| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress unnecessary pressure rise of an intermediate-pressure refrigerant of which a pressure is risen by a first compressing mechanism of a two-stage pressure rise-type compressor. <P>SOLUTION: A hot water supply temperature Twi at an inlet side of a water-refrigerant heat exchanger, an outside air temperature Tam, and an evaporation temperature Te of the refrigerant in the evaporator are detected as physical quantities having correlation to a suction pressure Ps of the refrigerant sucked to the two-stage pressure rise-type compressor, and a target pressure deciding means S4 lowers a target high-pressure Pt in accompany with the rise of physical quantities when the physical quantities are predetermined set values or above. Further the high pressure Pd is lowered by controlling an operation of an electric expansion valve to make the high pressure Pd to be close to the target pressure Pt. Thus the intermediate pressure Pm is prevented from being over a withstanding pressure of a housing in accompany with the rise of the suction pressure Ps. <P>COPYRIGHT: (C)2009,JPO&INPIT |
