A transcritical R-744 refrigeration system with a medium temperature section having a plurality of circuits, at least one evaporator receiving an R-744 refrigerant in a medium-pressure liquid state from a receiver and feeding at least one transcritical compressor to compress the R-744 refrigerant from a low-pressure gaseous state into a high-pressure gaseous state to feed a gas cooler and a throttling device to partially condense the R-744 refrigerant into a medium-pressure gaseous-liquid state, the system comprising a pressure reducing valve connected to a discharge conduit of the at least one transcritical compressor and feeding hot gas to a defrost manifold to defrost one of the plurality of circuits of the medium temperature section, wherein the hot gas being fed to the defrost manifold has a pressure value less than or equal to a maximum operating pressure of the at least one evaporator.

A vapor compression system and method for operating the vapor compression system are provided. The vapor compression system includes a first compressor, a second compressor, a condenser, and at least one check valve disposed between the first compressor and the condenser. The method provides for the transmitting of a shutdown command to at least one of the first compressor and the second compressor, at least one of the first compressor and the second compressor including a rotating shaft and a magnetic bearing, the magnetic bearing having an active mode and an inactive mode, the magnetic bearing levitating the rotating shaft in the active mode. The method further provides for the monitoring of at least one of a rotational speed of the rotating shaft and a differential pressure over the check valve for a preset time, wherein the magnetic bearing remains in the active mode at least during the preset time.

A method for controlling the power-on or power-off of an air conditioner is provided. The method includes the following steps: determining whether a variable capacity compressor of the air conditioner is in a standby single-cylinder operation state before starting the air conditioner, where the variable capacity compressor is configured to be switchable between a single-cylinder operation state and a dual-cylinder operation state; if so, starting the air conditioner; if not, switching the variable capacity compressor to the standby single-cylinder operation state, and then starting the air conditioner. With this control method, regardless of whether the air conditioner is shut down because the power supply of the unit is cut off or because a power-off signal is received, the air conditioner can be started in a single-cylinder operation state in the next startup, so that the operation state of the cylinder is always determined when starting the air conditioner.

Refrigeration circuit (1a) comprising in the direction of flow of a circulating refrigerant: a compressor unit (2) comprising at least one compressor (2a, 2b, 2c); a heat rejecting heat exchanger/gas cooler (4); a high pressure expansion device (6); a receiver (8); an expansion device (10); an evaporator (12); and a low pressure gas-liquid-separation unit comprising at least two collecting containers (32, 34) which are configured for alternately separating a liquid phase portion from the refrigerant leaving the evaporator (12) and delivering the separated liquid refrigerant back to the receiver (8).

A motor vehicle chiller with several evaporators of different cooling capacity, has a refrigerant circulation with at least one refrigerant compressor, at least one condenser, at least one expansion element as well as at least two evaporators disposed in parallel of different cooling capacity. A refrigerant collector is disposed downstream of the expansion element and upstream of the evaporator of lesser cooling capacity to separate liquid refrigerant. Between the refrigerant collector and the evaporator a refrigerant pump is disposed to convey the liquid refrigerant to the evaporator of lesser cooling capacity. The refrigerant vapor can be guided from the evaporator across the refrigerant collector functioning as a separator and be drawn in by the refrigerant compressor.

A refrigeration system having a heat pump function for a motor vehicle. The refrigeration system includes: a refrigerant compressor which is connectable or connected to a primary line; a directly or indirectly acting external heat exchanger, which is arranged in the primary line; a first evaporator, which is arranged in the primary line; a first directly or indirectly acting heat exchanger, in particular a chiller, which is arranged fluidically in parallel to the evaporator; and a refrigerant collector arranged on the low-pressure side. A single sensor device is arranged downstream of the evaporator and the further heat exchanger, in particular the chiller, which is configured to detect the pressure and the temperature of the refrigerant on the low-pressure side of the refrigeration system.

A heat pump device comprises a refrigerant circuit in which a compressor, a first indoor heat exchanger, an electric expansion valve, and a heat source-side heat exchanger are connected in a loop, a second indoor heat exchanger arranged between the compressor and the electric expansion valve and configured to store refrigerant during positive cycle defrost operation, an electromagnetic valve arranged between the second indoor heat exchanger and the electric expansion valve and configured to adjust an amount of refrigerant stored in the second indoor heat exchanger during the positive cycle defrost operation, and a control device that controls the compressor and the electric expansion valve.

A sorption heat pump having an evaporator containing a working fluid to evaporate the fluid to produce a gas, a sorber containing a sorption material to sorb the gas during a sorption phase, a vapor pathway connecting the evaporator and sorber, and a thermal control unit controlling the rate of vapor flow between the evaporator and sorber through the pathway, and being selectively operable to permit, stop and restart the flow of gas through the pathway. The pump may be used with a compartment storing temperature sensitive material. The evaporator may be positioned inside and the sorber outside the compartment, or the sorber may be positioned inside and the evaporator outside the compartment. The pump may be used in an apparatus including both cool and warm compartments, with an insulation layer in each. A method is disclosed for reusing the pump after the sorption material has been sorbed.

A temperature controller for a sorption system having an evaporator to produce a gas, a sorber containing a sorption material to sorb the gas during a sorption phase, a flow channel extending between the evaporator and sorber to provide a gas pathway connecting them, a valve to control the rate of gas flow in the flow channel, and a temperature sensor positioned to measure the temperature of an evaporator surface or the air adjacent thereto indicative of an evaporator surface temperature, and generate a temperature signal. The controller includes an inflatable member having first and second inflation states, and a control unit configured to evaluate the temperature signal and in response control the state of inflation of the inflatable member and thereby the operation of the valve to control the rate of gas flow between the evaporator and sorber through the gas pathway.

A refrigerant control system includes: a reversing valve including: a first inlet configured to receive refrigerant output from a condenser; a first outlet configured to output refrigerant to an inlet of an evaporator located inside of a building; a second inlet configured to receive refrigerant output from the evaporator; and a second outlet configured to output refrigerant to an inlet of a compressor that pumps refrigerant to the condenser; a reversing module configured to: selectively actuate the reversing valve to a first position such that: refrigerant flows directly from the second inlet to the second outlet; and refrigerant flows directly from the first inlet to the first outlet; and selectively actuate the reversing valve to a second position such that: refrigerant flows directly from the second inlet to the first outlet; and refrigerant flows directly from the first inlet to the second outlet.