Heat source unit and air conditioner having the heat source unit

An air conditioner comprising:

• a refrigerant circuit;
• and
• a heat source unit that comprises:
• an external housing that accommodates:
• a compressor connected to the refrigerant circuit;
• a heat source heat exchanger that is connected to the refrigerant circuit and that exchanges heat between a refrigerant circulating in the refrigerant circuit and a heat source;
• and
• an electric box that:
• includes a top and a plurality of side walls;
• accommodates electrical components;
• and
• further includes an air passage comprising an air inlet and an air outlet, wherein an air flow is induced through the air passage from the air inlet to the air outlet for cooling at least some of the electrical components;
• a cooling heat exchanger disposed in the external housing and that is connected to the refrigerant circuit, wherein
• the air flow flows through the cooling heat exchanger, and
• the cooling heat exchanger exchanges heat between the refrigerant and the air flow, and is connected to a bypass line disposed between a liquid refrigerant line and a gas suction line;
• a valve disposed on the bypass line upstream of the cooling heat exchanger;
• a controller that controls the valve;
• a first temperature sensor disposed within the external housing and out of the electric box and that measures air temperature at a location where the first temperature sensor is disposed;
• a second temperature sensor disposed at an exit line between an exit of the cooling heat exchanger and a connection of the bypass line to the gas suction line, wherein
• the controller:
• switches the valve between an OFF-mode in which the valve is closed and an ON-mode in which the valve is opened based on the air temperature measured,
• determines a superheat degree of the refrigerant in the exit line based on a temperature detected by the second temperature sensor,
• switches between the ON-mode and the OFF-mode of the valve based on the superheat degree, and
• switches to the OFF-mode of the valve when the superheat degree falls below a predetermined value for a predetermined period of time, wherein
• the heat source unit is connected to at least one indoor unit that comprises an indoor heat exchanger that forms the refrigerant circuit.