Heat pump heating system

Abstract

A heat pump heating system ( 1 A) includes: a refrigerant circuit ( 3 ) including a compressor ( 21 ), a radiator ( 22 ), and an expansion member ( 25 A), and an evaporator ( 26 ); a circulation path ( 5 ) for circulating a liquid through the radiator ( 22 ) to produce a heated liquid; and a heater ( 4 ) for dissipating heat of the heated liquid. The refrigerant circuit ( 3 ) is provided with an internal heat exchanger ( 23 A) for transferring heat from a high pressure refrigerant that has released heat in the radiator ( 22 ) to a low pressure refrigerant. The liquid flowing through the circulation path ( 5 ) is cooled in a liquid cooling heat exchanger ( 24 ) by means of the high pressure refrigerant flowing out of the internal heat exchanger ( 23 A), before the liquid flows into the radiator ( 22 ).

1 - 12 . (canceled) 
     
     
         13 . A method of controlling a heat pump heating system, comprising:
 circulating a refrigerant in a refrigerant circuit, the refrigerant circuit including a compressor, a radiator, a liquid cooling heat exchanger, an expansion member, an evaporator and an internal heat exchanger;   circulating a liquid in a circulation path, the circulation path including a heater, a supply pipe that introduces a liquid from the heater to the liquid cooling heat exchanger, an intermediate pipe that introduces the liquid from the liquid cooling heat exchanger to the radiator, and a recovery pipe that introduces the liquid heated by the radiator to the heater;   expanding a high pressure refrigerant to a low pressure refrigerant at the expansion member;   causing the low pressure refrigerant to absorb heat at the evaporator;   transferring heat from a high pressure refrigerant that has released heat at the radiator to the lower pressure refrigerant at the internal heat exchanger of the refrigerant circuit;   compressing the low pressure refrigerant into the high pressure refrigerant with the compressor;   transferring heat from the liquid in the circulation path to the high pressure refrigerant in the refrigerant circuit at the liquid cooling heat exchanger;   transferring heat from the high pressure refrigerant in the refrigerant circuit to the liquid in the circulation path at the radiator, and producing a heated liquid in the circulation path; and   dissipating heat from the heated liquid in the circulation path at the heater downstream of the radiator.   
     
     
         14 . The method according to  claim 13 , further comprising: inhibiting heat exchange between the heated liquid and the high pressure refrigerant at the liquid cooling heat exchanger when the heated liquid flowing in the supply pipe has a temperature equal to or lower than the temperature of the high pressure refrigerant flowing into the liquid cooling heat exchanger. 
     
     
         15 . The method according to  claim 13 , wherein the internal heat exchanger is configured to exchange heat between the high pressure refrigerant flowing out of the radiator and the low pressure refrigerant flowing out of the evaporator. 
     
     
         16 . The method according to  claim 13 , wherein the internal heat exchanger is configured to exchange heat between the high pressure refrigerant flowing out of the radiator and the low pressure refrigerant before flowing into the evaporator. 
     
     
         17 . The method according to  claim 13 , wherein
 the circulation path further includes a bypass pipe connecting the supply pipe and the intermediate pipe, and a switching member for switching between a circulation of the liquid not through the bypass pipe and a circulation of the liquid through the bypass pipe;   the method further comprising:   preventing the heated liquid from circulating through the bypass pipe by the switching member, and thereby performing heat exchange between the heated liquid and the high pressure refrigerant at the liquid cooling heat exchanger, when the heated liquid flowing in the supply pipe has a temperature higher than the temperature of the high pressure refrigerant flowing into the liquid cooling heat exchanger, or   directing the heated liquid through the bypass pipe by the switching member, and thereby inhibiting heat exchange between the heated liquid and the high pressure refrigerant at the liquid cooling heat exchanger, when the heated liquid flowing in the supply pipe has a temperature equal to or lower than the temperature of the high pressure refrigerant flowing into the liquid cooling heat exchanger.   
     
     
         18 . The method according to  claim 13 , wherein the supply pipe includes a temperature sensor that detects the temperature of the liquid flowing into the supply pipe. 
     
     
         19 . The method according to  claim 13 , wherein the refrigerant is carbon dioxide.