A heat pump system includes a first bypass pipe provided with a first bypass valve and connecting a liquid refrigerant pipe and a low-pressure refrigerant pipe, a refrigerant heat exchanger configured to cause a heat-exchange between refrigerant flowing in the liquid refrigerant pipe and refrigerant flowing in first bypass pipe, a second bypass pipe provided with a second bypass valve and connecting the liquid refrigerant pipe and the low-pressure refrigerant pipe, and a controller. The controller is configured to control opening degree of the first bypass valve based on detected superheated temperature of refrigerant flowing in the first bypass pipe, and detected discharge temperature of a compressor and control opening degree of the second bypass valve based on the detected discharge temperature.

A control method and device for an air conditioner outdoor unit, an outdoor unit and an air conditioner are provided. The outdoor unit has a compressor, a first sensor for detecting an air exhaust pressure of the compressor, and a second sensor for detecting an air return pressure of the compressor. According to the method, a target pressure value is determined; an air exhaust pressure value detected by the first sensor or an air return pressure value detected by the second sensor is periodically obtained as a first pressure value; and the frequency of the compressor is adjusted according to the first pressure value and the target pressure value.

A system is provided and includes a first controller, a non-transitory computer-readable medium and a second controller. The first controller is configured to control operation of at least one compressor circuit including one or more compressors. The non-transitory computer-readable medium is configured to store instructions of a stage profiler for execution by the controller. The instructions include: determining a target system capacity profile for the at least one compressor circuit; determining system stage capacities for stages of the at least one compressor circuit; selecting some of the system stage capacities based on the target system capacity profile to provide an available system capacity profile; generating modulation information based on the available system capacity profile and a load request signal; and controlling operation of the one or more compressors based on the modulation information and according to the available system capacity profile.

There is provided a HVAC system comprising: a fluid circuit for conveying a refrigerant; a compressor for compressing the refrigerant; three heat exchangers defining an evaporator, an outdoor exchanger and a heat recovery exchanger provided along the fluid circuit; an expansion valve provided along the fluid circuit; and a receiver connected in parallel to the expansion valve, wherein a fill valve is located between the receiver and a connection upstream of the expansion valve and a drain valve is located between the receiver and a connection downstream of the expansion valve; wherein the fluid circuit comprises a plurality of valves which are configured to be controlled based on a selected operating mode such that at least one of the outdoor exchanger and the heat recovery exchanger is connected to a discharge line of the compressor and in series with one of the other heat exchangers which is connected to a suction line of the compressor, with the expansion valve disposed between the heat exchangers; wherein the fill and drain valves are configured to be controlled to store a volume of refrigerant in the receiver so as to provide an effective refrigerant charge in the fluid circuit that corresponds to the selected operating mode.

There is provided a HVAC system comprising: a fluid circuit for conveying a refrigerant; a compressor for compressing the refrigerant; three heat exchangers defining an evaporator, an outdoor exchanger and a heat recovery exchanger provided along the fluid circuit; an expansion valve provided along the fluid circuit; and a receiver connected in parallel to the expansion valve, wherein a fill valve is located between the receiver and a connection upstream of the expansion valve and a drain valve is located between the receiver and a connection downstream of the expansion valve; wherein the fluid circuit comprises a plurality of valves which are configured to be controlled based on a selected operating mode such that at least one of the outdoor exchanger and the heat recovery exchanger is connected to a discharge line of the compressor and in series with one of the other heat exchangers which is connected to a suction line of the compressor, with the expansion valve disposed between the heat exchangers; wherein the fill and drain valves are configured to be controlled to store a volume of refrigerant in the receiver so as to provide an effective refrigerant charge in the fluid circuit that corresponds to the selected operating mode.

A cooling system includes an evaporator, connected through fluid lines to a first condenser, a second condenser, a compressor, and a thermal expansion valve. One or more valves are arranged in the fluid lines. The one or more valves operated to, in a first mode, circulate fluid between the evaporator the first condenser; in a second mode, circulate the fluid between a) the evaporator and the first condenser, and b) the evaporator, the second condenser, and the thermal expansion valve, and; in a third mode, circulate the fluid between a) the evaporator and the first condenser, and c) the evaporator, the compressor, the second condenser, and the thermal expansion valve.

A cooling system includes an evaporator, connected through fluid lines to a first condenser, a second condenser, a compressor, and a thermal expansion valve. One or more valves are arranged in the fluid lines. The one or more valves operated to, in a first mode, circulate fluid between the evaporator the first condenser; in a second mode, circulate the fluid between a) the evaporator and the first condenser, and b) the evaporator, the second condenser, and the thermal expansion valve, and; in a third mode, circulate the fluid between a) the evaporator and the first condenser, and c) the evaporator, the compressor, the second condenser, and the thermal expansion valve.

The cooling systems of the present disclosure include a first refrigerant circuit in thermal communication with a heat load and in fluid communication with a main condenser, a free cooling circuit in fluid communication with the main condenser and a free-cooled water source, a chilled water circuit in fluid communication with the main condenser and an evaporator, and a second refrigerant circuit in fluid communication with the evaporator and a secondary condenser. The free cooling circuit is in thermal communication with the first refrigerant circuit via the main condenser, the chilled water circuit is in thermal communication with the first refrigerant circuit via the main condenser, and the second refrigeration circuit is in thermal communication with the chilled water circuit and the free cooling circuit. The second refrigeration circuit cools a fluid flowing in the chilled water circuit. Methods of operating a cooling system are also disclosed.

The cooling systems of the present disclosure include a first refrigerant circuit in thermal communication with a heat load and in fluid communication with a main condenser, a free cooling circuit in fluid communication with the main condenser and a free-cooled water source, a chilled water circuit in fluid communication with the main condenser and an evaporator, and a second refrigerant circuit in fluid communication with the evaporator and a secondary condenser. The free cooling circuit is in thermal communication with the first refrigerant circuit via the main condenser, the chilled water circuit is in thermal communication with the first refrigerant circuit via the main condenser, and the second refrigeration circuit is in thermal communication with the chilled water circuit and the free cooling circuit. The second refrigeration circuit cools a fluid flowing in the chilled water circuit. Methods of operating a cooling system are also disclosed.

A method for controlling a vapour compression system (1) including two or more evaporators (5, 12), each evaporator (5, 12) being arranged in thermal contact with a refrigerated volume, the refrigerated volumes storing goods of various types, and each evaporator (5, 12) receiving refrigerant via an expansion device (6, 13) is disclosed. In response to receipt of a load shedding command originating from a power grid (17), the vapour compression system (1) reduces a compressor capacity of the compressor unit. The refrigerated volumes are divided into at least two prioritized categories of refrigerated volumes, where a first category (18) includes refrigerated volumes storing goods of a temperature critical type, and a second category (19) includes refrigerated volumes storing goods of a temperature non-critical type. Refrigerant supply to the evaporator(s) (5, 12) being in thermal contact with the refrigerated volume(s) of the second category (19) is discontinued, and refrigerant supply to the evaporator(s) (5, 12) being in thermal contact with the refrigerated volume(s) of the first category (18) is continued. Thereby the vapour compression system (1) is capable of providing load shedding services for an extended period of time without compromising temperature critical storage.