A method for operating and controlling a vapor-compression cycle includes providing a system comprising an evaporator with a fan, a compressor, a condenser with a fan, an integrated expander, and a flash tank device with a vapor/liquid two-phase inlet and two outlets wherein a first outlet is a vapor outlet and a second outlet is a liquid outlet, and a metering valve; bringing a vapor-compression cycle up to steady-state at a fixed operating condition; opening the metering valve until the desired compressor suction superheat is achieved; and maintaining the desired degree of superheat by selectively increasing and decreasing superheat by reducing and increasing metering valve flow rate respectively.

A fresh-air air conditioning system comprises: a first electromagnetic valve connected to a first interior heat exchanger, and the first electromagnetic valve is connected via a first accumulator to a compressor and a third electromagnetic valve; the third electromagnetic valve is connected via a second accumulator to the compressor and a second electromagnetic valve; and the second electromagnetic valve is connected to a second interior heat exchanger. When the first interior heat exchanger or the second interior heat exchanger is closed, the third electromagnetic valve opens so that the first accumulator and the second accumulator simultaneously communicate with the open one of the first interior heat exchanger or the second interior heat exchanger, avoiding poor oil return as a result of prolonged single-cylinder operation of the compressor, and ensuring the reliability of the compressor as well as interior comfort.

A refrigerant pump and a data center cooling system. The data center cooling system includes a refrigerant connected between a condenser and an evaporator. The refrigerant includes a housing, a partition plate, and a pump head. The housing is provided with a liquid inlet and a liquid outlet. The partition plate is disposed inside the housing, and they jointly form first space and second space. A pump body includes the pump head and a motor. An inlet of the pump head is located at the bottom of the first space in a gravity direction. The motor is located in the second space. The pump head is configured to transfer refrigerant in the first space to the second space. The liquid inlet is directly connected to the condenser by using a pipeline. The first space is configured to store refrigerant of the data center cooling system.

An air conditioner includes a blower unit to blow air at a predetermined amount, a cooling unit arranged downstream of the blower unit in an air flowing direction, a compressor which is operated at a variable operating frequency so that a revolving speed thereof is adjustable, a condenser, and a cooling coil connected in this order by pipes to circulate a heating medium to cool blown air with a heating unit arranged on a downstream side of the cooling unit in the air flowing direction in which the blown air is heated by a heater, and a control unit controls the operating frequency of the compressor and includes a compressor control part which adjusts the revolving speed of the compressor such that the operating frequency of the compressor is decreased by a predetermined frequency when an output of the heating unit exceeds a first threshold value.

A refrigeration system includes a dedicated defrost-mode compressor that delivers high pressure, high temperature refrigerant to one or more evaporators to defrost the evaporators.

A refrigeration system includes an expansion valve downstream of one or more medium temperature compressors. The expansion valve is configured to decrease pressure of a portion of refrigerant output by the one or more medium temperature compressors. When defrost operation of an evaporator is indicated, the refrigerant with decreased pressure from the expansion valve is provided to the evaporator for at least a period of time sufficient to defrost the evaporator.

A heat pump includes an internal heat exchanger and a regulating device designed to bring the temperature of the working fluid at the outlet of a compressor to a specifiable minimum difference above the dew point at the same pressure. This allows the use of novel coolants in heat pumps, e.g., coolants having a low dew line slope of under 1000/kJ in the temperature-entropy diagram and characterized by very good safety and environmental properties.

Upon detection of a leakage of refrigerant, a refrigerant recovery operation is performed for operating a compressor in a state where an outdoor expansion valve is closed. The refrigerant suctioned from an indoor unit passes through an outdoor heat exchanger so as to be liquefied and accumulated in an outdoor unit. When a low-pressure detection value by a pressure sensor decreases below a reference value, a termination condition for the refrigerant recovery operation is satisfied, and the compressor is stopped. Furthermore, when an abnormality in the refrigerant recovery operation is detected based on a behavior of the low-pressure detection value obtained until the termination condition is satisfied, the compressor is stopped to thereby end the refrigerant recovery operation. Also, guidance information for notification about an abnormality is output to a user.

An integrated system floods an air conditioning low side heat exchanger such that the air conditioning low side heat exchanger does not evaporate all the liquid refrigerant entering the air conditioning low side heat exchanger. As a result, both liquid and vapor refrigerant leave the air conditioning low side heat exchanger. The system includes an additional receiver that stores the refrigerant leaving the air conditioning low side heat exchanger. To prevent the liquid refrigerant in the receiver from overflowing, the liquid refrigerant in the receiver is used in a refrigeration system when the level of liquid refrigerant in the receiver exceeds a threshold (e.g., as detected by a sensor in the receiver).

An air conditioner including a refrigerant circuit including a compressor, an outdoor heat exchanger, an outdoor expansion valve, an indoor expansion valve, and an indoor heat exchanger. The refrigerant circuit including an auxiliary heat exchanger provided on a refrigerant pipe between the outdoor heat exchanger and the indoor expansion valve and connected in series with the outdoor expansion valve, and a rectifier configured to allow a refrigerant flowing from the outdoor heat exchanger toward the indoor expansion valve in a cooling operation or a refrigerant flowing from the indoor expansion valve toward the outdoor heat exchanger in a heating operation to sequentially flow through the auxiliary heat exchanger and the outdoor expansion valve.