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.

An air conditioner may include a controller; a compressor; an outdoor heat exchanger; a plurality of indoor heat exchangers; a switching valve that selectively guides a refrigerant discharged from the compressor to the outdoor heat exchanger or the plurality of indoor heat exchangers; high pressure pipes that connect the switching valve and the plurality of indoor heat exchangers; high pressure valves installed in the high pressure pipes; low pressure pipes that connect an inlet of the compressor and the high pressure pipes. low pressure valves installed in the low pressure pipes; indoor pipes, which are opposite to the high pressure pipes with respect to the plurality of indoor heat exchangers and connected to the plurality of indoor heat exchangers; indoor expansion valves installed in the indoor pipes; a liquid pipe that connects the outdoor heat exchanger and the indoor pipes; and an outdoor expansion valve installed in the liquid pipe.

A compressor for a refrigerating plant comprising at least one cylinder (12); at least one piston (13), which slides alternately inside the cylinder (12); at least one head (18a) provided with a suction chamber (19), connected to a suction line (9) of the plant (1) and to the cylinder (12) to supply the cylinder (12) with a refrigerating fluid, and with a suction valve (25a), configured to regulate the flow rate of refrigerating fluid; the suction valve (25a) is movable between a first position, wherein is defined a first flow area which allows the suction of a first flow rate of refrigerating fluid, and a second position wherein is defined a second flow area smaller than the first flow area which allows the suction of a second flow rate of refrigerating fluid lower than the first flow rate.

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.

An expander generates cold by expanding a refrigerant gas in a cryogenic refrigerator. A compressor compresses the refrigerant gas returning from the expander. Pipes are connected to the expander and the compressor and circulate the refrigerant gas between the expander and the compressor. A determiner determines whether or not a change cycle of the pressure of the refrigerant gas flowing in the pipes is in a predetermined range. The determiner may determine whether or not the change cycle of the pressure of a low-pressure pipe in which a low-pressure refrigerant gas flows toward the compressor from the expander is in a predetermined range.

The present invention has an object to suppress an overshoot in the outlet temperature of a heat medium. A heat source machine controlling apparatus includes a computing unit and a set temperature changing unit. The computing unit calculates a load change rate using a predetermined arithmetic expression. The set temperature changing unit determines whether or not the load change rate calculated by the computing unit exceeds a predetermined threshold value. In the case where the load change rate exceeds the predetermined threshold value, the set temperature changing unit changes a set chilled water outlet temperature so as to suppress a change in a chilled water outlet temperature. For example, in the case where the chilled water outlet temperature is on a falling trend, if the set chilled water outlet temperature is set to a relatively high value, the heat source machine load decreases, and the chilled water outlet temperature is controlled to coincide with the set chilled water outlet temperature after the change. Consequently, an overshoot can be suppressed.

A refrigeration system includes a compressor configured to compress a refrigerant, a condenser, and an evaporator. A heat exchanger is disposed downstream of the condenser and upstream of the evaporator, and disposed downstream of the evaporator and upstream of the compressor, the heat exchanger configured to facilitate heat exchange between the refrigerant supplied from the condenser and the refrigerant supplied from the evaporator. A first expansion device is disposed downstream of the heat exchanger and upstream of the evaporator, and a second expansion device is disposed downstream of the condenser and upstream of the heat exchanger. The second expansion device is configured to cool the refrigerant passing therethrough to cool the refrigerant in the heat exchanger supplied from the evaporator to the compressor.

A cryogenic refrigeration system and method are disclosed. The cryogenic refrigeration system comprises: a refrigerator unit comprising an expansion unit and a variable speed compressor configured to compress refrigerant. The variable speed compressor is configured to receive refrigerant from the refrigerator unit via a lower pressure line and to supply compressed refrigerant to the refrigerator unit via a higher pressure line. There is also control circuitry configured to control the variable speed compressor to maintain a power consumption of the variable speed compressor below a predetermined threshold value, by during cooldown controlling the compressor to initially operate at a reduced frequency and later increasing a frequency of operation of the variable speed compressor such that the variable speed compressor operates at a higher frequency.

Air conditioner for a vehicle in which low pressure protection is accurately performed to improve reliability. A controller adjusts a number of revolution Nc of a compressor 2 so that a detected value does not decrease below a limiting target value TGTs, on the basis of the detected value of a suction temperature sensor and a limiting target value TGTs set to a suction refrigerant temperature of the compressor 2. The controller has a predetermined limiting lower limit TGTsL and a predetermined limiting upper limit TGTsH which is higher than the predetermined limiting lower limit, and adjusts the number of revolution Nc of compressor 2 so that the limiting target value TGTs is the limiting upper limit TGTsH on startup of compressor 2, and the controller gradually decreases the limiting target value TGTs toward the limiting lower limit TGTsL, when the detected value decreases to the limiting upper limit TGTsH.