Closed-Loop Dehumidification Circuit For Refrigerant System

Abstract

A closed-loop reheat circuit decoupled from a main refrigerant circuit is provided as part of a refrigerant system. In the closed-loop reheat circuit refrigerant is flown through an auxiliary heat exchanger, at which it transfers heat to refrigerant in the main circuit, increasing its cooling and dehumidification potential prior to entering an evaporator. The closed-loop circuit also includes a reheat heat exchanger that is placed in the path of at least a portion of airflow having passed over an evaporator. The reheat heat exchanger reheats air supplied to a conditioned space to a desired temperature after sufficient amount of moisture has been removed from the air in the evaporator to provide a comfortable humidity level. By utilizing the closed-loop reheat circuit, a control for the overall refrigerant system becomes less complex and more flexible, and the refrigerant system operation turns out to be more reliable and satisfying a variety of environmental conditions and potential applications. Various features and options of the decoupled reheat circuit concept are also disclosed.

1 . A refrigerant system comprising:
 a main refrigerant circuit including a compressor, a condenser, an auxiliary heat exchanger, an expansion device, and an evaporator;   a closed-loop reheat circuit, said closed-loop reheat circuit passing a refrigerant through said auxiliary heat exchanger and a reheat heat exchanger;   an air-moving device moving air over said evaporator; and   said reheat heat exchanger being positioned such that at least a portion of air having passed over said evaporator then passes over said reheat heat exchanger.   
   
   
       2 . The refrigerant system as set forth in  claim 1 , wherein said auxiliary heat exchanger is positioned downstream of the condenser. 
   
   
       3 . The refrigerant system as set forth in  claim 1 , wherein said auxiliary heat exchanger is positioned upstream of the condenser. 
   
   
       4 . The refrigerant system as set forth in  claim 1 , wherein a liquid pump is included in said closed-loop circuit to drive refrigerant. 
   
   
       5 . The refrigerant system as set forth in  claim 4 , wherein a variable speed drive is provided for said liquid pump. 
   
   
       6 . The refrigerant system as set forth in  claim 4 , wherein an expansion device is included in said closed-loop circuit. 
   
   
       7 . The refrigerant system as set forth in  claim 1 , wherein a flow control device is included in said closed-loop reheat circuit. 
   
   
       8 . The refrigerant system as set forth in  claim 1 , wherein a bypass line allows selective bypass of at least a portion of refrigerant in said main refrigerant circuit around said condenser. 
   
   
       9 . The refrigerant system as set forth in  claim 1 , wherein refrigerant in said main circuit and refrigerant in said reheat circuit are different. 
   
   
       10 . The refrigerant system as set forth in  claim 1 , wherein refrigerant in said main circuit and refrigerant in said reheat circuit have identical constituents. 
   
   
       11 . The refrigerant system as set forth in  claim 1 , wherein refrigerant in said reheat circuit remains in a liquid state throughout the circuit. 
   
   
       12 . The refrigerant system as set forth in  claim 1 , wherein refrigerant in said reheat circuit undergoes phase transformation between liquid and vapor phases. 
   
   
       13 . A method of refrigerant system comprising:
 compressing a refrigerant at a compressor and delivering the refrigerant to a downstream condenser through a main flow line;   providing an auxiliary heat exchanger, and an evaporator downstream of said auxiliary heat exchanger;   compressed refrigerant in said main flow line passing to said condenser, to said auxiliary heat exchanger, to said evaporator, and back to said compressor;   providing a closed-loop reheat circuit, said closed-loop reheat circuit passing a refrigerant through said auxiliary heat exchanger, and then to a reheat heat exchanger;   an air-moving device moving air over said evaporator; and   said reheat heat exchanger being positioned such that at least a portion of air having passed over said evaporator then passes over said reheat heat exchanger.   
   
   
       14 . The method as set forth in  claim 13 , wherein a liquid pump drives refrigerant through said closed-loop circuit. 
   
   
       15 . The method as set forth in  claim 14 , wherein a variable speed drive varies the speed of said liquid pump. 
   
   
       16 . (canceled) 
   
   
       17 . The method as set forth in  claim 13 , wherein a bypass line selectively bypasses refrigerant from said main refrigerant line around said condenser. 
   
   
       18 . The method as set forth in  claim 13 , wherein said auxiliary heat exchanger is positioned downstream of the condenser. 
   
   
       19 . The method as set forth in  claim 13 , wherein said auxiliary heat exchanger is positioned upstream of the condenser. 
   
   
       20 .- 22 . (canceled) 
   
   
       23 . The method as set forth in  claim 13 , wherein refrigerant in said closed loop reheat circuit remains in a liquid state throughout the circuit. 
   
   
       24 . The method as set forth in  claim 13 , wherein refrigerant in said closed-loop reheat circuit undergoes phase transformation between liquid and vapor phases. 
   
   
       25 . The refrigerant system as set forth in  claim 1 , wherein refrigerant in said closed-loop reheat circuit and said main refrigerant circuit do not inter-mix as the refrigerant in the reheat circuit passes between the auxiliary heat exchanger and the reheat heat exchanger.