| 摘要 |
PURPOSE:To make it possible to obtain thermal output at a high temperature with high efficiency by selecting coolants suitably for two heat pump cycles. CONSTITUTION:A low boiling point coolant A is sealed in a coolant circuit 25 on a low temperature side and a high boiling point coolant B is sealed in a coolant circuit 29 on a high temperature side. A heat accumulating recycling circuit 37 is filled with water. When the water discharge temperature of a heat exchanger 27 for hot water supply is lower than a set value, a primary heat pump cycle is formed, compressing the coolant A evaporated in an evaporator 24 by a compressor 21 on the low temperature side, liquefying the coolant A through a coolant-to-coolant heat exchanger 22, and reducing its pressure by an expansion valve 23 on the low temperature side to flow into an evaporator 24. The coolant B that has evaporated in the heat exchanger 22 is liquefied in a heat exchanger 27 for hot water supply via a steam closing valve 30 to flow into the heat exchanger 22 via a liquid closing valve 32 and the tube of a check valve 33. When the water temperature goes over a set value, a steam closing valve 30 and a liquid closing valve 32 close, and a secondary heat pump cycle is formed. In this case the coolant B that has evaporated in the heat exchanger 22 is compressed by a compressor 26 on the high temperature side and liquefied in the heat exchanger 27 and its pressure is reduced by an expansion valve 28 on the high temperature side and the coolant B flows into the heat exchanger 22. |
