Outdoor unit

An outdoor unit comprising:

• a casing including an air passage;
• an outdoor fan disposed in the air passage;
• a compressor disposed in the casing;
• an outdoor heat exchanger disposed in the casing, the outdoor heat exchanger including fins and a heat transfer tube connected to the fins;
• a control board disposed in the casing, the control board including a control unit configured to control the compressor;
• and
• a heat sink disposed in the air passage in the casing, the heat sink being in contact with the control board,
• the heat transfer tube of the outdoor heat exchanger including a first region in which gas refrigerant or two-phase gas-liquid refrigerant flows when the outdoor heat exchanger is used as a condenser and a second region that is located downstream of the first region in a refrigerant flow direction and in which single-phase liquid refrigerant flows when the outdoor heat exchanger is used as a condenser,
• the heat sink being disposed downstream of the outdoor heat exchanger in an air flow direction in the air passage,
• the heat sink being located at a first distance from the first region and being located at a second distance from the second region, the second distance being shorter than the first distance,
• the outdoor unit further comprising a shield that is plate-shaped and disposed under the heat sink, and
• the shield being disposed at a level identical with a level of a lower end of the second region.

An outdoor unit comprising:

• a casing including an air passage;
• an outdoor fan disposed in the air passage;
• a compressor disposed in the casing;
• an outdoor heat exchanger disposed in the casing, the outdoor heat exchanger including fins and a heat transfer tube connected to the fins;
• a control board disposed in the casing, the control board including a control unit configured to control the compressor;
• and
• a heat sink disposed in the air passage in the casing, the heat sink being in contact with the control board,
• the heat transfer tube of the outdoor heat exchanger including a first region in which gas refrigerant or two-phase gas-liquid refrigerant flows when the outdoor heat exchanger is used as a condenser and a second region that is located downstream of the first region in a refrigerant flow direction and in which single-phase liquid refrigerant flows when the outdoor heat exchanger is used as a condenser,
• the heat sink being disposed downstream of the outdoor heat exchanger in an air flow direction in the air passage,
• the heat sink being located at a first distance from the first region and being located at a second distance from the second region, the second distance being shorter than the first distance,
• the outdoor unit further comprising:
• a temperature sensor disposed at the heat sink, the temperature sensor being configured to measure a temperature of the heat sink;
• and
• three-way valve connected to the heat transfer tube and an expansion device configured to reduce a pressure of refrigerant,
• the three-way valve including an inflow port connected to a most downstream portion of the heat transfer tube in the first region, a first outflow port connected to a most upstream portion of the heat transfer tube in the second region, and a second outflow port connected to the expansion device, and
• the control unit of the control board being configured to adjust the three-way valve on a basis of the temperature of the heat sink.