An operation control system includes a storage unit that stores electric-power information, and a determination unit. The determination unit determines, based on the electric-power information, a special-operation timing at which a special operation of a refrigerant cycle apparatus installed in at least one property or at least one area is to be executed. The electric-power information includes at least one of electric-power supply demand adjustment request information related to an electric-power supply demand adjustment request from an outside to the property or the area, and electric-power market price information related to an electric-power market price. The special operation includes at least one of a cooling-time oil return operation during a cooling operation of the refrigerant cycle apparatus, a heating-time oil return operation during a heating operation of the refrigerant cycle apparatus, and a defrosting operation during a heating operation of the refrigerant cycle apparatus.

A heat cycle system and a control method. The heat cycle system includes: driving devices, one or a plurality of outdoor units, and a plurality of indoor units, which are connected by pipelines; a bypass pipeline for the plurality of indoor units, a bypass valve being disposed in the bypass pipeline; a pressure sensor that senses a pressure difference ΔP.sub.o across the plurality of outdoor units; and a controller that is preset with a pressure difference set value ΔP.sub.set, wherein the controller calculates a pressure offset parameter ΔP=ΔP.sub.o−ΔP.sub.set and adjusts an opening degree of the bypass valve based on the pressure offset parameter ΔP so that the pressure offset parameter ΔP approaches zero, and wherein the controller is preset with a first pressure offset threshold P.sub.1, and the controller is configured such that closed indoor units enter a bypass mode one by one when ΔP>P.sub.1, until ΔP≤P.sub.1.

A heat cycle system and a control method. The heat cycle system includes: driving devices, one or a plurality of outdoor units, and a plurality of indoor units, which are connected by pipelines; a bypass pipeline for the plurality of indoor units, a bypass valve being disposed in the bypass pipeline; a pressure sensor that senses a pressure difference ΔP.sub.o across the plurality of outdoor units; and a controller that is preset with a pressure difference set value ΔP.sub.set, wherein the controller calculates a pressure offset parameter ΔP=ΔP.sub.o−ΔP.sub.set and adjusts an opening degree of the bypass valve based on the pressure offset parameter ΔP so that the pressure offset parameter ΔP approaches zero, and wherein the controller is preset with a first pressure offset threshold P.sub.1, and the controller is configured such that closed indoor units enter a bypass mode one by one when ΔP>P.sub.1, until ΔP≤P.sub.1.

An air-conditioning apparatus includes a compressor, an outdoor fan, and a controller configured to perform a fan intermittent operation for causing the outdoor fan to run and stop repeatedly after the compressor stops. The controller is configured to, in the fan intermittent operation, in a case where the outdoor fan is running and there is no snow accumulation on the outdoor fan, change a stop upper limit time for the outdoor fan depending on a running time of the outdoor fan in the fan intermittent operation and cause the outdoor fan to stop running after changing the stop upper limit time for the outdoor fan. The controller is configured to, in a case where a stop time of the outdoor fan exceeds the changed stop upper limit time, cause the outdoor fan to run.

An air conditioner capable of satisfactorily preventing noise from entering an indoor space includes: an indoor unit that is fixed to a wall surface of an indoor space and houses an indoor heat exchanger; and an outdoor unit that houses an outdoor heat exchanger connected to a refrigerant circuit that includes the indoor heat exchanger. The outdoor unit includes an outside casing that is fitted into an opening formed in a building wall partitioning an outdoor space and the indoor space from each other and defines an internal space that is open to the outdoor space and isolated from the indoor space by being surrounded by a sound insulation wall, and an inside casing that is disposed in the internal space and houses the outdoor heat exchanger.

A multi-outdoor unit parallel type non-reversing defrosting system, which includes an indoor heat exchanger and three or more outdoor units arranged in parallel. The outdoor units each include a compressor, a four-way valve, an outdoor heat exchanger, a first solenoid valve, and a bypass branch. Two ends of the bypass branch are respectively in bypass connection with a pipeline between the four-way valve and the outdoor heat exchanger and a pipeline between the first solenoid valve and the indoor heat exchanger. The bypass branch is provided with a second solenoid valve configured to control connection and disconnection of the bypass branch. When it is monitored that any outdoor unit is abnormal in frosting, the outdoor units which are not frosted are correspondingly distributed and started as required on the basis of a current heating energy requirement A of the indoor heat exchanger.

A multi-outdoor unit parallel type non-reversing defrosting system, which includes an indoor heat exchanger and three or more outdoor units arranged in parallel. The outdoor units each include a compressor, a four-way valve, an outdoor heat exchanger, a first solenoid valve, and a bypass branch. Two ends of the bypass branch are respectively in bypass connection with a pipeline between the four-way valve and the outdoor heat exchanger and a pipeline between the first solenoid valve and the indoor heat exchanger. The bypass branch is provided with a second solenoid valve configured to control connection and disconnection of the bypass branch. When it is monitored that any outdoor unit is abnormal in frosting, the outdoor units which are not frosted are correspondingly distributed and started as required on the basis of a current heating energy requirement A of the indoor heat exchanger.

The disclosed technology includes systems and methods of reducing frost accumulation on a heat pump evaporator coil. The disclosed technology can include a heat pump assembly having an evaporator coil, a fan configured to direct air across the evaporator coil, a temperature sensor, and a controller configured to energize the fan to direct air across the evaporator coil when the temperature of the evaporator coil is below a threshold temperature.

An air conditioner includes an indoor unit, an outdoor unit, and a controller. The outdoor unit is connected to the indoor unit, and the outdoor unit includes a housing, a compressor, a four-way valve, an outdoor fan, a separating device, and a plurality of outdoor heat exchangers arranged in parallel. The controller is coupled to the compressor, the four-way valve, the outdoor fan, and the driving assembly, and is configured to control a first portion of a refrigerant flowing out from the compressor to flow into an outdoor heat exchanger; control a second portion of the refrigerant flowing out from the compressor to flow into the indoor unit; and when a time in which the first portion of the refrigerant flows into the outdoor heat exchanger is less than a first preset time, prevent a refrigerant flowing out from the indoor unit from flowing into the outdoor heat exchanger, and control the driving assembly to drive the wind blocking portion to move, so as to separate the outdoor fan from the outdoor heat exchanger.

A method of defrost operation optimization in a heat pump includes launching a heating mode after completion of a performed defrost operation, measuring, after launching the heating mode, a heat transfer capability, determining if the measured heat transfer capability is less than or equal to a predetermined heat transfer capability limit for a non-iced condition, and reinforcing a next defrost operation if the measured heat transfer capability is greater than the predetermined gap limit.