JP5329535B2 - Humidity control system using desiccant equipment - Google Patents

Description

Cross-reference of related applications

  This application claims the priority benefit of US Provisional Application No. 60 / 924,764, filed May 30, 2007.

  The present invention relates to a humidity control system, and more particularly to a humidity control device that utilizes low-grade waste heat to assist in the regeneration of a desiccant device.

  Various systems have been proposed with an air treatment system that maintains a comfortable humidity level in indoor facilities. Some of these systems are intended for use in other applications such as ice arenas where the ice surface is maintained at freezing temperatures, or refrigerated storage facilities that can use waste heat from large ice plants. Specially designed. Such systems typically use a liquid refrigerant loop that is cooled by a direct vaporization type primary refrigerant system. Such a system that uses a dehumidifier unit connected to an ice rink coil to dry process air is disclosed, for example, in US Pat. Another such system is disclosed in U.S. Patent No. 5,677,097 that uses a reheat coil connected to the waste heat line from the compressor of the primary cooling unit to complement the dehumidification unit in the process air stream. This reheat coil heats the regeneration air supplied to the regeneration section of the desiccant wheel to increase the absorbency of the desiccant medium to further remove moisture from the process air stream. This reheat coil system is used with a dehumidification coil in the process air section of the dehumidification system connected to the liquid cooling system.

US Pat. No. 6,321,551 US Pat. No. 6,935,131

  According to one aspect of the present invention, a reactivation circuit is provided to preheat the regenerative air supplied to the desiccant unit of the dehumidification system. The reactivation circuit is connected directly to the evaporative cooling circuit with a compressor and a refrigerant heat exchanger (using water, brine, or other refrigerant) that acts as an evaporator for the circuit Air-cooled condenser coil / dehumidifier coil. This reactivation circuit functions as a water source heat pump to extract heat from the liquid refrigerant in the secondary cooling circuit that freezes the ice sheet. Low grade (85-95 ° F. (29.4-35 ° C.) low temperature) heat is removed from the secondary cooling plant and higher grade heat through the air cooled condenser coil to regenerate the desiccant material. To generate (high temperature of 115-130 degrees F (46.1-54.4 ° C.)), it is extracted by the reactivation circuit. The heated air removes moisture from the desiccant and releases it to the atmosphere.

  According to another aspect of the present invention, the return air or return air and the outside air circulated into an internal space including an ice rink or the like or an enclosure is dehumidified in a continuous process by the desiccant material. The desiccant is preferably a desiccant wheel that rotates through both the feed process air stream and the reactivated air stream. The dehumidification coil is located upstream of the reactivation air flow in the regeneration section of the dehumidification wheel and is connected to a direct vaporization cooling circuit with a continuous compressor and a subsequent separated air cooling condenser coil. This system increases the humidity level of the enclosed space, and if the humidity of the return air and / or the mixture of return air and outside air exceeds a predetermined level, the second stage compressor causes the air to reach the desiccant wheel. It will be activated to cool and dehumidify the air before doing so. If the humidity of the air entering the desiccant continues to rise, the third and fourth stage compressors will continue to operate. When the return air humidity is returned to its controlled set point, the compressor stages are turned off in reverse order and eventually the dehumidifier is deactivated.

  In a more general embodiment of the present invention, the cooling circuit that generates heat for the condensing coil that heats the desiccant regeneration or reactivation air stream may be of any low grade decoupled from ambient temperature. Connected with liquid heat loop. This means that the system is not constrained by environmental conditions and can provide appropriate reactivation temperature control independent of the ambient environmental temperature. Thus, the water, glycol and salt water loops need not be limited to heat removed from secondary coolant loops such as the ice sheet cooling system described above, but are known solar loops, cooling towers, groundwater loops, other Excluded heat cooling loops, or any loop designed to maintain temperature between 45 degrees F. (7.2 degrees C.) and 95 degrees F. (35 degrees C.) throughout the year will be included. For example, a low grade solar loop using water heated to a low temperature by the sun could be used.

  The above and other objects, features and advantages of the present invention will become apparent from the following detailed description of specific embodiments, which should be referred to in conjunction with the accompanying drawings.

Schematic of dehumidification system according to the present invention Detailed view of one of the cooling systems used in the present invention

  As shown in FIG. 1, the system 10 of the present invention comprises a cooling system 12 for freezing an ice sheet 14 in an enclosed space or building (not shown). The system 10 further comprises a humidity control unit 16 that is operable to control the humidity of the return air stream 18 that comes from the enclosure and returns to the enclosure by operation of the fan 20. If necessary, a proportion of outside air can be introduced into the return air stream through the duct 22 by known techniques.

  The cooling system 12 is disposed on the floor of an ice rink, ice plant 14, etc., and has a set of coils (not shown) connected to the evaporator 30 by supply and return lines 26, 28 and a pump 29. A secondary cooling system 24 is provided.

  The evaporator 30 forms part of a primary cooling system 32 having a condenser 34 and a compressor 36 connected by lines 38 to coils in the evaporator 30. The primary cooling system is a conventional direct vaporization system that absorbs heat from the liquid cooling system in the evaporator and releases it to the atmosphere in the condenser 34. The primary cooling system 32 includes a further heat exchanger 40 connected to the refrigerant line 38 by lines 42 and 44. This heat exchanger functions as an evaporator for the tertiary cooling system 50, which is also a direct evaporative cooling system. The system 50 includes a compressor 52 disposed within the housing 54 of the humidity controller 16. The apparatus comprises a regeneration air duct 56 and a process air duct 58 separated from each other by known walls and adjustment plates.

  The dehumidification system 16 also includes a desiccant wheel device 60 of known construction that is regenerated in the regeneration duct 56 and is rotatably mounted on the housing to dehumidify air in the process air duct 58. The desiccant wheel has a known structure and is rotatably attached by any method.

  The regeneration air is drawn from the atmosphere into the regeneration duct 56 through the opening 62 in the housing 54 by a fan 64 that releases the regeneration air into the atmosphere after it passes through the desiccant wheel.

  The cooling system 50 includes a condenser coil 66 attached to the regeneration duct 56 upstream of the desiccant wheel. The coil is connected by a refrigerant line 68 to a compressor 52 that is alternately connected to the heat exchanger 40 by a line 70.

  When it is necessary to dehumidify the return air supplied into the enclosed space and / or the return air and the outside air, the compressor 52 is activated to supply the cooled refrigerant from the condenser to the heat exchanger 40. The temperature of the coolant in line 70 rises in heat exchanger 40 (due to the coolant in line 38 flowing from line 42 through heat exchanger 40 to line 44) and back to compressor 52 where the refrigerant is compressed, It is heated and supplied to the capacitor coil 66. In the condenser coil, the refrigerant is cooled by the supply air entering the duct 62 and then transfers heat to the regeneration air entering the regeneration portion of the rotating desiccant wheel 60 before being released to the atmosphere. As a result, some of the low-grade heat (such as between 45 ° F (7.2 ° C) and 95 ° F (35 ° C)) from the liquid in the loops 26 and 28 is excluded from Air to regenerate the desiccant wheel to produce higher grade heat (e.g., between 105 degrees F (40.6 degrees C) and 135 degrees F (57.2 degrees C) of liquid in line 68). It is extracted by this heat pump arrangement through a cooling condenser coil. This heated air removes moisture from the desiccant and regenerates the desiccant. It also contributes to cooling the refrigerant in the system 32.

  The dehumidification process described above continues as the desiccant wheel rotates through the supply and reactivation air flow. However, if the humidity level of the link exceeds a predetermined point that requires additional dehumidification, the humidity controller 16 to perform further dehumidification before the return air and / or outside air / return air passes through the desiccant wheel. Is placed. As can be seen from FIG. 2, to perform further dehumidification, the dehumidifier includes an additional cooling circuit 80 that includes an air cooling condenser coil 90 attached to the dehumidifying coil 88 and one end of the housing 54. Are connected to multiple compressors 82, 83, 84 connected by a line 86. Thus, if further dehumidification is required beyond the dehumidification that the desiccant wheel can provide on its own, the compressed refrigerant is transferred to a dehumidifying coil that removes moisture from the air before it enters the desiccant wheel. To supply, the compressor 82 is activated. At the same time, it cools the air before it reaches the desiccant wheel. The heat absorbed from the air by the refrigerant in the dehumidifying coil is released to the atmosphere in the condenser coil 90 cooled by the fan 92 and returned to the compressor 82. If further dehumidification is required, the second and third stage compressors 83, 84 can be activated.

  As is more apparent from FIG. 2, the cooling circuit 80 is actually three independent cooling circuits and uses different portions of the coils 88, 90 in their respective cooling circuits. Thus, compressor 82 is connected to coil sections 88 'and 90' by line 82 '; compressor 83 is connected to coil sections 88 ", 90" by line 83'; compressor 84 is coil section by line 84 '. 88 '", 90'". Each circuit is operated separately on demand. This cooling and dehumidification of the return air before it enters the desiccant wheel increases the ability of the desiccant wheel to further remove moisture from the process air stream, making the return air desired by the wheel. Reheated to process return temperature.

  If desired or necessary, some or all of the process air can be diverted to the desiccant wheel using a suitable ductwork 100 known to those skilled in the art. Appropriate temperature and humidity sensors and associated controls, as would be conceived by those skilled in the art, are also provided for selectively operating various compressors.

  Thus, the system provides sufficient capacity to handle variable amounts of produced air as conditions change without changing the basic cooling system 12 or 32.

  Although specific embodiments of the present invention have been described herein with reference to the drawings, the present invention is not limited to these embodiments, and those skilled in the art will depart from the subject matter and spirit of the present invention. It will be understood that various changes and modifications can be made without doing so.

10 System 12, 24, 32, 50 Cooling system 16 Dehumidification system

Claims (8)

A humidity control system for an enclosed space comprising a heating load, a first cooling system for cooling the heating load, and a second cooling system for removing heat from the first system, the process comprising: A housing having an air duct and a regenerative air duct; means for supplying return air and / or atmosphere from the enclosed space to the processing air duct; means for supplying air to the regeneration duct; the processing air duct and the regeneration A desiccant wheel rotatably mounted on the housing for rotation through an air duct, thereby absorbing moisture in the process air duct and releasing the moisture in the regeneration duct; and the desiccant wheel in the regeneration duct A capacitor coil upstream of the compressor, a compressor connected to the capacitor coil, and A third cooling system having a compressor and a heat exchanger connected to said second cooling system, thereby, the to increase the temperature of the air supplied to the desiccant wheel in said regeneration duct A third cooling system in which low grade heat absorbed from the heat exchanger by the third cooling system is used by the compressor to generate high grade heat supplied to a capacitor coil; upstream of the dehumidification coil of the desiccant wheel in the process air flow, a plurality of compressors connected in dehumidification coil in said process air stream, and a fourth cooling system having a capacitor connected coils to the plurality of compressors So that in the process air duct before air enters the desiccant wheel To selectively dehumidified air, depending on the level of humidity of the air supplied to the desiccant wheel, a fourth cooling system the plurality of compressors in the cooling system of the fourth can be sequentially operated And a humidity control system. A housing having a process air duct and a regenerative air duct; and a humidity control system for an enclosed space, the means for supplying return air from the enclosed space and / or the atmosphere to the process air duct; Means for supplying to the duct, and is rotatably mounted on the housing for rotation through the processing air duct and the regeneration air duct, absorbs moisture in the processing air duct and releases the moisture in the regeneration air duct A cooling system having a condenser coil upstream of the desiccant wheel in the regeneration duct and a heat pump connected to the condenser coil, the heat pump comprising: a heat exchanger; and the condenser coil Recirculating liquid connected between the heat exchangers A-loop cooling system and having a recirculation liquid loop for transferring heat to the reactivation airflow from the recirculation liquid loop; upstream of the dehumidification coil of the desiccant wheel in the process air flow, Another cooling system having a plurality of compressors connected to a dehumidification coil in the process air stream and a condenser coil connected to the plurality of compressors, whereby in the process air duct, the air is the desiccant Depending on the level of humidity of the air supplied to the desiccant wheel, the plurality of compressors in the other cooling system can be operated sequentially to selectively dehumidify the air before entering the wheel. A humidity control system comprising another cooling system. The humidity control system according to claim 2 , wherein the liquid loop is isolated from the atmospheric temperature. The humidity control system of claim 2 , wherein the liquid loop includes liquid from a group consisting of groundwater or glycol loops. The humidity control system according to claim 2 , wherein the liquid loop is a cooling tower loop. The humidity control system of claim 2 , wherein the liquid loop is a low grade solar loop. The humidity control system of claim 2 , wherein the liquid loop is maintained between 45 degrees F (7.2 degrees C) and 95 degrees F (35 degrees C) throughout the year. The humidity control system according to claim 2, wherein the temperature of the regeneration air generated by the heat pump is between 105 degrees F (40.6 degrees C) and 135 degrees F (57.2 degrees C).

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