Air-conditioning device

An air-conditioning device configured to execute a heating operation, the air-conditioning device comprising:

• a compression machine configured to compress a refrigerant;
• a heater configured to heat air led to a vehicle interior using heat when the refrigerant compressed by the compression machine condenses;
• an expansion valve configured to expand the refrigerant condensed by the heater;
• an outdoor heat exchanger configured to vaporize the refrigerant expanded using the expansion valve by heat exchange with outside air;
• an air blower configured to blow air led to the vehicle interior so as to pass through the heater;
• an outside air temperature detector configured to detect a temperature of outside air before passing through the outdoor heat exchanger;
• a refrigerant temperature detector configured to detect a temperature of the refrigerant that passed through the outdoor heat exchanger;
• a frost determination unit configured to determine an occurrence of a frost risk state of the outdoor heat exchanger, based on an accumulated time of a state in which a difference between the temperature detected by the outside air temperature detector and the temperature detected by the refrigerant temperature detector is the same or greater than a frost temperature difference at which frost can occur on the outdoor heat exchanger;
• and
• an operation control unit configured to control the compression machine and the air blower so that the air led to the vehicle interior becomes a target blowout temperature set based on a required heating performance, and to execute a normal heating operation, wherein
• the operation control unit is configured to, when the frost determination unit has determined the occurrence of the frost risk state, execute a frost suppression operation of, compared to the normal heating operation, decreasing the target blowout temperature and increasing an air flow amount using the air blower.