A variable refrigerant flow (VRF) air conditioning system, a control method thereof, and a computer-readable storage medium are provided. When the VRF air conditioning system is cooling, indoor units in an operating state are obtained. Indoor units with humidity demand and indoor units without humidity demand in the operating state are obtained. A ratio of humidity demand is determined according to an output nominal value of each indoor unit in the operating state. The ratio can include a ratio of a total output nominal value of indoor units with humidity demand to a total output nominal value of indoor units without humidity demand When the ratio is greater than a preset ratio, a rotation speed of an outdoor fan can be adjusted according to an outdoor environment temperature.

A variable refrigerant flow (VRF) air conditioning system, a control method thereof, and a computer-readable storage medium are provided. When the VRF air conditioning system is cooling, indoor units in an operating state are obtained. Indoor units with humidity demand and indoor units without humidity demand in the operating state are obtained. A ratio of humidity demand is determined according to an output nominal value of each indoor unit in the operating state. The ratio can include a ratio of a total output nominal value of indoor units with humidity demand to a total output nominal value of indoor units without humidity demand When the ratio is greater than a preset ratio, a rotation speed of an outdoor fan can be adjusted according to an outdoor environment temperature.

A condenser fan assembly includes a first condenser fan and a first motor coupled to the first condenser fan via a first shaft, where the first motor is configured to drive rotation of the first condenser fan via the first shaft, and a second condenser fan and a second motor coupled to the second condenser fan via a second shaft, where the second motor is configured to drive rotation of the second condenser fan via the second shaft. The condenser fan assembly also includes a fan rotation restrictor configured to selectively block and enable rotation of the first shaft.

A refrigeration cycle apparatus suppresses a phenomenon that a condensed refrigerant accumulates in a heat source-side heat exchanger during a low-load operation. A refrigeration cycle apparatus performs air conditioning of a target space. The refrigeration cycle apparatus includes a refrigerant circuit and a controller. The refrigerant circuit includes a compressor, a heat source-side heat exchanger, an expansion mechanism, a usage-side heat exchanger, and a flow direction switching mechanism. The controller controls the compressor and the flow direction switching mechanism. The controller executes first control of temporarily increasing the pressure of the refrigerant flowing through the heat source-side heat exchanger in a low-load operation in which the refrigerant circuit is in a low-load state with a low air conditioning load and the compressor operates at a predetermined number of rotations or less.

A refrigeration cycle apparatus suppresses a phenomenon that a condensed refrigerant accumulates in a heat source-side heat exchanger during a low-load operation. A refrigeration cycle apparatus performs air conditioning of a target space. The refrigeration cycle apparatus includes a refrigerant circuit and a controller. The refrigerant circuit includes a compressor, a heat source-side heat exchanger, an expansion mechanism, a usage-side heat exchanger, and a flow direction switching mechanism. The controller controls the compressor and the flow direction switching mechanism. The controller executes first control of temporarily increasing the pressure of the refrigerant flowing through the heat source-side heat exchanger in a low-load operation in which the refrigerant circuit is in a low-load state with a low air conditioning load and the compressor operates at a predetermined number of rotations or less.

A method for controlling an air conditioner includes, after the air conditioner is turned on, controlling an indoor ambient temperature sensor, an indoor heat exchanger temperature sensor, an outdoor heat exchanger temperature sensor, an outdoor ambient temperature sensor, and an exhaust gas temperature sensor to determine an indoor ambient temperature, an indoor heat exchanger temperature, an outdoor heat exchanger temperature, an outdoor ambient temperature, and an exhaust gas temperature, respectively, determining a first, second, third, fourth, and fifth compressor frequencies based on the indoor ambient temperature, the indoor heat exchanger temperature, the outdoor heat exchanger temperature, the outdoor ambient temperature, and the exhaust gas temperature, respectively, determining a minimum compressor frequency based on the first, second, third, fourth, and fifth compressor frequencies, and controlling a compressor of the air conditioner to operate at the minimum compressor frequency.

A method for controlling an air conditioner includes, after the air conditioner is turned on, controlling an indoor ambient temperature sensor, an indoor heat exchanger temperature sensor, an outdoor heat exchanger temperature sensor, an outdoor ambient temperature sensor, and an exhaust gas temperature sensor to determine an indoor ambient temperature, an indoor heat exchanger temperature, an outdoor heat exchanger temperature, an outdoor ambient temperature, and an exhaust gas temperature, respectively, determining a first, second, third, fourth, and fifth compressor frequencies based on the indoor ambient temperature, the indoor heat exchanger temperature, the outdoor heat exchanger temperature, the outdoor ambient temperature, and the exhaust gas temperature, respectively, determining a minimum compressor frequency based on the first, second, third, fourth, and fifth compressor frequencies, and controlling a compressor of the air conditioner to operate at the minimum compressor frequency.

An HVAC system for a multi-unit building having a riser stack in flow communication with a single unit HVAC system. The single unit HVAC system has a first heat exchanger thermally connected to the riser stack, a second heat exchanger thermally connected to a fluid distribution system within the unit, and a closed loop fluid flow path extending between the first and second heat exchangers. The first heat exchanger exchanges heat between a riser stack fluid in the riser stack and the closed loop fluid in the closed loop fluid flow path and the second heat exchanger exchanges heat between the closed loop fluid and a distribution fluid of the fluid distribution system.

An HVAC system for a multi-unit building having a riser stack in flow communication with a single unit HVAC system. The single unit HVAC system has a first heat exchanger thermally connected to the riser stack, a second heat exchanger thermally connected to a fluid distribution system within the unit, and a closed loop fluid flow path extending between the first and second heat exchangers. The first heat exchanger exchanges heat between a riser stack fluid in the riser stack and the closed loop fluid in the closed loop fluid flow path and the second heat exchanger exchanges heat between the closed loop fluid and a distribution fluid of the fluid distribution system.

An outdoor unit of an air-conditioning apparatus includes an outdoor unit main body, a compressor, an outdoor heat exchanger, an outdoor fan, an outdoor air temperature detection unit, and a control unit. The control unit stores an outdoor air temperature that is detected when the outdoor unit main body receives an operation stop signal, a temperature determination unit configured to determine whether the outdoor air temperature stored in the storage unit is less than a temperature threshold value when the outdoor unit main body receives an operation start signal, and an operation timing setting unit configured to select an operation mode of the compressor based on an outdoor air temperature detected by the outdoor air temperature detection unit after operation of the outdoor fan is resumed in a case where the temperature determination unit determines that the outdoor air temperature is less than the temperature threshold value.