Refrigeration cycle device, and refrigeration cycle device control method

A refrigeration cycle device control method comprising:

• in a refrigeration cycle device including:
• a refrigerant circuit configured to circulate a refrigerant, to which
• a compressor configured to compress the refrigerant;
• an indoor heat exchanger configured to exchange heat between indoor air and the refrigerant;
• an outdoor heat exchanger configured to exchange heat between outdoor air and the refrigerant;
• a heat accumulation heat exchanger configured to exchange heat between a heat storage material and the refrigerant;
• a plurality of pressure reduction mechanisms having an adjustable opening degree;
• and
• a plurality of switching valves configured to switch a circulation path of the refrigerant in the refrigerant circuit between heating operation in which the indoor heat exchanger and the heat accumulation heat exchanger are caused to function as condensers and the outdoor heat exchanger is caused to function as an evaporator and defrosting operation in which the outdoor heat exchanger is caused to function as a condenser and the indoor heat exchanger or the heat accumulation heat exchanger is caused to function as an evaporator are connected;
• a heat storage temperature sensor configured to measure a temperature of the heat storage material;
• and
• a control unit configured to control the plurality of switching valves,
• the plurality of pressure reduction mechanisms having, in the circulation path of the refrigerant of the heating operation, a first pressure reduction mechanism provided on a downstream side of the indoor heat exchanger, a second pressure reduction mechanism provided on an upstream side of the heat accumulation heat exchanger, and a third pressure reduction mechanism provided on a downstream side of the heat accumulation heat exchanger,
• after the heating operation has shifted to the defrosting operation,
• determining by the control unit whether the temperature of the heat storage material acquired from the heat storage temperature sensor is equal to or less than a preset first threshold,
• when the temperature of the heat storage material has been determined to be equal to or less than the first threshold, performing control by the control unit to carry out reverse defrosting operation of defrosting the outdoor heat exchanger by controlling the plurality of switching valves such that the third pressure reduction mechanism is brought into a closed state, the outdoor heat exchanger functions as a condenser, and the indoor heat exchanger functions as an evaporator, and
• when the temperature of the heat storage material has been determined to be higher than the first threshold, performing control by the control unit to carry out indoor-heat-exchanger bypass defrosting operation of defrosting the outdoor heat exchanger by controlling the plurality of switching valves such that the first pressure reduction mechanism is brought into a closed state, the outdoor heat exchanger functions as a condenser, and the heat accumulation heat exchanger functions as an evaporator.