Apparatus and method for enhanced dehumidification

Abstract

A method and apparatus for enhancing performance of a dehumidifier that is operating in a substantially closed air environment facilitates air-to-air heat exchange between a first air stream derived from the closed air environment and a second air stream derived from a source other than the closed air environment, the second air stream being cooler than the first air stream.

Description

BACKGROUND OF THE INVENTION

The invention relates to dehumidifiers, and more particularly to improved performance and efficiency.

Dehumidifiers are known in the prior art. A compressor delivers hot compressed refrigerant gas. A condenser receives the refrigerant gas and condenses same into hot refrigerant liquid. An expansion device receives the refrigerant liquid from the condenser and expands same to drop the temperature and pressure of the liquid. An evaporator receives the cool liquid refrigerant from the expansion device and evaporates same to cold gas refrigerant, which is returned to the compressor to complete the refrigeration cycle. Air flow is directed across the evaporator to cool the air below the dew point such that water vapor in the air is condensed to liquid to dehumidify the air. The dehumidified air is then directed across the condenser to warm the air.

The present invention arose during continuing development efforts directed toward improved performance and efficiency in a dehumidifier.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows a dehumidifier known in the prior art.

FIG. 2 is a schematic illustration of a dehumidification system known in the prior art.

FIG. 3 is a perspective view showing a dehumidifier, including a portable cabinet, known in the prior art.

FIG. 4 shows the dehumidifier of FIG. 3 partially broken away, showing prior art.

FIG. 5 is a side view of the dehumidifier of FIG. 4, showing prior art.

FIG. 6 is a perspective view of a dehumidifier and apparatus for enhancing the performance of the dehumidifier, in accordance with the present invention.

FIG. 7 is a side view, broken away, of the arrangement shown in FIG. 6.

FIG. 8 is a perspective view, broken away, of apparatus for enhancing performance of a dehumidifier.

FIGS. 9a and 9b are partial views showing attachment points for coupling the apparatus for enhancing performance of a dehumidifier to a dehumidifier.

FIGS. 10a and 10b are partial views of further attachment points for coupling an apparatus for enhancing performance of a dehumidifier to a dehumidifier.

FIG. 11 is a schematic illustration of an arrangement in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

Prior Art

FIG. 1 shows a dehumidifier 10 known in the prior art. A compressor 12 delivers compressed hot gas refrigerant. A condenser 14 receives the hot gas refrigerant and condenses same to hot liquid refrigerant, and gives up heat to the air flow therethrough. An expansion device 16 receives the hot liquid refrigerant and expands same to a liquid and gas refrigerant mixture of reduced temperature and pressure. Expansion device 16 is typically a flow restrictor, capillary tube, or other pressure reducer. An evaporator 18 receives the cool liquid and gas refrigerant mixture and evaporates the liquid portion to cool gas refrigerant, and absorbs heat from the air flow therethrough. The refrigerant is circulated from compressor 12 to condenser 14 to expansion device 16 to evaporator 18 and back to compressor 12 in a refrigeration cycle. Air flow, typically driven by a fan (not shown), is directed by a duct or housing 19 along a path through evaporator 18 and condenser 14. As the air flows through evaporator 18 from point 20 to point 22, the temperature of the air drops below the dew point such that water vapor in the air is condensed to liquid to dehumidify the air. The air is heated as it flows through condenser 14 from point 22 to point 24, and the warmed and dehumidified air is discharged to the desired space, such as a basement, or other interior space of a house or building.

FIG. 2 further schematically illustrates the dehumidification of system of FIG. 1 and uses like reference numerals where appropriate to facilitate understanding. It is known to provide a heat exchanger 26a, 26b for pre-cooling the air upstream of evaporator 18 and then re-heating the air downstream of the evaporator.

FIGS. 3-5 show a dehumidifier 28 including a portable cabinet 30, compressor 12 in the cabinet for delivering hot compressed refrigerant, condenser coil 14 in the cabinet and receiving refrigerant from compressor 12 and condensing same, capillary tube expansion device 16 in the cabinet and receiving refrigerant from condenser coil 14 and expanding same, and evaporator coil 18 in the cabinet and receiving refrigerant from expansion device 16 and evaporating same, and delivering the refrigerant to compressor 12. The refrigerant is circulated from compressor 12 to condenser coil 14 to expansion device 16 to evaporator coil 18 and back to compressor 12 in a refrigeration cycle, as is known.

Cabinet 30 has an air flow path 32 therethrough, including a first segment 34, FIG. 5, passing ambient air to evaporator coil 18, a second segment 36 passing air from evaporator coil 18 to condenser coil 14, and a third segment 38 discharging air from condenser coil 14. The first, second and third segments, 34, 36 and 38, are in series from upstream to downstream, respectively. Heat exchanger 26 has first and second heat exchange paths 26a and 26b therethrough in heat exchange relation, for example provided by a plurality of layered corrugated sheets providing vertical air flow channels therethrough at 26a in heat exchange relation with a plurality of interdigitated corrugated layered sheets providing horizontal flow channels therethrough at 26b, providing an air-to-air cross flow heat exchanger as is known. Heat exchanger path 26a provides pre-cooled ambient air from which moisture is removed by evaporator coil 18. Pre-cooling incoming air improves grain depression, capacity (pints per day), and efficiency (pints per kilowatt hour). The removed moisture is collected at collection pan 40 having drainage outlet 42. The air is re-heated at heat exchanger flow path 26b, and the warm dry air is supplied to condenser coil 14 as pulled therethrough by squirrel cage blower 44 which discharges the dehumidified air at outlet 46 as shown as arrow 47. Portable cabinet 30 may be mounted on wheels such as 48 and have a handle such as 50 for maneuvering the cabinet and rolling it along a floor such as 52.

The dehumidifier shown in FIGS. 3-5 is often utilized to dry flooded surfaces and/or structures in a closed-air environment such as a basement, room, or other substantially enclosed area. In use, the dehumidifier takes in and removes moisture from air in the environment and thereafter emits warm, dry air back into the environment. The warm, dry air raises the temperature of the environment and advantageously speeds evaporation rates from the flooded surfaces, structures and/or other areas. However, increasing the air temperature of the environment simultaneously causes a decrease in performance of the dehumidifier in terms of its water removal rate. Therefore, according to known arrangements, there is a tradeoff between raising the air temperature to achieve rapid evaporation rates and lowering the air temperature to achieve effective dehumidification rates.

Present Invention

FIGS. 6-11 illustrate the concepts of the present invention and use like reference numerals from above when appropriate to facilitate understanding.

In FIGS. 6-11, an apparatus or amplifier 60 is provided for enhancing performance of a dehumidifier 28 that is operating in a substantially closed-air environment, such as a basement, room or other substantially enclosed area. As discussed further below, the apparatus 60 improves the grain depression, capacity, and efficiency of the dehumidifier 28.

In the illustrated embodiment, apparatus 60 includes a cabinet 62 containing an air-to-air heat exchanger 64. The cabinet 62 is formed from stainless steel, however it is recognized that any structurally rigid metal or other material could be used. The cabinet 62 has a first inlet 70 adapted to receive the aforementioned first air stream 32 from the closed air environment and a first outlet 74 discharging the first air stream 32 to the intake 108 on the dehumidifier 28 for dehumidification according to the above-described process. Intake air thus flows vertically through the apparatus 60 as shown in FIGS. 6 and 7. A second inlet 76 is adapted to receive a second air stream 78 originating from a cool air source other than the surrounding environment. The second air stream 78 must be cooler than the air from the closed-air environment and can derive from an air conditioning system or unaffected outside air. A second outlet 80 is provided for discharging the second air stream 78 to a location other than the closed-air environment. The second air stream 78 thus flows through the apparatus 60 horizontally, as shown in FIGS. 6 and 7. In the preferred arrangement, the second inlet 76 and second outlet 80 are ducted and therefore the second air stream 78 is separated from the closed-air environment.

In the arrangement shown, the heat exchanger 64 has first and second heat exchange paths 64a and 64b therethrough in heat exchange relation, for example provided by a plurality of layered corrugated sheets providing vertical air flow channels therethrough at 64a in heat exchange relation with a plurality of interdigitated corrugated layered sheets providing horizontal flow channels therethrough at 64b, providing an air-to-air cross flow heat exchanger 64. A motorized impeller 82 is arranged in the cabinet 62 to force the second air stream 78 horizontally along the second path 64b of the heat exchanger 64. In a preferred arrangement, the impeller 82 is controlled by a thermostatic controller, which automatically turns the impeller off when processed air reaches a predetermined temperature. Thermostatic controllers are known in the art and may include a bimetallic switch with a sensing element in the primary air stream. The controller is set to turn the impeller on when the process air temperature increases to 80 degrees Fahrenheit, and off when the process air cools to 70 degrees Fahrenheit. Alternatively, the impeller may be controlled manually and thus be set to run continuously, if desired. In the arrangement shown, a power switch is located on the back of the cabinet to allow for manual control and/or control by the thermostatic controller.

The cabinet 62 is designed to detachably mount to the intake 108 of the dehumidifier 28. It is recognized that various different means for mechanical connection may be employed to achieve this objective. In the arrangement shown, the bottom 87 of the cabinet 62 is sized to nest in the top 88 of the dehumidifier 28 and the top 89 of the cabinet 62 is arranged to receive the lid 84 and filter 86 of the dehumidifier 28. More specifically, prior to attachment of the cabinet 62 to the top 88 of the dehumidifier 28, the lid 84 and filter 86 are removed from the top 88. Slots 90 on the front lower end 92 of the cabinet 62 are sized and positioned to receive spring clips 94 located in the top 88 of the dehumidifier 28. Tabs 96 extending downward from the rear lower end 98 of the cabinet 62 have an aperture 100 sized and shaped to receive a knob 102 extending from the outer rear side 104 of the top 88 of the dehumidifier 28. As shown in FIGS. 9A and 9B, the front lower end 92 of the cabinet 62 is inserted at an angle into the top 88 of the dehumidifier 28. Slots 90 on the cabinet 62 are guided to receive tabs 94 of the dehumidifier 28. As shown in FIGS. 10A and 10B, the rear lower end 98 of the cabinet 62 is lowered and slid forward towards the front upper end 106 of the dehumidifier 28 until knobs 102 are engaged by the apertures 100 of tabs 96. The lid 84 and filter 86 of the dehumidifier 28 are then placed on the top 89 of the cabinet 62. When it is desired to remove the cabinet 62 from the dehumidifier 28, the above process is repeated in reverse.

The top 89 of the cabinet 62 is also sized slightly bigger than the bottom 87 of the cabinet 62, to allow for stacking and transporting of multiple cabinets 62. In a preferred arrangement, the cabinet 62 also includes handles 61 to simplify transport and use.

When the cabinet 62 is attached to the dehumidifier 28, the first outlet 74 aligns with the inlet 108 on the dehumidifier 28. The blower 44 on the dehumidifier 28 draws air flow vertically through the amplifier 60 as shown at 32. The second inlet 76 is pneumatically connected to the unaffected cool air source, such as an air conditioned system or an unaffected or ambient outside air source. The second air stream 78 has a lower temperature than the first air stream 32, which derives from the surrounding environment. As shown in FIG. 11, apparatus 60 is arranged to cool the input air stream 32 before it is drawn into the dehumidifier 28, thus preventing the dehumidifier 28 from losing performance, even if the air in the closed-air environment has a high temperature. Apparatus 60 cools the air by exchanging heat with the second, relatively cooler air stream 78.

In applications where the temperature of the secondary air stream 78 is significantly below the dew point of the primary air stream 32, condensation may occur inside the heat exchanger 64. A drip pan 99 underneath the heat exchanger 64, along with the mounting bracket 97 secured in the dehumidifier 28, direct condensate towards the front of the dehumidifier 28 and downward into the dehumidifier's drip pan 40 for removal.

According to the invention, an apparatus, system and method are provided that increase the efficiency of a dehumidifier. The invention increases water removal rates up to at least 100% and increases the grain depression up to 33% for faster drying of more materials. The invention preserves dehumidifier moisture removal rate that would otherwise be lost when surrounding air temperatures increase. The depicted arrangement is unique in that it couples directly to the intake of the dehumidifier 28 and provides an easy set-up having only two duct connections. Close-coupling to the dehumidifier 28 minimizes the imposed pressure drop on the dehumidifier's blower system. The drip pan 99 advantageously directs water into the dehumidifier 28 in case condensation occurs inside the apparatus 60. Also, the invention allows for use of additional heat generating equipment in the drying space, such as fans, additional dehumidifiers, etc. Use of such additional equipment further increases drying rates.

It should be understood that the drawings and specification are to be considered an exemplification of the principles of the invention, which is more particularly defined in the appended claims. For example, although the depicted arrangement is for attachment to a particular dehumidifier, the invention is applicable for use with a variety of dehumidifiers such as standard refrigerant-based or dessicant dehumidifiers. The concepts of the invention are also applicable for use in a system that that operates outside of an environment to be dehumidified, wherein the air streams are ducted to and from the environment.

Claims

1. An apparatus for enhancing performance of a dehumidifier that is operating in a substantially closed air environment, the apparatus comprising:

a cabinet adapted to removably attach to the dehumidifier, the cabinet having a first inlet receiving a first air stream from the closed air environment; a second inlet receiving a second air stream from a source other than the closed air environment, the second air stream being cooler than the first air stream; a first outlet discharging the first air stream to the dehumidifier; a second outlet discharging the second air stream; and an air-to-air heat exchanger in the cabinet, the air-to-air heat exchanger facilitating heat exchange between the first and second air flows to thereby cool the first air flow prior to discharge of the first air flow to the dehumidifier and warm the second air flow prior to discharge of the second air flow.

2. The apparatus of claim 1, comprising a fan for driving the second air stream through the cabinet.

3. The apparatus of claim 2, comprising means for thermostatically controlling the fan.

4. The apparatus of claim 1, comprising means for removably attaching the cabinet to a dehumidifier.

5. The apparatus of claim 4, wherein the means for removably attaching the cabinet to a dehumidifier comprise a slot on the cabinet.

6. The apparatus of claim 4, wherein the means for removably attaching the cabinet to a dehumidifier comprise a tab having an aperture.

7. The apparatus of claim 1, wherein the secondary air stream is discharged to an area other than the substantially closed air environment.

8. The apparatus of claim 1, comprising a baffle for directing condensate from the heat exchanger into the drip pan.

9. A method for enhancing performance of a dehumidifier that is operating in a substantially closed air environment, the apparatus comprising:

facilitating air-to-air heat exchange between a first air stream derived from the closed air environment and a second air stream derived from a source other than the closed air environment, the second air stream being cooler than the first air stream such that the first air stream is cooled;

discharging the cooled, first air stream to an inlet on the dehumidifier for dehumidification.

10. The method of claim 9, further comprising the step of dehumidifying the cooled first air stream and discharging the dehumidified first air stream to the closed air environment.

11. The method of claim 9, further comprising the step of discharging the second air stream to an area outside of the closed air environment.

12. The method of claim 9, wherein the source is an air-conditioned source.

13. An arrangement for dehumidification of a substantially closed air environment, the system comprising:

a dehumidifier having an inlet for receiving moist air and an outlet for discharging dehumidified air to the closed air environment; and

an air-to-air heat exchanger having a first inlet receiving a first air stream from the closed air environment, a second inlet receiving a second air stream from a source other than the closed air environment, the second air stream being cooler than the first air stream, a first outlet discharging the first air stream to the dehumidifier inlet, and a second outlet discharging the second air stream.

14. The arrangement of claim 13, comprising a cabinet housing the air-to-air heat exchanger, the cabinet adapted to removably attach to the dehumidifier.

15. The arrangement of claim 14, comprising an inlet cover adapted to interchangeably fit on the dehumidifier when the cabinet is not attached to the dehumidifier and on the cabinet when the cabinet is attached to the dehumidifier.

16. The arrangement of claim 15, wherein the inlet cover comprises an air filter.

17. The arrangement of claim 13, comprising a duct carrying the second air stream from the source to the second inlet.

18. The arrangement of claim 13, comprising a duct carrying the second air stream from the second outlet to an area other than the closed air environment.

19. The arrangement of claim 13, comprising a fan for driving the secondary air stream through the air-to-air heat exchanger.

20. The arrangement of claim 19, wherein the fan is thermostatically controlled.