A refrigeration cycle apparatus includes: a compressor; an indoor heat exchanger; an outdoor heat exchanger including first and second outdoor heat exchangers; a bypass flow passage causing a discharge side of the compressor to communicate with the first or second outdoor heat exchanger; a flow control valve at the bypass flow passage; and a controller performing a heating operation in which the first and second outdoor heat exchangers operate as an evaporator and the indoor heat exchanger operates as a condenser and a simultaneous heating and defrosting operation in which part of refrigerant the compressor discharges is supplied to one of the first and second outdoor heat exchangers through the bypass flow passage, the other of the outdoor heat exchangers operates as an evaporator, the indoor heat exchanger operates as a condenser, and an upper limit frequency of the compressor changes to a value higher than in the heating operation.

An air conditioner performs a heating operation and a cooling operation with enhanced heat exchange performance and also performs a heating continuous operation, while preventing increases in manufacturing cost and packaging volume. An air conditioner comprises a refrigerant circuit through which refrigerant circulates. A second heat exchanger includes a first refrigerant flow path and a second refrigerant flow path. A first port of the flow path switching device is connected to a discharge portion of a compressor. A second port is connected to a first heat exchanger. A third port is connected to an intake portion of the compressor. A fourth port is connected to a pipe that connects a branch point to the first refrigerant flow path. A fifth port is connected to the second refrigerant flow path. A sixth port is connected to the first refrigerant flow path.

An air-conditioning apparatus includes a main circuit in which a compressor, a refrigerant flow switching device, a load side heat exchanger, a load side expansion device, and a plurality of heat source side heat exchangers are sequentially connected. When the plurality of heat source side heat exchangers are used as condensers, the first heat source side heat exchanger and the second heat source side heat exchanger are connected in series. When the plurality of heat source side heat exchangers are used as evaporators, the first heat source side heat exchanger and the second heat source side heat exchanger are connected in parallel. A distribution adjustment header on an inlet side of at least either the first heat source side heat exchanger or the second heat source side heat exchanger when the plurality of heat source side heat exchangers are used as evaporators.

An air-conditioning apparatus includes a four-way valve, a first three-way valve and a second three-way valve each having a closed port, a compressor, an indoor heat exchanger, an expansion valve, a first outdoor heat exchanger, a second outdoor heat exchanger, a bypass expansion valve, a check valve, a discharge temperature sensor, an indoor pipe temperature sensor, an indoor temperature sensor, a current sensor, and a controller configured to detect switching failure at the four-way valve, the first three-way valve, and the second three-way valve. The controller is configured to detect switching failure at the four-way valve, the first three-way valve, or the second three-way valve by using the temperatures measured by the discharge temperature sensor, the indoor pipe temperature sensor, and the indoor temperature sensor and the current in consideration of an operation status.

Provided is a refrigeration apparatus in which adverse events caused by excess refrigerant can be suppressed even when defrosting is performed with some of a plurality of outdoor units designated as units to be defrosted. An air-conditioning apparatus is configured from a parallel connection of a first outdoor unit and a second outdoor unit, wherein when a second outdoor heat exchanger of the second outdoor unit is caused to function as an evaporator while a first outdoor heat exchanger of the first outdoor unit is caused to function as a condenser to defrost the first outdoor heat exchanger, a refrigerant circuit has a flow channel that supplies some of the refrigerant flowing out of the first outdoor heat exchanger to the second outdoor heat exchanger and a flow channel that supplies the rest of the refrigerant flowing out of the first outdoor heat exchanger to an indoor heat exchanger.

During heat applying operation, both an air-source heat exchanger that exchanges heat with the atmosphere as a heat source and an earth-source heat exchanger that uses geothermal heat as a heat source serve as evaporators to collect heat from the atmosphere and the geothermal heat. During defrosting operation, while a four-way valve is switched to cause the air-source heat exchanger to serve as a radiator, and the earth-source heat exchanger to serve as an evaporator to collect the geothermal heat, and the collected geothermal heat is collected in the main circuit via the sub-circuit.

Systems and methods are disclosed that may include recovering heat from a generator to defrost the heat exchanger by passing a heat transfer fluid from the generator through a recovery heat exchanger that is configured to promote heat transfer between the heat transfer fluid and a refrigerant flowing therethrough, reducing a restriction of the refrigerant, reducing an airflow through the heat exchanger, and delivering the heated refrigerant to the heat exchanger. Systems and methods may also include recovering heat from an exhaust of the generator to deter the formation of frozen condensate on the outdoor heat exchanger by diverting at least a portion of a hot exhaust fluid discharged by the generator onto the outdoor heat exchanger.