| 摘要 |
A refrigerant circuit (20) includes, in order to perform a vapor compression supercritical refrigeration cycle, a compression mechanism (30), an outdoor heat exchanger (21), an expansion mechanism (40), and an indoor heat exchanger (23). The expansion mechanism (40) includes, for the two-stage expansion of refrigerant in the refrigerant circuit (20), a first throttle mechanism (41) variable in the amount of throttling and a second throttle mechanism (42) variable in the amount of throttling. In the cooling operation mode, there is derived a target value for the pressure of high pressure refrigerant in the refrigerant circuit (20), from the temperature of refrigerant at the outlet of the outdoor heat exchanger (21) and the temperature of air at the inlet of the outdoor heat exchanger (21). In the heating operation mode, there is derived a target value for the pressure of high pressure refrigerant in the refrigerant circuit (20), from the temperature of refrigerant at the outlet of the indoor heat exchanger (23) and the temperature of air at the inlet of the indoor heat exchanger (23). The amount of throttling of either the first throttle mechanism (41) or the second throttle mechanism (42) is adjusted so that the high pressure refrigerant pressure becomes the target value.
|
