Engine Heat Pump

Abstract

An engine heat pump whose compression work is reduced without increase of consumed electric power, thereby improving its driving efficiency (energy efficiency). An engine heat pump comprises: an engine; a main compressor driven by the engine; a sub compressor delivering a refrigerant to be joined to a refrigerant delivered from the main compressor; an indoor heat exchanger; an outdoor heat exchanger; an expansion valve for the indoor heat exchanger; an expansion valve for the outdoor heat exchanger; and a supercooling heat exchanger disposed on a liquid refrigerant passage (main passage) of a connection passage between the indoor heat exchanger and the outdoor heat exchanger. In the supercooling heat exchanger, a supercooling liquid refrigerant branched into a branching passage supercools a liquid refrigerant before being branched. The sub compressor is driven by the engine so as to compress the supercooling liquid refrigerant. A ratio (R) of a capacity of the sub compressor to a total capacity of the main compressor and the sub compressor ranges between 20% and 29%.

1 . An engine heat pump comprising: 
 (a) an engine;    (b) a main compressor driven by the engine;    (c) a sub compressor delivering a refrigerant to be joined to a refrigerant delivered from the main compressor;    (d) an indoor heat exchanger;    (e) an outdoor heat exchanger;    (f) an expansion valve for the indoor heat exchanger;    (g) an expansion valve for the outdoor heat exchanger; and    (h) a supercooling heat exchanger disposed on a liquid refrigerant passage of a connection passage between the indoor heat exchanger and the outdoor heat exchanger, wherein, in the supercooling heat exchanger, a supercooling liquid refrigerant branched into a branching passage supercools a liquid refrigerant before being branched,    (i) characterized in that the sub compressor is driven by the engine so as to compress the supercooling liquid refrigerant, and a ratio of a capacity of the sub compressor to a total capacity of the main compressor and the sub compressor ranges between 20% and 29%.    
     
     
         2 . The engine heat pump according to  claim 1 , further comprising: 
 (a) an engine exhaust heat recovery unit disposed in parallel to the outdoor heat exchanger, wherein the supercooling liquid refrigerant is evaporated by the engine exhaust heat recovery unit and compressed by the sub compressor.