Split dehumidification system with secondary evaporator and condenser coils

A dehumidification system includes a compressor, a primary evaporator, a primary condenser, a secondary evaporator, and a secondary condenser. The secondary evaporator receives an inlet airflow and outputs a first airflow to the primary evaporator. The primary evaporator receives the first airflow and outputs a second airflow to the secondary condenser. The secondary condenser receives the second airflow and outputs a third airflow to the primary condenser. The primary condenser receives the third airflow and outputs a dehumidified airflow. The compressor receives a flow of refrigerant from the primary evaporator and provides the flow of refrigerant to the primary condenser.

BACKGROUND OF THE INVENTION

In certain situations, it is desirable to reduce the humidity of air within a structure. For example, in fire and flood restoration applications, it may be desirable to quickly remove water from areas of a damaged structure. To accomplish this, one or more portable dehumidifiers may be placed within the structure to direct dry air toward water-damaged areas. Current dehumidifiers, however, have proven inefficient in various respects.

SUMMARY OF THE INVENTION

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

In certain embodiments, a dehumidification system comprises a dehumidification unit comprising a primary metering device, a secondary metering device, and a secondary evaporator. The secondary evaporator operable to receive a flow of refrigerant from the primary metering device; and receive an inlet airflow and output a first airflow, the first airflow comprising cooler air than the inlet airflow, the first airflow generated by transferring heat from the inlet airflow to the flow of refrigerant as the inlet airflow passes through the secondary evaporator. The dehumidification unit further comprises a primary evaporator operable to receive the flow of refrigerant from the secondary metering device and receive the first airflow and output a second airflow, the second airflow comprising cooler air than the first airflow, the second airflow generated by transferring heat from the first airflow to the flow of refrigerant as the first airflow passes through the primary evaporator. The dehumidification unit further comprises a secondary condenser operable to receive the flow of refrigerant from the secondary evaporator and receive the second airflow and output a third airflow, the third airflow comprising warmer air with a lower relative humidity than the second airflow, the third airflow generated by transferring heat from the flow of refrigerant to the third airflow as the second airflow passes through the secondary condenser. The dehumidification unit further comprises a compressor operable to receive the flow of refrigerant from the primary evaporator and provide the flow of refrigerant to a primary condenser, the flow of refrigerant provided to the primary condenser comprising a higher pressure than the flow of refrigerant received at the compressor. The dehumidification system further comprises a condenser unit comprising the primary condenser operable to receive the flow of refrigerant from the compressor and transfer heat from the flow of refrigerant to a fourth airflow as the fourth airflow contacts the primary condenser.

Certain embodiments of the present disclosure may provide one or more technical advantages. For example, certain embodiments include two evaporators, two condensers, and two metering devices that utilize a closed refrigeration loop. This configuration causes part of the refrigerant within the system to evaporate and condense twice in one refrigeration cycle, thereby increasing the compressor capacity over typical systems without adding any additional power to the compressor. This, in turn, increases the overall efficiency of the system by providing more dehumidification per kilowatt of power used. The lower humidity of the output airflow may allow for increased drying potential, which may be beneficial in certain applications (e.g., fire and flood restoration).

Certain 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 those skilled in the art from the figures, descriptions, and claims included herein.

DETAILED DESCRIPTION OF THE DRAWINGS

In certain situations, it is desirable to reduce the humidity of air within a structure. For example, in fire and flood restoration applications, it may be desirable to remove water from a damaged structure by placing one or more portable dehumidifiers unit within the structure. As another example, in areas that experience weather with high humidity levels, or in buildings where low humidity levels are required (e.g., libraries), it may be desirable to install a dehumidification unit within a central air conditioning system. Furthermore, it may be necessary to hold a desired humidity level in some commercial applications. Current dehumidifiers, however, have proven inadequate or inefficient in various respects.

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

FIG.1illustrates an example dehumidification system100for supplying dehumidified air106to a structure102, according to certain embodiments. Dehumidification system100includes an evaporator system104located within structure102. Structure102may include all or a portion of a building or other suitable enclosed space, such as an apartment building, a hotel, an office space, a commercial building, or a private dwelling (e.g., a house). Evaporator system104receives inlet air101from within structure102, reduces the moisture in received inlet air101, and supplies dehumidified air106back to structure102. Evaporator system104may distribute dehumidified air106throughout structure102via air ducts, as illustrated.

In general, dehumidification system100is a split system wherein evaporator system104is coupled to a remote condenser system108that is located external to structure102. Remote condenser system108may include a condenser unit112and a compressor unit114that facilitate the functions of evaporator system104by processing a flow of refrigerant as part of a refrigeration cycle. The flow of refrigerant may include any suitable cooling material, such as R410a refrigerant. In certain embodiments, compressor unit114may receive the flow of refrigerant vapor from evaporator system104via a refrigerant line116. Compressor unit114may pressurize the flow of refrigerant, thereby increasing the temperature of the refrigerant. The speed of the compressor may be modulated to effectuate desired operating characteristics. Condenser unit112may receive the pressurized flow of refrigerant vapor from compressor unit114and cool the pressurized refrigerant by facilitating heat transfer from the flow of refrigerant to the ambient air exterior to structure102. In certain embodiments, remote condenser system108may utilize a heat exchanger, such as a microchannel heat exchanger to remove heat from the flow of refrigerant. Remote condenser system108may include a fan that draws ambient air from outside structure102for use in cooling the flow of refrigerant. In certain embodiments, the speed of this fan is modulated to effectuate desired operating characteristics. An illustrative embodiment of an example condenser system is shown, for example, inFIG.7(described in further detail below).

After being cooled and condensed to liquid by condenser unit112, the flow of refrigerant may travel by a refrigerant line118to evaporator system104. In certain embodiments, the flow of refrigerant may be received by an expansion device (described in further detail below) that reduces the pressure of the flow of refrigerant, thereby reducing the temperature of the flow of refrigerant. An evaporator unit (described in further detail below) of evaporator system104may receive the flow of refrigerant from the expansion device and use the flow of refrigerant to dehumidify and cool an incoming airflow. The flow of refrigerant may then flow back to remote condenser system108and repeat this cycle.

In certain embodiments, evaporator system104may be installed in series with an air mover. An air mover may include a fan that blows air from one location to another. An air mover may facilitate distribution of outgoing air from evaporator system104to various parts of structure102. An air mover and evaporator system104may have separate return inlets from which air is drawn. In certain embodiments, outgoing air from evaporator system104may be mixed with air produced by another component (e.g., an air conditioner) and blown through air ducts by the air mover. In other embodiments, evaporator system104may perform both cooling and dehumidifying and thus may be used without a conventional air conditioner.

Although a particular implementation of dehumidification system100is illustrated and primarily described, the present disclosure contemplates any suitable implementation of dehumidification system100, according to particular needs. Moreover, although various components of dehumidification system100have been depicted as being located at particular positions, the present disclosure contemplates those components being positioned at any suitable location, according to particular needs.

FIG.2illustrates an example portable dehumidification system200for reducing the humidity of air within structure102, according to certain embodiments of the present disclosure. Dehumidification system200may be positioned anywhere within structure102in order to direct dehumidified air106towards areas that require dehumidification (e.g., water-damaged areas). In general, dehumidification system200receives inlet airflow101, removes water from the inlet airflow101, and discharges dehumidified air106air back into structure102. In certain embodiments, structure102includes a space that has suffered water damage (e.g., as a result of a flood or fire). In order to restore the water-damaged structure102, one or more dehumidification systems200may be strategically positioned within structure102in order to quickly reduce the humidity of the air within the structure102and thereby dry the portions of structure102that suffered water damage.

Although a particular implementation of portable dehumidification system200is illustrated and primarily described, the present disclosure contemplates any suitable implementation of portable dehumidification system200, according to particular needs. Moreover, although various components of portable dehumidification system200have been depicted as being located at particular positions within structure102, the present disclosure contemplates those components being positioned at any suitable location, according to particular needs.

FIGS.3and4illustrate an example dehumidification system300that may be used by dehumidification system100and portable dehumidification system200ofFIGS.1and2to reduce the humidity of air within structure102. Dehumidification system300includes a primary evaporator310, a primary condenser330, a secondary evaporator340, a secondary condenser320, a compressor360, a primary metering device380, a secondary metering device390, and a fan370. In some embodiments, dehumidification system300may additionally include a sub-cooling coil350. In certain embodiments, sub-cooling coil350and primary condenser330are combined into a single coil. A flow of refrigerant305is circulated through dehumidification system300as illustrated. In general, dehumidification system300receives inlet airflow101, removes water from inlet airflow101, and discharges dehumidified air106. Water is removed from inlet air101using a refrigeration cycle of flow of refrigerant305. By including secondary evaporator340and secondary condenser320, however, dehumidification system300causes at least part of the flow of refrigerant305to evaporate and condense twice in a single refrigeration cycle. This increases the refrigeration capacity over typical systems without adding any additional power to the compressor, thereby increasing the overall dehumidification efficiency of the system.

In general, dehumidification system300attempts to match the saturating temperature of secondary evaporator340to the saturating temperature of secondary condenser320. The saturating temperature of secondary evaporator340and secondary condenser320generally is controlled according to the equation: (temperature of inlet air101+temperature of second airflow315)/2. As the saturating temperature of secondary evaporator340is lower than inlet air101, evaporation happens in secondary evaporator340. As the saturating temperature of secondary condenser320is higher than second airflow315, condensation happens in the secondary condenser320. The amount of refrigerant305evaporating in secondary evaporator340is substantially equal to that condensing in secondary condenser320.

Primary evaporator310receives flow of refrigerant305from secondary metering device390and outputs flow of refrigerant305to compressor360. Primary evaporator310may be any type of coil (e.g., fin tube, micro channel, etc.). Primary evaporator310receives first airflow345from secondary evaporator340and outputs second airflow315to secondary condenser320. Second airflow315, in general, is at a cooler temperature than first airflow345. To cool incoming first airflow345, primary evaporator310transfers heat from first airflow345to flow of refrigerant305, thereby causing flow of refrigerant305to evaporate at least partially from liquid to gas. This transfer of heat from first airflow345to flow of refrigerant305also removes water from first airflow345.

Secondary condenser320receives flow of refrigerant305from secondary evaporator340and outputs flow of refrigerant305to secondary metering device390. Secondary condenser320may be any type of coil (e.g., fin tube, micro channel, etc.). Secondary condenser320receives second airflow315from primary evaporator310and outputs third airflow325. Third airflow325is, in general, warmer and drier (i.e., the dew point will be the same but relative humidity will be lower) than second airflow315. Secondary condenser320generates third airflow325by transferring heat from flow of refrigerant305to second airflow315, thereby causing flow of refrigerant305to condense at least partially from gas to liquid.

Primary condenser330receives flow of refrigerant305from compressor360and outputs flow of refrigerant305to either primary metering device380or sub-cooling coil350. Primary condenser330may be any type of coil (e.g., fin tube, micro channel, etc.). Primary condenser330receives either third airflow325or fourth airflow355and outputs dehumidified air106. Dehumidified air106is, in general, warmer and drier (i.e., have a lower relative humidity) than third airflow325and fourth airflow355. Primary condenser330generates dehumidified air106by transferring heat from flow of refrigerant305, thereby causing flow of refrigerant305to condense at least partially from gas to liquid. In some embodiments, primary condenser330completely condenses flow of refrigerant305to a liquid (i.e., 100% liquid). In other embodiments, primary condenser330partially condenses flow of refrigerant305to a liquid (i.e., less than 100% liquid). In certain embodiments, as shown inFIG.4, a portion of primary condenser330receives a separate airflow in addition to airflow101. For example, the right-most edge of primary condenser330ofFIG.4extends beyond, or overhangs, the right-most edges of secondary evaporator340, primary evaporator310, secondary condenser320, and sub-cooling coil350. This overhanging portion of primary condenser330may receive an additional separate airflow.

Secondary evaporator340receives flow of refrigerant305from primary metering device380and outputs flow of refrigerant305to secondary condenser320. Secondary evaporator340may be any type of coil (e.g., fin tube, micro channel, etc.). Secondary evaporator340receives inlet air101and outputs first airflow345to primary evaporator310. First airflow345, in general, is at a cooler temperature than inlet air101. To cool incoming inlet air101, secondary evaporator340transfers heat from inlet air101to flow of refrigerant305, thereby causing flow of refrigerant305to evaporate at least partially from liquid to gas.

Sub-cooling coil350, which is an optional component of dehumidification system300, sub-cools the liquid refrigerant305as it leaves primary condenser330. This, in turn, supplies primary metering device380with a liquid refrigerant that is up to 30 degrees (or more) cooler than before it enters sub-cooling coil350. For example, if flow of refrigerant305entering sub-cooling coil350is 340 psig/105° F./60% vapor, flow of refrigerant305may be 340 psig/80° F./0% vapor as it leaves sub-cooling coil350. The sub-cooled refrigerant305has a greater heat enthalpy factor as well as a greater density, which results in reduced cycle times and frequency of the evaporation cycle of flow of refrigerant305. This results in greater efficiency and less energy use of dehumidification system300. Embodiments of dehumidification system300may or may not include a sub-cooling coil350. For example, embodiments of dehumidification system300utilized within portable dehumidification system200that have a microchannel condenser330or320may include a sub-cooling coil350, while embodiments of dehumidification system300that utilize another type of condenser330or320may not include a sub-cooling coil350. As another example, dehumidification system300utilized within a split system such as dehumidification system100may not include a sub-cooling coil350.

Compressor360pressurizes flow of refrigerant305, thereby increasing the temperature of refrigerant305. For example, if flow of refrigerant305entering compressor360is 128 psig/52° F./100% vapor, flow of refrigerant305may be 340 psig/150° F./100% vapor as it leaves compressor360. Compressor360receives flow of refrigerant305from primary evaporator310and supplies the pressurized flow of refrigerant305to primary condenser330.

Fan370may include any suitable components operable to draw inlet air101into dehumidification system300and through secondary evaporator340, primary evaporator310, secondary condenser320, sub-cooling coil350, and primary condenser330. Fan370may be any type of air mover (e.g., axial fan, forward inclined impeller, and backward inclined impeller, etc.). For example, fan370may be a backward inclined impeller positioned adjacent to primary condenser330as illustrated inFIG.3. While fan370is depicted inFIG.3as being located adjacent to primary condenser330, it should be understood that fan370may be located anywhere along the airflow path of dehumidification system300. For example, fan370may be positioned in the airflow path of any one of airflows101,345,315,325,355, or106. Moreover, dehumidification system300may include one or more additional fans positioned within any one or more of these airflow paths.

Primary metering device380and secondary metering device390are any appropriate type of metering/expansion device. In some embodiments, primary metering device380is a thermostatic expansion valve (TXV) and secondary metering device390is a fixed orifice device (or vice versa). In certain embodiments, metering devices380and390remove pressure from flow of refrigerant305to allow expansion or change of state from a liquid to a vapor in evaporators310and340. The high-pressure liquid (or mostly liquid) refrigerant entering metering devices380and390is at a higher temperature than the liquid refrigerant305leaving metering devices380and390. For example, if flow of refrigerant305entering primary metering device380is 340 psig/80° F./0% vapor, flow of refrigerant305may be 196 psig/68° F./5% vapor as it leaves primary metering device380. As another example, if flow of refrigerant305entering secondary metering device390is 196 psig/68° F./4% vapor, flow of refrigerant305may be 128 psig/44° F./14% vapor as it leaves secondary metering device390.

Refrigerant305may be any suitable refrigerant such as R410a. In general, dehumidification system300utilizes a closed refrigeration loop of refrigerant305that passes from compressor360through primary condenser330, (optionally) sub-cooling coil350, primary metering device380, secondary evaporator340, secondary condenser320, secondary metering device390, and primary evaporator310. Compressor360pressurizes flow of refrigerant305, thereby increasing the temperature of refrigerant305. Primary and secondary condensers330and320, which may include any suitable heat exchangers, cool the pressurized flow of refrigerant305by facilitating heat transfer from the flow of refrigerant305to the respective airflows passing through them (i.e., fourth airflow355and second airflow315). The cooled flow of refrigerant305leaving primary and secondary condensers330and320may enter a respective expansion device (i.e., primary metering device380and secondary metering device390) that is operable to reduce the pressure of flow of refrigerant305, thereby reducing the temperature of flow of refrigerant305. Primary and secondary evaporators310and340, which may include any suitable heat exchanger, receive flow of refrigerant305from secondary metering device390and primary metering device380, respectively. Primary and secondary evaporators310and340facilitate the transfer of heat from the respective airflows passing through them (i.e., inlet air101and first airflow345) to flow of refrigerant305. Flow of refrigerant305, after leaving primary evaporator310, passes back to compressor360, and the cycle is repeated.

In certain embodiments, the above-described refrigeration loop may be configured such that evaporators310and340operate in a flooded state. In other words, flow of refrigerant305may enter evaporators310and340in a liquid state, and a portion of flow of refrigerant305may still be in a liquid state as it exits evaporators310and340. Accordingly, the phase change of flow of refrigerant305(liquid to vapor as heat is transferred to flow of refrigerant305) occurs across evaporators310and340, resulting in nearly constant pressure and temperature across the entire evaporators310and340(and, as a result, increased cooling capacity).

In operation of example embodiments of dehumidification system300, inlet air101may be drawn into dehumidification system300by fan370. Inlet air101passes though secondary evaporator340in which heat is transferred from inlet air101to the cool flow of refrigerant305passing through secondary evaporator340. As a result, inlet air101may be cooled. As an example, if inlet air101is 80° F./60% humidity, secondary evaporator340may output first airflow345at 70° F./84% humidity. This may cause flow of refrigerant305to partially vaporize within secondary evaporator340. For example, if flow of refrigerant305entering secondary evaporator340is 196 psig/68° F./5% vapor, flow of refrigerant305may be 196 psig/68° F./38% vapor as it leaves secondary evaporator340.

The cooled inlet air101leaves secondary evaporator340as first airflow345and enters primary evaporator310. Like secondary evaporator340, primary evaporator310transfers heat from first airflow345to the cool flow of refrigerant305passing through primary evaporator310. As a result, first airflow345may be cooled to or below its dew point temperature, causing moisture in first airflow345to condense (thereby reducing the absolute humidity of first airflow345). As an example, if first airflow345is 70° F./84% humidity, primary evaporator310may output second airflow315at 54° F./98% humidity. This may cause flow of refrigerant305to partially or completely vaporize within primary evaporator310. For example, if flow of refrigerant305entering primary evaporator310is 128 psig/44° F./14% vapor, flow of refrigerant305may be 128 psig/52° F./100% vapor as it leaves primary evaporator310. In certain embodiments, the liquid condensate from first airflow345may be collected in a drain pan connected to a condensate reservoir, as illustrated inFIG.4. Additionally, the condensate reservoir may include a condensate pump that moves collected condensate, either continually or at periodic intervals, out of dehumidification system300(e.g., via a drain hose) to a suitable drainage or storage location.

The cooled first airflow345leaves primary evaporator310as second airflow315and enters secondary condenser320. Secondary condenser320facilitates heat transfer from the hot flow of refrigerant305passing through the secondary condenser320to second airflow315. This reheats second airflow315, thereby decreasing the relative humidity of second airflow315. As an example, if second airflow315is 54° F./98% humidity, secondary condenser320may output third airflow325at 65° F./68% humidity. This may cause flow of refrigerant305to partially or completely condense within secondary condenser320. For example, if flow of refrigerant305entering secondary condenser320is 196 psig/68° F./38% vapor, flow of refrigerant305may be 196 psig/68° F./4% vapor as it leaves secondary condenser320.

In some embodiments, the dehumidified second airflow315leaves secondary condenser320as third airflow325and enters primary condenser330. Primary condenser330facilitates heat transfer from the hot flow of refrigerant305passing through the primary condenser330to third airflow325. This further heats third airflow325, thereby further decreasing the relative humidity of third airflow325. As an example, if third airflow325is 65° F./68% humidity, secondary condenser320may output dehumidified air106at 102° F./19% humidity. This may cause flow of refrigerant305to partially or completely condense within primary condenser330. For example, if flow of refrigerant305entering primary condenser330is 340 psig/150° F./100% vapor, flow of refrigerant305may be 340 psig/105° F./60% vapor as it leaves primary condenser330.

As described above, some embodiments of dehumidification system300may include a sub-cooling coil350in the airflow between secondary condenser320and primary condenser330. Sub-cooling coil350facilitates heat transfer from the hot flow of refrigerant305passing through sub-cooling coil350to third airflow325. This further heats third airflow325, thereby further decreasing the relative humidity of third airflow325. As an example, if third airflow325is 65° F./68% humidity, sub-cooling coil350may output fourth airflow355at 81° F./37% humidity. This may cause flow of refrigerant305to partially or completely condense within sub-cooling coil350. For example, if flow of refrigerant305entering sub-cooling coil350is 340 psig/150° F./60% vapor, flow of refrigerant305may be 340 psig/80° F./0% vapor as it leaves sub-cooling coil350.

Some embodiments of dehumidification system300may include a controller that may include one or more computer systems at one or more locations. Each computer system may include any appropriate input devices (such as a keypad, touch screen, mouse, or other device that can accept information), output devices, mass storage media, or other suitable components for receiving, processing, storing, and communicating data. Both the input devices and output devices may include fixed or removable storage media such as a magnetic computer disk, CD-ROM, or other suitable media to both receive input from and provide output to a user. Each computer system may include a personal computer, workstation, network computer, kiosk, wireless data port, personal data assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. In short, the controller may include any suitable combination of software, firmware, and hardware.

The controller may additionally include one or more processing modules. Each processing module may each include one or more microprocessors, controllers, or any other suitable computing devices or resources and may work, either alone or with other components of dehumidification system300, to provide a portion or all of the functionality described herein. The controller may additionally include (or be communicatively coupled to via wireless or wireline communication) computer memory. The memory may include any memory or database module and may take the form of volatile or non-volatile memory, including, without limitation, 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 implementations of dehumidification system300are illustrated and primarily described, the present disclosure contemplates any suitable implementation of dehumidification system300, according to particular needs. Moreover, although various components of dehumidification system300have been depicted as being located at particular positions and relative to one another, the present disclosure contemplates those components being positioned at any suitable location, according to particular needs.

FIG.5illustrates an example dehumidification method500that may be used by dehumidification system100and portable dehumidification system200ofFIGS.1and2to reduce the humidity of air within structure102. Method500may begin in step510where a secondary evaporator receives an inlet airflow and outputs a first airflow. In some embodiments, the secondary evaporator is secondary evaporator340. In some embodiments, the inlet airflow is inlet air101and the first airflow is first airflow345. In some embodiments, the secondary evaporator of step510receives a flow of refrigerant from a primary metering device such as primary metering device380and supplies the flow of refrigerant (in a changed state) to a secondary condenser such as secondary condenser320. In some embodiments, the flow of refrigerant of method500is flow of refrigerant305described above.

At step520, a primary evaporator receives the first airflow of step510and outputs a second airflow. In some embodiments, the primary evaporator is primary evaporator310and the second airflow is second airflow315. In some embodiments, the primary evaporator of step520receives the flow of refrigerant from a secondary metering device such as secondary metering device390and supplies the flow of refrigerant (in a changed state) to a compressor such as compressor360.

At step530, a secondary condenser receives the second airflow of step520and outputs a third airflow. In some embodiments, the secondary condenser is secondary condenser320and the third airflow is third airflow325. In some embodiments, the secondary condenser of step530receives a flow of refrigerant from the secondary evaporator of step510and supplies the flow of refrigerant (in a changed state) to a secondary metering device such as secondary metering device390.

At step540, a primary condenser receives the third airflow of step530and outputs a dehumidified airflow. In some embodiments, the primary condenser is primary condenser330and the dehumidified airflow is dehumidified air106. In some embodiments, the primary condenser of step540receives a flow of refrigerant from the compressor of step520and supplies the flow of refrigerant (in a changed state) to the primary metering device of step510. In alternate embodiments, the primary condenser of step540supplies the flow of refrigerant (in a changed state) to a sub-cooling coil such as sub-cooling coil350which in turn supplies the flow of refrigerant (in a changed state) to the primary metering device of step510.

At step550, a compressor receives the flow of refrigerant from the primary evaporator of step520and provides the flow of refrigerant (in a changed state) to the primary condenser of step540. After step550, method500may end.

Particular embodiments may repeat one or more steps of method500ofFIG.5, where appropriate. Although this disclosure describes and illustrates particular steps of the method ofFIG.5as occurring in a particular order, this disclosure contemplates any suitable steps of the method ofFIG.5occurring in any suitable order. Moreover, although this disclosure describes and illustrates an example dehumidification method for reducing the humidity of air within a structure including the particular steps of the method ofFIG.5, this disclosure contemplates any suitable method for reducing the humidity of air within a structure including any suitable steps, which may include all, some, or none of the steps of the method ofFIG.5, where appropriate. Furthermore, although this disclosure describes and illustrates particular components, devices, or systems carrying out particular steps of the method ofFIG.5, this disclosure contemplates any suitable combination of any suitable components, devices, or systems carrying out any suitable steps of the method ofFIG.5.

While the example method ofFIG.5is described at times above with respect to dehumidification system300ofFIG.3, it should be understood that the same or similar methods can be carried out using any of the dehumidification systems described herein, including dehumidification systems600and800ofFIGS.6A-6B and8(described below). Moreover, it should be understood that, with respect to the example method ofFIG.5, reference to an evaporator or condenser can refer to an evaporator portion or condenser portion of a single coil pack operable to perform the functions of these components, for example, as described above with respect to examples ofFIGS.9and10.

FIGS.6A and6Billustrate an example air conditioning and dehumidification system600that may be used in accordance with split dehumidification system100ofFIG.1to reduce the humidity of air within structure102. Dehumidification system600includes a dehumidification unit602, which is generally indoors, and a condenser system604(e.g., condenser system108ofFIG.1). As illustrated inFIG.6A, dehumidification unit602includes a primary evaporator610, a secondary evaporator640, a secondary condenser620, a primary metering device680, a secondary metering device690, and a first fan670, while condenser system604includes a primary condenser630, a compressor660, an optional sub-cooling coil650and a second fan695. In the embodiment illustrated inFIG.6B, the compressor660may be disposed within the dehumidification unit602rather than disposed within the condenser system604.

With reference to bothFIGS.6A and6B, a flow of refrigerant605is circulated through dehumidification system600as illustrated. In general, dehumidification unit602receives inlet airflow601, removes water from inlet airflow601, and discharges dehumidified air625into a conditioned space. Water is removed from inlet air601using a refrigeration cycle of flow of refrigerant605. The flow of refrigerant605through system600ofFIGS.6A AND6Bproceeds in a similar manner to that of the flow of refrigerant305through dehumidification system300ofFIG.3. However, the path of airflow through system600is different than that through system300, as described herein. By including secondary evaporator640and secondary condenser620, however, dehumidification system600causes at least part of the flow of refrigerant605to evaporate and condense twice in a single refrigeration cycle. This increases refrigerating capacity over typical systems without requiring any additional power to the compressor, thereby increasing the overall efficiency of the system.

The split configuration of system600, which includes dehumidification unit602and condenser system604, allows heat from the cooling and dehumidification process to be rejected outdoors or to an unconditioned space (e.g., external to a space being dehumidified). This allows dehumidification system600to have a similar footprint to that of typical central air conditioning systems or heat pumps. In general, the temperature of third airflow625output to the conditioned space from system600is significantly decreased compared to that of airflow106output from system300ofFIG.3. Thus, the configuration of system600allows dehumidified air to be provided to the conditioned space at a decreased temperature. Accordingly, system600may perform functions of both a dehumidifier (dehumidifying air) and a central air conditioner (cooling air).

In general, dehumidification system600attempts to match the saturating temperature of secondary evaporator640to the saturating temperature of secondary condenser620. The saturating temperature of secondary evaporator640and secondary condenser620generally is controlled according to the equation: (temperature of inlet air601+temperature of second airflow615)/2. As the saturating temperature of secondary evaporator640is lower than inlet air601, evaporation happens in secondary evaporator640. As the saturating temperature of secondary condenser620is higher than second airflow615, condensation happens in secondary condenser620. The amount of refrigerant605evaporating in secondary evaporator640is substantially equal to that condensing in secondary condenser620.

Primary evaporator610receives flow of refrigerant605from secondary metering device690and outputs flow of refrigerant605to compressor660. Primary evaporator610may be any type of coil (e.g., fin tube, micro channel, etc.). Primary evaporator610receives first airflow645from secondary evaporator640and outputs second airflow615to secondary condenser620. Second airflow615, in general, is at a cooler temperature than first airflow645. To cool incoming first airflow645, primary evaporator610transfers heat from first airflow645to flow of refrigerant605, thereby causing flow of refrigerant605to evaporate at least partially from liquid to gas. This transfer of heat from first airflow645to flow of refrigerant605also removes water from first airflow645.

Secondary condenser620receives flow of refrigerant605from secondary evaporator640and outputs flow of refrigerant605to secondary metering device690. Secondary condenser620may be any type of coil (e.g., fin tube, micro channel, etc.). Secondary condenser620receives second airflow615from primary evaporator610and outputs third airflow625. Third airflow625is, in general, warmer and drier (i.e., the dew point will be the same but relative humidity will be lower) than second airflow615. Secondary condenser620generates third airflow625by transferring heat from flow of refrigerant605to second airflow615, thereby causing flow of refrigerant605to condense at least partially from gas to liquid. As described above, third airflow625is output into the conditioned space. In other embodiments (e.g., as shown inFIGS.8Aand8B), third airflow625may first pass through and/or over sub-cooling coil650before being output into the conditioned space at a further decreased relative humidity.

As shown inFIG.6A, refrigerant605flows outdoors or to an unconditioned space to compressor660of condenser system604. Alternatively, the refrigerant605may continue to flow to the compressor660within the dehumidification unit602prior to flowing outdoors or to an unconditioned space, as seen inFIG.6B. In bothFIGS.6A and6B, compressor660pressurizes flow of refrigerant605, thereby increasing the temperature of refrigerant605. For example, if flow of refrigerant605entering compressor660is 128 psig/52° F./100% vapor, flow of refrigerant605may be 340 psig/150° F./100% vapor as it leaves compressor660. Compressor660receives flow of refrigerant605from primary evaporator610and supplies the pressurized flow of refrigerant605to primary condenser630.

Primary condenser630receives flow of refrigerant605from compressor660and outputs flow of refrigerant605to sub-cooling coil650. Primary condenser630may be any type of coil (e.g., fin tube, micro channel, etc.). Primary condenser630and sub-cooling coil650receive first outdoor airflow606and output second outdoor airflow608. Second outdoor airflow608is, in general, warmer (i.e., have a lower relative humidity) than first outdoor airflow606. Primary condenser630transfers heat from flow of refrigerant605, thereby causing flow of refrigerant605to condense at least partially from gas to liquid. In some embodiments, primary condenser630completely condenses flow of refrigerant605to a liquid (i.e., 100% liquid). In other embodiments, primary condenser630partially condenses flow of refrigerant605to a liquid (i.e., less than 100% liquid).

Sub-cooling coil650, which is an optional component of dehumidification system600, sub-cools the liquid refrigerant605as it leaves primary condenser630. This, in turn, supplies primary metering device680with a liquid refrigerant that is 30 degrees (or more) cooler than before it enters sub-cooling coil650. For example, if flow of refrigerant605entering sub-cooling coil650is 340 psig/105° F./60% vapor, flow of refrigerant605may be 340 psig/80° F./0% vapor as it leaves sub-cooling coil650. The sub-cooled refrigerant605has a greater heat enthalpy factor as well as a greater density, which improves energy transfer between airflow and evaporator resulting in the removal of further latent heat from refrigerant605. This further results in greater efficiency and less energy use of dehumidification system600. Embodiments of dehumidification system600may or may not include a sub-cooling coil650.

In certain embodiments, sub-cooling coil650and primary condenser630are combined into a single coil. Such a single coil includes appropriate circuiting for flow of airflows606and608and refrigerant605. An illustrative example of a condenser system604comprising a single coil condenser and sub-cooling coil is shown inFIG.7. The single unit coil comprises interior tubes710corresponding to the condenser and exterior tubes705corresponding to the sub-cooling coil. Refrigerant may be directed through the interior tubes710before flowing through exterior tubes705. In the illustrative example shown inFIG.7, airflow is drawn through the single unit coil by fan695and expelled upwards. It should be understood, however, that condenser systems of other embodiments can include a condenser, compressor, optional sub-cooling coil, and fan with other configurations known in the art.

Secondary evaporator640receives flow of refrigerant605from primary metering device680and outputs flow of refrigerant605to secondary condenser620. Secondary evaporator640may be any type of coil (e.g., fin tube, micro channel, etc.). Secondary evaporator640receives inlet air601and outputs first airflow645to primary evaporator610. First airflow645, in general, is at a cooler temperature than inlet air601. To cool incoming inlet air601, secondary evaporator640transfers heat from inlet air601to flow of refrigerant605, thereby causing flow of refrigerant605to evaporate at least partially from liquid to gas.

Fan670may include any suitable components operable to draw inlet air601into dehumidification unit602and through secondary evaporator640, primary evaporator610, and secondary condenser620. Fan670may be any type of air mover (e.g., axial fan, forward inclined impeller, and backward inclined impeller, etc.). For example, fan670may be a backward inclined impeller positioned adjacent to secondary condenser620.

While fan670is depicted inFIGS.6A and6Bas being located adjacent to condenser620, it should be understood that fan670may be located anywhere along the airflow path of dehumidification unit602. For example, fan670may be positioned in the airflow path of any one of airflows601,645,615, or625. Moreover, dehumidification unit602may include one or more additional fans positioned within any one or more of these airflow paths. Similarly, while fan695of condenser system604is depicted inFIGS.6A and6Bas being located above primary condenser630, it should be understood that fan695may be located anywhere (e.g., above, below, beside) with respect to condenser630and sub-cooling coil650, so long fan695is appropriately positioned and configured to facilitate flow of airflow606towards primary condenser630and sub-cooling coil650.

The rate of airflow generated by fan670may be different than that generated by fan695. For example, the flow rate of airflow606generated by fan695may be higher than the flow rate of airflow601generated by fan670. This difference in flow rates may provide several advantages for the dehumidification systems described herein. For example, a large airflow generated by fan695may provide for improved heat transfer at the sub-cooling coil650and primary condenser630of the condenser system604. In general, the rate of airflow generated by second fan695is between about 2-times to 5-times that of the rate of airflow generated by first fan670. For example, the rate of airflow generated by first fan670may be from about 200 to 400 cubic feet per minute (cfm). For example, the rate of airflow generated by second fan695may be from about 900 to 1200 cubic feet per minute (cfm).

Primary metering device680and secondary metering device690are any appropriate type of metering/expansion device. In some embodiments, primary metering device680is a thermostatic expansion valve (TXV) and secondary metering device690is a fixed orifice device (or vice versa). In certain embodiments, metering devices680and690remove pressure from flow of refrigerant605to allow expansion or change of state from a liquid to a vapor in evaporators610and640. The high-pressure liquid (or mostly liquid) refrigerant entering metering devices680and690is at a higher temperature than the liquid refrigerant605leaving metering devices680and690. For example, if flow of refrigerant605entering primary metering device680is 340 psig/80° F./0% vapor, flow of refrigerant605may be 196 psig/68° F./5% vapor as it leaves primary metering device680. As another example, if flow of refrigerant605entering secondary metering device690is 196 psig/68° F./4% vapor, flow of refrigerant605may be 128 psig/44° F./14% vapor as it leaves secondary metering device690.

In certain embodiments, secondary metering device690is operated in a substantially open state (referred to herein as a “fully open” state) such that the pressure of refrigerant605entering metering device690is substantially the same as the pressure of refrigerant605exiting metering device605. For example, the pressure of refrigerant605may be 80%, 90%, 95%, 99%, or up to 100% of the pressure of refrigerant605entering metering device690. With the secondary metering device690operated in a “fully open” state, primary metering device680is the primary source of pressure drop in dehumidification system600. In this configuration, airflow615is not substantially heated when it passes through secondary condenser620, and the secondary evaporator640, primary evaporator610, and secondary condenser620effectively act as a single evaporator. Although, less water may be removed from airflow601when the secondary metering device690is operated in a “fully open” state, airflow606will be output to the conditioned space at a lower temperature than when secondary metering device690is not in a “fully open” state. This configuration corresponds to a relatively high sensible heat ratio (SHR) operating mode such that dehumidification system600may produce a cool airflow625with properties similar to those of an airflow produced by a central air conditioner. If the rate of airflow601is increased to a threshold value (e.g., by increasing the speed of fan670or one or more other fans of dehumidification system600), dehumidification system600may perform sensible cooling without removing water from airflow601.

Refrigerant605may be any suitable refrigerant such as R410a. In general, dehumidification system600utilizes a closed refrigeration loop of refrigerant605that passes from compressor660through primary condenser630, (optionally) sub-cooling coil650, primary metering device680, secondary evaporator640, secondary condenser620, secondary metering device690, and primary evaporator610. Compressor660pressurizes flow of refrigerant605, thereby increasing the temperature of refrigerant605. Primary and secondary condensers630and620, which may include any suitable heat exchangers, cool the pressurized flow of refrigerant605by facilitating heat transfer from the flow of refrigerant605to the respective airflows passing through them (i.e., first outdoor airflow606and second airflow615). The cooled flow of refrigerant605leaving primary and secondary condensers630and620may enter a respective expansion device (i.e., primary metering device680and secondary metering device690) that is operable to reduce the pressure of flow of refrigerant605, thereby reducing the temperature of flow of refrigerant605. Primary and secondary evaporators610and640, which may include any suitable heat exchanger, receive flow of refrigerant605from secondary metering device690and primary metering device680, respectively. Primary and secondary evaporators610and640facilitate the transfer of heat from the respective airflows passing through them (i.e., inlet air601and first airflow645) to flow of refrigerant605. Flow of refrigerant605, after leaving primary evaporator610, passes back to compressor660, and the cycle is repeated.

In certain embodiments, the above-described refrigeration loop may be configured such that evaporators610and640operate in a flooded state. In other words, flow of refrigerant605may enter evaporators610and640in a liquid state, and a portion of flow of refrigerant605may still be in a liquid state as it exits evaporators610and640. Accordingly, the phase change of flow of refrigerant605(liquid to vapor as heat is transferred to flow of refrigerant605) occurs across evaporators610and640, resulting in nearly constant pressure and temperature across the entire evaporators610and640(and, as a result, increased cooling capacity).

In operation of example embodiments of dehumidification system600, inlet air601may be drawn into dehumidification system600by fan670. Inlet air601passes though secondary evaporator640in which heat is transferred from inlet air601to the cool flow of refrigerant605passing through secondary evaporator640. As a result, inlet air601may be cooled. As an example, if inlet air601is 80° F./60% humidity, secondary evaporator640may output first airflow645at 70° F./84% humidity. This may cause flow of refrigerant605to partially vaporize within secondary evaporator640. For example, if flow of refrigerant605entering secondary evaporator640is 196 psig/68° F./5% vapor, flow of refrigerant605may be 196 psig/68° F./38% vapor as it leaves secondary evaporator640.

The cooled inlet air601leaves secondary evaporator640as first airflow645and enters primary evaporator610. Like secondary evaporator640, primary evaporator610transfers heat from first airflow645to the cool flow of refrigerant605passing through primary evaporator610. As a result, first airflow645may be cooled to or below its dew point temperature, causing moisture in first airflow645to condense (thereby reducing the absolute humidity of first airflow645). As an example, if first airflow645is 70° F./84% humidity, primary evaporator610may output second airflow615at 54° F./98% humidity. This may cause flow of refrigerant605to partially or completely vaporize within primary evaporator610. For example, if flow of refrigerant605entering primary evaporator610is 128 psig/44° F./14% vapor, flow of refrigerant605may be 128 psig/52° F./100% vapor as it leaves primary evaporator610. In certain embodiments, the liquid condensate from first airflow645may be collected in a drain pan connected to a condensate reservoir, as illustrated inFIG.4. Additionally, the condensate reservoir may include a condensate pump that moves collected condensate, either continually or at periodic intervals, out of dehumidification system600(e.g., via a drain hose) to a suitable drainage or storage location.

The cooled first airflow645leaves primary evaporator610as second airflow615and enters secondary condenser620. Secondary condenser620facilitates heat transfer from the hot flow of refrigerant605passing through the secondary condenser620to second airflow615. This reheats second airflow615, thereby decreasing the relative humidity of second airflow615. As an example, if second airflow615is 54° F./98% humidity, secondary condenser620may output dehumidified airflow625at 65° F./68% humidity. This may cause flow of refrigerant605to partially or completely condense within secondary condenser620. For example, if flow of refrigerant605entering secondary condenser620is 196 psig/68° F./38% vapor, flow of refrigerant605may be 196 psig/68° F./4% vapor as it leaves secondary condenser620. In some embodiments, second airflow615leaves secondary condenser620as dehumidified airflow625and is output to a conditioned space.

Primary condenser630facilitates heat transfer from the hot flow of refrigerant605passing through the primary condenser630to a first outdoor airflow606. This heats outdoor airflow606, which is output to the unconditioned space (e.g., outdoors) as second outdoor airflow608. As an example, if first outdoor airflow606is 65° F./68% humidity, primary condenser630may output second outdoor airflow608at 102° F./19% humidity. This may cause flow of refrigerant605to partially or completely condense within primary condenser630. For example, if flow of refrigerant605entering primary condenser630is 340 psig/150° F./100% vapor, flow of refrigerant605may be 340 psig/105° F./60% vapor as it leaves primary condenser630.

As described above, some embodiments of dehumidification system600may include a sub-cooling coil650in the airflow between an inlet of the condenser system604and primary condenser630. Sub-cooling coil650facilitates heat transfer from the hot flow of refrigerant605passing through sub-cooling coil650to first outdoor airflow606. This heats first outdoor airflow606, thereby increasing the temperature of first outdoor airflow606. As an example, if first outdoor airflow606is 65° F./68% humidity, sub-cooling coil650may output an airflow at 81° F./37% humidity. This may cause flow of refrigerant605to partially or completely condense within sub-cooling coil650. For example, if flow of refrigerant605entering sub-cooling coil650is 340 psig/150° F./60% vapor, flow of refrigerant605may be 340 psig/80° F./0% vapor as it leaves sub-cooling coil650.

In the embodiment depicted inFIGS.6A and6B, sub-cooling coil650is within condenser system604. This configuration minimizes the temperature of third airflow625, which is output into the conditioned space. An alternative embodiment is shown as dehumidification system800ofFIGS.8A and8Bin which dehumidification unit802includes sub-cooling coil650. In these embodiments, airflow625first passes through sub-cooling coil650before being output to the conditioned space as airflow855via fan670. As described herein, fan670can alternatively be located anywhere along the path of airflow in dehumidification unit802, and one or more additional fans can be included in dehumidification unit802.

Without wishing to be bound to any particular theory, the configuration of dehumidification system800is believed to be more energy efficient under common operating conditions than that of dehumidification system600ofFIGS.6A-6B. For example, if the temperature of third airflow625is less than the outdoor temperature (i.e., the temperature of airflow606), then refrigerant605will be more effectively cooled, or sub-cooled, with sub-cooling coil650placed in the dehumidification unit802. Such operating conditions may be common, for example, in locations with warm climates and/or during summer months. As illustrated inFIG.8B, indoor dehumidification unit802also includes compressor660, which may, for example, be located near secondary evaporator640, primary evaporator610, and/or secondary condenser620. In certain embodiments, the dehumidification unit802may comprise the compressor660, but the dehumidification system800may lack the optional sub-cooling coil650, as illustrated inFIG.8C. The dehumidification system800ofFIG.8Cmay not require the sub-cooling coil650if, for example, the primary condenser630is operable to facilitate heat transfer from the flow of refrigerant605to a first outdoor airflow606in order to effectively condense the refrigerant prior to the flow of refrigerant entering a primary metering device680.

In operation of example embodiments of dehumidification system800, as illustrated in each ofFIGS.8A-8C, inlet air601may be drawn into dehumidification system800by fan670. Inlet air601passes though secondary evaporator640in which heat is transferred from inlet air601to the cool flow of refrigerant605passing through secondary evaporator640. As a result, inlet air601may be cooled. As an example, if inlet air601is 80° F./60% humidity, secondary evaporator640may output first airflow645at 70° F./84% humidity. This may cause flow of refrigerant605to partially vaporize within secondary evaporator640. For example, if flow of refrigerant605entering secondary evaporator640is 196 psig/68° F./5% vapor, flow of refrigerant605may be 196 psig/68° F./38% vapor as it leaves secondary evaporator640.

The cooled inlet air601leaves secondary evaporator640as first airflow645and enters primary evaporator610. Like secondary evaporator640, primary evaporator610transfers heat from first airflow645to the cool flow of refrigerant605passing through primary evaporator610. As a result, first airflow645may be cooled to or below its dew point temperature, causing moisture in first airflow645to condense (thereby reducing the absolute humidity of first airflow645). As an example, if first airflow645is 70° F./84% humidity, primary evaporator610may output second airflow615at 54° F./98% humidity. This may cause flow of refrigerant605to partially or completely vaporize within primary evaporator610. For example, if flow of refrigerant605entering primary evaporator610is 128 psig/44° F./14% vapor, flow of refrigerant605may be 128 psig/52° F./100% vapor as it leaves primary evaporator610. In certain embodiments, the liquid condensate from first airflow645may be collected in a drain pan connected to a condensate reservoir, as illustrated inFIG.4. Additionally, the condensate reservoir may include a condensate pump that moves collected condensate, either continually or at periodic intervals, out of dehumidification system800(e.g., via a drain hose) to a suitable drainage or storage location.

The cooled first airflow645leaves primary evaporator610as second airflow615and enters secondary condenser620. Secondary condenser620facilitates heat transfer from the hot flow of refrigerant605passing through the secondary condenser620to second airflow615. This reheats second airflow615, thereby decreasing the relative humidity of second airflow615. As an example, if second airflow615is 54° F./98% humidity, secondary condenser620may output dehumidified airflow625at 65° F./68% humidity. This may cause flow of refrigerant605to partially or completely condense within secondary condenser620. For example, if flow of refrigerant605entering secondary condenser620is 196 psig/68° F./38% vapor, flow of refrigerant605may be 196 psig/68° F./4% vapor as it leaves secondary condenser620. In some embodiments, second airflow615leaves secondary condenser620as dehumidified airflow625and is output to a conditioned space.

With reference back to each ofFIGS.8A-8C, primary condenser630facilitates heat transfer from the hot flow of refrigerant605passing through the primary condenser630to a first outdoor airflow606. This heats outdoor airflow606, which is output to the unconditioned space as second outdoor airflow608. As an example, if first outdoor airflow606is 65° F./68% humidity, primary condenser630may output second outdoor airflow608at 102° F./19% humidity. This may cause flow of refrigerant605to partially or completely condense within primary condenser630. For example, if flow of refrigerant605entering primary condenser630is 340 psig/150° F./100% vapor, flow of refrigerant605may be 340 psig/105° F./60% vapor as it leaves primary condenser630.

Some embodiments of dehumidification systems600and800ofFIGS.6A-6B and8A-8Cmay include a controller that may include one or more computer systems at one or more locations. Each computer system may include any appropriate input devices (such as a keypad, touch screen, mouse, or other device that can accept information), output devices, mass storage media, or other suitable components for receiving, processing, storing, and communicating data. Both the input devices and output devices may include fixed or removable storage media such as a magnetic computer disk, CD-ROM, or other suitable media to both receive input from and provide output to a user. Each computer system may include a personal computer, workstation, network computer, kiosk, wireless data port, personal data assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. In short, the controller may include any suitable combination of software, firmware, and hardware.

The controller may additionally include one or more processing modules. Each processing module may each include one or more microprocessors, controllers, or any other suitable computing devices or resources and may work, either alone or with other components of dehumidification systems600and800, to provide a portion or all of the functionality described herein. The controller may additionally include (or be communicatively coupled to via wireless or wireline communication) computer memory. The memory may include any memory or database module and may take the form of volatile or non-volatile memory, including, without limitation, 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 implementations of dehumidification systems600and800are illustrated and primarily described, the present disclosure contemplates any suitable implementation of dehumidification systems600and800, according to particular needs. Moreover, although various components of dehumidification systems600and800have been depicted as being located at particular positions and relative to one another, the present disclosure contemplates those components being positioned at any suitable location, according to particular needs.

In certain embodiments, the secondary evaporator (340,640), primary evaporator (310,610), and secondary condenser (320,620) ofFIG.3,6A-6B, or8A-8C are combined in a single coil pack. The single coil pack may include portions (e.g., separate refrigerant circuits) to accommodate the respective functions of secondary evaporator, primary evaporator, and secondary condenser, described above. An illustrative example of such a single coil pack is shown inFIG.9.FIG.9shows a single coil pack900which includes a plurality of coils (represented by circles inFIG.9). Coil pack900includes a secondary evaporator portion940, primary evaporator portion910, and secondary condenser portion920. The coil pack may include and/or be fluidly connectable to metering devices980and990as shown in the exemplary case ofFIG.9. In certain embodiments, metering devices980and990correspond to primary metering device380and secondary metering device390ofFIG.3.

In general, metering devices980and990may be any appropriate type of metering/expansion device. In some embodiments, metering device980is a thermostatic expansion valve (TXV) and secondary metering device990is a fixed orifice device (or vice versa). In general, metering devices980and990remove pressure from flow of refrigerant905to allow expansion or change of state from a liquid to a vapor in evaporator portions910and940. The high-pressure liquid (or mostly liquid) refrigerant905entering metering devices980and990is at a higher temperature than the liquid refrigerant905leaving metering devices980and990. For example, if flow of refrigerant905entering metering device980is 340 psig/80° F./0% vapor, flow of refrigerant905may be 196 psig/68° F./5% vapor as it leaves primary metering device980. As another example, if flow of refrigerant905entering secondary metering device990is 196 psig/68° F./4% vapor, flow of refrigerant905may be 128 psig/44° F./14% vapor as it leaves secondary metering device990. Refrigerant905may be any suitable refrigerant, as described above with respect to refrigerant305ofFIG.3.

In operation of example embodiments of the single coil pack900, inlet airflow901passes though secondary evaporator portion940in which heat is transferred from inlet air901to the cool flow of refrigerant905passing through secondary evaporator portion940. As a result, inlet air901may be cooled. As an example, if inlet air901is 80° F./60% humidity, secondary evaporator portion940may output first airflow at 70° F./84% humidity. This may cause flow of refrigerant905to partially vaporize within secondary evaporator portion940. For example, if flow of refrigerant905entering secondary evaporator portion940is 196 psig/68° F./5% vapor, flow of refrigerant905may be 196 psig/68° F./38% vapor as it leaves secondary evaporator portion940.

The cooled inlet air901proceeds through coil pack900, reaching primary evaporator portion910. Like secondary evaporator portion940, primary evaporator portion910transfers heat from airflow901to the cool flow of refrigerant905passing through primary evaporator portion910. As a result, airflow901may be cooled to or below its dew point temperature, causing moisture in airflow901to condense (thereby reducing the absolute humidity of airflow901). As an example, if airflow901is 70° F./84% humidity, primary evaporator portion910may cool airflow901to 54° F./98% humidity. This may cause flow of refrigerant905to partially or completely vaporize within primary evaporator portion910. For example, if flow of refrigerant905entering primary evaporator portion910is 128 psig/44° F./14% vapor, flow of refrigerant905may be 128 psig/52° F./100% vapor as it leaves primary evaporator portion910. In certain embodiments, the liquid condensate from airflow through primary evaporator portion910may be collected in a drain pan connected to a condensate reservoir (e.g., as illustrated inFIG.4and described herein). Additionally, the condensate reservoir may include a condensate pump that moves collected condensate, either continually or at periodic intervals, out of coil pack900(e.g., via a drain hose) to a suitable drainage or storage location.

The cooled airflow901leaving primary evaporator portion910enters secondary condenser portion920. Secondary condenser portion920facilitates heat transfer from the hot flow of refrigerant905passing through the secondary condenser portion920to airflow901. This reheats airflow901, thereby decreasing its relative humidity. As an example, if airflow901is 54° F./98% humidity, secondary condenser portion920may output an outlet airflow925at 65° F./68% humidity. This may cause flow of refrigerant905to partially or completely condense within secondary condenser portion920. For example, if flow of refrigerant905entering secondary condenser portion920is 196 psig/68° F./38% vapor, flow of refrigerant905may be 196 psig/68° F./4% vapor as it leaves secondary condenser portion920. Outlet airflow925may, for example, enter primary condenser portion330or sub-cooling coil350ofFIG.3.

Although a particular implementation of coil pack900is illustrated and primarily described, the present disclosure contemplates any suitable implementation of coil pack900, according to particular needs. Moreover, although various components of coil pack900have been depicted as being located at particular positions, the present disclosure contemplates those components being positioned at any suitable location, according to particular needs.

In certain embodiments, secondary evaporator (340,640) and secondary condenser (320,620) ofFIG.3,6A-6B, or8A-8C are combined in a single coil pack such that the single coil pack includes 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 inFIG.10.FIG.10shows a single coil pack1000which includes a secondary evaporator portion1040and secondary condenser portion1020. As shown in the illustrative example ofFIG.10, a primary evaporator1010is located between the secondary evaporator portion1040and secondary condenser portion1020of the single coil pack1000. In this exemplary embodiment, the single coil pack1000is shown as a “U”-shaped coil. However, alternate embodiments may be used as long as flow airflow1001passes sequentially through secondary evaporator portion1040, primary evaporator1010, and secondary condenser portion1020. In general, single coil pack1000can include the same or a different coil type compared to that of primary evaporator1010. For example, single coil pack1000may include a microchannel coil type, while primary evaporator1010may include a fin tube coil type. This may provide further flexibility for optimizing a dehumidification system in which single coil pack1000and primary evaporator1010are used.

In operation of example embodiments of the single coil pack1000, inlet air1001passes though secondary evaporator portion1040in which heat is transferred from inlet air1001to the cool flow of refrigerant passing through secondary evaporator portion1040. As a result, inlet air1001may be cooled. As an example, if inlet air1001is 80° F./60% humidity, secondary evaporator portion1040may output airflow at 70° F./84% humidity. This may cause flow of refrigerant to partially vaporize within secondary evaporator portion1040. For example, if flow of refrigerant entering secondary evaporator1040is 196 psig/68° F./5% vapor, flow of refrigerant1005may be 196 psig/68° F./38% vapor as it leaves secondary evaporator portion1040.

The cooled inlet air1001leaves secondary evaporator portion1040and enters primary evaporator1010. Like secondary evaporator portion1040, primary evaporator1010transfers heat from airflow1001to the cool flow of refrigerant passing through primary evaporator1010. As a result, airflow1001may be cooled to or below its dew point temperature, causing moisture in airflow1001to condense (thereby reducing the absolute humidity of airflow1001). As an example, if airflow1001entering primary evaporator1010is 70° F./84% humidity, primary evaporator1010may output airflow at 54° F./98% humidity. This may cause flow of refrigerant to partially or completely vaporize within primary evaporator1010. For example, if flow of refrigerant entering primary evaporator1010is 128 psig/44° F./14% vapor, flow of refrigerant may be 128 psig/52° F./100% vapor as it leaves primary evaporator1010. In certain embodiments, the liquid condensate from airflow1010may be collected in a drain pan connected to a condensate reservoir, as illustrated inFIG.4. Additionally, the condensate reservoir may include a condensate pump that moves collected condensate, either continually or at periodic intervals, out of primary evaporator1010, and the associated dehumidification system (e.g., via a drain hose) to a suitable drainage or storage location.

The cooled airflow1001leaves primary evaporator1010and enters secondary condenser portion1020. Secondary condenser portion1020facilitates heat transfer from the hot flow of refrigerant passing through the secondary condenser1020to airflow1001. This reheats airflow1001, thereby decreasing its relative humidity. As an example, if airflow1001entering secondary condenser portion1020is 54° F./98% humidity, secondary condenser1020may output airflow1025at 65° F./68% humidity. This may cause flow of refrigerant to partially or completely condense within secondary condenser1020. For example, if flow of refrigerant entering secondary condenser portion1020is 196 psig/68° F./38% vapor, flow of refrigerant may be 196 psig/68° F./4% vapor as it leaves secondary condenser1020. Outlet airflow925may, for example, enter primary condenser330or sub-cooling cooling350ofFIG.3.

Although a particular implementation of coil pack1000is illustrated and primarily described, the present disclosure contemplates any suitable implementation of coil pack1000, according to particular needs. Moreover, although various components of coil pack1000have been depicted as being located at particular positions, the present disclosure contemplates those components being positioned at any suitable location, according to particular needs.

In certain embodiments, one or both of the secondary evaporator (340,640) and primary evaporator (310,610) ofFIG.3,6A-6B, or8A-8C are subdivided into two or more circuits. In such embodiments, each circuit of the subdivided evaporator(s) is fed refrigerant by a corresponding metering device. The metering devices may include passive metering devices, active metering devices, or combinations thereof. For example, metering device380(or690) may be an active thermostatic expansion valve (TXV) and secondary metering device390(or690) may be a passive fixed orifice device (or vice versa). The metering devices may be configured to feed refrigerant to each circuit within the evaporators at a desired mass flow rate. Metering devices for feeding refrigerant to each circuit of the subdivided evaporator(s) may be used in combination with metering devices380and390or may replace one or both of metering devices380and390.

FIGS.11,12,13, and14show an illustrative example of a portion1100of a dehumidification system in which the primary evaporator1110comprises three circuits for flow of refrigerant, according to certain embodiments. Portion1100includes a primary metering device1180, secondary metering devices1190a-c, a secondary evaporator1140, a primary evaporator1110, and a secondary condenser1120. Primary evaporator1110includes three circuits for receiving flow of refrigerant from secondary metering devices1190a-c. In the example ofFIGS.11,12,13, and14, each of secondary metering devices1190a-cis a passive metering device (i.e., with an orifice of a fixed inner diameter and length). It should, however be understood that one or more (up to all) of the secondary metering devices1190a-cmay be active metering devices (e.g., thermostatic expansion valves).

In operation of example embodiments of portion1100of a dehumidification system, flow of cooled (or sub-cooled) refrigerant is received at inlet1102, for example, from sub-cooling coil350or primary condenser330of dehumidification system300ofFIG.3. Primary metering device1180determines the flow rate of refrigerant into secondary evaporator1140. WhileFIGS.11,12,13, and14are shown to have a single primary metering device1180, other embodiments can include multiple primary metering devices in parallel (e.g., if the secondary evaporator1140comprises two or more circuits for flow of refrigerant).

As the cooled refrigerant passes through secondary evaporator1140, heat is exchanged between the refrigerant and airflow passing through secondary evaporator1140, cooling the inlet air. As an example, if inlet air is 80° F./60% humidity, secondary evaporator1140may output airflow at 70° F./84% humidity. This may cause flow of refrigerant to partially vaporize within secondary evaporator1140. For example, if flow of refrigerant entering secondary evaporator1140is 196 psig/68° F./5% vapor, flow of refrigerant may be 196 psig/68° F./38% vapor as it leaves secondary evaporator1140.

Secondary condenser1120receives warmed refrigerant from secondary evaporator1140via tube1106. Secondary condenser1120facilitates heat transfer from the hot flow of refrigerant passing through the secondary condenser1120to the airflow. This reheats the airflow, thereby decreasing its relative humidity. As an example, if the airflow is 54° F./98% humidity, secondary condenser1120may output an airflow at 65° F./68% humidity. This may cause flow of refrigerant to partially or completely condense within secondary condenser1120. For example, if flow of refrigerant entering secondary condenser1120is 196 psig/68° F./38% vapor, flow of refrigerant may be 196 psig/68° F./4% vapor as it leaves secondary condenser1120.

The cooled refrigerant exits the secondary condenser at1108and is received by metering devices1190a-c, which distributes the flow of refrigerant into the three circuits of primary evaporator1110.FIG.14shows a view which includes the circuiting of primary evaporator1110. Airflow passing through primary evaporator1110may be cooled to or below its dew point temperature, causing moisture in the airflow to condense (thereby reducing the absolute humidity of the air). As an example, if the airflow is 70° F./84% humidity, primary evaporator1110may output airflow at 54° F./98% humidity. This may cause flow of refrigerant to partially or completely vaporize within primary evaporator1110.

Each of secondary metering devices1190a,1190b, and1190cis configured to provide flow of refrigerant to each circuit of primary evaporator1110at a desired flow rate. For example, the flow rate provided to each circuit may be optimized to improve performance of the primary evaporator1110. For example, under certain operating conditions, it may be beneficial to prevent the entire flow of refrigerant from passing through the entire evaporator, as occurs in a traditional evaporator coil. Refrigerant flowing through such an evaporator might undergo a change from liquid to gas phase before exiting the coil, resulting in poor performance in the potion of the evaporator that only contacts gaseous refrigerant. To significantly reduce or eliminate this problem, the present disclosure provides for refrigerant flow at a desired flow rate through each circuit. The desired flow rate may be predetermined (e.g., based on known design criteria and/or operating conditions) and/or variable (e.g., manually and/or automatically adjustable in real time) during operation. The flow rate may be configured such that the flow of refrigerant exits its respective circuit just after transitioning to a gas. For example, the rate of airflow near the edges of an evaporator may be less than near the center of the evaporator. Therefore, a lower rate of refrigerant flow may be supplied by secondary metering devices1190a-cto the circuits corresponding to the edge of primary evaporator1110.

While the example ofFIGS.11,12,13, and14include a primary evaporator that is subdivided into two or more circuits. In other embodiments, secondary evaporator1110may also, or alternatively, be subdivided into two or more circuits. It should also be appreciated that the circuiting exemplified byFIGS.11,12,13, and14can also be achieved in single coil packs such as those shown inFIGS.9and10.

Although a particular implementation of portion1100of a dehumidification system is illustrated and primarily described, the present disclosure contemplates any suitable implementation of portion1100of a dehumidification system, according to particular needs. Moreover, although various components of portion1100of a dehumidification system have been depicted as being located at particular positions, the present disclosure contemplates those components being positioned at any suitable location, according to particular needs.

FIGS.15A-15Billustrate an example dehumidification system1500that may be used in accordance with dehumidification system300ofFIG.3to reduce the humidity of air within a structure. Dehumidification system1500includes a dehumidification unit1502, which is generally indoors, and a heat exchanger1504or an external source1506configured to contain a volume of a fluid operable to be used by the dehumidification system1500to cool a separate fluid flow within the dehumidification unit1502.FIG.15Aillustrates the dehumidification system1500comprising the heat exchanger1504, andFIG.15Billustrates the dehumidification system comprising the external source1506. With reference to bothFIGS.15A-15B, dehumidification unit1502includes a primary evaporator1508, a primary condenser1510, a secondary evaporator1512, a secondary condenser1514, a compressor1516, a primary metering device1518, a secondary metering device1520, and a fan1522.

With continued reference to bothFIGS.15A-15B, a flow of refrigerant1524is circulated through dehumidification unit1502as illustrated. In general, dehumidification unit1502receives an inlet airflow1526, removes water from inlet airflow1526, and discharges dehumidified air1528. Water is removed from inlet air1526using a refrigeration cycle of flow of refrigerant1524. By including secondary evaporator1512and secondary condenser1514, however, dehumidification system1500causes at least part of the flow of refrigerant1524to evaporate and condense twice in a single refrigeration cycle. This increases the refrigeration capacity over typical systems without adding any additional power to the compressor, thereby increasing the overall dehumidification efficiency of the system.

In general, dehumidification system1500attempts to match the saturating temperature of secondary evaporator1512to the saturating temperature of secondary condenser1514. The saturating temperature of secondary evaporator1512and secondary condenser1514generally is controlled according to the equation: (temperature of inlet air1526+temperature of a second airflow1530)/2. As the saturating temperature of secondary evaporator1512is lower than inlet air1526, evaporation happens in secondary evaporator1512. As the saturating temperature of secondary condenser1514is higher than second airflow1530, condensation happens in the secondary condenser1514. The amount of refrigerant1524evaporating in secondary evaporator1512is substantially equal to that condensing in secondary condenser1514.

Primary evaporator1508receives flow of refrigerant1524from secondary metering device1520and outputs flow of refrigerant1524to compressor1516. Primary evaporator1508may be any suitable type of coil (e.g., fin tube, micro channel, etc.). Primary evaporator1508receives a first airflow1532from secondary evaporator1512and outputs second airflow1530to secondary condenser514. Second airflow1530, in general, is at a cooler temperature than first airflow1532. To cool incoming first airflow1532, primary evaporator1508transfers heat from first airflow1532to flow of refrigerant1524, thereby causing flow of refrigerant1524to evaporate at least partially from liquid to gas. This transfer of heat from first airflow1532to flow of refrigerant1524also removes water from first airflow1532.

Secondary condenser1514receives flow of refrigerant1524from secondary evaporator1512and outputs flow of refrigerant1524to secondary metering device1520. Secondary condenser1514may be any type of coil (e.g., fin tube, micro channel, etc.). Secondary condenser1514receives second airflow1530from primary evaporator1508and outputs dehumidified airflow1528. Dehumidified airflow1528is, in general, warmer and drier (i.e., the dew point will be the same but relative humidity will be lower) than second airflow1530. Secondary condenser1514generates dehumidified airflow1528by transferring heat from flow of refrigerant1524to second airflow1530, thereby causing flow of refrigerant1524to condense at least partially from gas to liquid.

Primary condenser1510receives flow of refrigerant1524from compressor1516and outputs flow of refrigerant1524to primary metering device1518. Primary condenser1510may be any type of liquid-cooled heat exchanger operable to transfer heat from the flow of refrigerant1524to the flow of a fluid1534. In embodiments, the fluid1534may be any suitable fluid, such as water or a mixture of water and glycol. Primary condenser1510receives both the flow of fluid1534and the flow of refrigerant1524during operation of dehumidification system1500, wherein the primary condenser1510is operable to transfer heat from the flow of refrigerant1524, thereby causing flow of refrigerant1524to condense at least partially from gas to liquid. In some embodiments, primary condenser1510completely condenses flow of refrigerant1524to a liquid (i.e., 100% liquid). In other embodiments, primary condenser1510partially condenses flow of refrigerant1524to a liquid (i.e., less than 100% liquid).

As illustrated, the dehumidification system1500may further comprise a first water pump1536. The first water pump1536may be disposed internal or external to the dehumidification unit1502. The first water pump1536may be any suitable device operable to provide for the flow of fluid1534. As depicted inFIG.15A, the first water pump1536may be disposed at any suitable position in relation to the primary condenser1510and the heat exchanger1504operable to cycle the flow of fluid1534between the heat exchanger1504and the primary condenser1510. As depicted inFIG.15B, the first water pump1536may be disposed at any suitable position in relation to the primary condenser1510and the external source1506operable to cycle the flow of fluid1534between the external source1506and the primary condenser1510.

With reference toFIG.15A, heat exchanger1504may receive the flow of fluid1534from primary condenser1510at a first temperature and output flow of fluid1534to primary condenser1510at a second temperature after transferring heat away from the flow of fluid1534, wherein the second temperature is lower than the first temperature. Heat exchanger1504may be any suitable type of heat exchanger, such as, for example, a cooling tower or a dry cooler. Heat exchanger1504receives the flow of fluid1534and a first outdoor airflow1540, wherein heat is transferred between the flow of fluid1534and the first outdoor airflow1540. Heat exchanger1504may further output the flow of fluid1534and a second outdoor airflow1542, wherein the flow of fluid1534leaving the heat exchanger1504is at a lower temperature than the flow of fluid1534received by the heat exchanger1504, and the second outdoor airflow1542is at a greater temperature than the first outdoor airflow1540.

In embodiments wherein the heat exchanger1504is a cooling tower, the heat exchanger1504may be operable to dispense the flow of fluid1534within its internal structure, wherein the fluid1534directly contacts the first outdoor airflow1540as the fluid1534flows through the heat exchanger1504and transfers heat to the first outdoor airflow1540. At least a portion of the fluid1534may evaporate and exit to the atmosphere as the heat transfers from the fluid1534to the first outdoor airflow1540, and the heat exchanger1504may collect a remaining portion of the fluid1534after transferring heat to the first outdoor airflow1540, wherein the remaining portion of the fluid1534is at a lower temperature. In embodiments wherein the heat exchanger1504is a dry cooler, the heat exchanger1504may be operable to induce the first outdoor airflow1540to flow through the heat exchanger1504where heat transfers indirectly between the first outdoor airflow1540and the flow of fluid1534. In these embodiments, heat transfer would not result in loss of a portion of the fluid1534through evaporation to the atmosphere.

With reference now toFIG.15B, external source1506may receive the flow of fluid1534from the primary condenser1510and output flow of fluid1534to the primary condenser1510via first water pump1536. External source1506may be configured to contain and/or store a volume of fluid1534to be used by primary condenser1510to lower the temperature of the flow of refrigerant1524in the dehumidification unit1502. The external source1506may be configured to receive the flow of fluid1534from primary condenser1510at a first temperature and output flow of fluid1534to primary condenser1510at a second temperature after transferring heat away from the flow of fluid1534, wherein the second temperature is lower than the first temperature. Without limitations, the external source1506may be any suitable number and combination of a ground reservoir, a natatorium, and an outdoor body of water, among others. In embodiments wherein the external source1506is a ground reservoir, the external source1506may implement an open or closed ground water system, wherein the conduit providing for the flow of fluid1534within the ground reservoir may be disposed substantially parallel to a horizontal plane of the ground surface, substantially perpendicular to the horizontal plane of the ground surface, or combinations thereof.

With reference to bothFIGS.15A-15B, secondary evaporator1512receives flow of refrigerant1524from primary metering device1518and outputs flow of refrigerant1524to secondary condenser1514. Secondary evaporator1512may be any type of coil (e.g., fin tube, micro channel, etc.). Secondary evaporator1512receives inlet air1526and outputs first airflow1532to primary evaporator1508. First airflow1532, in general, is at a cooler temperature than inlet air1526. To cool incoming inlet air1526, secondary evaporator1512transfers heat from inlet air1526to flow of refrigerant1524, thereby causing flow of refrigerant1524to evaporate at least partially from liquid to gas.

Compressor1516pressurizes flow of refrigerant1524, thereby increasing the temperature of refrigerant1524. For example, if flow of refrigerant1524entering compressor1516is 128 psig/52° F./100% vapor, flow of refrigerant1524may be 340 psig/150° F./100% vapor as it leaves compressor1516. Compressor1516receives flow of refrigerant1524from primary evaporator1508and supplies the pressurized flow of refrigerant1524to primary condenser1510.

Fan1522may include any suitable components operable to draw inlet air1526into dehumidification unit1502and through secondary evaporator1512, primary evaporator1508, and secondary condenser1514. Fan1522may be any type of air mover (e.g., axial fan, forward inclined impeller, and backward inclined impeller, etc.). For example, fan1522may be a backward inclined impeller positioned adjacent to secondary condenser1514. While fan1522is depicted as being located adjacent to secondary condenser1514, it should be understood that fan1522may be located anywhere along the airflow path of dehumidification unit1502. For example, fan1522may be positioned in the airflow path of any one of airflows1526,1532,1530, or1528. Moreover, dehumidification unit1502may include one or more additional fans positioned within any one or more of these airflow paths.

Primary metering device1518and secondary metering device1520are any appropriate type of metering/expansion device. In some embodiments, primary metering device1518is a thermostatic expansion valve (TXV) and secondary metering device1520is a fixed orifice device (or vice versa). In certain embodiments, metering devices1518and1520remove pressure from flow of refrigerant1524to allow expansion or change of state from a liquid to a vapor in evaporators1512and1508. The high-pressure liquid (or mostly liquid) refrigerant1524entering metering devices1518and1520is at a higher temperature than the liquid refrigerant1524leaving metering devices1518and1520. For example, if flow of refrigerant1524entering primary metering device1518is 340 psig/80° F./0% vapor, flow of refrigerant1524may be 196 psig/68° F./5% vapor as it leaves primary metering device1518. As another example, if flow of refrigerant1524entering secondary metering device1520is 196 psig/68° F./4% vapor, flow of refrigerant1524may be 128 psig/44° F./14% vapor as it leaves secondary metering device1520.

Refrigerant1524may be any suitable refrigerant such as R410a. In general, dehumidification system1500utilizes a closed refrigeration loop of refrigerant1524that passes from compressor1516through primary condenser1510, primary metering device1518, secondary evaporator1512, secondary condenser1514, secondary metering device1520, and primary evaporator1508. Compressor1516pressurizes flow of refrigerant1524, thereby increasing the temperature of refrigerant1524. Primary condenser1510, which may include any suitable water-cooled heat exchanger, cools the pressurized flow of refrigerant1524by facilitating heat transfer from the flow of refrigerant1524to the flow of fluid provided by the external source1506passing through it (i.e., flow of fluid1534). Secondary condenser, which may include any suitable air-cooled heat exchanger, cools the pressurized flow of refrigerant1524by facilitating heat transfer from the flow of refrigerant1524to the respective airflow passing through it (i.e., second airflow1530).

The cooled flow of refrigerant1524leaving primary and secondary condensers1510and1514may enter a respective expansion device (i.e., primary metering device1518and secondary metering device1520) that is operable to reduce the pressure of flow of refrigerant1524, thereby reducing the temperature of flow of refrigerant1524. Primary and secondary evaporators1508and1512, which may include any suitable heat exchanger, receive flow of refrigerant1524from secondary metering device1520and primary metering device1518, respectively. Primary and secondary evaporators1508and1512facilitate the transfer of heat from the respective airflows passing through them (i.e., inlet air1526and first airflow1532) to flow of refrigerant1524. Flow of refrigerant1524, after leaving primary evaporator1508, passes back to compressor1516, and the cycle is repeated.

In certain embodiments, the above-described refrigeration loop may be configured such that evaporators1508and1512operate in a flooded state. In other words, flow of refrigerant1524may enter evaporators1508and1512in a liquid state, and a portion of flow of refrigerant1524may still be in a liquid state as it exits evaporators1508and1512. Accordingly, the phase change of flow of refrigerant1524(liquid to vapor as heat is transferred to flow of refrigerant1524) occurs across evaporators1508and1512, resulting in nearly constant pressure and temperature across the entire evaporators1508and1512(and, as a result, increased cooling capacity).

In operation of example embodiments of dehumidification system1500, inlet air1526may be drawn into dehumidification unit1502by fan1522. Inlet air1526passes though secondary evaporator1512in which heat is transferred from inlet air1526the cool flow of refrigerant1524passing through secondary evaporator1512. As a result, inlet air1526may be cooled. As an example, if inlet air1526is 80° F./60% humidity, secondary evaporator1512may output first airflow1532at 70° F./84% humidity. This may cause flow of refrigerant1524to partially vaporize within secondary evaporator1512. For example, if flow of refrigerant1524entering secondary evaporator1512is 196 psig/68° F./5% vapor, flow of refrigerant1524may be 196 psig/68° F./38% vapor as it leaves secondary evaporator1512.

The cooled inlet air1526leaves secondary evaporator1512as first airflow1532and enters primary evaporator1508. Like secondary evaporator1512, primary evaporator1508transfers heat from first airflow1532to the cool flow of refrigerant1524passing through primary evaporator1508. As a result, first airflow1532may be cooled to or below its dew point temperature, causing moisture in first airflow1532to condense (thereby reducing the absolute humidity of first airflow1532). As an example, if first airflow1532is 70° F./84% humidity, primary evaporator1508may output second airflow1530at 54° F./98% humidity. This may cause flow of refrigerant1524to partially or completely vaporize within primary evaporator1508. For example, if flow of refrigerant1524entering primary evaporator1508is 128 psig/44° F./14% vapor, flow of refrigerant1524may be 128 psig/52° F./100% vapor as it leaves primary evaporator1508.

The cooled first airflow1532leaves primary evaporator1508as second airflow1530and enters secondary condenser1514. Secondary condenser1514facilitates heat transfer from the hot flow of refrigerant1524passing through the secondary condenser1514to second airflow1530. This reheats second airflow1530, thereby decreasing the relative humidity of second airflow1530. As an example, if second airflow1530is 54° F./98% humidity, secondary condenser1514may output dehumidified airflow1528at 65° F./68% humidity. This may cause flow of refrigerant1524to partially or completely condense within secondary condenser1514. For example, if flow of refrigerant1524entering secondary condenser1514is 196 psig/68° F./38% vapor, flow of refrigerant1524may be 196 psig/68° F./4% vapor as it leaves secondary condenser1514.

Some embodiments of dehumidification system1500may include a controller that may include one or more computer systems at one or more locations. Each computer system may include any appropriate input devices (such as a keypad, touch screen, mouse, or other device that can accept information), output devices, mass storage media, or other suitable components for receiving, processing, storing, and communicating data. Both the input devices and output devices may include fixed or removable storage media such as a magnetic computer disk, CD-ROM, or other suitable media to both receive input from and provide output to a user. Each computer system may include a personal computer, workstation, network computer, kiosk, wireless data port, personal data assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. In short, the controller may include any suitable combination of software, firmware, and hardware.

The controller may additionally include one or more processing modules. Each processing module may each include one or more microprocessors, controllers, or any other suitable computing devices or resources and may work, either alone or with other components of dehumidification system1500, to provide a portion or all of the functionality described herein. The controller may additionally include (or be communicatively coupled to via wireless or wireline communication) computer memory. The memory may include any memory or database module and may take the form of volatile or non-volatile memory, including, without limitation, 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 implementations of dehumidification system1500are illustrated and primarily described, the present disclosure contemplates any suitable implementation of dehumidification system1500, according to particular needs. Moreover, although various components of dehumidification system1500have been depicted as being located at particular positions and relative to one another, the present disclosure contemplates those components being positioned at any suitable location, according to particular needs.

FIGS.16A,16B,16C, and16Dillustrate an example dehumidification system1600with a modulating valve1602that may be used in accordance with split dehumidification system600ofFIGS.6A-6Bto reduce humidity of an airflow. Dehumidification system1600includes the modulating valve1602, a primary evaporator1604, a primary condenser1606, a secondary evaporator1608, a secondary condenser1610, a compressor1612, a primary metering device1614, a secondary metering device1616, a fan1618, and an alternate condenser1620. In some embodiments, dehumidification system1600may additionally include an optional sub-cooling coil1622. As illustrated inFIGS.16A-16B, the alternate condenser1620may be disposed in an external condenser unit1624. With reference toFIG.16A, the optional sub-cooling coil1622may be disposed in the external condenser unit1624with the alternate condenser1620, wherein the sub-cooling coil1622and the alternate condenser1620may be combined into a single coil. With reference toFIG.16B, the optional sub-cooling coil1622may be disposed adjacent to the primary condenser1606, wherein sub-cooling coil1620and primary condenser1606may be combined into a single coil.FIGS.16C-16Dillustrate an embodiment of dehumidification system1600wherein both optional sub-cooling coil1622and alternate condenser1620are not in the external condenser unit1624and where alternate condenser1620is liquid-cooled.

With reference to each ofFIGS.16A-16D, a flow of refrigerant1626is circulated through dehumidification system1600as illustrated. In general, dehumidification system1600receives inlet airflow1628, removes water from inlet airflow1628, and discharges dehumidified air1630. Water is removed from inlet air1628using a refrigeration cycle of flow of refrigerant1626. By including secondary evaporator1608and secondary condenser1610, however, dehumidification system1600causes at least part of the flow of refrigerant1626to evaporate and condense twice in a single refrigeration cycle. This increases the refrigeration capacity over typical systems without adding any additional power to the compressor, thereby increasing the overall dehumidification efficiency of the system.

In general, dehumidification system1600attempts to match the saturating temperature of secondary evaporator1608to the saturating temperature of secondary condenser1610. The saturating temperature of secondary evaporator1608and secondary condenser1610generally is controlled according to the equation: (temperature of inlet air1628+temperature of a second airflow1632)/2. As the saturating temperature of secondary evaporator1608is lower than inlet air1628, evaporation happens in secondary evaporator1608. As the saturating temperature of secondary condenser1610is higher than second airflow1632, condensation happens in the secondary condenser1610. The amount of refrigerant1626evaporating in secondary evaporator1608is substantially equal to that condensing in secondary condenser1610.

Primary evaporator1604receives flow of refrigerant1626from secondary metering device1616and outputs flow of refrigerant1626to compressor1612. Primary evaporator1604may be any type of coil (e.g., fin tube, micro channel, etc.). Primary evaporator1604receives a first airflow1634from secondary evaporator1608and outputs second airflow1632to secondary condenser1610. Second airflow1632, in general, is at a cooler temperature than first airflow1634. To cool incoming first airflow1634, primary evaporator1604transfers heat from first airflow1634to flow of refrigerant1626, thereby causing flow of refrigerant1626to evaporate at least partially from liquid to gas. This transfer of heat from first airflow1634to flow of refrigerant1626also removes water from first airflow1634.

Secondary condenser1610receives flow of refrigerant1626from secondary evaporator1608and outputs flow of refrigerant1626to secondary metering device1616. Secondary condenser1610may be any type of coil (e.g., fin tube, micro channel, etc.). Secondary condenser1610receives second airflow1632from primary evaporator1604and outputs a third airflow1636. Third airflow1636is, in general, warmer and drier (i.e., the dew point will be the same but relative humidity will be lower) than second airflow1632. Secondary condenser1610generates third airflow1632by transferring heat from flow of refrigerant1626to second airflow1632, thereby causing flow of refrigerant1626to condense at least partially from gas to liquid.

Primary condenser1606may be any type of coil (e.g., fin tube, micro channel, etc.). Primary condenser1606is operable to receive flow of refrigerant1626from modulating valve1602and outputs flow of refrigerant1626to either primary metering device1614or sub-cooling coil1622. As shown inFIG.16A, primary condenser1606outputs flow of refrigerant1626to primary metering device1614. In these embodiments, primary condenser1606receives third airflow1636and outputs dehumidified air1630. But with reference toFIGS.16B-16D, primary condenser1606outputs flow of refrigerant1626to the optional sub-cooling coil1622before the flow of refrigerant1626flows to primary metering device1614. In these embodiments, primary condenser1606receives a fourth airflow1638generated by the sub-cooling col1622and outputs dehumidified air1630. With reference to each ofFIGS.16A-16D, dehumidified air1630is, in general, warmer and drier (i.e., have a lower relative humidity) than either third airflow1636or fourth airflow1638. Primary condenser1606generates dehumidified air1630by transferring heat away from flow of refrigerant1626, thereby causing flow of refrigerant1626to condense at least partially from gas to liquid. In some embodiments, primary condenser1606completely condenses flow of refrigerant1626to a liquid (i.e., 100% liquid). In other embodiments, primary condenser1606partially condenses flow of refrigerant1626to a liquid (i.e., less than 100% liquid.

Secondary evaporator1608receives flow of refrigerant1626from primary metering device1614and outputs flow of refrigerant1626to secondary condenser1610. Secondary evaporator1608may be any type of coil (e.g., fin tube, micro channel, etc.). Secondary evaporator1608receives inlet air1628and outputs first airflow1634to primary evaporator1604. First airflow1634, in general, is at a cooler temperature than inlet air1628. To cool incoming inlet air1628, secondary evaporator1608transfers heat from inlet air1608to flow of refrigerant1626, thereby causing flow of refrigerant1626to evaporate at least partially from liquid to gas.

Sub-cooling coil1622, which is an optional component of dehumidification system1600, sub-cools the liquid refrigerant1626as it leaves the primary condenser1606, the alternate condenser1620, or combinations thereof. In embodiments wherein the sub-cooling coil1622is disposed within the external condenser unit1624, the sub-cooling coil1622may receive refrigerant1626as it leaves the alternate condenser1620, as seen inFIG.16A. In embodiments wherein the sub-cooling coil1622is disposed adjacent to the primary condenser1606, the sub-cooling coil1622may receive refrigerant1626as it leaves the primary condenser1606and/or the alternate condenser1620, as seen inFIGS.16B-16D. With reference to each ofFIGS.16A-16D, this, in turn, supplies primary metering device1614with a liquid refrigerant that is up to 30 degrees (or more) cooler than before it enters sub-cooling coil1622. For example, if flow of refrigerant1626entering sub-cooling coil1622is 340 psig/105° F./60% vapor, flow of refrigerant1626may be 340 psig/80° F./0% vapor as it leaves sub-cooling coil1622. The sub-cooled refrigerant1626has a greater heat enthalpy factor as well as a greater density, which results in reduced cycle times and frequency of the evaporation cycle of flow of refrigerant1626. This results in greater efficiency and less energy use of dehumidification system1600.

Compressor1612pressurizes flow of refrigerant1626, thereby increasing the temperature of refrigerant1626. For example, if flow of refrigerant1626entering compressor1612is 128 psig/52° F./100% vapor, flow of refrigerant1626may be 340 psig/150° F./100% vapor as it leaves compressor1612. Compressor1612receives flow of refrigerant1626from primary evaporator1604and supplies the pressurized flow of refrigerant1626to modulating valve1602.

Modulating valve1602is operable to receive the pressurized flow of refrigerant1626from compressor1612and to direct the flow of refrigerant to primary condenser1606, to alternate condenser1620, or to both. In embodiments, the modulating valve1602may operate based, at least in part, on a pre-determined temperature set point for the dehumidified airflow1630and on an actual temperature of the dehumidified airflow1630output by dehumidification system1600. Dehumidification system1600may utilize modulating valve1602to direct heat to be rejected from the flow of refrigerant1626away from the primary condenser1606and towards the alternate condenser1620. Depending on a feedback loop comprising of the pre-determined temperature set point and the actual temperature of the dehumidified airflow1630, modulating valve1602may be configured to partially open and/or close to direct at least a portion of the flow of refrigerant1626to the alternate condenser1620and direct a remaining portion of the flow of refrigerant1626to the primary condenser1606.

During operation of dehumidification system1600, the modulating valve1602may direct the flow of refrigerant1626to primary condenser1606if the temperature of the dehumidified airflow1630output by the primary condenser1606does not exceed the pre-determined temperature set point monitored by the dehumidification system1600. If the temperature of the dehumidified airflow1630is greater than the pre-determined temperature set point, the modulating valve1602may be actuated to direct at least a portion of the flow of refrigerant1626to the alternate condenser1620and direct a remaining portion of the flow of refrigerant to the primary condenser1606. As the dehumidification system1600operates, reduction in the volume of flow of refrigerant1626to primary condenser1606may reduce the available heat to be rejected into the dehumidified airflow1630. With the reduced flow of refrigerant1626passing through primary condenser1606(for example, the remaining portion of the flow of refrigerant), the rate of heat transfer to the dehumidified airflow1630may subsequently be reduced, thereby producing a reduction in the temperature change of an incoming airflow and the output dehumidified airflow1630. Once the temperature of the dehumidified airflow1630is lower than the pre-determined temperature set point, the modulating valve1602may be actuated to direct the at least a portion of the flow of refrigerant1626back to the primary condenser1606. Any remaining refrigerant1626that had been directed to alternate condenser1620may combine with the flow of refrigerant1626further downstream.

With reference toFIGS.16A and16B, alternate condenser1620may be disposed in the external condenser unit1624and may be any type of coil (e.g., fin tube, micro channel, etc.) operable to receive flow of refrigerant1626from modulating valve1602and output flow of refrigerant1626at a lower temperature. Alternate condenser1620transfers heat from flow of refrigerant1626, thereby causing flow of refrigerant1626to condense at least partially from gas to liquid. In some embodiments, alternate condenser1620completely condenses flow of refrigerant1626to a liquid (i.e., 100% liquid). In other embodiments, alternate condenser1620partially condenses flow of refrigerant1626to a liquid (i.e., less than 100% liquid). As seen inFIG.16A, the flow of refrigerant1626may be output to sub-cooling coil1622disposed adjacent to alternate condenser1620within the external condenser unit1624. Alternate condenser1620and sub-cooling coil1622may receive a first outdoor airflow1640and output a second outdoor airflow1642. Second outdoor airflow1642is, in general, warmer (i.e., have a lower relative humidity) than first outdoor airflow1640. In other embodiments, as shown inFIG.16B, the first outdoor airflow1640may be received by the alternate condenser1620without previously flowing through sub-cooling coil1622. InFIG.16B, the external condenser unit1624may include the alternate condenser1620and a fan1644and may not include the sub-cooling coil1622, wherein fan1644may be configured to facilitate flow of first outdoor airflow1640towards alternate condenser1620.

With reference now toFIGS.16C-16D, alternate condenser1620may be any type of liquid-cooled heat exchanger operable to transfer heat from the flow of refrigerant1626to the flow of a fluid1646, wherein the alternate condenser1620receives flow of refrigerant1626from modulating valve1602and outputs flow of refrigerant1626to sub-cooling coil1622. In embodiments, the fluid1646may be any suitable fluid, such as water or a mixture of water and glycol. Alternate condenser1620receives both the flow of fluid1646and the flow of refrigerant1626during operation of dehumidification system1600, wherein the alternate condenser1620is operable to transfer heat from the flow of refrigerant1626, thereby causing flow of refrigerant1626to condense at least partially from gas to liquid. In some embodiments, alternate condenser1620completely condenses flow of refrigerant1626to a liquid (i.e., 100% liquid). In other embodiments, alternate condenser1620partially condenses flow of refrigerant1626to a liquid (i.e., less than 100% liquid).

As illustrated inFIGS.16C-16D, the dehumidification system1600may further comprise a first water pump1648. The first water pump1648may be disposed external to the alternate condenser1620. The first water pump may be any suitable device operable to provide for the flow of fluid1646. As depicted inFIG.16C, the first water pump1648may be disposed at any suitable location between the alternate condenser1620and a heat exchanger1654operable to cycle the flow of fluid1646between the heat exchanger1654and the alternate condenser1620. As depicted inFIG.16D, the first water pump1648may be disposed at any suitable location between the alternate condenser1620and an external source1652operable to cycle the flow of fluid1646between the external source1652and the alternate condenser1620.

With reference toFIG.16C, heat exchanger1654may receive the flow of fluid1646from alternate condenser1620and output flow of fluid1646after transferring heat away from the flow of fluid1646. Heat exchanger1654may be any suitable type of heat exchanger, such as a cooling tower or a dry cooler. Heat exchanger1654receives the flow of fluid1646and a first outdoor airflow1656, wherein heat is transferred between the flow of fluid1646and the first outdoor airflow1656. Heat exchanger1654may further output the flow of fluid1646and a second outdoor airflow1658, wherein the flow of fluid1646leaving the heat exchanger1654is at a lower temperature than the flow of fluid1646received by the heat exchanger1654, and the second outdoor airflow1658is at a greater temperature than the first outdoor airflow1654.

In embodiments wherein the heat exchanger1654is a cooling tower, the heat exchanger1654may be operable to dispense the flow of fluid1646within its internal structure, wherein the fluid1646directly contacts the first outdoor airflow1656as the fluid1646flows through the heat exchanger1654and transfers heat to the first outdoor airflow1656. At least a portion of the fluid1646may evaporate and exit to the atmosphere as the heat transfers from the fluid1646to the first outdoor airflow1656, and the heat exchanger1654may collect a remaining portion of the fluid1646after transferring heat to the first outdoor airflow1656, wherein the remaining portion of the fluid1646is at a lower temperature. In embodiments wherein the heat exchanger1654is a dry cooler, the heat exchanger1654may be operable to induce the first outdoor airflow1656to flow through the heat exchanger1654where heat transfers indirectly between the first outdoor airflow1656and the flow of fluid1646. In these embodiments, heat transfer would not result in loss of a portion of the fluid1646through evaporation to the atmosphere.

With reference toFIG.16D, external source1652may receive the flow of fluid1646and output flow of fluid1646to the alternate condenser1620via first water pump1648. External source1652may be configured to contain and/or store a volume of fluid1646to be used by alternate condenser1620to lower the temperature of the flow of refrigerant1626in the dehumidification system1600. Without limitations, the external source1652may be selected from a group consisting of a ground reservoir, a natatorium, an outdoor body of water, and any combinations thereof. In embodiments wherein the external source1652is a ground reservoir, the external source1652may implement an open or closed ground water system, wherein the conduit providing for the flow of fluid1646within the ground reservoir may be disposed substantially parallel to a horizontal plane of the ground surface, substantially perpendicular to the horizontal plane of the ground surface, or combinations thereof.

In embodiments wherein the external source1652is a natatorium, the external source1652may be within a multi-loop system operable to contain and cool the flow of fluid1646before the alternate condenser1620uses the flow of fluid1646to lower the temperature of the flow of refrigerant1626. The external source1652may be configured to receive the flow of fluid1646from alternate condenser1620at a first temperature and output flow of fluid1646to alternate condenser1620at a second temperature after transferring heat away from the flow of fluid1646, wherein the second temperature is lower than the first temperature. External source1652receives the flow of fluid1646and may receive a flow of a secondary fluid (not shown), wherein heat is transferred between the flow of fluid1646and the flow of secondary fluid. External source1652may then output the flow of fluid1646and the flow of secondary fluid, wherein the flow of fluid1646leaving the external source1652is at a lower temperature than the flow of fluid1646received by the external source1652, and wherein the flow of secondary fluid leaving the external source1652is at a greater temperature than the flow of secondary fluid received by the external source1652.

The flow of secondary fluid may then be directed to a tertiary condenser (not shown). The tertiary condenser receives the flow of secondary fluid from external source1652and outputs flow of secondary fluid back to the external source1652at a lower temperature. The tertiary condenser may be any type of air-cooled or liquid-cooled heat exchanger operable to transfer heat away from the flow of secondary fluid. In embodiments, a second pump (not shown) may be at any suitable position in relation to the external source1652and the tertiary condenser operable to cycle the flow of secondary fluid between the external source1652and the tertiary condenser, wherein the second pump may be any suitable device operable to provide for the flow of secondary fluid.

Referring back to each ofFIGS.16A-16D, fan1618may include any suitable components operable to draw inlet air1628into dehumidification system1600and through secondary evaporator1608, primary evaporator1604, secondary condenser1610, sub-cooling coil1622, and primary condenser1606. Fan1618may be any type of air mover (e.g., axial fan, forward inclined impeller, and backward inclined impeller, etc.). For example, fan1618may be a backward inclined impeller positioned adjacent to primary condenser1606as illustrated inFIGS.16A-16D. While fan1618is depicted inFIGS.16A-16Das being located adjacent to primary condenser1606, it should be understood that fan1618may be located anywhere along the airflow path of dehumidification system1600. For example, fan1618may be positioned in the airflow path of any one of airflows1628,1634,1632,1636,1638, or1630. Moreover, dehumidification system1600may include one or more additional fans positioned within any one or more of these airflow paths. Similarly, with reference toFIGS.16A-16B, while a fan1644of external condenser unit1624is depicted as being located above alternate condenser1620, it should be understood that fan1644may be located anywhere (e.g., above, below, beside) with respect to alternate condenser1620and optional sub-cooling coil1622, so long as fan1644is appropriately positioned and configured to facilitate flow of first outdoor airflow1640towards alternate condenser1620.

Primary metering device1614and secondary metering device1616are any appropriate type of metering/expansion device. In some embodiments, primary metering device1614is a thermostatic expansion valve (TXV) and secondary metering device1616is a fixed orifice device (or vice versa). In certain embodiments, metering devices1614and1616remove pressure from flow of refrigerant1626to allow expansion or change of state from a liquid to a vapor in evaporators1604and1608. The high-pressure liquid (or mostly liquid) refrigerant entering metering devices1614and1616is at a higher temperature than the liquid refrigerant1626leaving metering devices1614and1616. For example, if flow of refrigerant1626entering primary metering device1614is 340 psig/80° F./0% vapor, flow of refrigerant1626may be 196 psig/68° F./5% vapor as it leaves primary metering device1614. As another example, if flow of refrigerant1626entering secondary metering device1616is 196 psig/68° F./4% vapor, flow of refrigerant1626may be 128 psig/44° F./14% vapor as it leaves secondary metering device1616.

Refrigerant1626may be any suitable refrigerant such as R410a. In general, dehumidification system1600utilizes a closed refrigeration loop of refrigerant1626that passes from compressor1612through modulating valve1602, primary condenser1612and/or alternate condenser1620, (optionally) sub-cooling coil1622, primary metering device1614, secondary evaporator1608, secondary condenser1610, secondary metering device1616, and primary evaporator1604. Compressor1612pressurizes flow of refrigerant1626, thereby increasing the temperature of refrigerant1626. Primary and secondary condensers1606and1610, which may include any suitable heat exchangers, cool the pressurized flow of refrigerant1626by facilitating heat transfer from the flow of refrigerant1626to the respective airflows passing through them (i.e., third or fourth airflow1636,1638and second airflow1632). Further, alternate condenser1620, which may include any suitable heat exchanger, cools the pressurized flow of refrigerant1626by facilitating heat transfer from the flow of refrigerant1626to either the airflow passing through it (i.e., first outdoor airflow1640as illustrated inFIGS.16A-16B) or to the flow of fluid provided by the external source1652passing through it (i.e., flow of fluid1646as illustrated inFIGS.16C-16D). The cooled flow of refrigerant1626leaving primary and/or alternate condensers1606and1620may enter primary metering device1614, which is operable to reduce the pressure of flow of refrigerant1626, thereby reducing the temperature of flow of refrigerant1626. The cooled flow of refrigerant1626leaving secondary condenser1610may enter secondary metering device1616, which is operable to reduce the pressure of flow of refrigerant1626, thereby reducing the temperature of flow of refrigerant1626. Primary and secondary evaporators1604and1608, which may include any suitable heat exchanger, receive flow of refrigerant1626from secondary metering device1616and primary metering device1614, respectively. Primary and secondary evaporators1604and1608facilitate the transfer of heat from the respective airflows passing through them (i.e., inlet air1628and first airflow1634) to flow of refrigerant1626. Flow of refrigerant1626, after leaving primary evaporator1604, passes back to compressor1612, and the cycle is repeated.

In certain embodiments, the above-described refrigeration loop may be configured such that evaporators1604and1608operate in a flooded state. In other words, flow of refrigerant1626may enter evaporators1604and1608in a liquid state, and a portion of flow of refrigerant1626may still be in a liquid state as it exits evaporators1604and1608. Accordingly, the phase change of flow of refrigerant1626(liquid to vapor as heat is transferred to flow of refrigerant1626) occurs across evaporators1604and1608, resulting in nearly constant pressure and temperature across the entire evaporators1604and1608(and, as a result, increased cooling capacity).

In operation of example embodiments of dehumidification system1600, inlet air1628may be drawn into dehumidification system1600by fan1618. Inlet air1628passes though secondary evaporator1608in which heat is transferred from inlet air1628to the cool flow of refrigerant1626passing through secondary evaporator1608. As a result, inlet air1628may be cooled. As an example, if inlet air1628is 80° F./60% humidity, secondary evaporator1608may output first airflow1634at 70° F./84% humidity. This may cause flow of refrigerant1626to partially vaporize within secondary evaporator1608. For example, if flow of refrigerant1626entering secondary evaporator1608is 196 psig/68° F./5% vapor, flow of refrigerant1626may be 196 psig/68° F./38% vapor as it leaves secondary evaporator1608.

The cooled inlet air1628leaves secondary evaporator1608as first airflow1634and enters primary evaporator1604. Like secondary evaporator1608, primary evaporator1604transfers heat from first airflow1634to the cool flow of refrigerant1626passing through primary evaporator1604. As a result, first airflow1634may be cooled to or below its dew point temperature, causing moisture in first airflow1634to condense (thereby reducing the absolute humidity of first airflow1634). As an example, if first airflow1634is 70° F./84% humidity, primary evaporator1604may output second airflow1632at 54° F./98% humidity. This may cause flow of refrigerant1626to partially or completely vaporize within primary evaporator1604. For example, if flow of refrigerant1626entering primary evaporator1604is 128 psig/44° F./14% vapor, flow of refrigerant1626may be 128 psig/52° F./100% vapor as it leaves primary evaporator1604.

The cooled first airflow1634leaves primary evaporator1604as second airflow1632and enters secondary condenser1610. Secondary condenser1610facilitates heat transfer from the hot flow of refrigerant1626passing through the secondary condenser1610to second airflow1632. This reheats second airflow1632, thereby decreasing the relative humidity of second airflow1632. As an example, if second airflow1632is 54° F./98% humidity, secondary condenser1610may output third airflow1636at 65° F./68% humidity. This may cause flow of refrigerant1626to partially or completely condense within secondary condenser1610. For example, if flow of refrigerant1626entering secondary condenser1610is 196 psig/68° F./38% vapor, flow of refrigerant1626may be 196 psig/68° F./4% vapor as it leaves secondary condenser1610.

In some embodiments, the dehumidified second airflow1632leaves secondary condenser1610as third airflow1636and enters primary condenser1606, as illustrated inFIG.16A. Primary condenser1606facilitates heat transfer from the hot flow of refrigerant1626passing through the primary condenser1606to third airflow1636. This further heats third airflow1636, thereby further decreasing the relative humidity of third airflow1636. As an example, if third airflow1636is 65° F./68% humidity, primary condenser1606may output dehumidified air1630at 102° F./19% humidity. This may cause flow of refrigerant1626to partially or completely condense within primary condenser1606. For example, if flow of refrigerant1626entering primary condenser1606is 340 psig/150° F./100% vapor, flow of refrigerant1626may be 340 psig/105° F./60% vapor as it leaves primary condenser1606.

As described above, some embodiments of dehumidification system1600may include a sub-cooling coil1622in the airflow between secondary condenser1610and primary condenser1606, as best seen inFIGS.16B-16D. Sub-cooling coil1622facilitates heat transfer from the hot flow of refrigerant1626passing through sub-cooling coil1622to third airflow1636. This further heats third airflow1636, thereby further decreasing the relative humidity of third airflow1636. As an example, if third airflow1636is 65° F./68% humidity, sub-cooling coil1622may output fourth airflow1638at 81° F./37% humidity. This may cause flow of refrigerant1626to partially or completely condense within sub-cooling coil1622. For example, if flow of refrigerant1626entering sub-cooling coil1622is 340 psig/150° F./60% vapor, flow of refrigerant1626may be 340 psig/80° F./0% vapor as it leaves sub-cooling coil1622. In these embodiments, the fourth airflow1638may then undergo heat transfer in primary condenser1606to produce dehumidified airflow1630.

Some embodiments of dehumidification system1600may include a controller that may include one or more computer systems at one or more locations. Each computer system may include any appropriate input devices (such as a keypad, touch screen, mouse, or other device that can accept information), output devices, mass storage media, or other suitable components for receiving, processing, storing, and communicating data. Both the input devices and output devices may include fixed or removable storage media such as a magnetic computer disk, CD-ROM, or other suitable media to both receive input from and provide output to a user. Each computer system may include a personal computer, workstation, network computer, kiosk, wireless data port, personal data assistant (PDA), one or more processors within these or other devices, or any other suitable processing device. In short, the controller may include any suitable combination of software, firmware, and hardware.

The controller may additionally include one or more processing modules. Each processing module may each include one or more microprocessors, controllers, or any other suitable computing devices or resources and may work, either alone or with other components of dehumidification system1600, to provide a portion or all of the functionality described herein. The controller may additionally include (or be communicatively coupled to via wireless or wireline communication) computer memory. The memory may include any memory or database module and may take the form of volatile or non-volatile memory, including, without limitation, 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 implementations of dehumidification system1600are illustrated and primarily described, the present disclosure contemplates any suitable implementation of dehumidification system1600, according to particular needs. Moreover, although various components of dehumidification system1600have been depicted as being located at particular positions and relative to one another, the present disclosure contemplates those components being positioned at any suitable location, according to particular needs.

Herein, “or” is inclusive and not exclusive, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A or B” means “A, B, or both,” unless expressly indicated otherwise or indicated otherwise by context. Moreover, “and” is both joint and several, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A and B” means “A and B, jointly or severally,” unless expressly indicated otherwise or indicated otherwise by context. The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, feature, 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 that a person having ordinary skill in the art would comprehend. Furthermore, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Additionally, although this disclosure describes or illustrates particular embodiments as providing particular advantages, particular embodiments may provide none, some, or all of these advantages.