Water heat exchanger and hot water heat source apparatus

Abstract

A water heat exchanger exchanges heat between a refrigerant and water, and includes a pair of flat refrigerant pipes and a flat water pipe. Each flat refrigerant pipe has a plurality of refrigerant passageway holes. The flat water pipe has at least one water passageway hole. The number of water passageway holes is fewer than the number of refrigerant passageway holes of the flat refrigerant pipes. Long side surfaces of the flat water pipe and a long side surface of each of the pair of flat refrigerant pipes are in tight contact with each other as viewed in cross section. The flat water pipe is interposed by the pair of flat refrigerant pipes.

1 . A water heat exchanger configured to exchange heat between a refrigerant and water, the water heat exchanger comprising:
 a pair of flat refrigerant pipes, each flat refrigerant pipe having a plurality of refrigerant passageway holes arranged to have the refrigerant flow therethrough; and   a flat water pipe having at least one water passageway hole arranged to have the water flow therethrough, the number of water passage holes being fewer than the number of refrigerant passageway holes of the flat refrigerant pipes,   long side surfaces of the flat water pipe and a long side surface of each of the pair of flat refrigerant pipes are in tight contact with each other as viewed in cross section, and   the flat water pipe being interposed by the pair of flat refrigerant pipes.   
     
     
         2 . The water heat exchanger according to  claim 1 , wherein
 the number of the water passageway holes of the flat water pipe is one or two.   
     
     
         3 . The water heat exchanger according to  claim 1 , wherein
 the flat water pipe is joined to each of the pair of flat refrigerant pipes by brazing using a brazing filler material or by adhesives.   
     
     
         4 . The water heat exchanger according to  claim 1 , wherein
 at least one of the flat refrigerant pipes and the flat water pipe is formed by drawing or extruding.   
     
     
         5 . The water heat exchanger according to  claim 1 , wherein
 the flat water pipe is formed by bending a flat plate.   
     
     
         6 . The water heat exchanger according to  claim 5 , wherein
 the flat water pipe is an electro-resistance welded pipe formed by bringing two sides of the flat plate into contact by the bending, and then joining the two sides.   
     
     
         7 . The water heat exchanger according to  claim 5 , wherein
 the flat plate is embossed prior to the bending.   
     
     
         8 . The water heat exchanger according to  claim 1 , wherein
 the refrigerant that flows through an interior of the flat refrigerant pipes and the water that flows through an interior of the flat water pipe flow in mutually opposing directions.   
     
     
         9 . The water heat exchanger according to  claim 1 , wherein
 the refrigerant is CO 2 .   
     
     
         10 . A hot water heat source apparatus configured to be used with a refrigerant circuit using a supercritical refrigerant, a high pressure side of a refrigeration cycle being in a supercritical region in the refrigerant circuit, the hot water heat source apparatus comprising:
 a compressor arranged to compress the supercritical refrigerant;   a water heat exchanger arranged to cool the supercritical refrigerant and to heat water by exchanging heat between the water and the high temperature and high pressure supercritical refrigerant compressed by the compressor;   an expansion mechanism arranged to reduce pressure of the supercritical refrigerant cooled by the water heat exchanger; and   an evaporator arranged to evaporate the refrigerant whose pressure was reduced by the expansion mechanism,   the water heat exchanger including
 a pair of flat refrigerant pipes, each refrigerant pipe having a plurality of refrigerant passageway holes arranged to have the refrigerant flow therethrough, and 
 a flat water pipe having at least one water passageway hole arranged to have the water flow therethrough, the number of water passage holes being fewer than the number of the refrigerant passageway holes of the flat refrigerant pipes; 
 a refrigerant inlet header having inlets of the pair of flat refrigerant pipes connected thereto; and 
 a refrigerant outlet header having outlets of the pair of flat refrigerant pipes connected thereto, 
 long side surfaces of the flat water pipe and a long side surface of each of the pair of flat refrigerant pipes are in tight contact with each other as viewed in cross section, 
 the flat water pipe being interposed by the pair of flat refrigerant pipes, and 
 the refrigerant that flows through an interior of the flat refrigerant pipes and the water that flows through an interior of the flat water pipe flowing in mutually opposing directions.