Liquid level detection device, accumulator, and air-conditioning apparatus

An air-conditioning apparatus, comprising:

• an accumulator that separates refrigerant into liquid refrigerant and gaseous refrigerant, and is a container that stores the liquid refrigerant;
• a heater configured to heat the accumulator;
• a plurality of temperature sensors respectively disposed at different heights with respect to the accumulator, and detects a surface temperature of the accumulator;
• a controller configured to control a liquid level of the liquid refrigerant in the accumulator based on the surface temperature of the accumulator detected by the plurality of the temperature sensors;
• a liquid level detection device that detects liquid level of the liquid refrigerant stored in the accumulator;
• a compressor in which a suction side of the refrigerant is connected to an outflow side of the refrigerant in the accumulator, and configured to compress the refrigerant flowing out from the accumulator and discharge the refrigerant;
• a heat exchanger configured to condense the refrigerant;
• a bypass configured to bypass a high-pressure side and a low-pressure side of the compressor;
• a bypass valve provided in the bypass, and configured to circulate or shut off the refrigerant flowing in the bypass by opening and closing;
• a discharge temperature sensor configured to detect a discharge temperature of the refrigerant discharged from the compressor;
• and
• a condensing temperature sensor configured to detect a condensing temperature of the refrigerant flowing in the heat exchanger, wherein
• the controller
• calculates a difference value between the discharge temperature and the condensing temperature, and controls opening and closing of the bypass valve based on the calculated difference value, and a position of the liquid level of the liquid refrigerant that is detected.