Heat pump type hot water supply outdoor apparatus

A heat pump type hot water supply outdoor apparatus, in which a compressor, a water heat exchanger for carrying out heat exchange between water and refrigerant, a first pressure reduction unit, a medium pressure receiver, a second pressure reduction unit, and an air heat exchanger for carrying out heat exchange between water and refrigerant are connected circularly, heat is supplied from outside air by the air heat exchanger, and heat is supplied to water by the water heat exchanger comprising:

• an injection circuit which is a bypass for a part of the refrigerant between the medium pressure receiver and the second pressure reduction unit, to inject the part of refrigerant into a compression chamber of the compressor, and has a third pressure reduction unit and an internal heat exchanger for carrying out heat exchange between the refrigerant whose pressure is reduced by the third pressure reduction unit and the refrigerant between the medium pressure receiver and the second pressure reduction unit;
• a pressure detection sensor disposed in the vicinity of a discharge port of the compressor, for detecting a condensing pressure of the refrigerant;
• a liquid refrigerant temperature sensor attached to a refrigerant inlet of the air heat exchanger, for detecting an evaporation temperature of liquid refrigerant;
• and
• a controller for carrying out a control for starting an injection control by the third pressure reduction unit at the time when the ratio between the condensing pressure detected by the pressure sensor and the evaporation pressure calculated from evaporation temperature detected by the liquid refrigerant temperature sensor, or the ratio between the condensing temperature calculated from the condensing pressure and the evaporation temperature becomes a first a predetermined ratio or more, and stopping the injection control at the time when the ratio between the condensing pressure and the evaporation pressure or the ratio between the condensing temperature and the evaporation temperature becomes a second predetermined ratio which is smaller than the first predetermined ratio, or less.

A heat pump type hot water supply outdoor apparatus, in which a compressor, a water heat exchanger for carrying out heat exchange between water and refrigerant, a first pressure reduction unit, a medium pressure receiver, a second pressure reduction unit, and an air heat exchanger for carrying out heat exchange between water and refrigerant are connected circularly, heat is supplied from outside air by the air heat exchanger, and heat is supplied to water by the water heat exchanger, comprising:

• an injection circuit which is a bypass for a part of the refrigerant between the medium pressure receiver and the second pressure reduction unit, to inject the part of refrigerant into a compression chamber of the compressor, and has a third pressure reduction unit and an internal heat exchanger for carrying out heat exchange between the refrigerant whose pressure is reduced by the third pressure reduction unit and the refrigerant between the medium pressure receiver and the second pressure reduction unit;
• a pressure detection sensor disposed in the vicinity of a discharge port of the compressor for detecting the condensing pressure of the refrigerant;
• a liquid refrigerant temperature sensor attached to a refrigerant inlet of the air heat exchanger for detecting an evaporation temperature of liquid refrigerant;
• and
• a controller for carrying out a control for starting an injection control by the third pressure reduction unit at the time when a difference between the condensing pressure detected by the pressure sensor and the evaporation pressure calculated from evaporation temperature detected by the liquid refrigerant temperature sensor, or a difference between the condensing temperature calculated from the condensing pressure and the evaporation temperature becomes a first a predetermined difference or more, and stopping the injection control at the time when the difference between the condensing pressure and the evaporation pressure or the difference between the condensing temperature and the evaporation temperature becomes a second predetermined difference which is smaller than the first predetermined difference, or less.