Hybrid air-conditioning system for efficient cooling and dehumidification and method

Abstract

A hybrid air conditioning system for cooling a chamber, the hybrid system including a desiccant-coated heat pump configured to cool, through evaporation and condensation of a refrigerant, a first air stream OA, and an indirect evaporative cooling, IEC, unit configured to cool a second air stream MA, which is related to the first air stream OA, through direct heat exchange between wet channels that are placed adjacent to dry channels. The desiccant-coated heat pump is fluidly connected to the IEC unit so that a generated supply air stream SA is dehumidified by a desiccant material coated on first and second heat exchangers of the desiccant-coated heat pump.

1 . A hybrid air conditioning system for cooling a chamber, the hybrid system comprising:
 a desiccant-coated heat pump configured to cool, through evaporation and condensation of a refrigerant, a first air stream OA; and   an indirect evaporative cooling, IEC, unit configured to cool a second air stream MA, which is related to the first air stream OA, through direct heat exchange between wet channels that are placed adjacent to dry channels,   wherein the desiccant-coated heat pump is fluidly connected to the IEC unit so that a generated supply air stream SA is dehumidified by a desiccant material coated on first and second heat exchangers of the desiccant-coated heat pump.   
     
     
         2 . The system of  claim 1 , wherein the first air stream OA is supplied during a first cycle, only to the first exchanger, but not the second heat exchanger, and during a second cycle, only to the second heat exchanger, but not to the first heat exchanger. 
     
     
         3 . The system of  claim 1 , wherein each of the first heat exchanger and the second heat exchanger includes coils directly covered with the desiccant material. 
     
     
         4 . The system of  claim 3 , wherein the desiccant-coated heat pump further includes:
 a compressor that compresses a refrigerant that flows through the first and second heat exchangers;   an evaporator fluidly connected to the first and second heat exchangers and configured to evaporate the refrigerant; and   a four-way valve fluidly connecting the compressor to the first and second heat exchangers so that,   during the first cycle, the refrigerant flows from the compressor to the four-way valve, to the second heat exchanger, to a throttling valve, to the first heat exchanger, and back to the four-way valve and then to the compressor, and   during the second cycle, the refrigerant flows from the compressor to the four-way valve, to the first heat exchanger, to the throttling valve, to the second heat exchanger, and back to the four-way valve and then to the compressor.   
     
     
         5 . The system of  claim 4 , further comprising:
 air flow piping configured to fluidly connect the first and second heat exchangers to the dry channels of the IEC system, the dry channels directly to the evaporator, and the evaporator directly to the chamber.   
     
     
         6 . The system of  claim 5 , wherein the air flow piping is further configured to fluidly connect (1) the first and second heat exchangers to the dry channels of the IEC system, and (2) the wet channels of the IEC system back to the first and second heat exchangers, and
 wherein distilled water is used in the wet channels to reduce biofouling in the first and second exchangers.   
     
     
         7 . The system of  claim 6 , wherein the air flow piping is further configured to fluidly connect an output of the chamber to (1) the wet channels and (2) to the dry channels. 
     
     
         8 . The system of  claim 5 , wherein the air flow piping is further configured to fluidly connect the first and second heat exchangers to the dry channels of the IEC system, and the wet channels of the IEC system directly to the ambient. 
     
     
         9 . The system of  claim 8 , wherein the air flow piping is further configured to fluidly connect an output of the chamber to (1) the wet channels and (2) the dry channels, and
 wherein distilled water is used in the wet channels to reduce biofouling in the first and second exchangers.   
     
     
         10 . A desiccant-coated heat pump comprising:
 a first heat exchanger having a coil coated with a desiccant material;   a second heat exchanger having a coil coated with the desiccant material;   a first pipe junction housing only one first air damper V 1 ; and   a second pipe junction housing only one second air damper V 2 ,   wherein the heat pump includes no more than two air dampers.   
     
     
         11 . The heat pump of  claim 10 , wherein the first pipe junction is fluidly, directly connected to each of the first heat exchanger, the second heat exchanger, a chamber to be cooled, and an ambient outside the chamber. 
     
     
         12 . The heat pump of  claim 11 , wherein the second pipe junction is fluidly, directly connected to each of the first heat exchanger, the second heat exchanger, the chamber to be cooled, and the ambient outside the chamber. 
     
     
         13 . The heat pump of  claim 12 , wherein the first and second air dampers are in a first state so that outside air enters the first pipe junction, flows into the first heat exchanger to be dehumidified, then flows into the second pipe junction and then enters into the chamber. 
     
     
         14 . The heat pump of  claim 13 , wherein return air from the chamber, during the first state, enters the first pipe junction, then the second heat exchanger to regenerate the desiccant material, then enters the second pipe junction and then is discharged into the ambient. 
     
     
         15 . The heat pump of  claim 14 , wherein the first and second air dampers are in a second state so that the outside air enters the first pipe junction, flows into the second heat exchanger to be dehumidified, then flows into the second pipe junction and then enters into the chamber. 
     
     
         16 . The heat pump of  claim 15 , wherein the return air from the chamber, during the second state, enters the first pipe junction, then the first heat exchanger to regenerate the desiccant material, then enters the second pipe junction and then is discharged into the ambient. 
     
     
         17 . The heat pump of  claim 16 , wherein the first and second heat exchangers are placed in direct contact with each other. 
     
     
         18 . A method for supplying cool air, to a chamber, with a desiccant-coated heat pump, the method comprising:
 setting a first air damper V 1  in a first pipe junction and a second air damper V 2  in a second pipe junction to a first state, wherein there are no other air dampers in the heat pump;   receiving an outside air stream OA at the first pipe junction;   dehumidifying and cooling the outside air stream OA with a first heat exchanger having a coil coated with a desiccant material, to generate a dried air stream DA;   supplying the dried air stream DA to the chamber through a second pipe junction that houses the second air damper V 2 ;   providing a return air stream PA 1  from the chamber, via the first pipe junction, to a second heat exchanger having a coil coated with the desiccant material, to regenerate the desiccant material; and   discharging a humid air stream PA 2  from the second heat exchanger, via the second pipe junction, to the ambient.   
     
     
         19 . The method of  claim 18 , further comprising:
 switching the first and second air dampers from the first state to a second state to reverse an air flow through the first and second heat exchangers to regenerate the desiccant material in the first heat exchanger and use the desiccant material in the second heat exchanger for drying and cooling the outside air stream OA.   
     
     
         20 . The method of  claim 18 , further comprising:
 flowing the dry air stream DA from the first heat exchanger though dry channels of an indirect evaporative cooler, IEC, system before providing the dry air stream DA to the chamber; and   flowing the return air stream PA 1  through wet channels of the IEC system before arriving at the first pipe junction.