Heat pump system

Abstract

A heat pump system includes a heat source unit, a discharge refrigerant communication tube, a liquid refrigerant communication tube, a gas refrigerant communication tube, a first usage unit and a second usage unit. The first usage unit has a first usage-side heat exchanger capable of functioning as a radiator of the heat-source-side refrigerant introduced from the discharge refrigerant communication tube. The first usage unit is capable of performing operation in which an aqueous medium is heated by radiation of the heat-source-side refrigerant in the first usage-side heat exchanger. The second usage unit has a second usage-side heat exchanger capable of functioning as an evaporator of the heat-source-side refrigerant introduced from the liquid refrigerant communication tube. The second usage unit is capable of performing operation in which an air medium is cooled by evaporation of the heat-source-side refrigerant in the second usage-side heat exchanger.

What is claimed is: 
     
         1 . A heat pump system comprising:
 a heat source unit having
 a heat-source-side compressor arranged to compress a heat-source-side refrigerant, 
 a heat-source-side heat exchanger, and 
 a heat-source-side switching mechanism switchable between
 a heat-source-side radiating operation state in which said heat-source-side heat exchanger functions as a radiator of a heat-source-side refrigerant, and 
 a heat-source-side evaporating operation state in which said heat-source-side heat exchanger functions as an evaporator of the heat-source-side refrigerant; 
 
   a discharge refrigerant communication tube capable of directing the heat-source-side refrigerant to the outside of said heat source unit from a discharge of said heat-source-side compressor in said heat-source-side radiating operation state and said heat-source-side evaporating operation state of said heat-source-side switching mechanism;   a liquid refrigerant communication tube capable of
 directing the heat-source-side refrigerant to the outside of said heat source unit from an outlet of said heat-source-side heat exchanger functioning as a radiator of the heat-source-side refrigerant in said heat-source-side radiating operation state of said heat-source-side switching mechanism, and 
 introducing the heat-source-side refrigerant into an inlet of said heat-source-side heat exchanger functioning as an evaporator of the heat-source-side refrigerant from outside said heat source unit in said heat-source-side evaporating operation state of said heat-source-side switching mechanism: 
   a gas refrigerant communication tube capable of introducing the heat-source-side refrigerant into an intake of said heat-source-side compressor from outside said heat source unit;   a first usage unit connected to said discharge refrigerant communication tube and said liquid refrigerant communication tube, the first usage unit having a first usage-side heat exchanger capable of functioning as a radiator of the heat-source-side refrigerant introduced from said discharge refrigerant communication tube, and the first usage unit being capable of performing operation in which
 the heat-source-side refrigerant radiated in said first usage-side heat exchanger is directed to said liquid refrigerant communication tube, and 
 an aqueous medium is heated by radiation of the heat-source-side refrigerant in said first usage-side heat exchanger, and 
   a second usage unit connected to said liquid refrigerant communication tube and said gas refrigerant communication tube, the second usage unit having a second usage-side heat exchanger capable of functioning as an evaporator of the heat-source-side refrigerant introduced from said liquid refrigerant communication tube in said heat-source-side radiating operation state of said heat-source-side switching mechanism, and the second usage unit being capable of
 directing the heat-source-side refrigerant evaporated in said second usage-side heat exchanger to said gas refrigerant communication tube, and 
 performing operation in which an air medium is cooled by evaporation of the heat-source-side refrigerant in said second usage-side heat exchanger. 
   
     
     
         2 . The heat pump system according to  claim 1 , further comprising:
 a usage-side switching mechanism switchable between
 an aqueous-medium heating operation state in which said first usage-side heat exchanger functions as a radiator of the heat-source-side refrigerant introduced from said discharge refrigerant communication tube, and 
 an aqueous-medium cooling operation state in which said first usage-side heat exchanger functions as an evaporator of the heat-source-side refrigerant introduced from said liquid refrigerant communication tube, 
   said first usage unit being further connected to said gas refrigerant communication tube, and said first usage unit being capable of
 performing operation in which the heat-source-side refrigerant radiated in said first usage-side heat exchanger is directed to said liquid refrigerant communication tube, and the aqueous medium is heated by radiation of the heat-source-side refrigerant in said first usage-side heat exchanger in said aqueous-medium heating operation state of said usage-side switching mechanism; and 
 performing operation in which the heat-source-side refrigerant evaporated in said first usage-side heat exchanger is directed to said gas refrigerant communication tube, and the aqueous medium is cooled by evaporation of the heat-source-side refrigerant in said first usage-side heat exchanger in said aqueous-medium cooling operation state of said usage-side switching mechanism. 
   
     
     
         3 . The heat pump system according to  claim 1 , wherein
 said gas refrigerant communication tube is capable of
 introducing the heat-source-side refrigerant to an intake of said heat-source-side compressor from outside said heat source unit in said heat-source-side radiating operation state of said heat-source-side switching mechanism, and 
 directing the heat-source-side refrigerant to the outside of said heat source unit from a discharge of said heat-source-side compressor in said heat-source-side evaporating operation state of said heat-source-side switching mechanism, and 
   said second usage unit is capable of performing operation in which
 said second usage-side heat exchanger functions as a radiator of the heat-source-side refrigerant introduced from said gas refrigerant communication tube in said heat-source-side evaporating operation state of said heat-source-side switching mechanism, 
 the heat-source-side refrigerant radiated in said second usage-side heat exchanger is directed to said liquid refrigerant communication tube, and 
 the air medium is heated by radiation of the heat-source-side refrigerant in said second usage-side heat exchanger; and 
   
       the heat pump system further comprises
 a usage-side switching mechanism switchable between
 an aqueous-medium heating operation state in which said first usage-side heat exchanger functions as a radiator of the heat-source-side refrigerant introduced from said discharge refrigerant communication tube, and 
 an aqueous-medium cooling operation state in which said first usage-side heat exchanger functions as an evaporator of the heat-source-side refrigerant introduced from said liquid refrigerant communication tube, 
 
 said first usage unit being-further connected to said gas refrigerant communication tube, and said first usage unit being capable of
 performing operation in which the heat-source-side refrigerant radiated in said first usage-side heat exchanger is directed to said liquid refrigerant communication tube, and the aqueous medium is heated by radiation of the heat-source-side refrigerant in said first usage-side heat exchanger in said aqueous-medium heating operation state of said usage-side switching mechanism, and 
 performing operation in which the heat-source-side refrigerant evaporated in said first usage-side heat exchanger is directed to said gas refrigerant communication tube, and the aqueous medium is cooled by evaporation of the heat-source-side refrigerant in said first usage-side heat exchanger in said aqueous-medium cooling operation state of said usage-side switching mechanism, and 
 
 a defrosting operation being performed in which
 said heat-source-side heat exchanger is caused to function as a radiator of the heat-source-side refrigerant, and said second usage-side heat exchanger is caused to function as an evaporator of the heat-source-side refrigerant by placing said heat-source-side switching mechanism in said heat-source-side radiating operation state, and 
 said first usage-side heat exchanger is caused to function as an evaporator of the heat-source-side refrigerant by placing said usage-side switching mechanism in said aqueous-medium cooling operation state in a case in which defrosting of said heat-source-side heat exchanger is determined to be necessary. 
 
 
     
     
         4 . The heat pump system according to  claim 3 , wherein
 functioning of said first usage-side heat exchanger as an evaporator of the heat-source-side refrigerant is stopped in a case in which temperature of the aqueous medium cooled by evaporation of the heat-source-side refrigerant in said first usage-side heat exchanger is equal to or less than a predetermined freezing-lower-limit temperature during said defrosting operation.   
     
     
         5 . The heat pump system according to  claim 3 , further comprising:
 a first usage-side flow rate adjustment valve capable of varying flow rate of the heat-source-side refrigerant that flows through said first usage-side heat exchanger,   during said defrosting operation, control being performed to reduce an opening degree of said first usage-side flow rate adjustment valve
 in a case in which the temperature of the aqueous medium cooled by evaporation of the heat-source-side refrigerant in said first usage-side heat exchanger is equal to or less than a predetermined freeze-warning temperature, and 
 in a case in which a defrosting operation time, which is an elapsed time from a start of defrosting operation, is equal to or less than a predetermined defrosting operation set time, and defrosting of said heat-source-side heat exchanger is not completed, a predetermined defrosting time interval setting value until the start of the next defrosting of said heat-source-side heat exchanger is reduced. 
   
     
     
         6 . The heat pump system according to  claim 2 , further comprising:
 a first refrigerant recovery mechanism arranged to communicate said discharge refrigerant communication tube and said gas refrigerant communication tube in any of said aqueous medium heating operation state and said aqueous medium cooling operation state of said usage-side switching mechanism.   
     
     
         7 . The heat pump system according to  claim 2 , further comprising:
 a second refrigerant recovery mechanism arranged to communicate said first usage-side heat exchanger and said gas refrigerant communication tube in any of said aqueous medium heating operation state and said aqueous medium cooling operation state of said usage-side switching mechanism.   
     
     
         8 . The heat pump system according to  claim 2 , wherein
 a refrigerant recovery operation is performed in which said usage-side switching mechanism is placed in said aqueous medium heating operation state, and said first usage-side heat exchanger is thereby caused to function as a radiator of the heat-source-side refrigerant in a case in which the flow rate of the heat-source-side refrigerant taken into said heat-source-side compressor is determined to be inadequate in a case in which said usage-side switching mechanism is in said aqueous medium cooling operation state and said second usage unit is at least operating.   
     
     
         9 . The heat pump system according to  claim 1 , wherein
 said first usage-side heat exchanger is arranged to exchange heat between the heat-source-side refrigerant and the aqueous medium.   
     
     
         10 . The heat pump system according to  claim 9 , further comprising:
 an aqueous medium circuit through which an aqueous medium circulates in order to exchange heat with the heat-source-side refrigerant in said first usage-side heat exchanger, the aqueous medium circuit having a variable-capacity circulation pump,   the capacity of said circulation pump being controlled so that the flow rate of the aqueous medium circulated through said aqueous medium circuit decreases in a case in which a heat-source-side outlet/inlet pressure difference is equal to or less than a predetermined heat-source-side low differential pressure protection pressure difference, and   the heat-source-side outlet/inlet pressure difference being the difference between the pressure of the heat-source-side refrigerant in the discharge of said heat-source-side compressor and the pressure of the heat-source-side refrigerant in the intake of said heat-source-side compressor.   
     
     
         11 . The heat pump system according to  claim 10 , wherein
 the capacity of said circulation pump is controlled so that an aqueous medium outlet/inlet temperature is equal to a predetermined target aqueous medium outlet/inlet temperature difference in a case in which said heat-source-side outlet/inlet pressure difference is greater than said heat-source-side low differential pressure protection pressure difference; and   the aqueous medium outlet/inlet temperature difference is the difference between the temperature of the aqueous medium in an outlet of said first usage-side heat exchanger and the temperature of the aqueous medium in an inlet of said first usage-side heat exchanger.   
     
     
         12 . The heat pump system according to  claim 11 , wherein
 said target aqueous medium outlet/inlet temperature difference is increased in a case in which said heat-source-side outlet/inlet pressure difference is equal to or less than said heat-source-side low differential pressure protection pressure difference.   
     
     
         13 . The heat pump system according to  claim 1 , wherein
 said first usage-side heat exchanger is arranged to exchange heat with the heat-source-side refrigerant introduced from said discharge refrigerant communication tube and a usage-side refrigerant other than the heat-source-side refrigerant;   said first usage unit further has
 a usage-side compressor arranged to compress the usage-side refrigerant, and 
 a refrigerant/water heat exchanger capable of functioning as a radiator of the usage-side refrigerant and heating the aqueous medium, and 
   said first usage unit together with said first usage-side heat exchanger constitute a usage-side refrigerant circuit through which the usage-side refrigerant circulates.   
     
     
         14 . The heat pump system according to  claim 13 , further comprising:
 an aqueous medium circuit through which an aqueous medium circulates in order to exchange heat with the usage-side refrigerant in said refrigerant/water heat exchanger, the aqueous medium circuit having a variable-capacity circulation pump,   the capacity of said circulation pump being controlled so that the flow rate of the aqueous medium circulated through said aqueous medium circuit decreases in a case in which a usage-side outlet/inlet pressure difference is equal to or less than a predetermined usage-side low differential pressure protection pressure difference,   the usage-side outlet/inlet pressure difference being the difference between the pressure of the usage-side refrigerant in the discharge of said usage-side compressor and the pressure of the usage-side refrigerant in the intake of said usage-side compressor.   
     
     
         15 . The heat pump system according to  claim 14 , wherein
 the capacity of said circulation pump is controlled so that the aqueous medium outlet/inlet temperature difference is equal to a predetermined target aqueous medium outlet/inlet temperature difference in a case in which said usage-side outlet/inlet pressure difference is greater than said usage-side low differential pressure protection pressure difference; and   the aqueous medium outlet/inlet temperature difference is the difference between the temperature of the aqueous medium in an outlet of said refrigerant/water heat exchanger and the temperature of the aqueous medium in an inlet of said refrigerant/water heat exchanger.   
     
     
         16 . The heat pump system according to  claim 15 , wherein
 said target aqueous medium outlet/inlet temperature difference is increased in a case in which said usage-side outlet/inlet pressure difference is equal to or less than said usage-side low differential pressure protection pressure difference.   
     
     
         17 . The heat pump system according to  claim 1 , wherein
 a plurality of said second usage units are connected to each other in parallel via said liquid refrigerant communication tube and said gas refrigerant communication tube.   
     
     
         18 . The heat pump system according to  claim 1 , wherein
 a plurality of said first usage units are connected to each other in parallel via said discharge refrigerant communication tube and said liquid refrigerant communication tube.