Shut-off valve control device for refrigeration cycle, and air conditioner

An air conditioner, comprising:

• an indoor unit installed indoors;
• an outdoor unit;
• a leakage detector which is installed indoors where the indoor unit is installed and which is configured to detect leakage of a refrigerant that is used in a refrigeration cycle made up of the indoor unit and the outdoor unit;
• and
• a shut-off valve device which is provided midway along a pipe that connects the indoor unit and the outdoor unit with each other and which is equipped with a shut-off valve configured to open or shut off a flow of the refrigerant between the indoor unit and the outdoor unit by electric power,
• wherein the shut-off valve device includes:
• a power failure detector configured to detect a power failure in an AC power supply configured to supply electric power to the shut-off valve;
• wherein a backup power supply capable of alternatively supplying electric power upon an occurrence of a power failure;
• wherein a shut-off valve control circuit configured to control the shut-off valve to be closed when the power failure detector detects leakage of the refrigerant and to control the shut-off valve to be closed when the power failure detector continues to detect a power failure for a predetermined time period,
• wherein the shut-off valve is an electronically controlled valve configured to be driven by a motor and of which an opening degree can be controlled from completely closed to completely open, and
• wherein the shut-off valve control circuit is configured to, upon acquiring a charge amount of the backup power supply at power-on, change the opening degree of the electronically controlled valve in accordance with the charge amount.