The present disclosure relates to the field of air conditioning technology. In particular, it involves a heat pump system and control method.

A multi-air conditioner for heating and cooling may include at least one indoor unit installed in an indoor space and comprising an indoor heat exchanger and an indoor expansion valve; an outdoor unit connected to the at least one indoor unit via a refrigerant pipeline and comprising an outdoor heat exchanger, a compressor, an outdoor expansion valve, and a four-way valve; and at least one leak shut-off valve provided on the refrigerant pipeline, that blocks a flow of refrigerant in the refrigerant pipeline when a refrigerant leak from the refrigerant pipeline occurs in the indoor space. The outdoor unit may decrease a pressure of the refrigerant pipeline when a refrigerant leak occurs from the refrigerant pipeline. Therefore, it is possible to minimize an amount of refrigerant leakage when there is a refrigerant leak in the indoor space.

A cryocooler includes a cold head, a valve unit which includes a rotary valve configured to periodically switch a pressure of a working gas in the cold head between a first high pressure and a second high pressure lower than the first high pressure and a valve motor configured to rotate the rotary valve, the valve unit having a rotation angle range in which the rotary valve seals the working gas having the second high pressure in the cold head, a cryocooler control unit configured to control the valve motor, a cryocooler stop instruction unit configured to output a cryocooler stop instruction signal to the cryocooler control unit, and a valve stop timing control unit configured to control the valve motor to stop the rotary valve in the rotation angle range, according to the cryocooler stop instruction signal.

A bypass line is described that is capable of equalizing pressure within an HVAC system. The bypass line can also cause less noise than other solutions. A bypass line under the present disclosure can comprise a line from a high pressure side to a low pressure side of an HVAC system. Valves and orifices can be disposed within the bypass line. The valves and orifices help to slow the speed of fluid from high pressure to low pressure locations, thus reducing noise during pressure equalization.

A fluid injection control system, a fluid injection control method and a fluid circulation system including the fluid injection control system are provided. The fluid injection control system includes an injection valve, control apparatus and energy storage apparatus. The injection valve is arranged in a path along which a fluid flows into a device; the energy storage apparatus is configured to supply, in response to the control apparatus being powered off, power to the control apparatus so as to maintain an operation of the control apparatus.

A vapor compression refrigeration system has a main refrigerant circuit having a primary compressor group, a gas cooler or condenser, an expansion device, a liquid receiver, and at least one evaporator. An emergency circulation duct fluidically connects the liquid receiver to the main circuit to allow a flow of refrigerant from the liquid receiver to the gas cooler. An emergency compressor group in the emergency circulation duct is activatable when pressure inside the liquid receiver or in the duct upstream of the emergency compressor group meets or exceeds a predefined emergency pressure threshold. An uninterruptible power supply powers the emergency compressor group and expansion device during a shutdown of the refrigeration system. When pressure inside the liquid receiver or in the duct upstream of the emergency compressor group equals or exceeds the predefined emergency pressure threshold, an emergency circulation of refrigerant fluid is activated through the emergency circulation duct.

A water electrolysis system includes a water electrolysis device; a water circulation circuit section including a water circulation pump; an antifreeze circulation circuit section including an antifreeze circulation pump; and a heat exchanger configured to perform heat exchange between the water circulation circuit section and the antifreeze circulation circuit section. Before water electrolysis is started by the water electrolysis device, a control device of the water electrolysis system circulates water by driving the water circulation pump and sets the antifreeze circulation pump to an operationally stopped state.

A vapor compression system comprises a compressor (22). The compressor comprises an inlet (40) and an outlet (42) and an electric motor (28). The motor has a stator (30) and a rotor (32). A plurality of bearings (36) support the rotor. A fluid flowpath (126) extends to the plurality of bearings. A branch (310) from the fluid flowpath extends to the compressor. A liquid sensor (330) is along the branch.

Provided is a system for air-conditioning and hot-water supply configured to selectively perform cooling and heating operations, comprising: an outdoor unit having a compressor and an outdoor heat exchanger; at least one or more indoor units each of which is connected to the outdoor unit and includes an indoor heat exchanger; a hot-water supply unit connected to the outdoor unit so as to be arranged in parallel to the indoor unit and including a refrigerant-water heat exchanger; a controller configured to monitor for a request for hot-water supply from the hot-water supply unit while a cooling operation is being performed in at least one of the indoor units, and then to start the heating operation in accordance with the request; wherein the controller transmits to all of the indoor units, which are turned on for said cooling operation, a fan-stop command to stop a fan arranged at each indoor unit.

The air conditioner includes a compressor and an indoor unit. The method includes: obtaining a coil temperature of the indoor unit and selectively adjusting the frequency of the compressor according to the coil temperature of the indoor unit. According to the method, the operating frequency of the compressor is adjusted by determining a temperature interval in which the coil temperature of the indoor unit is, so as to avoid the icing of the indoor unit of the air conditioner, thereby effectively solving the icing problem of the indoor unit of the air conditioner, and also improving the operation stability and reliability of the air conditioner.