Provided is a heat pump system having a liquid-side on-off valve, a gas-side on-off valve, an ambient temperature detector configured to detect temperature of fluid which passes through a heatsource-side heat exchanger, and a controller. The controller is configured to perform a refrigerant recovery operation for recovering refrigerant from a utilization-side piping section to a heatsource-side piping section by operating a compressor while the liquid-side on-off valve is closed and the gas-side on-off valve is open, and control the compressor such that, when the ambient temperature is higher than or equal to a predetermined value, increase rate of compressor rotation speed is low compared with that of when the ambient temperature is lower than the predetermined value.

Provided is a heat pump system having a liquid-side on-off valve, a gas-side on-off valve, an ambient temperature detector configured to detect temperature of fluid which passes through a heatsource-side heat exchanger, and a controller. The controller is configured to perform a refrigerant recovery operation for recovering refrigerant from a utilization-side piping section to a heatsource-side piping section by operating a compressor while the liquid-side on-off valve is closed and the gas-side on-off valve is open, and control the compressor such that, when the ambient temperature is higher than or equal to a predetermined value, increase rate of compressor rotation speed is low compared with that of when the ambient temperature is lower than the predetermined value.

An economizer control system includes a compressor including a compression area, a piston chamber, and an economizer inlet configured to receive economizer vapor into the compression area via a flow path that extends between the economizer inlet and the compression area. At least a portion of the flow path traverses the piston chamber. The economizer control system also includes a piston disposed within the piston chamber and configured to contact the economizer vapor. The piston is moveable between an open position that opens the flow path and a closed position that closes the flow path. Additionally, the economizer control system includes a biasing system configured to apply force to the piston to bias the piston toward the closed position.

A heat pump includes a refrigerant loop. The refrigerant loop includes a first heat exchanger, a first region of a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a compressor, a vapor generator, a first check valve, and a second check valve. The compressor includes a low-pressure inlet, a mid-pressure inlet, and an outlet. The vapor generator is positioned downstream of the outlet of the compressor and upstream of both the low-pressure inlet and the mid-pressure inlet. The first check valve is positioned immediately downstream of the third heat exchanger. The second check valve is positioned immediately downstream of the fourth heat exchanger.

A heat pump includes a refrigerant loop. The refrigerant loop includes a first heat exchanger, a first region of a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a compressor, a vapor generator, and a four-way valve. The compressor includes a low-pressure inlet, a mid-pressure inlet, and an outlet. The vapor generator is positioned downstream of the outlet of the compressor and upstream of both the low-pressure inlet and the mid-pressure inlet. The four-way valve is positioned immediately upstream of the first heat exchanger. At least one component chosen from the first heat exchanger, the second heat exchanger, and the vapor generator is free from compressor-driven flow of the first heat exchange fluid during a first predetermined set of heating modes of operation of the heat pump and a first predetermined set of cooling modes of operation of the heat pump.

A carbon dioxide refrigerating system and a refrigerating method thereof. A carbon dioxide refrigerating system, comprising a compressor (10), a condenser (11), a liquid storage device (12), and an evaporator (13) connected in sequence; a suction assembly (15) is arranged between the compressor (10) and the condenser (11), the suction assembly (1%) being in communication with the liquid storage device (12) and in communication with a gas-liquid separator (14), the gas-liquid separator (14) being arranged between the condenser (11) and the liquid storage device (12), and the carbon dioxide gas in the liquid storage device (12) or the gas-liquid separator (14) being capable of being sucked back into the pipeline between the compressor (10) and the condenser (11) by means of the suction assembly (15). The refrigerating system can effectively separate gas and liquid, and can also flash evaporate part of the liquid and supercool the carbon dioxide; the flash evaporation-type condenser (11) can achieve a refrigerating effect by means of radiation, and aerosol is formed in the cavity, quickly evaporating and cooling, and thereby increasing the refrigerating efficiency; the refrigerating system has a simple structure, convenient operation, and low installation and maintenance costs.

Systems and methods for controlled subcooling of working fluid in a heating, ventilation, air conditioning and refrigeration (HVACR) system through a suction line heat exchanger are disclosed. The suction line heat exchanger may receive a first fluid flow travelling to a suction of the compressor in the HVACR system and second flow of working fluid that is travelling from a heat exchanger receiving the discharge of the compressor to an expansion device. Superheating of the first working fluid may be determined based on temperature measurements prior to and following the suction line heat exchanger. The superheating may be used to control the quantity of the second flow of working fluid introduced into the suction line heat exchanger, for example to maintain superheat that is below a threshold value. These systems may include chillers and heat pump systems, and methods may be applied to chillers or heat pump systems.

Systems and methods for controlled subcooling of working fluid in a heating, ventilation, air conditioning and refrigeration (HVACR) system through a suction line heat exchanger are disclosed. The suction line heat exchanger may receive a first fluid flow travelling to a suction of the compressor in the HVACR system and second flow of working fluid that is travelling from a heat exchanger receiving the discharge of the compressor to an expansion device. Superheating of the first working fluid may be determined based on temperature measurements prior to and following the suction line heat exchanger. The superheating may be used to control the quantity of the second flow of working fluid introduced into the suction line heat exchanger, for example to maintain superheat that is below a threshold value. These systems may include chillers and heat pump systems, and methods may be applied to chillers or heat pump systems.

The heat source controller transmits the drive permission signal (SE) to the utilization controller when the compression element is drivable. The utilization controller opens a utilization expansion valve when heat exchange in a utilization heat exchanger is required, on condition that the utilization controller receive the drive permission signal (SE).

A heat pump system for a vehicle, which makes refrigerant bypass an external heat exchanger and turns off a fan mounted on the external heat exchanger when temperature of the outdoor air is lower than setting temperature and the vehicle enters into an idle state in a heat pump mode, thereby continuously operating the heat pump mode even in the below zero temperature so as to keep heating performance, reducing consumption of electrical power without needing to operate an electric heater, and preventing excessive noise of a fan when the vehicle enters into an idle state in the below zero temperature.