In a refrigeration cycle apparatus, refrigerant circulates in order of a compressor, first and second heat exchangers. The refrigeration cycle apparatus has a refrigerant container, first and second switch units, and a controller. When a first condition meaning that an amount of refrigerant in liquid state stored in the refrigerant container is excessive is satisfied, the controller controls the first switch unit to guide the refrigerant from the compressor to the first heat exchanger through the refrigerant container and controls the second switch unit to guide the refrigerant from the second heat exchanger to the compressor not through the refrigerant container. When the first condition is not satisfied, the controller controls the first switch unit to guide the refrigerant from the compressor to the first heat exchanger not through the refrigerant container and controls the second switch unit to guide the refrigerant from the refrigerant container to the compressor.

A climate-control system may include a compressor, a condenser, an evaporator, a first sensor, a second sensor, a third sensor, and a control module. The compressor may include a motor and a compression mechanism. The condenser receives compressed working fluid from the compressor. The evaporator is in fluid communication with the compressor and disposed downstream of the condenser and upstream of the compressor. The first sensor may detect an electrical operating parameter of the motor. The second sensor may detect a discharge temperature of working fluid discharged by the compression mechanism. The third sensor may detect a suction temperature of working fluid between the evaporator and the compression mechanism. The control module is in communication with the first, second and third sensors and may determine whether a refrigerant floodback condition is occurring in the compressor based on data received from the first, second and third sensors.

A preheater for a compressor that is capable of heating a lubricant oil efficiently with smaller power is provided. A preheater for a compressor includes: a capacitive oil surface sensor that is provided at a compressor used in a refrigerating cycle, and detects an oil surface of a lubricant oil A in the compressor; and a power supply unit that applies high-frequency voltage to the oil surface sensor.

A climate-control system may include a compressor, a condenser, an evaporator, a first sensor, a second sensor, a third sensor, and a control module. The compressor may include a motor and a compression mechanism. The condenser receives compressed working fluid from the compressor. The evaporator is in fluid communication with the compressor and disposed downstream of the condenser and upstream of the compressor. The first sensor may detect an electrical operating parameter of the motor. The second sensor may detect a discharge temperature of working fluid discharged by the compression mechanism. The third sensor may detect a suction temperature of working fluid between the evaporator and the compression mechanism. The control module is in communication with the first, second and third sensors and may determine whether a refrigerant floodback condition is occurring in the compressor based on data received from the first, second and third sensors.

A vapor compression system includes a compressor configured to circulate a refrigerant through a refrigerant loop, a sump configured to receive a mixture of lubricant and the refrigerant from the compressor, and a controller having a memory and a processor. The processor is configured to receive a first signal indicative of a temperature of the mixture within the sump, receive a second signal indicative of a pressure of the mixture within the sump, determine a relative amount of the refrigerant in the mixture based on the first signal and the second signal, and output a control signal in response to the relative amount of the refrigerant in the mixture exceeding a threshold value.

A device for storing refrigerant of a refrigeration circuit and a method of operating the device, in particular for an air conditioning system of a motor vehicle. The device has a housing having a volume-enclosing wall with an inlet for introducing a refrigerant-oil mixture, and an outlet, a refrigerant discharge line arranged in the interior of the housing with an inlet opening arranged above a liquid level of the refrigerant for receiving gaseous refrigerant, and a system for returning oil to a compressor having at least one through hole formed below the liquid level of the refrigerant, in particular below a filling level of the oil, in the refrigerant discharge line. In addition, at least one through hole formed in the refrigerant discharge line is formed with an adjustable through-flow cross section, which can be varied by means of a closing apparatus.

A refrigeration machine control device according to an embodiment of the present invention serves to control a turbo refrigeration machine and is equipped with a pressure reduction rate identification unit for identifying a pressure reduction rate at which foaming does not occur in an oil tank, and a pressure adjustment unit for adjusting the pressure of an evaporator on the basis of the identified pressure reduction rate. The pressure reduction rate identification unit is equipped with: a refrigerant precipitation gas volume calculation unit for calculating the volume of refrigerant gas precipitated from lubricating oil when the pressure is reduced at a prescribed pressure reduction rate; and a determination unit for determining whether or not foaming is permissible on the basis of a comparison between the calculated volume and the volume on the surface of the oil in the oil tank.

An inside air-conditioning device includes a refrigerant circuit (50) and a refrigerant that is sealed in the refrigerant circuit (50). The refrigerant circuit (50) includes a compressor (10), a condenser (25), an electronic expansion valve (13), and an evaporator (17). The refrigerant contains at least 1,2-difluoroethylene.

In a refrigerant compressor for refrigeration plants, comprising a compressor unit driven by a drive unit, wherein at least one of these units is provided with a control unit which is controllable by means of a delivery rate control system in order to control the refrigerant compressor at different delivery rates, wherein an external delivery rate setpoint value is communicated to the delivery rate control system, in order to prevent critical operating states, it is proposed that the delivery rate control system acquires, by means of a sensor, a compressor reference temperature of the compressor unit, that the delivery rate control system ascertains an operating state value group for the acquisition of an operating state of the refrigerant compressor and, taking account of specified reference values, if the value of the ascertained operating state value group based upon the compressor reference temperature permits a critical operating state of the refrigerant compressor, specifies a delivery rate which has as its result an operation of the refrigerant compressor outside of the critical operating states.

In order to reduce the effect on a compressor caused by foaming in an oil tank, a control unit for controlling an oil pump starts the oil pump before a compressor is started (SA1), starts the compressor (SA4) when an oil supply differential pressure P satisfies a compressor startup condition during a reference time Tas from the starting of the oil pump (“Yes” in SA3), and extends the operation of the oil pump for a prescribed time without starting the compressor (Step SA5) when the compressor startup condition is not satisfied (“No” in SA3).