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).

In a method for operating a compressor (22) having an inlet (26) and an outlet (28), the method includes: running the compressor to compress a fluid; shutting down (422) the compressor; determining (420) a condition-dependent threshold restart pressure difference (threshold) across the compressor; relieving the pressure difference to reach the threshold; and, after the threshold is reached, restarting (434) the compressor.

A multi-air conditioner for cooling and heating is provided to remove latent heat and sensible heat by using a single outdoor unit. The multi-air conditioner includes: at least one indoor unit installed in a room, that comprises an indoor heat exchanger and an indoor expansion valve; an outdoor unit connected to the indoor unit via a refrigerant pipeline, that comprises an outdoor heat exchanger, a plurality of compressors, an outdoor expansion valve, and a four-way valve; and a dedicated outdoor air ventilation unit connected to the indoor unit and the outdoor unit via the refrigerant pipeline, that dehumidifies and ventilates outdoor air and supplies the outdoor air to the room, wherein the outdoor unit provides a refrigerant to both the dedicated outdoor air ventilation unit and the indoor unit by controlling the compressors depending on an operation mode of the dedicated outdoor air ventilation unit and the indoor unit. Accordingly, it is possible to run an air conditioner for cooling and heating and a dedicated outdoor air conditioner simultaneously by using a single outdoor unit. Moreover, the handling of sensible and latent heats can be controlled by a single outdoor unit, thereby minimizing facility costs and enhancing control reliability.

A refrigeration cycle apparatus includes a refrigeration cycle circuit, a bypass flow path, a first valve provided in the refrigeration cycle circuit, a second valve provided at the bypass flow path, a first temperature sensor configured to detect a temperature of an indoor space, a second temperature sensor configured to detect a temperature of refrigerant on a liquid side of an indoor heat exchanger, and a notification part. The refrigeration cycle apparatus is able to operate in an operation state where the compressor operates, the indoor heat exchanger functions as an evaporator, and the first valve is open while the second valve is closed. In the operation state, the notification part issues notification of an abnormality of an electronic expansion valve or the first valve when a temperature detected by the second temperature sensor is higher than an evaporation temperature of refrigerant in the refrigeration cycle circuit.

A method of managing a compressor start operation, the method includes controlling a valve disposed upstream of a compressor to lower a saturated suction temperature of a refrigerant to be below an ambient temperature while starting the compressor.

A closed cooling system for cooling a fluid of an open fluid system including a first heat exchanger and a compressor facilitating circulation of a refrigerant in the closed cooling system, where the refrigerant facilitates providing a solid state cooling bank which is thermally coupled to the open fluid system thereby cooling fluid conducted through the open fluid system.

A movable platen cooling apparatus includes: a compressor; a cold head that includes a cooling part; a refrigerator gas supply line that supplies a refrigerant gas from the compressor to the cold head; a refrigerator gas exhaust line that exhausts the refrigerant gas from the cold head to the compressor; a first gas inflow line that is connected to a first movable platen flow path and includes a heat exchange part thermally coupled to the cooling part; a first gas outflow line connected to the first movable platen flow path and merged with the refrigerator gas exhaust line; a second gas inflow line connected to a second movable platen flow path and disposed to be thermally non-coupled with the cooling part; and a second gas outflow line connected to the second movable platen flow path and merged with the refrigerator gas exhaust line.

A device and process for refuelling containers with pressurized gas comprising a pressurized gas source, a transfer circuit intended to be removably connected to a container, the device comprising a refrigeration system for cooling the gas flowing from the gas source prior to its entering into the container and comprising a refrigerant cooling loop circuit comprising, arranged in series, a compressor, a condenser section, an expansion valve and an evaporator section, the refrigeration system comprising a cold source in heat exchange with the condenser section and a heat exchanger located in the transfer circuit and comprising a heat exchange section between the gas flowing in the transfer circuit and the evaporator section, the device comprising an electronic controller configured to switch the refrigeration system in first standby mode when the device is not refuelling a container wherein the compressor is switched off when the temperature of the heat exchanger is equal or below a predefined first standby temperature threshold and for started and operated for producing cooling power and cooling the heat exchanger when the sensed temperature of the heat exchanger is above a second standby threshold temperature.

A controller in a refrigeration cycle apparatus performs a refrigerant recovery operation when switching an operation mode from a defrosting mode to a heating mode. During the refrigerant recovery operation, by rotating a fan of a blower while monitoring a pressure at a discharge side of the compressor, the controller is configured to perform feedback control to cause a high-pressure side pressure to be close to a high-pressure side target pressure value. During the refrigerant recovery operation, by controlling a driving frequency of the compressor while monitoring a pressure at a suction side of the compressor, the controller is configured to perform feedback control to cause a low-pressure side pressure to be close to a low-pressure side target pressure value.

The present invention is provided with: a turbo compressor that compresses a refrigerant; a condenser that condenses the refrigerant compressed by the turbo compressor; an expansion valve that expands a liquid refrigerant introduced from the condenser; an evaporator that evaporates the refrigerant expanded by the expansion valve; an oil tank that stores a lubricating oil supplied to the turbo compressor; a pressure equalizing pipe that connects the oil tank and the evaporator; and a control unit that controls start-up. The control unit calculates the amount of a refrigerant eluded into the lubricating oil in the oil tank at the time of start-up, and reduces a pressure reduction speed in the oil tank by limiting the opening operation of an IGV when the refrigerant elution amount per prescribed time exceeds a prescribed value.