 facilitate heat transfer from the respective streams passing through them (i.e., the inlet air 601 and the first stream 645) to the stream of refrigerant 605. The flow of refrigerant 605 returns to the compressor 660 after leaving the main evaporator 610 and repeats the cycle.

In certain embodiments, the refrigeration loop described above may be configured such that the evaporators 610 and 640 operate at a flooded condition. In other words, the flow of refrigerant 605 may enter the evaporators 610 and 640 in a liquid state, and a portion of the flow of refrigerant 605 remains in a liquid state upon exiting the evaporators 610 and 640. Accordingly, a phase change in the flow of refrigerant 605 (as heat is transferred to the flow of refrigerant 605, the liquid changes to vapor) occurs across the evaporators 610 and 640, resulting in an almost constant pressure and temperature across the entire evaporators 610 and 640 (and thus, increased cooling capacity).

In operation of an exemplary embodiment of the dehumidification system 600, inlet air 601 may be drawn into the dehumidification system 600 by a fan 670. The inlet air 601 passes through the secondary evaporator 640 where heat is transferred from the inlet air 601 to the cold refrigerant 605 stream passing through the secondary evaporator 640. As a result, the inlet air 601 may be cooled. For example, if the inlet air 601 is 80°f/60% humidity, the secondary evaporator 640 may output a first air stream 645 of 70°f/84% humidity. This may cause the flow of refrigerant 605 to partially evaporate within secondary evaporator 640. For example, if the flow of refrigerant 605 into secondary evaporator 640 is 196 psig/68F/5% vapor, the flow of refrigerant 605 may be 196 psig/68F/38% vapor upon exiting secondary evaporator 640.

The cooled inlet air 601 exits the secondary evaporator 640 as a first air stream 645 and enters the primary evaporator 610. Similar to the secondary evaporator 640, the primary evaporator 610 transfers heat from the first air stream 645 to the flow of cold refrigerant 605 through the primary evaporator 610. As a result, the first gas stream 645 may be cooled to or below its dew point temperature, resulting in condensation of water vapor in the first gas stream 645 (thereby reducing the absolute humidity of the first gas stream 645). For example, if the first air stream 645 is 70°f/84% humidity, the main evaporator 610 may output a second air stream 615 of 54°f/98% humidity. This may result in the flow of refrigerant 605 partially or completely evaporating within the main evaporator 610. For example, if the flow of refrigerant 605 into the main evaporator 610 is 128 psig/44°f/14% steam, the flow of refrigerant 605 may be 128 psig/52°f/100% steam as it exits the main evaporator 610. In some embodiments, liquid condensate from the first gas stream 645 may be collected in a drain pan connected to a condensate reservoir, as shown in fig. 4. Further, the condensate reservoir may include a condensate pump that moves collected condensate from the dehumidification system 600 (e.g., via a drain hose) to a suitable drain or storage location, either continuously or at periodic time intervals.

The cooled first air stream 645 exits the primary evaporator 610 as the second air stream 615 and enters the secondary condenser 620. The secondary condenser 620 facilitates heat transfer from the flow of hot refrigerant 605 through the secondary condenser 620 to the second airflow 615. This will reheat the second air stream 615, thereby reducing the relative humidity of the second air stream 615. For example, if the second airflow 615 is 54°f/98% humidity, the secondary condenser 620 may output a dehumidified airflow 625 of 65°f/68% humidity. This may result in partial or complete condensation of the flow of refrigerant 605 within secondary condenser 620. For example, if the flow of refrigerant 605 into secondary condenser 620 is 196 psig/68F/38% steam, the flow of refrigerant 605 may be 196 psig/68F/4% steam upon exiting secondary condenser 620. In some embodiments, the second airflow 615 exits the secondary condenser 620 as a dehumidified airflow 625 and is output to the conditioned space.

The main condenser 630 facilitates heat transfer from the flow of hot refrigerant 605 through the main condenser 630 to the first outdoor air stream 606. This heats the outdoor airflow 606, which is output as a second outdoor airflow 608 to an unregulated space (e.g., outdoors). For example, if the first outdoor air stream 606 is 65F/68% humidity, the main condenser 630 may output a second outdoor air stream 608 of 102F/19% humidity. This may result in partial or complete condensation of the flow of refrigerant 605 within the main condenser 630. For example, if the flow of refrigerant 605 into main condenser 630 is 340 psig/150F/100% steam, then the flow of refrigerant 605 may be 340 psig/105F/60% steam as it exits main condenser 630.

As described above, some embodiments of the dehumidification system 600 may include a subcooling coil 650 positioned in the air stream between the inlet of the condenser system 604 and the main condenser 630. Subcooling coil 650 facilitates transfer of heat from the flow of hot refrigerant 605 through subcooling coil 650 to first outdoor air stream 606. This heats the first outdoor air stream 606, thereby increasing the temperature of the first outdoor air stream 606. For example, if the first outdoor air stream 606 is 65F/68% humidity, then the subcooling coil 650 may output an air stream of 81F/37% humidity. This may result in partial or complete condensation of the flow of refrigerant 605 within subcooling coil 650. For example, if the flow of refrigerant 605 into subcooling coil 650 is 340 psig/150F/60% steam, then the flow of refrigerant 605 may be 340 psig/80F/0% steam upon exiting subcooling coil 650.

In the embodiment depicted in fig. 6A and 6B, a subcooling coil 650 is located within the condenser system 604. This configuration minimizes the temperature of the third air stream 625 output into the conditioned space. Fig. 8A and 8B illustrate an alternative embodiment of a dehumidification system 800 in which a dehumidification unit 802 includes a subcooling coil 650. In these embodiments, the air stream 625 first passes through the subcooling coil 650 and then is output as air stream 855 to the conditioned space via fan 670. As described herein, the fan 670 may alternatively be located at any location along the airflow path in the dehumidification unit 802, and one or more additional fans may be included in the dehumidification unit 802.

Without being bound by any particular theory, the configuration of the dehumidification system 800 is believed to be more energy efficient than the dehumidification system 600 shown in fig. 6A-6B under common operating conditions. For example, if the temperature of the third air stream 625 is less than the outdoor temperature (i.e., the temperature of the air stream 606), the refrigerant 605 may be more efficiently cooled or subcooled with the subcooling coil 650 located in the dehumidification unit 802. Such operating conditions may be common, for example, in warm climates and/or in summer. As shown in fig. 8B, the indoor dehumidification unit 802 also includes a compressor 660, which may be located, for example, near the secondary evaporator 640, the primary evaporator 610, and/or the secondary condenser 620. In some embodiments, the dehumidification unit 802 may include a compressor 660, but the dehumidification system 800 may not include an optional subcooling coil 650, as shown in fig. 8C. For example, if the main condenser 630 is capable of facilitating heat transfer from the flow of refrigerant 605 to the first outdoor air stream 606, thereby effectively condensing the refrigerant before it flows into the main metering device 680, the dehumidification system 800 illustrated in FIG. 8C may not require a subcooling coil 650.

In operation of an exemplary embodiment of the dehumidification system 800, as shown in each of fig. 8A-8C, inlet air 601 may be drawn into the dehumidification system 800 by a fan 670. The inlet air 601 passes through the secondary evaporator 640, wherein heat is transferred from the inlet air 601 to the flow of cold refrigerant 605 passing through the secondary evaporator 640. As a result, the inlet air 601 may be cooled. For example, if the inlet air 601 is 80°f/60% humidity, the secondary evaporator 640 may output a first air stream 645 of 70°f/84% humidity. This may cause the flow of refrigerant 605 to partially evaporate within secondary evaporator 640. For example, if the flow of refrigerant 605 into secondary evaporator 640 is 196 psig/68F/5% steam, then the flow of refrigerant 605 may be 196 psig/68F/38% steam as it exits secondary evaporator 640.

The cooled inlet air 601 exits the secondary evaporator 640 as a first air stream 645 and enters the primary evaporator 610. Similar to the secondary evaporator 640, the primary evaporator 610 transfers heat from the first air stream 645 to the cold flow of refrigerant 605 through the primary evaporator 610. As a result, the first gas stream 645 may be cooled to or below its dew point temperature, resulting in condensation of water vapor in the first gas stream 645 (thereby reducing the absolute humidity of the first gas stream 645). For example, if the first air stream 645 is 70°f/84% humidity, the main evaporator 610 may output a second air stream 615 of 54°f/98% humidity. This may result in the flow of refrigerant 605 partially or completely evaporating within the main evaporator 610. For example, if the flow of refrigerant 605 into the main evaporator 610 is 128 psig/44F/14% steam, the flow of refrigerant 605 out of the main evaporator 610 may be 128 psig/52F/100% steam. In some embodiments, liquid condensate from the first gas stream 645 may be collected in a drain pan connected to a condensate reservoir, as shown in fig. 4. Further, the condensate reservoir may include a condensate pump that moves collected condensate from the dehumidification system 800 (e.g., via a drain hose) to a suitable drain or storage location, either continuously or at periodic time intervals.

The cooled first air stream 645 exits the primary evaporator 610 as the second air stream 615 and enters the secondary condenser 620. The secondary condenser 620 facilitates transfer of heat from the hot refrigerant 605 stream passing through the secondary condenser 620 to the second air stream 615. This will reheat the second air stream 615, thereby reducing the relative humidity of the second air stream 615. For example, if the second airflow 615 is 54°f/98% humidity, the secondary condenser 620 may output a dehumidified airflow 625 of 65°f/68% humidity. This may result in partial or complete condensation of the flow of refrigerant 605 within secondary condenser 620. For example, if the flow of refrigerant 605 into secondary condenser 620 is 196 psig/68F/38% steam, then the flow of refrigerant 605 may be 196 psig/68F/4% steam as it exits secondary condenser 620. In some embodiments, the second airflow 615 exits the secondary condenser 620 as a dehumidified airflow 625 and is output to the conditioned space.

In both fig. 8A and 8B, dehumidified gas stream 625 enters subcooling coil 650, which facilitates heat transfer from the hot refrigerant 605 stream passing through subcooling coil 650 to dehumidified gas stream 625. This heats the dehumidified gas stream 625, thereby further reducing the humidity of the dehumidified gas stream 625. For example, if dehumidified airflow 625 is 65°f/68% humidity, then subcooling coil 650 may output an airflow 855 of 81°f/37% humidity. This may result in partial or complete condensation of the flow of refrigerant 605 within subcooling coil 650. For example, if the flow of refrigerant 605 into subcooling coil 650 is 340 psig/150F/60% steam, then the flow of refrigerant 605 out of subcooling coil 650 may be 340 psig/80F/0% steam.

Referring again to each of fig. 8A-8C, the main condenser 630 facilitates heat transfer from the hot refrigerant 605 stream passing through the main condenser 630 to the first outdoor air stream 606. This heats the outdoor air stream 606, which is output as a second outdoor air stream 608 to the unregulated space. For example, if the first outdoor air stream 606 is 65F/68% humidity, the main condenser 630 may output a second outdoor air stream 608 of 102F/19% humidity. This may result in partial or complete condensation of the flow of refrigerant 605 within the main condenser 630. For example, if the flow of refrigerant 605 into main condenser 630 is 340 psig/150F/100% steam, then the flow of refrigerant 605 may be 340 psig/105F/60% steam as it exits main condenser 630.

Some embodiments of the dehumidification systems 600 and 800 of fig. 6A-6B and 8A-8C may include a controller, which may include one or more computer systems located at one or more locations. Each computer system may include any suitable input device (e.g., keyboard, touch screen, mouse, or other device that can accept information), output device, mass storage medium, or other suitable means for receiving, processing, storing, and transmitting data. Both the input device and the output device may include fixed or removable storage media such as a computer disk, CD-ROM, or other suitable media to receive input from a user and provide output to the user. Each computer system may include a personal computer, a workstation, a network computer, a self-service terminal, a wireless data port, a Personal Data Assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. In short, the controller may comprise any suitable combination of software, firmware, and hardware.

The controller may additionally include one or more processing modules. Each processing module may include one or more microprocessors, controllers, or any other suitable computing devices or resources, and may operate alone or in conjunction with other components of the dehumidification systems 600 and 800 to provide some or all of the functionality described herein. The controller may also include (or be communicatively coupled to via wireless or wired communications) a computer memory. The memory may include any memory or database module and may take the form of volatile or nonvolatile memory including, but not limited to, magnetic media, optical media, random Access Memory (RAM), read Only Memory (ROM), removable media, or any other suitable local or remote memory component.

Although particular embodiments of the dehumidification systems 600 and 800 are illustrated and described primarily, the present disclosure contemplates any suitable embodiments of the dehumidification systems 600 and 800 according to particular needs. Furthermore, while the various components of the dehumidification systems 600 and 800 have been described as being positioned in particular locations and relative to one another, the present disclosure contemplates positioning the components in any suitable locations according to particular needs.

In certain embodiments, the secondary evaporator (340, 640), the primary evaporator (310, 610), and the secondary condenser (320, 620) of fig. 3, 6A-6B, or 8A-8C are combined into a single coil group. A single coil group may include multiple sections (e.g., separate refrigerant circuits) to accommodate the respective functions of the secondary evaporator, primary evaporator, and secondary condenser described above. An illustrative example of such a single coil set is shown in fig. 9. Fig. 9 shows a single coil set 900 comprising a plurality of coils (represented by circles in fig. 9). The coil assembly 900 includes a secondary evaporator section 940, a primary evaporator section 910, and a secondary condenser section 920. The coil set may include and/or be fluidly connected to metering devices 980 and 990, as shown in the exemplary case of fig. 9. In certain embodiments, metering devices 980 and 990 correspond to primary metering device 380 and secondary metering device 390 of fig. 3.

In general, the metering devices 980 and 990 may be any suitable type of metering/expansion devices. In some embodiments, metering device 980 is a thermostatic expansion valve (TXV) and secondary metering device 990 is a fixed orifice device (or vice versa). In general, metering devices 980 and 990 remove pressure from the flow of refrigerant 905 to allow the refrigerant to expand in evaporator sections 910 and 940 or change state from a liquid to a vapor. The temperature of the high pressure liquid (or mostly liquid) refrigerant 905 entering metering devices 980 and 990 is higher than the temperature of the liquid refrigerant 905 exiting metering devices 980 and 990. For example, if the flow of refrigerant 905 into metering device 980 is 340 psig/80°f/0% steam, the flow of refrigerant 905 may be 196 psig/68°f/5% steam upon exiting the main metering device 980. As another example, if the flow of refrigerant 905 into secondary metering device 990 is 196 psig/68F/4% vapor, the flow of refrigerant 905 may be 128 psig/44F/14% vapor upon exiting secondary metering device 990. The flow of refrigerant 905 may be any suitable refrigerant, as described above with respect to refrigerant 305 of fig. 3.

In operation of the exemplary embodiment of a single coil assembly 900, the inlet airflow 901 passes through the secondary evaporator portion 940, wherein heat is transferred from the inlet air 901 to the flow of cold refrigerant 905 passing through the secondary evaporator portion 940. As a result, the inlet air 901 may be cooled. For example, if the inlet air 901 is 80°f/60% humidity, the secondary evaporator portion 940 can output a first air flow of 70°f/84% humidity. This may cause the flow of refrigerant 905 to partially evaporate within the secondary evaporator portion 940. For example, if the flow of refrigerant 905 into the secondary evaporator section 940 is 196 psig/68°f/5% steam, the flow of refrigerant 905 out of the secondary evaporator section 940 may be 196 psig/68°f/38% steam.

The cooled inlet air 901 proceeds through the coil stack 900 to the main evaporator section 910. Similar to the secondary evaporator portion 940, the primary evaporator portion 910 transfers heat from the air flow 901 to a flow of cold refrigerant 905 passing through the primary evaporator portion 910. As a result, the air stream 901 may be cooled to or below its dew point temperature, resulting in condensation of water vapor in the air stream 901 (thereby reducing the absolute humidity of the air stream 901). For example, if airflow 901 is 70F/84% humidity, main evaporator portion 910 may cool airflow 901 to 54F/98% humidity. This may result in the flow of refrigerant 905 partially or completely evaporating within the main evaporator portion 910. For example, if the flow of refrigerant 905 into the main evaporator section 910 is 128 psig/44°f/14% steam, the flow of refrigerant 905 out of the main evaporator section 910 may be 128 psig/52°f/100% steam. In certain embodiments, liquid condensate from the airflow through the main evaporator portion 910 may be collected in a drain pan connected to a condensate reservoir (e.g., as shown in fig. 4 and described herein). Further, the condensate reservoir may include a condensate pump that moves collected condensate from the coil set 900 (e.g., via a drain hose) to a suitable drain or storage location, either continuously or at periodic intervals.

The cooling air flow 901 leaving the primary evaporator section 910 enters the secondary condenser section 920. The secondary condenser portion 920 facilitates heat transfer from the flow of hot refrigerant 905 through the secondary condenser portion 920 to the airflow 901. This will reheat the air stream 901, thereby reducing its relative humidity. For example, if airflow 901 is 54°f/98% humidity, secondary condenser section 920 may output an outlet airflow 925 of 65°f/68% humidity. This may result in partial or complete condensation of the flow of refrigerant 905 within the secondary condenser portion 920. For example, if the flow of refrigerant 905 into the secondary condenser section 920 is 196 psig/68F/38% steam, the flow of refrigerant 905 out of the secondary condenser section 920 may be 196 psig/68F/4% steam. The outlet gas stream 925 may, for example, enter the main condenser section 330 or the subcooling coil 350 of FIG. 3.

Although a particular embodiment of the coil assembly 900 is shown and described primarily, the present disclosure contemplates any suitable embodiment of the coil assembly 900 according to particular needs. Further, while the various components of the coil assembly 900 have been described as being positioned in particular locations, the present disclosure contemplates positioning these components in any suitable location according to particular needs.

In certain embodiments, the secondary evaporator (340, 640) and secondary condenser (320, 620) of fig. 3, 6A-6B, or 8A-8C are combined into a single coil group such that the single coil group includes multiple portions (e.g., separate refrigerant circuits) to accommodate the respective functions of the secondary evaporator and secondary condenser. An illustrative example of such an embodiment is shown in fig. 10. Fig. 10 shows a single coil assembly 1000 that includes a secondary evaporator section 1040 and a secondary condenser section 1020. As shown in the illustrative example of fig. 10, the primary evaporator 1010 is located between the secondary evaporator portion 1040 and the secondary condenser portion 1020 of the single coil assembly 1000. In the exemplary embodiment, a single coil set 1000 is shown as a "U" shaped coil. However, alternative embodiments may be used as long as the airflow 1001 passes through the secondary evaporator section 1040, the primary evaporator 1010, and the secondary condenser section 1020 in that order. In general, a single coil set 1000 may include the same or different coil types as the main evaporator 1010. For example, a single coil set 1000 may comprise a microchannel coil type, while the primary evaporator 1010 may comprise a fin tube coil type. This may provide further flexibility for optimizing a dehumidification system using a single coil set 1000 and a primary evaporator 1010.

In operation of the exemplary embodiment of the single coil assembly 1000, inlet air 1001 passes through secondary evaporator section 1040, wherein heat is transferred from inlet air 1001 to the cold refrigerant flow passing through secondary evaporator section 1040. As a result, the inlet air 1001 may be cooled. For example, if the inlet air 1001 is 80°f/60% humidity, the secondary evaporator portion 1040 can output an airflow of 70°f/84% humidity. This may cause the refrigerant flow to partially evaporate within the secondary evaporator portion 1040. For example, if the refrigerant flow entering the secondary evaporator 1040 is 196 psig/68°f/5% vapor, the refrigerant 1005 flow may be 196 psig/68°f/38% vapor upon exiting the secondary evaporator section 1040.

The cooled inlet air 1001 exits the secondary evaporator portion 1040 and enters the primary evaporator 1010. Similar to the secondary evaporator portion 1040, the primary evaporator 1010 transfers heat from the airflow 1001 to the cold refrigerant flow through the primary evaporator 1010. As a result, the airflow 1001 may be cooled to or below its dew point temperature, causing water vapor in the airflow 1001 to condense (thereby reducing the absolute humidity of the airflow 1001). For example, if the airflow 1001 into the main evaporator 1010 is 70F/84% humidity, the main evaporator 1010 may output an airflow of 54F/98% humidity. This may result in partial or complete evaporation of the refrigerant flow within the main evaporator 1010. For example, if the refrigerant flow entering the main evaporator 1010 is 128 psig/44F/14% vapor, the refrigerant flow exiting the main evaporator 1010 may be 128 psig/52F/100% vapor. In certain embodiments, liquid condensate from the gas stream 1010 may be collected in a drain pan connected to a condensate reservoir, as shown in fig. 4. Further, the condensate reservoir may include a condensate pump that continuously or at periodic time intervals removes collected condensate from the main evaporator 1010 and associated dehumidification system (e.g., via a drain hose) to a suitable drain or storage location.

The cooled airflow 1001 exits the primary evaporator 1010 and enters the secondary condenser section 1020. The secondary condenser portion 1020 facilitates heat transfer from the hot refrigerant stream passing through the secondary condenser 1020 to the airflow 1001. This will reheat the airflow 1001, thereby reducing its relative humidity. For example, if the airflow 1001 entering the secondary condenser portion 1020 is 54°f/98% humidity, the secondary condenser 1020 may output an airflow 1025 of 65°f/68% humidity. This may result in partial or complete condensation of the refrigerant flow within the secondary condenser 1020. For example, if the refrigerant flow entering the secondary condenser portion 1020 is 196 psig/68°f/38% vapor, the refrigerant flow may be 196 psig/68°f/4% vapor upon exiting the secondary condenser 1020. The outlet gas stream 925 may, for example, enter the main condenser 330 or subcooling 350 of fig. 3.

Although a particular embodiment of the coil assembly 1000 is illustrated and described primarily, the present disclosure contemplates any suitable embodiment of the coil assembly 1000 according to particular needs. Further, while the various components of the coil assembly 1000 have been described as being located in particular locations, the present disclosure contemplates positioning these components in any suitable location according to particular needs.

In certain embodiments, one or both of the secondary evaporator (340, 640) and the primary evaporator (310, 610) in fig. 3, 6A-6B, or 8A-8C are subdivided into two or more loops. In such an embodiment, each circuit of the sub-divided evaporator is supplied with refrigerant by a respective metering device. The metering device may comprise a passive metering device, an active metering device, or a combination thereof. For example, the metering device 380 (or 690) may be an active thermostatic expansion valve (TXV) and the secondary metering device 390 (or 690) may be a passive fixed orifice device (or vice versa). The metering device may be configured to supply refrigerant to each circuit within the evaporator at a desired mass flow rate. Metering devices for supplying refrigerant to each circuit of the subdivided evaporator may be used in conjunction with metering devices 380 and 390, or may replace one or both of metering devices 380 and 390.

Fig. 11, 12, 13, and 14 show illustrative examples of a portion 1100 of a dehumidification system in which a main evaporator 1110 includes three circuits for refrigerant flow, in accordance with certain embodiments. Portion 1100 includes a primary metering device 1180, secondary metering devices 1190a-c, a secondary evaporator 1140, a primary evaporator 1110, and a secondary condenser 1120. The primary evaporator 1110 includes three circuits for receiving refrigerant flow from the secondary metering devices 1190 a-c. In the example of fig. 11, 12, 13, and 14, each secondary metering device 1190a-c is a passive metering device (i.e., has an orifice with a fixed inner diameter and length). However, it should be appreciated that one or more (up to all) of the secondary metering devices 1190a-c may be active metering devices (e.g., thermostatic expansion valves).

In operation of an exemplary embodiment of portion 1100 of the dehumidification system, a cooled (or subcooled) refrigerant stream is received at inlet 1102, for example, from subcooling coil 350 or main condenser 330 of dehumidification system 300 of FIG. 3. The primary metering device 1180 determines the flow rate of refrigerant into the secondary evaporator 1140. While fig. 11, 12, 13, and 14 are shown with a single primary metering device 1180, other embodiments may include multiple primary metering devices in parallel (e.g., if the secondary evaporator 1140 includes two or more circuits for refrigerant flow).

As the cooled refrigerant passes through the secondary evaporator 1140, heat is exchanged between the refrigerant and the air flow through the secondary evaporator 1140, thereby cooling the inlet air. For example, if the inlet air is 80°f/60% humidity, the secondary evaporator 1140 may output a 70°f/84% humidity airflow. This may cause the refrigerant flow to evaporate within the secondary evaporator 1140. For example, if the refrigerant flow entering the secondary evaporator 1140 is 196 psig/68F/5% steam, the refrigerant flow may be 196 psig/68F/38% steam as it exits the secondary evaporator 1140.

The secondary condenser 1120 receives warm refrigerant from the secondary evaporator 1140 via a tube 1106. The secondary condenser 1120 facilitates heat transfer from the hot refrigerant stream passing through the secondary condenser 1120 to the gas stream. This will reheat the air stream, thereby reducing its relative humidity. For example, if the air flow is 54°f/98% humidity, the secondary condenser 1120 may output an air flow of 65°f/68% humidity. This may result in partial or complete condensation of the refrigerant flow within the secondary condenser 1120. For example, if the refrigerant flow entering the secondary condenser 1120 is 196 psig/68F/38% vapor, the refrigerant flow may be 196 psig/68F/4% vapor as it exits the secondary condenser 1120.

The cooled refrigerant exits the secondary condenser at 1108 and is received by metering devices 1190a-c, where metering devices 1190a-c distribute the refrigerant flow to three circuits of the primary evaporator 1110. Fig. 14 shows a view of a circuit including a main evaporator 1110. The air stream passing through the primary evaporator 1110 may be cooled to or below its dew point temperature, causing condensation of water vapor in the air stream (thereby reducing the absolute humidity of the air). For example, if the airflow is 70F/84% humidity, the main evaporator 1110 may output an airflow of 54F/98% humidity. This may result in partial or complete evaporation of the refrigerant flow within the main evaporator 1110.

Each secondary metering device 1190a, 1190b, and 1190c is configured to provide a flow of refrigerant to each loop of the primary evaporator 1110 at a desired flow rate. For example, the flow rate provided to each circuit may be optimized to improve the performance of the main evaporator 1110. For example, under certain operating conditions, it may be beneficial to prevent all refrigerant flow through the entire evaporator, as occurs in conventional evaporator coils. The refrigerant flowing through such an evaporator may change from a liquid phase to a vapor phase before exiting the coil, resulting in poor performance of the evaporator in only the portion that contacts the gaseous refrigerant. To substantially reduce or eliminate this problem, the present disclosure provides a refrigerant flow through each circuit at a desired flow rate. The desired flow rate may be predetermined (e.g., based on known design criteria and/or operating conditions) and/or variable during operation (e.g., manually and/or automatically adjustable in real time). The flow rates may be configured such that the refrigerant streams leave their respective circuits just after conversion to gas. For example, the airflow rate near the edges of the evaporator may be less than the airflow rate near the center of the evaporator. Thus, the secondary metering devices 1190a-c may supply a lower rate of refrigerant flow to the circuits corresponding to the edges of the primary evaporator 1110.

Although the examples of fig. 11, 12, 13 and 14 include a main evaporator subdivided into two or more circuits. In other embodiments, the secondary evaporator 1110 may be equally or alternatively subdivided into two or more loops. It should also be appreciated that the circuits illustrated in fig. 11, 12, 13 and 14 may also be implemented in a single coil assembly, such as the single coil assembly shown in fig. 9 and 10.

Although particular embodiments of the portion 1100 of the dehumidification system are shown and described primarily, the present disclosure contemplates any suitable embodiments of the portion 1100 of the dehumidification system according to particular needs. Furthermore, while the various components of the portion 1100 of the dehumidification system have been described as being positioned in particular locations, the present disclosure contemplates positioning the components in any suitable locations according to particular needs.

Fig. 15A-15B illustrate an exemplary dehumidification system 1500 that may be used in accordance with the dehumidification system 300 of fig. 3 to reduce air humidity within a structure. The dehumidification system 1500 includes a dehumidification unit 1502 (typically located indoors) and a heat exchanger 1504 or external source 1506, the heat exchanger 1504 or external source 1506 configured to contain an amount of fluid that may be used by the dehumidification system 1500 to cool separate fluid streams within the dehumidification unit 1502. Fig. 15A illustrates a dehumidification system 1500 including a heat exchanger 1504, and fig. 15B illustrates a dehumidification system including an external source 1506. Referring to fig. 15A-15B, the dehumidification unit 1502 includes a primary evaporator 1508, a primary condenser 1510, a secondary evaporator 1512, a secondary condenser 1514, a compressor 1516, a primary metering device 1518, a secondary metering device 1520, and a fan 1522.

With continued reference to both fig. 15A-15B, as shown, a flow of refrigerant 1524 is circulated through the dehumidification unit 1502. Generally, the dehumidification unit 1502 receives the inlet air stream 1526, removes water from the inlet air stream 1526, and discharges dehumidified air 1528. The refrigeration cycle utilizing the flow of refrigerant 1524 removes water from the inlet air 1526. However, by including the secondary evaporator 1512 and the secondary condenser 1514, the dehumidification system 1500 causes at least a portion of the flow of refrigerant 1524 to evaporate and condense twice in a single refrigeration cycle. This increases the cooling capacity over typical systems without adding any additional energy to the compressor, thereby increasing the overall dehumidification efficiency of the system.

In general, the dehumidification system 1500 attempts to match the saturation temperature of the secondary evaporator 1512 to the saturation temperature of the secondary condenser 1514. The saturation temperatures of the secondary evaporator 1512 and the secondary condenser 1514 are generally controlled according to the following formula (temperature of the inlet air 1526 + temperature of the second air stream 1530)/2. Evaporation occurs in the secondary evaporator 1512 because the saturation temperature of the secondary evaporator 1512 is lower than the inlet air 1526. Since the saturation temperature of the secondary condenser 1514 is higher than the second air stream 1530, condensation occurs in the secondary condenser 1514. The amount of refrigerant 1524 evaporated in the secondary evaporator 1512 is substantially equal to the amount of refrigerant 1524 condensed in the secondary condenser 1514.

The primary evaporator 1508 receives a flow of refrigerant 1524 from the secondary metering device 1520 and outputs the flow of refrigerant 1524 to the compressor 1516. The primary evaporator 1508 can be any suitable type of coil (e.g., finned tubes, microchannels, etc.). The primary evaporator 1508 receives the first airflow 1532 from the secondary evaporator 1512 and outputs the second airflow 1530 to the secondary condenser 514. Typically, the temperature of the second air stream 1530 is lower than the temperature of the first air stream 1532. To cool the incoming first stream 1532, the main evaporator 1508 transfers heat from the first stream 1532 to the stream of refrigerant 1524, thereby evaporating the stream of refrigerant 1524 at least partially from a liquid to a gas. Heat transfer from the first gas stream 1532 to the flow of refrigerant 1524 also removes water from the first gas stream 1532.

The secondary condenser 1514 receives the flow of refrigerant 1524 from the secondary evaporator 1512 and outputs the flow of refrigerant 1524 to the secondary metering device 1520. The secondary condenser 1514 may be any type of coil (e.g., finned tube, microchannel, etc.). The secondary condenser 1514 receives the second air stream 1530 from the primary evaporator 1508 and outputs a dehumidified air stream 1528. The dehumidified airflow 1528 is typically warmer and drier (i.e., the dew point is the same, but the relative humidity is lower) than the second airflow 1530. The secondary condenser 1514 generates a dehumidified gas stream 1528 by transferring heat from the refrigerant 1524 stream to the second gas stream 1530, thereby condensing the refrigerant 1524 stream at least partially from a gas to a liquid.

The main condenser 1510 receives a flow of refrigerant 1524 from the compressor 1516 and outputs the flow of refrigerant 1524 to the main metering device 1518. The main condenser 1510 may be any type of liquid-cooled heat exchanger operable to transfer heat from a refrigerant 1524 stream to a fluid 1534 stream. In embodiments, the fluid 1534 may be any suitable fluid, such as water or a mixture of water and ethylene glycol. During operation of the dehumidification system 1500, the main condenser 1510 receives both a flow of fluid 1534 and a flow of refrigerant 1524, wherein the main condenser 1510 is operable to transfer heat from the flow of refrigerant 1524 to condense the flow of refrigerant 1524 at least partially from a gas to a liquid. In some embodiments, the main condenser 1510 fully condenses the refrigerant 1524 stream into a liquid (i.e., 100% liquid). In other embodiments, the main condenser 1510 partially condenses the refrigerant 1524 stream into a liquid (i.e., less than 100% liquid).

As shown, the dehumidification system 1500 may also include a first water pump 1536. The first water pump 1536 may be disposed inside or outside the dehumidifying unit 1502. The first water pump 1536 may be any suitable device operable to provide a flow of fluid 1534. As shown in fig. 15A, the first water pump 1536 may be disposed in any suitable position relative to the main condenser 1510 and the heat exchanger 1504 so as to be operable to circulate a flow of fluid 1534 between the heat exchanger 1504 and the main condenser 1510. As shown in fig. 15B, the first water pump 1536 may be disposed in any suitable position relative to the main condenser 1510 and the external source 1506, and thus operable to circulate a flow of fluid 1534 between the external source 1506 and the main condenser 1510.

Referring to fig. 15A, the heat exchanger 1504 may receive a flow of fluid 1534 at a first temperature from the main condenser 1510 and output a flow of fluid 1534 at a second temperature to the main condenser 1510 after transferring heat from the flow of fluid 1534, wherein the second temperature is lower than the first temperature. The heat exchanger 1504 may be any suitable type of heat exchanger, such as, for example, a cooling tower or a dry cooler. The heat exchanger 1504 receives a fluid 1534 flow and a first outdoor airflow 1540, wherein heat is transferred between the fluid 1534 flow and the first outdoor airflow 1540. The heat exchanger 1504 may also output a flow of fluid 1534 and a second outdoor airflow 1542, wherein the temperature of the flow of fluid 1534 exiting the heat exchanger 1504 is lower than the temperature of the flow of fluid 1534 received by the heat exchanger 1504, and the temperature of the second outdoor airflow 1542 is higher than the temperature of the first outdoor airflow 1540.

In embodiments where the heat exchanger 1504 is a cooling tower, the heat exchanger 1504 is operable to distribute a flow of fluid 1534 within its internal structure, wherein the fluid 1534 directly contacts the first outdoor air flow 1540 and transfers heat to the first outdoor air flow 1540 as the fluid 1534 flows through the heat exchanger 1504. As heat is transferred from the fluid 1534 to the first outdoor airflow 1540, at least a portion of the fluid 1534 may evaporate and vent to the atmosphere, and the heat exchanger 1504 may collect a remaining portion of the fluid 1534 after heat transfer to the first outdoor airflow 1540, wherein the remaining portion of the fluid 1534 is at a lower temperature. In embodiments where the heat exchanger 1504 is a dry cooler, the heat exchanger 1504 is operable to induce a first outdoor airflow 1540 to flow through the heat exchanger 1504, wherein heat is indirectly transferred between the first outdoor airflow 1540 and the fluid 1534 flow. In these embodiments, heat transfer does not result in a loss of a portion of the fluid 1534 from evaporation into the atmosphere.

Referring now to fig. 15B, the external source 1506 may receive the fluid 1534 stream from the main condenser 1510 and output the fluid 1534 stream to the main condenser 1510 via the first water pump 1536. The external source 1506 may be configured to contain and/or store an amount of fluid 1534 for use by the main condenser 1510 to reduce the temperature of the flow of refrigerant 1524 in the dehumidification unit 1502. The external source 1506 may be configured to receive a flow of fluid 1534 at a first temperature from the main condenser 1510 and output a flow of fluid 1534 at a second temperature to the main condenser 1510 after transferring heat from the flow of fluid 1534, wherein the second temperature is lower than the first temperature. The external source 1506 may be, without limitation, any suitable number and combination of floor reservoirs, swimming pools, outdoor bodies of water, and the like. In embodiments where the external source 1506 is a surface reservoir, the external source 1506 may be implemented as an open or closed surface water system, wherein the conduit providing for the flow of fluid 1534 within the surface reservoir may be disposed substantially parallel to the surface level, substantially perpendicular to the surface level, or a combination thereof.

15A-15B, the secondary evaporator 1512 receives a flow of refrigerant 1524 from the primary metering device 1518 and outputs the flow of refrigerant 1524 to the secondary condenser 1514. The secondary evaporator 1512 can be any type of coil (e.g., finned tubes, microchannels, etc.). The secondary evaporator 1512 receives the inlet air 1526 and outputs a first airflow 1532 to the primary evaporator 1508. Typically, the temperature of the first air stream 1532 is lower than the temperature of the inlet air 1526. To cool the incoming inlet air 1526, the secondary evaporator 1512 transfers heat from the inlet air 1526 to the flow of refrigerant 1524, thereby evaporating the flow of refrigerant 1524 at least partially from a liquid to a gas.

The compressor 1516 pressurizes the flow of refrigerant 1524, thereby increasing the temperature of the refrigerant 1524. For example, if the flow of refrigerant 1524 into the compressor 1516 is 128 psig/52°f/100% steam, the flow of refrigerant 1524 out of the compressor 1516 may be 340 psig/150°f/100% steam. The compressor 1516 receives a flow of refrigerant 1524 from the main evaporator 1508 and supplies a pressurized flow of refrigerant 1524 to the main condenser 1510.

The fan 1522 may comprise any suitable component operable to draw inlet air 1526 into the dehumidification unit 1502 and through the secondary evaporator 1512, the primary evaporator 1508, and the secondary condenser 1514. The fan 1522 may be any type of air mover (e.g., an axial fan, a forward-leaning impeller, a backward-leaning impeller, etc.). For example, the fan 1522 may be a retroverted impeller located near the secondary condenser 1514. Although the fan 1522 is depicted as being located near the secondary condenser 1514, it should be appreciated that the fan 1522 may be located anywhere along the airflow path of the dehumidification unit 1502. For example, the fan 1522 may be located in the airflow path of any of the airflows 1526, 1532, 1530, or 1528. Further, the dehumidification unit 1502 may include one or more additional fans located within any one or more of the airflow paths.

The primary metering device 1518 and the secondary metering device 1520 are any suitable type of metering/expansion devices. In some embodiments, the primary metering device 1518 is a thermostatic expansion valve (TXV) and the secondary metering device 1520 is a fixed orifice device (or vice versa). In certain embodiments, metering devices 1518 and 1520 remove pressure from the flow of refrigerant 1524 to allow expansion in evaporators 1512 and 1508 or change state from liquid to vapor. The temperature of the high pressure liquid (or mostly liquid) refrigerant 1524 entering metering devices 1518 and 1520 is higher than the temperature of the liquid refrigerant 1524 exiting metering devices 1518 and 1520. For example, if the flow of refrigerant 1524 into the main metering device 1518 is 340 psig/80F/0% steam, the flow of refrigerant 1524 may be 196 psig/68F/5% steam when exiting the main metering device 1518. For another example, if the flow of refrigerant 1524 into the secondary metering device 1520 is 196 psig/68°f/4% steam, the flow of refrigerant 1524 may be 128 psig/44°f/14% steam upon exiting the secondary metering device 1520.

Refrigerant 1524 may be any suitable refrigerant, such as R410a. Generally, the dehumidification system 1500 employs a closed refrigeration loop of refrigerant 1524 passing from a compressor 1516 through a main condenser 1510, a main metering device 1518, a secondary evaporator 1512, a secondary condenser 1514, a secondary metering device 1520, and a main evaporator 1508. The compressor 1516 pressurizes the flow of refrigerant 1524, thereby increasing the temperature of the refrigerant 1524. The main condenser 1510 may include any suitable water-cooled heat exchanger, with the main condenser 1510 cooling the pressurized refrigerant 1524 stream by facilitating heat transfer from the refrigerant 1524 stream to a fluid stream provided by the external source 1506 (i.e., a fluid 1534 stream) passing through the main condenser 1510. The secondary condenser may include any suitable air-cooled heat exchanger that cools the pressurized refrigerant 1524 stream by facilitating heat transfer from the refrigerant 1524 stream to a corresponding gas stream (i.e., second gas stream 1530) passing through the secondary condenser.

The cooled refrigerant 1524 stream exiting the primary condenser 1510 and the secondary condenser 1514 may enter respective expansion devices (i.e., the primary metering device 1518 and the secondary metering device 1520) operable to reduce the pressure of the refrigerant 1524 stream, thereby reducing the temperature of the refrigerant 1524 stream. The primary evaporator 1508 and the secondary evaporator 1512 may include any suitable heat exchangers, with the primary evaporator 1508 and the secondary evaporator 1512 receiving a flow of refrigerant 1524 from the secondary metering device 1520 and the primary metering device 1518, respectively. The primary evaporator 1508 and the secondary evaporator 1512 facilitate heat transfer from the respective streams passing through them (i.e., the inlet air 1526 and the first stream 1532) to the stream of refrigerant 1524. The flow of refrigerant 1524 returns to the compressor 1516 after leaving the main evaporator 1508 and repeats the cycle.

In certain embodiments, the refrigeration loop described above may be configured such that the evaporators 1508 and 1512 operate at a flooded condition. In other words, the flow of refrigerant 1524 may enter the evaporators 1508 and 1512 in a liquid state, and a portion of the flow of refrigerant 1524 may remain in a liquid state upon exiting the evaporators 1508 and 1512. Accordingly, a phase change of the flow of refrigerant 1524 (as heat is transferred into the flow of refrigerant 1524, the liquid becomes vapor) occurs across the evaporators 1508 and 1512, resulting in an almost constant pressure and temperature across the entire evaporators 1508 and 1512 (and, therefore, increased cooling capacity).

In operation of an exemplary embodiment of the dehumidification system 1500, inlet air 1526 may be drawn into the dehumidification unit 1502 by a fan 1522. Inlet air 1526 passes through secondary evaporator 1512, wherein heat is transferred from inlet air 1526 to a cold flow of refrigerant 1524 passing through secondary evaporator 1512. As a result, inlet air 1526 may be cooled. For example, if the inlet air 1526 is 80°f/60% humidity, the secondary evaporator 1512 may output a first airflow 1532 of 70°f/84% humidity. This may cause the flow of refrigerant 1524 to partially evaporate within the secondary evaporator 1512. For example, if the flow of refrigerant 1524 into the secondary evaporator 1512 is 196 psig/68°f/5% steam, the flow of refrigerant 1524 may be 196 psig/68°f/38% steam upon exiting the secondary evaporator 1512.

Cooled inlet air 1526 exits secondary evaporator 1512 as first air stream 1532 and enters primary evaporator 1508. Similar to the secondary evaporator 1512, the primary evaporator 1508 transfers heat from the first air stream 1532 to the cold flow of refrigerant 1524 passing through the primary evaporator 1508. As a result, the first air stream 1532 may be cooled to or below its dew point temperature, resulting in condensation of moisture in the first air stream 1532 (thereby reducing the absolute humidity of the first air stream 1532). For example, if the first air stream 1532 is 70°f/84% humidity, the main evaporator 1508 may output a second air stream 1530 of 54°f/98% humidity. This may result in the flow of refrigerant 1524 partially or completely evaporating within the main evaporator 1508. For example, if the flow of refrigerant 1524 into the main evaporator 1508 is 128 psig/44°f/14% steam, the flow of refrigerant 1524 may be 128 psig/52°f/100% steam upon exiting the main evaporator 1508.

The cooled first air stream 1532 exits the primary evaporator 1508 as the second air stream 1530 and enters the secondary condenser 1514. The secondary condenser 1514 facilitates heat transfer from the hot refrigerant 1524 stream passing through the secondary condenser 1514 to the second air stream 1530. This will reheat the second air stream 1530, thereby reducing the relative humidity of the second air stream 1530. For example, if the second air stream 1530 is 54°f/98% humidity, the secondary condenser 1514 can output a dehumidified air stream 1528 of 65°f/68% humidity. This may result in partial or complete condensation of the flow of refrigerant 1524 within the secondary condenser 1514. For example, if the flow of refrigerant 1524 into the secondary condenser 1514 is 196 psig/68°f/38% steam, the flow of refrigerant 1524 may be 196 psig/68°f/4% steam upon exiting the secondary condenser 1514.

Some embodiments of the dehumidification system 1500 may include a controller, which may include one or more computer systems located at one or more locations. Each computer system may include any suitable input device (e.g., keyboard, touch screen, mouse, or other device that can accept information), output device, mass storage medium, or other suitable means for receiving, processing, storing, and transmitting data. Both the input device and the output device may include fixed or removable storage media such as a computer disk, CD-ROM, or other suitable media to receive input from a user and provide output to the user. Each computer system may include a personal computer, a workstation, a network computer, a self-service terminal, a wireless data port, a Personal Data Assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. In short, the controller may comprise any suitable combination of software, firmware, and hardware.

The controller may additionally include one or more processing modules. Each processing module may include one or more microprocessors, controllers, or any other suitable computing device or resource, and may operate alone or in conjunction with other components of the dehumidification system 1500 to provide some or all of the functionality described herein. The controller may also include (or be communicatively coupled to via wireless or wired communications) a computer memory. The memory may include any memory or database module and may take the form of volatile or nonvolatile memory including, but not limited to, magnetic media, optical media, random Access Memory (RAM), read Only Memory (ROM), removable media, or any other suitable local or remote memory component.

Although particular embodiments of the dehumidification system 1500 are illustrated and described primarily, the present disclosure contemplates any suitable embodiments of the dehumidification system 1500 according to particular needs. Further, while the various components of the dehumidification system 1500 have been described as being positioned in particular locations and relative to one another, the present disclosure contemplates positioning the components in any suitable locations according to particular needs.

Fig. 16A, 16B, 16C, and 16D illustrate an exemplary dehumidification system 1600 with a modulation valve 1602 that may be used in accordance with the split dehumidification system 600 of fig. 6A-6B to reduce the humidity of an air stream. The dehumidification system 1600 includes a modulation valve 1602, a primary evaporator 1604, a primary condenser 1606, a secondary evaporator 1608, a secondary condenser 1610, a compressor 1612, a primary metering device 1614, a secondary metering device 1616, a fan 1618, and a backup condenser 1620. In some embodiments, the dehumidification system 1600 may additionally include an optional subcooling coil 1622. As shown in fig. 16A-16B, the backup condenser 1620 may be disposed in an external condenser unit 1624. Referring to fig. 16A, an optional subcooling coil 1622 may be provided in an external condenser unit 1624 along with a backup condenser 1620, wherein the subcooling coil 1622 and the backup condenser 1620 may be combined into a single coil. Referring to fig. 16B, an optional subcooling coil 1622 may be disposed adjacent to the main condenser 1606, wherein the subcooling coil 1620 and the main condenser 1606 may be combined into a single coil. Fig. 16C-16D illustrate an embodiment of a dehumidification system 1600 in which neither the optional subcooling coil 1622 nor the backup condenser 1620 is in an external condenser unit 1624, and the backup condenser 1620 is liquid cooled.

Referring to each of fig. 16A-16D, as shown, a flow of refrigerant 1626 is circulated through the dehumidification system 1600. In general, the dehumidification system 1600 receives an inlet airflow 1628, removes water from the inlet airflow 1628, and discharges dehumidified air 1630. Water is removed from the inlet air 1628 using a refrigeration cycle of the flow of refrigerant 1626. However, by including the secondary evaporator 1608 and the secondary condenser 1610, the dehumidification system 1600 causes at least a portion of the flow of refrigerant 1626 to evaporate and condense twice in a single refrigeration cycle. This increases the cooling capacity over typical systems without adding any additional energy to the compressor, thereby increasing the overall dehumidification efficiency of the system.

In general, the dehumidification system 1600 attempts to match the saturation temperature of the secondary evaporator 1608 to the saturation temperature of the secondary condenser 1610. The saturation temperature of the secondary evaporator 1608 and secondary condenser 1610 is typically controlled according to the following equation (temperature of the inlet air 1628 + temperature of the second air stream 1632)/2. Evaporation occurs in the secondary evaporator 1608 because the saturation temperature of the secondary evaporator 1608 is lower than the inlet air 1628. Because the saturation temperature of the secondary condenser 1610 is higher than the second air stream 1632, condensation occurs in the secondary condenser 1610. The amount of refrigerant 1626 evaporated in the secondary evaporator 1608 is substantially equal to the amount of refrigerant condensed in the secondary condenser 1610.

The primary evaporator 1604 receives a flow of refrigerant 1626 from the secondary metering device 1616 and outputs the flow of refrigerant 1626 to the compressor 1612. The primary evaporator 1604 may be any type of coil (e.g., fin tubes, microchannels, etc.). The primary evaporator 1604 receives the first air stream 1634 from the secondary evaporator 1608 and outputs a second air stream 1632 to the secondary condenser 1610. Typically, the temperature of the second air stream 1632 is lower than the temperature of the first air stream 1634. To cool the incoming first gas stream 1634, the main evaporator 1604 transfers heat from the first gas stream 1634 to the flow of refrigerant 1626, thereby evaporating the flow of refrigerant 1626 at least partially from a liquid to a gas. Heat transfer from the first gas stream 1634 to the flow of refrigerant 1626 also removes water from the first gas stream 1634.

The secondary condenser 1610 receives the flow of refrigerant 1626 from the secondary evaporator 1608 and outputs the flow of refrigerant 1626 to the secondary metering device 1616. The secondary condenser 1610 may be any type of coil (e.g., finned tube, microchannel, etc.). The secondary condenser 1610 receives the second air stream 1632 from the primary evaporator 1604 and outputs a third air stream 1636. The third air stream 1636 is typically warmer and drier (i.e., the dew point is the same but the relative humidity is lower) than the second air stream 1632. The secondary condenser 1610 generates a third air flow 1632 by transferring heat from the flow of refrigerant 1626 to the second air flow 1632, thereby condensing the flow of refrigerant 1626 at least partially from a gas to a liquid.

The main condenser 1606 may be any type of coil (e.g., finned tubes, microchannels, etc.). The main condenser 1606 is operable to receive a flow of refrigerant 1626 from the modulating valve 1602 and output the flow of refrigerant 1626 to the main metering device 1614 or to the subcooling coil 1622. As shown in fig. 16A, the main condenser 1606 outputs a flow of refrigerant 1626 to the main metering device 1614. In these embodiments, the main condenser 1606 receives the third air stream 1636 and outputs dehumidified air 1630. Referring to fig. 16B-16D, however, the main condenser 1606 outputs a flow of refrigerant 1626 to an optional subcooling coil 1622, and the flow of refrigerant 1626 then flows to the main metering device 1614. In these embodiments, the main condenser 1606 receives the fourth air stream 1638 generated by the subcooling coil 1622 and outputs dehumidified air 1630. Referring to each of fig. 16A-16D, the dehumidified air 1630 is typically warmer, drier (i.e., has a lower relative humidity) than the third air stream 1636 and the fourth air stream 1638. The main condenser 1606 generates dehumidified air 1630 by transferring heat from the flow of refrigerant 1626, thereby condensing the flow of refrigerant 1626 at least partially from a gas to a liquid. In some embodiments, the main condenser 1606 fully condenses the refrigerant 1626 stream to a liquid (i.e., 100% liquid). In other embodiments, the main condenser 1606 partially condenses the stream of refrigerant 1626 as liquid (i.e., less than 100% liquid).

The secondary evaporator 1608 receives the flow of refrigerant 1626 from the primary metering device 1614 and outputs the flow of refrigerant 1626 to the secondary condenser 1610. The secondary evaporator 1608 may be any type of coil (e.g., finned tube, microchannel, etc.). The secondary evaporator 1608 receives the inlet air 1628 and outputs a first air stream 1634 to the primary evaporator 1604. Typically, the temperature of the first air stream 1634 is lower than the temperature of the inlet air 1628. To cool the incoming inlet air 1628, the secondary evaporator 1608 transfers heat from the inlet air 1608 to the flow of refrigerant 1626, thereby evaporating the flow of refrigerant 1626 at least partially from a liquid to a gas.

Subcooling coil 1622 is an optional component of dehumidification system 1600, and subcooling coil 1622 subcools liquid refrigerant 1626 as liquid refrigerant 1626 exits main condenser 1606, backup condenser 1620, or a combination thereof. In embodiments where the subcooling coil 1622 is disposed within the external condenser unit 1624, the subcooling coil 1622 may receive the refrigerant 1626 as the refrigerant 1626 exits the backup condenser 1620, as can be seen in fig. 16A. In embodiments where subcooling coil 1622 is disposed proximate to main condenser 1606, subcooling coil 1622 may receive refrigerant 1626 as refrigerant 1626 exits main condenser 1606 and/or backup condenser 1620, as can be seen in fig. 16B-16D. Referring to each of fig. 16A-16D, this in turn provides the main metering device 1614 with liquid refrigerant at a temperature 30 degrees (or more) lower than before entering the subcooling coil 1622. For example, if the flow of refrigerant 1626 entering subcooling coil 1622 is 340 psig/105°f/60% steam, then the flow of refrigerant 1626 may be 340 psig/80°f/0% steam upon exiting subcooling coil 1622. The subcooled refrigerant 1626 has a greater enthalpy factor and a greater density, which results in a reduction in the cycle time and frequency of the evaporation cycle of the refrigerant 1626 flow. This results in a more efficient and less energy usage of the dehumidification system 1600.

The compressor 1612 pressurizes the flow of refrigerant 1626, thereby increasing the temperature of the refrigerant 1626. For example, if the flow of refrigerant 1626 entering compressor 1612 is 128 psig/52°f/100% steam, the flow of refrigerant 1626 may be 340 psig/150°f/100% steam as it exits compressor 1612. The compressor 1612 receives a flow of refrigerant 1626 from the main evaporator 1604 and supplies a flow of pressurized refrigerant 1626 to the modulation valve 1602.

The modulation valve 1602 is operable to receive a flow of pressurized refrigerant 1626 from the compressor 1612 and direct the flow of refrigerant to the main condenser 1606, the backup condenser 1620, or both. In an embodiment, the modulation valve 1602 may operate based at least in part on a predetermined temperature set point of the dehumidified airflow 1630 and an actual temperature of the dehumidified airflow 1630 output by the dehumidification system 1600. The dehumidification system 1600 may utilize a modulation valve 1602 to direct heat to be rejected from the flow of refrigerant 1626 away from the main condenser 1606 and to the backup condenser 1620. In accordance with a feedback loop including a predetermined temperature set point and an actual temperature of the dehumidified airstream 1630, the modulation valve 1602 may be configured to partially open and/or close to direct at least a portion of the flow of refrigerant 1626 to the backup condenser 1620 and the remainder of the flow of refrigerant 1626 to the main condenser 1606.

During operation of the dehumidification system 1600, if the temperature of the dehumidified airstream 1630 output by the main condenser 1606 does not exceed a predetermined temperature set point (which is monitored by the dehumidification system 1600), the modulation valve 1602 may direct a flow of refrigerant 1626 to the main condenser 1606. If the temperature of the dehumidified airstream 1630 is above the predetermined temperature set point, the modulation valve 1602 may be actuated to direct at least a portion of the flow of refrigerant 1626 to the backup condenser 1620 and the remainder of the flow of refrigerant to the main condenser 1606. When the dehumidification system 1600 is operating, the reduced volume of the flow of refrigerant 1626 to the main condenser 1606 may reduce the available heat to be rejected into the dehumidified airstream 1630. With a reduced flow of refrigerant 1626 through the main condenser 1606 (e.g., the remainder of the refrigerant flow), the heat transfer rate to the dehumidified airflow 1630 may then decrease, resulting in a reduced temperature change of the incoming airflow and the outgoing dehumidified airflow 1630. Once the temperature of the dehumidified airstream 1630 is below the predetermined temperature set point, the modulation valve 1602 is actuated to direct at least a portion of the flow of refrigerant 1626 back to the main condenser 1606. Any remaining refrigerant 1626 that has been directed to the backup condenser 1620 may be combined with the further downstream flow of refrigerant 1626.

Referring to fig. 16A and 16B, a backup condenser 1620 may be disposed in an external condenser unit 1624 and may be any type of coil (e.g., finned tube, microchannel, etc.) operable to receive a flow of refrigerant 1626 from the modulation valve 1602 and output a flow of refrigerant 1626 at a lower temperature. The backup condenser 1620 transfers heat from the flow of refrigerant 1626, thereby condensing the flow of refrigerant 1626 at least partially from a gas to a liquid. In some embodiments, backup condenser 1620 fully condenses the flow of refrigerant 1626 to liquid (i.e., 100% liquid). In other embodiments, backup condenser 1620 condenses the flow of refrigerant 1626 partially to a liquid (i.e., less than 100% liquid). As can be seen in fig. 16A, the flow of refrigerant 1626 may be output to a subcooling coil 1622 disposed adjacent to the backup condenser 1620 within the external condenser unit 1624. Backup condenser 1620 and subcooling coil 1622 may receive first outdoor air stream 1640 and output second outdoor air stream 1642. The second outdoor air stream 1642 is generally warmer (i.e., has a lower relative humidity) than the first outdoor air stream 1640. In other embodiments, as shown in fig. 16B, the first outdoor air stream 1640 may be received by the backup condenser 1620 without prior flowing through the subcooling coil 1622. In fig. 16B, the external condenser unit 1624 may include a backup condenser 1620 and a fan 1644, and may not include a subcooling coil 1622, wherein the fan 1644 may be configured to facilitate the flow of the first outdoor air stream 1640 to the backup condenser 1620.

Referring now to fig. 16C-16D, the backup condenser 1620 may be any type of liquid-cooled heat exchanger operable to transfer heat from a flow of refrigerant 1626 to a flow of fluid 1646, wherein the backup condenser 1620 receives the flow of refrigerant 1626 from the modulating valve 1602 and outputs the flow of refrigerant 1626 to the subcooling coil 1622. In embodiments, the fluid 1646 may be any suitable fluid, such as water or a mixture of water and ethylene glycol. During operation of the dehumidification system 1600, the backup condenser 1620 receives both a flow of fluid 1646 and a flow of refrigerant 1626, wherein the backup condenser 1620 is operable to transfer heat from the flow of refrigerant 1626 to condense the flow of refrigerant 1626 at least partially from a gas to a liquid. In some embodiments, backup condenser 1620 fully condenses the flow of refrigerant 1626 to liquid (i.e., 100% liquid). In other embodiments, backup condenser 1620 condenses the flow of refrigerant 1626 partially to a liquid (i.e., less than 100% liquid).

As shown in fig. 16C-16D, the dehumidification system 1600 may also include a first water pump 1648. The first water pump 1648 may be disposed outside the backup condenser 1620. The first water pump may be any suitable device operable to provide a flow of fluid 1646. As shown in fig. 16C, a first water pump 1648 may be disposed at any suitable location between backup condenser 1620 and heat exchanger 1654, operable to circulate a flow of fluid 1646 between heat exchanger 1654 and backup condenser 1620. As shown in fig. 16D, a first water pump 1648 may be disposed at any suitable location between the backup condenser 1620 and the external source 1652, operable to circulate a flow of fluid 1646 between the external source 1652 and the backup condenser 1620.

Referring to fig. 16C, a heat exchanger 1654 may receive a flow of fluid 1646 from backup condenser 1620 and output a flow of fluid 1646 after transferring heat from the flow of fluid 1646. Heat exchanger 1654 may be any suitable type of heat exchanger, such as a cooling tower or a dry cooler. The heat exchanger 1654 receives a flow of fluid 1646 and a first flow of outdoor air 1656, wherein heat is transferred between the flow of fluid 1646 and the first flow of outdoor air 1656. The heat exchanger 1654 may also output a flow of fluid 1646 and a second flow of outdoor air 1658, wherein the temperature of the flow of fluid 1646 exiting the heat exchanger 1654 is lower than the temperature of the flow of fluid 1646 received by the heat exchanger 1654, and the temperature of the second flow of outdoor air 1658 is higher than the temperature of the first flow of outdoor air 1654.

In embodiments where the heat exchanger 1654 is a cooling tower, the heat exchanger 1654 is operable to distribute a flow of the fluid 1646 within its internal structure, wherein the fluid 1646 directly contacts the first outdoor air stream 1656 and transfers heat to the first outdoor air stream 1656 as the fluid 1646 flows through the heat exchanger 1654. As heat is transferred from the fluid 1646 to the first outdoor air stream 1656, at least a portion of the fluid 1646 may evaporate and vent to the atmosphere, and the heat exchanger 1654 may collect a remaining portion of the fluid 1646 after transferring heat to the first outdoor air stream 1656, wherein the remaining portion of the fluid 1646 is at a lower temperature. In embodiments where the heat exchanger 1654 is a dry cooler, the heat exchanger 1654 is operable to induce a flow of the first outdoor air stream 1656 through the heat exchanger 1654, where heat is indirectly transferred between the first outdoor air stream 1656 and the flow of fluid 1646. In these embodiments, heat transfer does not result in a loss of a portion of the fluid 1646 from evaporation into the atmosphere.

Referring to fig. 16D, an external source 1652 may receive the flow of fluid 1646 and output the flow of fluid 1646 to the backup condenser 1620 via a first water pump 1648. The external source 1652 may be configured to contain and/or store an amount of fluid 1646 for use by the backup condenser 1620 to reduce the temperature of the flow of refrigerant 1626 in the dehumidification system 1600. Without limitation, the external source 1652 may be selected from the group consisting of a floor reservoir, a swimming pool, an outdoor body of water, and any combination thereof. In embodiments where the external source 1652 is a surface reservoir, the external source 1652 may be implemented as an open or closed surface water system, where the conduit providing for the flow of fluid 1646 within the surface reservoir may be disposed substantially parallel to the surface level, substantially perpendicular to the surface level, or a combination of both.

In embodiments where the external source 1652 is a swimming pool, the external source 1652 may be located within a multi-loop system that is operable to contain and cool the flow of fluid 1646 prior to the backup condenser 1620 using the flow of fluid 1646 to reduce the temperature of the flow of refrigerant 1626. The external source 1652 may be configured to receive a flow of fluid 1646 at a first temperature from the backup condenser 1620 and output a flow of fluid 1646 at a second temperature to the backup condenser 1620 after transferring heat from the flow of fluid 1646, wherein the second temperature is lower than the first temperature. The external source 1652 receives a flow of fluid 1646 and may receive a secondary flow of fluid (not shown), wherein heat is transferred between the flow of fluid 1646 and the secondary flow of fluid. The external source 1652 may then output a stream of fluid 1646 and a stream of secondary fluid, wherein the temperature of the stream of fluid 1646 exiting the external source 1652 is lower than the temperature of the stream of fluid 1646 received by the external source 1652, and wherein the temperature of the stream of secondary fluid exiting the external source 1652 is higher than the temperature of the stream of secondary fluid received by the external source 1652.

The secondary fluid stream may then be directed to a tertiary condenser (not shown). The tertiary condenser receives the secondary fluid stream from the external source 1652 and outputs the secondary fluid stream back to the external source 1652 at a lower temperature. The tertiary condenser may be any type of air-cooled or liquid-cooled heat exchanger operable to transfer heat from the secondary fluid stream. In embodiments, a second pump (not shown) may be located in any suitable position relative to the external source 1652 and the tertiary condenser, the second pump being operable to circulate the secondary fluid stream between the external source 1652 and the tertiary condenser, wherein the second pump may be operable to provide any suitable means of secondary fluid stream.

Referring again to each of fig. 16A-16D, the fan 1618 may include any suitable components operable to draw inlet air 1628 into the dehumidification system 1600 and through the secondary evaporator 1608, the primary evaporator 1604, the secondary condenser 1610, the subcooling coil 1622, and the primary condenser 1606. The fan 1618 may be any type of air mover (e.g., an axial fan, a forward-tilted impeller, a backward-tilted impeller, etc.). For example, as shown in fig. 16A-16D, the fan 1618 may be a retroverted impeller located near the main condenser 1606. While the fan 1618 is depicted in fig. 16A-16D as being located near the main condenser 1606, it should be appreciated that the fan 1618 may be located anywhere along the airflow path of the dehumidification system 1600. For example, the fan 1618 may be located in the airflow path of any of the airflows 1628, 1634, 1632, 1636, 1638, or 1630. Further, the dehumidification system 1600 may include one or more additional fans located within any one or more of these airflow paths. Similarly, referring to fig. 16A-16B, while the fan 1644 of the external condenser unit 1624 is depicted as being positioned above the backup condenser 1620, it should be appreciated that the fan 1644 may be positioned anywhere (e.g., above, below, beside) with respect to the backup condenser 1620 and the optional subcooling coil 1622, so long as the fan 1644 is suitably positioned and configured to facilitate the flow of the first outdoor air stream 1640 to the backup condenser 1620.

The primary and secondary metering devices 1614, 1616 are any suitable type of metering/expansion devices. In some embodiments, the primary metering device 1614 is a thermostatic expansion valve (TXV) and the secondary metering device 1616 is a fixed orifice device (or vice versa). In certain embodiments, metering devices 1614 and 1616 remove pressure from the flow of refrigerant 1626 to allow expansion in evaporators 1604 and 1608 or change state from liquid to vapor. The temperature of the high pressure liquid (or mostly liquid) refrigerant entering metering devices 1614 and 1616 is higher than the temperature of liquid refrigerant 1626 exiting metering devices 1614 and 1616. For example, if the flow of refrigerant 1626 into the primary metering device 1614 is 340 psig/80F/0% steam, the flow of refrigerant 1626 may be 196 psig/68F/5% steam as it exits the primary metering device 1614. As another example, if the flow of refrigerant 1626 entering the secondary metering device 1616 is 196 psig/68F/4% steam, the flow of refrigerant 1626 may be 128 psig/44F/14% steam when exiting the secondary metering device 1616.

Refrigerant 1626 may be any suitable refrigerant, such as R410a. In general, the dehumidification system 1600 employs a closed refrigeration loop of refrigerant 1626 passing from the compressor 1612 through the modulation valve 1602, the main condenser 1612, and/or the backup condenser 1620, (optional) subcooling coil 1622, the main metering device 1614, the secondary evaporator 1608, the secondary condenser 1610, the secondary metering device 1616, and the main evaporator 1604. The compressor 1612 pressurizes the flow of refrigerant 1626, thereby increasing the temperature of the refrigerant 1626. The main condenser 1606 and the secondary condenser 1610 may include any suitable heat exchanger, and the main condenser 1606 and the secondary condenser 1610 cool the pressurized flow of refrigerant 1626 by facilitating heat transfer from the flow of refrigerant 1626 to the respective flows (i.e., the third or fourth flows 1636, 1638 and the second flow 1632) passing through the main condenser 1606 and the secondary condenser 1610. Further, backup condenser 1620 may include any suitable heat exchanger, and backup condenser 1620 cools the pressurized flow of refrigerant 1626 by facilitating heat transfer from the flow of refrigerant 1626 to the flow of air through backup condenser 1620 (i.e., first outdoor air flow 1640, as shown in fig. 16A-16B) or to the flow of fluid provided by external source 1652 (i.e., flow 1646, as shown in fig. 16C-16D) through backup condenser 1620. The cooled refrigerant 1626 stream exiting the main condenser 1606 and/or backup condenser 1620 may enter a main metering device 1614, which main metering device 1614 is operable to reduce the pressure of the refrigerant 1626 stream, thereby reducing the temperature of the refrigerant 1626 stream. The cooled flow of refrigerant 1626 exiting the secondary condenser 1610 may enter a secondary metering device 1616, the secondary metering device 1616 being operable to reduce the pressure of the flow of refrigerant 1626, thereby reducing the temperature of the flow of refrigerant 1626. The primary and secondary evaporators 1604, 1608 may include any suitable heat exchanger, with the primary and secondary evaporators 1604, 1608 receiving a flow of refrigerant 1626 from a secondary metering device 1616 and a primary metering device 1614, respectively. The primary evaporator 1604 and the secondary evaporator 1608 facilitate heat transfer from the respective air streams passing through them (i.e., the inlet air 1628 and the first air stream 1634) to the flow of refrigerant 1626. The flow of refrigerant 1626 returns to compressor 1612 after exiting main evaporator 1604 and the cycle is repeated.

In some embodiments, the refrigeration loop described above may be configured such that the evaporators 1604 and 1608 operate in a flooded condition. In other words, the flow of refrigerant 1626 may enter the evaporators 1604 and 1608 in a liquid state, and a portion of the flow of refrigerant 1626 may remain in a liquid state upon exiting the evaporators 1604 and 1608. Accordingly, a phase change of the flow of refrigerant 1626 (as heat is transferred to refrigerant flow 1626, the liquid turns into vapor) occurs across evaporators 1604 and 1608, resulting in a nearly constant pressure and temperature across the entire evaporators 1604 and 1608 (and thus an increased cooling capacity).

In operation of an exemplary embodiment of the dehumidification system 1600, inlet air 1628 may be drawn into the dehumidification system 1600 by a fan 1618. The inlet air 1628 passes through the secondary evaporator 1608, wherein heat is transferred from the inlet air 1628 to a flow of cold refrigerant 1626 passing through the secondary evaporator 1608. As a result, the inlet air 1628 may be cooled. For example, if the inlet air 1628 is 80°f/60% humidity, the secondary evaporator 1608 may output a first airflow 1634 of 70°f/84% humidity. This may cause the flow of refrigerant 1626 to partially evaporate within the secondary evaporator 1608. For example, if the flow of refrigerant 1626 entering the secondary evaporator 1608 is 196 psig/68°f/5% steam, the flow of refrigerant 1626 exiting the secondary evaporator 1608 may be 196 psig/68°f/38% steam.

The cooled inlet air 1628 exits the secondary evaporator 1608 as a first air stream 1634 and enters the primary evaporator 1604. Similar to the secondary evaporator 1608, the primary evaporator 1604 transfers heat from the first air stream 1634 to a stream of cold refrigerant 1626 passing through the primary evaporator 1604. As a result, the first air stream 1634 may be cooled to or below its dew point temperature, resulting in condensation of moisture in the first air stream 1634 (thereby reducing the absolute humidity of the first air stream 1634). For example, if the first air stream 1634 is 70°f/84% humidity, the main evaporator 1604 may output a second air stream 1632 of 54°f/98% humidity. This may result in the partial or complete evaporation of the flow of refrigerant 1626 within main evaporator 1604. For example, if the flow of refrigerant 1626 entering the main evaporator 1604 is 128 psig/44°f/14% steam, the flow of refrigerant 1626 may be 128 psig/52°f/100% steam when exiting the main evaporator 1604.

The cooled first air stream 1634 exits the primary evaporator 1604 as a second air stream 1632 and enters the secondary condenser 1610. The secondary condenser 1610 facilitates heat transfer from the flow of hot refrigerant 1626 passing through the secondary condenser 1610 to the second air stream 1632. This will reheat the second air stream 1632, thereby reducing the relative humidity of the second air stream 1632. For example, if the second air stream 1632 is 54°f/98% humidity, the secondary condenser 1610 may output a third air stream 1636 of 65°f/68% humidity. This may result in partial or complete condensation of the flow of refrigerant 1626 within the secondary condenser 1610. For example, if the flow of refrigerant 1626 entering secondary condenser 1610 is 196 psig/68°f/38% steam, the flow of refrigerant 1626 exiting secondary condenser 1610 may be 196 psig/68°f/4% steam.

In some embodiments, the dehumidified second air stream 1632 exits the secondary condenser 1610 as a third air stream 1636 and enters the main condenser 1606 as shown in fig. 16A. The main condenser 1606 facilitates heat transfer from the flow of hot refrigerant 1626 through the main condenser 1606 to the third air stream 1636. This further heats the third air stream 1636, thereby further reducing the relative humidity of the third air stream 1636. For example, if the third air stream 1636 is 65F/68% humidity, the main condenser 1606 may output dehumidified air 1630 at 102F/19% humidity. This may result in partial or complete condensation of the flow of refrigerant 1626 within the main condenser 1606. For example, if the flow of refrigerant 1626 entering the main condenser 1606 is 340 psig/150°f/100% steam, the flow of refrigerant 1626 may be 340 psig/105°f/60% steam when exiting the main condenser 1606.

As described above, some embodiments of the dehumidification system 1600 may include a subcooling coil 1622 positioned in the air stream between the secondary condenser 1610 and the main condenser 1606, as best seen in fig. 16B-16D. The subcooling coil 1622 facilitates heat transfer from the flow of hot refrigerant 1626 through the subcooling coil 1622 to the third air flow 1636. This further heats the third air stream 1636, thereby further reducing the relative humidity of the third air stream 1636. For example, if the third air stream 1636 is 65°f/68% humidity, the subcooling coil 1622 may output a fourth air stream 1638 of 81°f/37% humidity. This may result in partial or complete condensation of the flow of refrigerant 1626 within the subcooling coil 1622. For example, if the flow of refrigerant 1626 entering subcooling coil 1622 is 340 psig/150°f/60% steam, then the flow of refrigerant 1626 may be 340 psig/80°f/0% steam upon exiting subcooling coil 1622. In these embodiments, the fourth air stream 1638 may then be heat transferred in the main condenser 1606 to produce a dehumidified air stream 1630.

Some embodiments of the dehumidification system 1600 may include a controller, which may include one or more computer systems located at one or more locations. Each computer system may include any suitable input device (e.g., keyboard, touch screen, mouse, or other device that can accept information), output device, mass storage medium, or other suitable means for receiving, processing, storing, and transmitting data. Both the input device and the output device may include fixed or removable storage media such as a computer disk, CD-ROM, or other suitable media to receive input from a user and provide output to the user. Each computer system may include a personal computer, a workstation, a network computer, a self-service terminal, a wireless data port, a Personal Data Assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. In short, the controller may comprise any suitable combination of software, firmware, and hardware.

The controller may additionally include one or more processing modules. Each processing module may include one or more microprocessors, controllers, or any other suitable computing devices or resources, and may operate alone or in conjunction with other components of the dehumidification system 1600 to provide some or all of the functionality described herein. The controller may also include (or be communicatively coupled to via wireless or wired communications) a computer memory. The memory may include any memory or database module and may take the form of volatile or nonvolatile memory including, but not limited to, magnetic media, optical media, random Access Memory (RAM), read Only Memory (ROM), removable media, or any other suitable local or remote memory component.

Although a particular embodiment of a dehumidification system 1600 is illustrated and described primarily, the present disclosure contemplates any suitable embodiment of a dehumidification system 1600 according to particular needs. Further, while the various components of the dehumidification system 1600 have been described as being positioned in particular locations and relative to one another, the present disclosure contemplates positioning the components in any suitable locations according to particular needs.

17A, 17B, and 17C illustrate an exemplary dehumidification system 1700 with a first modulation valve 1702 that can be used to control the sensible to latent ratio of ambient air flow. The first modulating valve 1702 may be configured to actuate between different modes of operation based on inputs received from the superheat control evaporator 1704. For example, the operation of the dehumidification system 1700 may be based at least in part on superheat control of one or more evaporator coils of the dehumidification system 1700. Providing enhanced superheat control may prevent cooling of the airflow determined to be at a controlled or set temperature.

The dehumidification system 1700 may include a first modulation valve 1702, a superheat control evaporator 1704, a main evaporator 1706, a main condenser 1708, a secondary evaporator 1710, a secondary condenser 1712, a compressor 1714, a main metering device 1716, a secondary metering device 1718, a fan 1720, a second modulation valve 1722, and a backup condenser 1724. As shown, backup condenser 1724 may be disposed in external condenser unit 1726 and may be air cooled. In alternative embodiments, backup condenser 1724 may be liquid cooled. In some embodiments, the dehumidification system 1700 may additionally include an optional subcooling coil 1728. Referring to the drawings, an optional subcooling coil 1728 may be disposed adjacent to the main condenser 1708, wherein the subcooling coil 1728 and the main condenser 1708 may be combined into a single coil. Fig. 17A and 17B illustrate an embodiment of the dehumidification system 1700 in which the superheat control evaporator 1704 is disposed separately from the secondary evaporator 1710, and fig. 17C illustrates an embodiment of the dehumidification system 1700 in which the superheat control evaporator 1704 and the secondary evaporator 1710 are co-integrated as a hybrid coil unit 1730.

Referring to each of fig. 17A-17C, as shown, a flow of refrigerant 1732 is circulated through the dehumidification system 1700. In general, the dehumidification system 1700 may receive one or more inlet airflows 1734, remove water from the one or more inlet airflows 1734, and output an dischargeable airflow 1736. In embodiments, the dischargeable stream 1736 may be at least partially dehumidified and/or at a lower temperature than the one or more inlet streams 1734. Water may be removed from one or more inlet streams 1734 using a refrigeration cycle of a flow of refrigerant 1732. However, by including secondary evaporator 1710 and secondary condenser 1712, dehumidification system 1700 may cause at least a portion of the flow of refrigerant 1732 to evaporate and condense twice in a single refrigeration cycle. This increases the cooling capacity over typical systems without adding any additional energy to the compressor, thereby increasing the overall dehumidification efficiency of the system.

In general, the dehumidification system 1700 may attempt to match the saturation temperature of the secondary evaporator 1710 with the saturation temperature of the secondary condenser 1712. The saturation temperatures of the secondary evaporator 1710 and the secondary condenser 1712 are typically controlled according to the following equation (temperature of the inlet airflow 1734 + temperature of the airflow received by the secondary condenser 1712)/2. Evaporation occurs in the secondary evaporator 1710 because the saturation temperature of the secondary evaporator 1710 is lower than the inlet airflow 1734. Condensation occurs in secondary condenser 1712 because the saturation temperature of secondary condenser 1712 is higher than the airflow received by secondary condenser 1712. The amount of refrigerant 1732 evaporated in the secondary evaporator 1710 may be substantially equal to the amount of refrigerant condensed in the secondary condenser 1712.

The superheat-controlled evaporator 1704 may receive a flow of refrigerant 1732 from the main evaporator 1706 and may output the flow of refrigerant 1732 to the compressor 1714. The superheat control evaporator 1704 may be any type of coil (e.g., finned tube, microchannel, etc.). Referring to fig. 17A, the superheat control evaporator 1704 may receive the inlet airflow 1734 and may output a first airflow 1738 to the secondary evaporator 1710. Typically, the temperature of the first gas stream 1738 is lower than the temperature of the inlet gas stream 1734. To cool the incoming inlet airflow 1734, the superheat-controlled evaporator 1734 may transfer heat from the inlet airflow 1734 to the flow of refrigerant 1732, thereby evaporating the flow of refrigerant 1732 at least partially from a liquid to a gas.

The secondary evaporator 1710 can receive the flow of refrigerant 1732 from the primary metering device 1716 and can output the flow of refrigerant 1732 to the first modulation valve 1702. Similar to the superheat control evaporator 1704, the secondary evaporator 1710 may be any type of coil (e.g., a finned tube, a microchannel, etc.). The secondary evaporator 1710 receives the first airflow 1738 and outputs a second airflow 1740 to the primary evaporator 1706. Typically, the temperature of the second airflow 1740 is lower than the temperature of the first airflow 1738. To cool the incoming first gas stream 1738, the secondary evaporator 1710 transfers heat from the first gas stream 1738 to the flow of refrigerant 1732, thereby evaporating the flow of refrigerant 1732 at least partially from a liquid to a gas.

In this embodiment, the superheat control evaporator 1704 may be disposed upstream of both the secondary evaporator 1710 and the primary evaporator 1706 relative to the air flow through the dehumidification system 1700. For example, the superheat control evaporator 1704 may be disposed in series with other coils of the dehumidification system 1700 and may be the first component to receive one or more inlet airflows 1734. In other embodiments, the superheat control evaporator 1704 may be provided in various other configurations depending on other components of the dehumidification system 1700.

For example, referring now to fig. 17B, a superheat control evaporator 1704 may be provided in parallel with the secondary evaporator 1710. The superheat control evaporator 1704 and the secondary evaporator 1710 may receive one or more inlet airflows 1734 and may discharge treated air to the primary evaporator 1706. In this embodiment, the superheat control evaporator 1704 may receive a first inlet airflow 1734a and the secondary evaporator 1710 may receive a second inlet airflow 1734b. The superheat control evaporator 1704 may transfer heat from the first inlet air stream 1734a to a flow of refrigerant 1732 through the superheat control evaporator 1704 and output a resulting first air stream 1738 to the main evaporator 1706. Similarly, the secondary evaporator 1710 can transfer heat from the second inlet airflow 1734b to a flow of refrigerant 1732 flowing through the secondary evaporator 1710 and output a second airflow 1740 to the primary evaporator 1706. As shown, the main evaporator 1706 may receive both the first airflow 1738 and the second airflow 1740 for further operation within the dehumidification system 1700. The present embodiment may provide a superheat control evaporator 1704 and a secondary evaporator 1710 that are disposed apart from one another and receive a separate inlet airflow 1734. Further, there may be separate ducts and/or conduits to direct the air streams received by the dehumidification system 1700 (i.e., the inlet air streams 1734a, 1734 b) to the main evaporator 1706.

Fig. 17C illustrates another embodiment of a dehumidification system 1700 in which a superheat control evaporator 1704 and a secondary evaporator 1710 are integrated together as a hybrid coil unit 1730. In certain embodiments, the superheat control evaporator 1704 and the secondary evaporator 1710, when coupled together, may be collectively referred to as a "mixed coil unit 1730". The mixing coil unit 1730 may include any suitable size, height, shape, and any combination thereof. The mixing coil unit 1730 may also include any suitable housing or containment device for the superheat control evaporator 1704 and the secondary evaporator 1710. For example, the superheat control evaporator 1704 may be physically coupled or secured to the secondary evaporator 1710 such that both evaporator coils 1704, 1710 receive the same inlet airflow 1734. While both the superheat control evaporator 1704 and the secondary evaporator 1710 may be coupled together, the flow paths of the refrigerant 1732 through the superheat control evaporator 1704 and the secondary evaporator 1710 may be separate (as shown). In an embodiment, the mixing coil unit 1730 may receive the inlet airflow 1734 and may output a first airflow 1738 to the main evaporator 1706. The first stream 1738 may be generated by transferring heat from the inlet stream 1734 to the flow of refrigerant 1732 within both the superheat controlled evaporator 1704 and the secondary evaporator 1710 as the inlet stream 1734 passes through both the superheat controlled evaporator 1704 and the secondary evaporator 1710.

Referring again to each of fig. 17A-17C, the main evaporator 1706 can receive the flow of refrigerant 1732 and can output the flow of refrigerant 1732 to the superheat control evaporator 1704. As shown, the primary evaporator 1706 may receive a flow of refrigerant 1732 from a secondary metering device 1718, wherein the secondary metering device 1718 may receive the flow of refrigerant 1732 from the secondary condenser 1712 and/or the first modulating valve 1702. In other embodiments, the primary evaporator 1706 may receive a flow of refrigerant 1732 from the first modulating valve 1702, wherein the first modulating valve 1702 may direct the refrigerant around both the secondary condenser 1712 and the secondary metering device 1718, wherein the output of the first modulating valve 1702 is connected to a location downstream of the secondary metering device 1718 but upstream of the primary evaporator 1706.

The main evaporator 1706 may be any type of coil (e.g., finned tubes, microchannels, etc.). The main evaporator 1706 may be configured to receive the first airflow 1738 and/or the second airflow 1740 and generate a third airflow 1742 to be discharged. For example, referring to fig. 17A, the primary evaporator 1706 can receive a second air stream 1740 from the secondary evaporator 1710. Referring to fig. 17B, the primary evaporator 1706 may receive a second air stream 1740 from the secondary evaporator 1710 and may receive a first air stream 1738 from the superheat control evaporator 1704. Referring to fig. 17C, the main evaporator 1706 may receive a first air stream 1738 from a mixing coil unit 1730. The third airflow 1742 is generally cooler than the first airflow 1738 and/or the second airflow 1740. In an embodiment, the primary evaporator 1706 may transfer heat from the first gas stream 1738 and/or the second gas stream 1740 to the flow of refrigerant 1732, thereby evaporating the flow of refrigerant 1732 at least partially from a liquid to a gas. This heat transfer from the first and/or second streams 1738, 1740 to the flow of refrigerant 1732 may further remove water from the first and/or second streams 1738, 1740.

The secondary condenser 1712 may receive the flow of refrigerant 1732 from the first modulation valve 1702 and may output the flow of refrigerant 1732 to a secondary metering device 1718. The secondary condenser 1712 may be any type of coil (e.g., finned tubes, microchannels, etc.). The secondary condenser 1712 may receive the third air stream 1742 from the primary evaporator 1706 and may output a fourth air stream 1744. The fourth airflow 1744 is generally warmer, drier (i.e., the dew point may be the same but the relative humidity may be lower) than the third airflow 1742. The secondary condenser 1712 may generate a fourth gas stream 1744 by transferring heat from the flow of refrigerant 1732 to the third gas stream 1742, thereby condensing the flow of refrigerant 1732 at least partially from a gas to a liquid.

The first modulation valve 1702 may be configured to receive the flow of refrigerant 1732 from the secondary evaporator 1710 and direct the flow of refrigerant 1732 to the secondary condenser 1712, the primary evaporator 1706, or both. In an embodiment, the first modulating valve 1702 may be operated based at least in part on superheat measured at one or more evaporator coils (such as at the superheat control evaporator 1704) within the dehumidification system 1700. The dehumidification system 1700 may utilize a first modulation valve 1702 to direct a flow of refrigerant 1732 to a secondary condenser 1712, bypass the secondary condenser 1712 and flow to a primary evaporator 1706, or a combination thereof. According to a feedback loop, the first modulation valve 1702 may be configured to be partially opened and/or closed to direct at least a portion of the flow of refrigerant 1732 to the secondary condenser 1712 and to direct the remaining portion of the flow of refrigerant 1732 to the primary evaporator 1706.

In an embodiment, the dehumidification system 1700 may operate in a first mode of operation. During the first mode of operation, the first modulation valve 1702 may be actuated to direct the flow of refrigerant 1732 to the secondary condenser 1712. As refrigerant 1732 flows through secondary condenser 1712, secondary condenser 1712 may generate fourth airflow 1744. The dehumidification system 1700 may operate in a first mode of operation to dehumidify or remove water from air to be output as an exhaust stream 1736. In further embodiments, the dehumidification system 1700 may operate in a second mode of operation. During the second mode of operation, the first modulation valve 1702 may be actuated to direct the flow of refrigerant 1732 to the primary evaporator 1706, bypassing the secondary condenser 1712. Because refrigerant 1732 does not flow through secondary condenser 1712, secondary condenser 1712 may not transfer heat between refrigerant 1732 and received third air stream 1742. Thus, the resulting air stream passing through the secondary condenser 1712 (i.e., the fourth air stream 1744) may have approximately the same temperature and humidity as the third air stream 1742. The dehumidification system 1700 may operate in a second mode of operation to reduce the temperature of air to be output as the dischargeable air stream 1736 and without dehumidification. In other embodiments, the dehumidification system 1700 may operate in a third mode of operation, wherein the first modulation valve 1702 is operable to direct a portion of the flow of refrigerant 1732 to the secondary condenser 1712 and a remaining portion of the flow of refrigerant 1732 to the primary evaporator 1706. As at least a portion of refrigerant 1732 flows through secondary condenser 1712, secondary condenser 1712 may generate fourth air stream 1744 by transferring heat from the portion of refrigerant 1732 to received third air stream 1742. In an embodiment, the fourth airflow 1744 of the third mode of operation may be more humid than the fourth airflow 1744 of the first mode of operation and less humid than the fourth airflow 1744 of the second mode of operation. Further, the temperature of the fourth air stream 1744 of the third mode of operation may be higher than the temperature of the fourth air stream 1744 of the second mode of operation and lower than the temperature of the fourth air stream 1744 of the first mode of operation.

The main condenser 1708 may be any type of coil (e.g., finned tubes, microchannels, etc.). The main condenser 1708 is operable to receive the flow of refrigerant 1732 from the second modulating valve 1722 and output the flow of refrigerant 1732 to the main metering device 1716 or to the subcooling coil 1728. As shown, the main condenser 1708 may output a stream of refrigerant 1732 to an optional subcooling coil 1728, and then the stream of refrigerant 1732 to the main metering device 1716. In these embodiments, the subcooling coil 1728 may be optional to the dehumidification system 1700, and the main condenser 1708 may instead direct the flow of refrigerant 1732 to the main metering device 1716. The main condenser 1708 may be configured to receive a fifth air stream 1746 generated by the subcooling coil 1728 and output an dischargeable air stream 1736. 17A-17C, the dischargeable air stream 1736 is generally warmer, drier (i.e., has a lower relative humidity) than the fourth air stream 1744 and the fifth air stream 1746. The main condenser 1708 may generate an dischargeable gas stream 1736 by transferring heat from the stream of refrigerant 1732, thereby condensing the stream of refrigerant 1732 at least partially from a gas to a liquid. In some embodiments, main condenser 1708 fully condenses refrigerant 1732 stream into a liquid (i.e., 100% liquid). In other embodiments, the main condenser 1708 partially condenses the stream of refrigerant 1732 into a liquid (i.e., less than 100% liquid).

Subcooling coil 1728 is an optional component of dehumidification system 1700 that may be configured to subcool liquid refrigerant 1732 as liquid refrigerant 1732 exits main condenser 1708, backup condenser 1724, or a combination thereof. In embodiments where the subcooling coil 1728 is disposed adjacent to the main condenser 1708, the subcooling coil 1728 may receive refrigerant 1732 as the refrigerant 1732 exits the main condenser 1708 and/or the backup condenser 1724, as shown in fig. 17A-17C. This in turn may supply liquid refrigerant to the main metering device 1716 at a temperature 30 degrees less (or more) than before entering the subcooling coil 1728. For example, if the flow of refrigerant 1732 into the subcooling coil 1728 is 340 psig/105F/60% steam, the flow of refrigerant 1732 may be 340 psig/80F/0% steam upon exiting the subcooling coil 1728. The subcooled refrigerant 1732 has a greater enthalpy factor and a greater density, which results in a reduction in the cycle time and frequency of the evaporation cycle of the flow of refrigerant 1732. This may result in a more efficient dehumidification system 1700 and less energy used.

Compressor 1714 may be configured to pressurize a flow of refrigerant 1732, thereby increasing the temperature of refrigerant 1732. For example, if the flow of refrigerant 1732 into compressor 1714 is 128 psig/52°f/100% steam, the flow of refrigerant 1732 out of compressor 1714 may be 340 psig/150°f/100% steam. The compressor 1714 may be configured to receive the flow of refrigerant 1732 from the superheat control evaporator 1704 and supply a pressurized flow of refrigerant 1732 to the second modulation valve 1722.

Second modulation valve 1722 is operable to receive a pressurized flow of refrigerant 1732 from compressor 1714 and to direct the flow of refrigerant 1732 to main condenser 1708, backup condenser 1724, or both. In an embodiment, the second modulation valve 1722 may operate based at least in part on a predetermined temperature set point of the dischargeable airflow 1736 and an actual temperature of the dischargeable airflow 1736 output by the dehumidification system 1700. The dehumidification system 1700 may utilize a second modulation valve 1722 to direct heat to be rejected from the flow of refrigerant 1732 away from the main condenser 1708 and toward the backup condenser 1724. In accordance with a feedback loop including a predetermined temperature set point and an actual temperature of the dischargeable gas stream 1736, the second modulation valve 1722 may be configured to partially open and/or close to direct at least a portion of the flow of refrigerant 1732 to the backup condenser 1724 and a remaining portion of the flow of refrigerant 1732 to the main condenser 1708.

During operation of the dehumidification system 1700, the second modulation valve 1722 may direct the flow of refrigerant 1732 to the main condenser 1708 if the temperature of the dischargeable gas stream 1736 output by the main condenser 1708 does not exceed a predetermined temperature set point monitored by the dehumidification system 1700. If the temperature of the dischargeable stream 1736 is above the predetermined temperature set point, the second modulating valve 1722 may be actuated to direct at least a portion of the stream of refrigerant 1732 to the backup condenser 1724 and the remaining portion of the stream of refrigerant 1732 to the main condenser 1708. When the dehumidification system 1700 is operated, the reduced volume of the flow of refrigerant 1732 to the main condenser 1708 may reduce the available heat to be evolved into the dischargeable gas stream 1736. With the reduced flow of refrigerant 1732 through the main condenser 1708 (e.g., the remainder of the refrigerant flow), the rate of heat transfer to the dischargeable gas stream 1736 may then be reduced, resulting in a reduced temperature change of the incoming gas stream and the outgoing dischargeable gas stream 1736. Once the temperature of the dischargeable stream 1736 is below the predetermined temperature set point, the second modulation valve 1722 may be actuated to direct at least a portion of the stream of refrigerant 1732 back to the main condenser 1708. Any remaining refrigerant 1732 that has been directed to backup condenser 1724 may be combined with the further downstream flow of refrigerant 1732.

As shown, a backup condenser 1724 may be provided in the external condenser unit 1726 and may be any type of coil (e.g., finned tube, microchannel, etc.) operable to receive the flow of refrigerant 1732 from the second modulation valve 1722 and output a lower temperature flow of refrigerant 1732. Backup condenser 1724 may be configured to transfer heat from refrigerant 1732 stream, thereby condensing refrigerant 1732 stream at least partially from a gas to a liquid. In some embodiments, backup condenser 1724 fully condenses refrigerant 1732 stream into a liquid (i.e., 100% liquid). In other embodiments, backup condenser 1724 partially condenses refrigerant 1732 stream into a liquid (i.e., less than 100% liquid). Backup condenser 1724 may receive first outdoor air stream 1748 and output second outdoor air stream 1750. The second outdoor airflow 1750 is typically warmer (i.e., has a lower relative humidity) than the first outdoor airflow 1748. As shown, the external condenser unit 1726 may include a backup condenser 1724 and a fan 1752, wherein the fan 1752 may be configured to facilitate the flow of the first outdoor air stream 1748 to the backup condenser 1724. While backup condenser 1724 may be air cooled, backup condenser 1724 may alternatively be liquid cooled. In one or more embodiments, backup condenser 1724 can be any type of liquid-cooled heat exchanger operable to transfer heat from refrigerant 1732 stream to a suitable fluid stream, such as water or a mixture of water and glycol.

Referring again to each of fig. 17A-17C, the fan 1720 may include any suitable component operable to draw one or more inlet airflows 1734 into the dehumidification system 1700 and through the superheat control evaporator 1704, the secondary evaporator 1710, the primary evaporator 1706, the secondary condenser 1712, the subcooling coil 1728, and the primary condenser 1708. The fan 1720 may be any type of air mover (e.g., an axial fan, a forward-tilted impeller, a backward-tilted impeller, etc.). For example, the fan 1720 may be a back-rake impeller located near the main condenser 1720, as shown in fig. 17A-17C. Although the fan 1720 is depicted as being located near the main condenser 1708, it should be appreciated that the fan 1720 may be located anywhere along the airflow path of the dehumidification system 1700. For example, fan 1720 may be located in the airflow path of any one of airflows 1734, 1738, 1740, 1742, 1744, 1746, or 1736. Further, the dehumidification system 1700 may include one or more additional fans located within any one or more of these airflow paths. Similarly, while the fan 1752 of the external condenser unit 1726 is depicted as being positioned proximate to the backup condenser 1724, it should be appreciated that the fan 1752 may be positioned anywhere (e.g., above, below, beside) with respect to the backup condenser 1724, so long as the fan 1752 is suitably positioned and configured to facilitate the flow of the first outdoor airflow 1748 to the backup condenser 1724.

The primary metering device 1716 and the secondary metering device 1718 are any suitable type of metering/expansion devices. In some embodiments, the primary metering device 1716 is a thermostatic expansion valve (TXV) and the secondary metering device 1718 is a fixed orifice device (or vice versa). In certain embodiments, the metering devices 1716, 1718 remove pressure from the flow of refrigerant 1732 to allow expansion in the evaporators 1710, 1706 or change state from liquid to vapor. The temperature of the high pressure liquid (or mostly liquid) refrigerant entering the metering devices 1716, 1718 is higher than the temperature of the liquid refrigerant 1732 exiting the metering devices 1716, 1718. For example, if the flow of refrigerant 1732 into the primary metering device 1716 is 340 psig/80F/0% steam, the flow of refrigerant 1732 out of the primary metering device 1716 may be 196 psig/68F/5% steam. As another example, if the flow of refrigerant 1732 into secondary metering device 1718 is 196 psig/68F/4% steam, the flow of refrigerant 1732 may be 128 psig/44F/14% steam upon exiting secondary metering device 1718.

Refrigerant 1732 may be any suitable refrigerant, such as R410a. In general, the dehumidification system 1700 employs a closed refrigeration loop of refrigerant 1732, with the refrigerant 1732 passing from the compressor 1714 through a second modulation valve 1722, a main condenser 1708 and/or a backup condenser 1724, an (optional) subcooling coil 1728, a main metering device 1716, a secondary evaporator 1710, a first modulation valve 1702, a secondary condenser 1712 and/or a secondary metering device 1718 (where the refrigerant 1732 may bypass the secondary condenser 1712), a main evaporator 1704 and a superheat control evaporator 1704. Compressor 1714 pressurizes the flow of refrigerant 1732, thereby increasing the temperature of refrigerant 1732. The main condenser 1708 and the secondary condenser 1712 may include any suitable heat exchanger, and the main condenser 1708 and the secondary condenser 1712 cool the pressurized flow of refrigerant 1732 by facilitating heat transfer from the flow of refrigerant 1732 to the respective flows of gas passing through the main condenser 1708 and the secondary condenser 1712 (i.e., the fourth or fifth flows 1744, 1746 and the third flow 1742, respectively). Further, backup condenser 1724 may include any suitable heat exchanger, and backup condenser 1724 cools the pressurized flow of refrigerant 1732 by facilitating heat transfer from the flow of refrigerant 1732 to the flow of gas through backup condenser 1724 (i.e., first outdoor flow 1748) or to a flow of fluid provided by an external source. The cooled refrigerant 1732 stream exiting the main condenser 1708 and/or the backup condenser 1724 may enter the main metering device 1716, which main metering device 1716 is operable to reduce the pressure of the refrigerant 1732 stream, thereby reducing the temperature of the refrigerant 1732 stream. In an embodiment, refrigerant 1732 may first flow through optional subcooling coil 1728 and then merge into main metering device 1716. Depending on the mode of operation, the cooled refrigerant 1732 stream exiting the secondary condenser 1712 may enter a secondary metering device 1718, the secondary metering device 1718 being operable to reduce the pressure of the refrigerant 1732 stream, thereby reducing the temperature of the refrigerant 1732 stream. Alternatively, the refrigerant 1732 may bypass the secondary condenser 1712 to be received by the secondary metering device 1718 from the first modulation valve 1702. The primary and secondary evaporators 1706, 1710 may include any suitable heat exchanger, with the primary and secondary evaporators 1706, 1710 receiving a flow of refrigerant 1732 from secondary metering devices 1718, 1716, respectively. The primary evaporator 1706 and the secondary evaporator 1710 facilitate heat transfer from the respective air streams passing through them to the flow of refrigerant 1732. The flow of refrigerant 1732 may be received by the superheat control evaporator 1704 after exiting the main evaporator 1706. the superheat control evaporator 1704 may facilitate heat transfer from the inlet airflow 1734 passing therethrough to the flow of refrigerant 1732. Refrigerant 1732 may then be directed back to compressor 1714 and the cycle repeated.

In some embodiments, the refrigeration loop described above may be configured such that the evaporators 1706, 1710 operate in a flooded condition. In other words, the flow of refrigerant 1732 may enter the evaporators 1706, 1710 in a liquid state, and a portion of the flow of refrigerant 1732 may remain in a liquid state upon exiting the evaporators 1706, 1710. Accordingly, a phase change of the flow of refrigerant 1732 (as heat is transferred into the flow of refrigerant 1732, the liquid changes to vapor) occurs across the evaporators 1706, 1710, resulting in an almost constant pressure and temperature across the entire evaporators 1706, 1710 (and thus an increased cooling capacity). In these embodiments, the superheat control evaporator 1704 may also operate in a flooded condition.

In operation of an example embodiment of the dehumidification system 1700, one or more inlet airflows 1734 may be drawn into the dehumidification system 1700 by the fan 1720. One or more inlet airflows 1734 may be passed through the superheat control evaporator 1704 and/or the secondary evaporator 1710, wherein heat is transferred from the one or more inlet airflows 1734 to a cooler refrigerant 1732 stream passing through the evaporators 1704, 1710. As a result, one or more inlet airflows 1734 may be cooled. For example, if one or more of the inlet airflows 1734 are 80°f/60% humidity, the superheat control evaporator 1704 and/or the secondary evaporator 1710 may output a first airflows 1738 and/or a second airflows 1740 of 70°f/84% humidity. This may cause refrigerant 1732 to flow partially vaporized within superheat control evaporator 1704 and/or secondary evaporator 1710. For example, if the flow of refrigerant 1732 into the superheat control evaporator 1704 and/or secondary evaporator 1710 is 196 psig/68°f/5% steam, the flow of refrigerant 1732 out of the superheat control evaporator 1704 and/or secondary evaporator 1710 may be 196 psig/68°f/38% steam.

The cooled one or more inlet airflows 1734 may be discharged as first airflows 1738 and/or second airflows from the superheat control evaporator 1704 and/or the secondary evaporator 1710, respectively, and may enter the main evaporator 1706. Similar to the superheat control evaporator 1704 and/or the secondary evaporator 1710, the primary evaporator 1706 can transfer heat from the first air stream 1738 and/or the second air stream 1740 to a cold flow of refrigerant 1732 through the primary evaporator 1706. As a result, the air may be cooled to or below its dew point temperature, causing condensation of water vapor in the first airflow 1738 and/or the second airflow 1740 (thereby reducing the absolute humidity of the first airflow 1738 and/or the second airflow 1740). For example, if the first airflow 1738 and/or the second airflow 1740 is 70°f/84% humidity, the main evaporator 1706 may output a third airflow 1742 of 54°f/98% humidity. This may result in the partial or complete evaporation of the flow of refrigerant 1732 within the main evaporator 1706. For example, if the flow of refrigerant 1732 into the main evaporator 1706 is 128 psig/44°f/14% steam, the flow of refrigerant 1732 may be 128 psig/52°f/100% steam upon exiting the main evaporator 1706.

The third air stream 1742 may exit the primary evaporator 1706 and may enter the secondary condenser 1712. Depending on the mode of operation, the secondary condenser 1712 may be configured to facilitate heat transfer from the flow of hot refrigerant 1732 through the secondary condenser 1712 to the third airflow 1742. This will reheat the third air stream 1742, thereby reducing the relative humidity of the third air stream 1742. For example, if the third airflow 1742 is 54°f/98% humidity, the secondary condenser 1712 may output a fourth airflow 1744 of 65°f/68% humidity. This may result in partial or complete condensation of the flow of refrigerant 1732 within secondary condenser 1712. For example, if the flow of refrigerant 1732 into secondary condenser 1712 is 196 psig/68°f/38% steam, the flow of refrigerant 1732 out of secondary condenser 1712 may be 196 psig/68°f/4% steam.

In some embodiments, the fourth air stream 1744 can be discharged and can enter the optional subcooling coil 1728. The subcooling coil 1728 facilitates heat transfer from the flow of hot refrigerant 1732 through the subcooling coil 1728 to the fourth air stream 1744 to produce the fifth air stream 1746 to be output to the main condenser 1708. In other embodiments, the fourth air stream 1744 may be discharged and may enter the main condenser 1708 without flowing through the subcooling coil 1728. The main condenser 1708 facilitates heat transfer from the hot refrigerant 1732 stream passing through the main condenser 1708 to either the fourth stream 1744 or the fifth stream 1746. This further heats the fourth airflow 1744 or the fifth airflow 1746, thereby further reducing the relative humidity of the fourth airflow 1744 or the fifth airflow 1746. For example, if either the fourth airflow 1744 or the fifth airflow 1746 is 65°f/68% humidity, the main condenser 1708 may output an dischargeable airflow 1736 of 102°f/19% humidity. This may result in partial or complete condensation of the flow of refrigerant 1732 within the main condenser 1708. For example, if the flow of refrigerant 1732 into the main condenser 1708 is 340 psig/150F/100% steam, the flow of refrigerant 1732 out of the main condenser 1708 may be 340 psig/105F/60% steam.

Some embodiments of the dehumidification system 1700 may include a controller, which may include one or more computer systems located at one or more locations. Each computer system may include any suitable input device (e.g., keyboard, touch screen, mouse, or other device that can accept information), output device, mass storage medium, or other suitable means for receiving, processing, storing, and transmitting data. Both the input device and the output device may include fixed or removable storage media such as a computer disk, CD-ROM, or other suitable media to receive input from a user and provide output to the user. Each computer system may include a personal computer, a workstation, a network computer, a self-service terminal, a wireless data port, a Personal Data Assistant (PDA), one or more processor devices among these or other devices, or any other suitable processing device. In short, the controller may comprise any suitable combination of software, firmware, and hardware.

The controller may also include one or more processing modules. Each processing module may include one or more microprocessors, controllers, or any other suitable computing devices or resources, and may operate alone or in conjunction with other components of the dehumidification system 1700 to provide some or all of the functionality described herein. The controller may also include (or be communicatively coupled to via wireless or wired communications) a computer memory. The memory may include any memory or database module and may take the form of volatile or nonvolatile memory including, but not limited to, magnetic media, optical media, random Access Memory (RAM), read Only Memory (ROM), removable media, or any other suitable local or remote memory component.

Although a particular embodiment of the dehumidification system 1700 is illustrated and described primarily, the present disclosure contemplates any suitable embodiment of the dehumidification system 1700 according to particular needs. Further, while the various components of the dehumidification system 1700 have been described as being positioned in particular locations and relative to one another, the present disclosure contemplates positioning the components in any suitable locations according to particular needs.

Herein, a computer-readable non-transitory storage medium may include one or more semiconductor-based integrated circuits or other Integrated Circuits (ICs) (such as, for example, a Field Programmable Gate Array (FPGA) or Application Specific IC (ASIC)), a Hard Disk Drive (HDD), a hybrid hard disk drive (HHD), an Optical Disk Drive (ODD), a magneto-optical disk, a Floppy Disk Drive (FDD), a magnetic tape, a Solid State Drive (SSD), a RAM drive, a secure digital card or drive, any other suitable computer-readable non-transitory storage medium, or any suitable combination of two or more thereof, as the case may be. The computer readable non-transitory storage medium may be volatile, nonvolatile, or a combination of volatile and nonvolatile, as the case may be.

The use of "or" herein is inclusive and not exclusive, unless otherwise specified or indicated by context. Thus, "a or B" herein means "A, B or both" unless explicitly stated otherwise or the context indicates otherwise. Furthermore, "and" are both conjunctive and separate unless otherwise indicated explicitly or by context. Thus, herein, "a and B" means "a and B, jointly or individually," unless explicitly stated otherwise or the context indicates otherwise.

The scope of the present disclosure encompasses all changes, substitutions, variations, modifications, and improvements that will occur to those of ordinary skill in the art upon describing or illustrating the exemplary embodiments herein. The scope of the present disclosure is not limited to the exemplary embodiments described or illustrated herein. Furthermore, although the present disclosure describes and illustrates respective embodiments herein as including particular components, elements, features, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, features, functions, operations, or steps described or illustrated anywhere herein as would be understood by one of ordinary skill in the art. Furthermore, in the appended claims, references to a device or system or component of a device or system being adapted, arranged, capable, configured, enabled, operable, or functional to perform a particular function encompass the device, system, or component, whether or not it or that particular function is activated, or unlocked, so long as the device, system, or component is so adapted, arranged, capable, configured, enabled, operable, or functional. Furthermore, although the disclosure describes or illustrates particular embodiments as providing particular advantages, particular embodiments may not provide such advantages, provide some of the advantages, or provide all of the advantages.

Claims

1. A dehumidification system, comprising:

Main metering device;

Secondary metering devices;

Superheat control evaporator, which can be operated to:

Receives refrigerant flow from the main evaporator; and

The system receives inlet airflow and outputs a first airflow, the first airflow comprising air colder than the inlet airflow, the first airflow being generated by transferring heat from the inlet airflow to the refrigerant flow as the inlet airflow passes through the superheat control evaporator;

A secondary evaporator, which is connected in series with the superheat control evaporator, is operable to:

Receive refrigerant flow from the main metering device; and

The system receives the first airflow and outputs a second airflow, the second airflow comprising air that is colder than the first airflow, the second airflow being generated by transferring heat from the first airflow to the refrigerant flow as the first airflow passes through the secondary evaporator;

The main evaporator is capable of operating as follows:

Receive refrigerant flow from the first modulation valve and/or the secondary condenser; and

The system receives the second airflow and outputs a third airflow, the third airflow comprising air that is colder than the second airflow, the third airflow being generated by transferring heat from the second airflow to the refrigerant flow as the second airflow passes through the main evaporator;

The secondary condenser is operable to:

Receives refrigerant flow from the first modulation valve; and

Receive the third airflow and output the fourth airflow;

The first modulation valve is operable to:

Receive refrigerant flow from the secondary evaporator;

During the first operating mode, the refrigerant flow is directed to the secondary condenser;

During the second operating mode, the refrigerant flow is directed to the main evaporator, wherein the refrigerant flow bypasses the secondary condenser; and

During the third operating mode, a portion of the refrigerant flow is directed to the secondary condenser, and the remainder of the refrigerant flow is directed to the main evaporator;

The compressor is configured as follows:

Receives a refrigerant stream from the superheat-controlled evaporator and discharges the refrigerant stream at a higher pressure than the refrigerant stream received at the compressor; and

The main condenser is operable as follows:

Receive the refrigerant flow discharged from the compressor;

In response to receiving a refrigerant flow from the compressor, a dischargeable gas flow is output.

2. The dehumidification system according to claim 1 further includes a subcooling coil, which is operable to:

Receive refrigerant flow from the main condenser;

The refrigerant flow is output to the main metering device; and

The system receives the fourth airflow and outputs a fifth airflow, which is generated by transferring heat from the refrigerant flow to the fourth airflow as it passes through the subcooling coil.

3. The dehumidification system according to claim 2, wherein the subcooling coil and the main condenser are combined into a single coil unit.

4. The dehumidification system according to claim 2, wherein the main condenser is further operable to:

The fifth airflow is received and the ventable airflow is generated based on the received fifth airflow, the ventable airflow being generated by transferring heat from the refrigerant flow to the fifth airflow when the fifth airflow contacts the main condenser.

5. The dehumidification system according to claim 1, wherein the main condenser is further operable to:

The system receives the fourth airflow and generates the ventable airflow based on the received fourth airflow, the ventable airflow being generated by transferring heat from the refrigerant stream to the fourth airflow when the fourth airflow contacts the main condenser.

6. The dehumidification system according to claim 1, wherein during the first operating mode:

The fourth airflow comprises air that is warmer and less humid than the third airflow, and is generated by transferring heat from the refrigerant stream to the third airflow as it passes through the secondary condenser.

7. The dehumidification system of claim 1, wherein during the second operating mode, the fourth airflow comprises approximately the same temperature and humidity as the third airflow.

8. The dehumidification system according to claim 1 further includes a standby condenser disposed in the external condenser unit, the standby condenser being operable to:

Receive the refrigerant flow discharged from the compressor;

In response to receiving a refrigerant flow from the compressor, a second outdoor airflow is output, the second ventable airflow being generated by transferring heat from the refrigerant flow received by the compressor.

9. The dehumidification system of claim 1, wherein two or more components selected from the group consisting of the secondary evaporator, the primary evaporator and the secondary condenser are combined into a single coil assembly.

10. The dehumidification system of claim 1, wherein at least one of the primary evaporator and the secondary evaporator comprises two or more loops for refrigerant flow.

11. A dehumidification system, comprising:

A superheat-controlled evaporator is operable to receive an inlet airflow and output a first airflow, the first airflow comprising air colder than the inlet airflow, the first airflow being generated by transferring heat from the inlet airflow to the refrigerant flow as the inlet airflow passes through the superheat-controlled evaporator;

A secondary evaporator is connected in series with the superheat control evaporator and is operable to receive the first airflow and output a second airflow, the second airflow comprising air that is colder than the first airflow, the second airflow being generated by transferring heat from the first airflow to the refrigerant flow as the first airflow passes through the secondary evaporator;

A main evaporator is operable to receive the second airflow and output a third airflow, the third airflow comprising air that is colder than the second airflow, the third airflow being generated by transferring heat from the second airflow to the refrigerant flow as the second airflow passes through the main evaporator;

A secondary condenser, operable to receive the third gas flow and output a fourth gas flow; and

The main condenser is operable to output a venting gas flow.

12. The dehumidification system of claim 11 further includes a subcooling coil operable to receive the fourth airflow and output a fifth airflow, the fifth airflow being generated by transferring heat from the refrigerant flow to the fourth airflow as the fourth airflow passes through the subcooling coil.

13. The dehumidification system according to claim 12, wherein the subcooling coil and the main condenser are combined into a single coil unit.

14. The dehumidification system according to claim 12, wherein the main condenser is further operable to:

15. The dehumidification system of claim 11 further includes a first fan operable to generate the inlet airflow, the first airflow, the second airflow, the third airflow, the fourth airflow, and the exhaust airflow.

16. The dehumidification system according to claim 11 further includes a standby condenser disposed in the external condenser unit, the standby condenser being operable to:

Receive the first outdoor airflow; and

Heat is transferred from the refrigerant flow to the first outdoor airflow to output a second exhaustable airflow.

17. The dehumidification system of claim 16, wherein the external condenser unit further comprises a second fan, the second fan being operable to generate the first outdoor airflow and the second exhaustable airflow.

18. The dehumidification system of claim 11, wherein during a first operating mode, the fourth airflow comprises air that is warmer and less humid than the third airflow, and wherein during a second operating mode, the fourth airflow comprises air with approximately the same temperature and humidity as the third airflow.

19. The dehumidification system of claim 11, wherein at least one of the primary evaporator and the secondary evaporator comprises two or more loops for refrigerant flow.

20. The dehumidification system of claim 11, wherein two or more components selected from the group consisting of the secondary evaporator, the primary evaporator and the secondary condenser are combined into a single coil assembly.