Abstract: A process and system for recovering refrigerant from refrigeration systems without substantial contamination of the atmosphere. The system includes devices for removing refrigerant from the system under the vapor pressure of the refrigerant or with aid from a pump, a conduit for conveying the refrigerant from the system, and a collapsible bag constructed of a flexible material substantially impermeable to refrigerant and to air, having at least one inlet for introducing refrigerant to be salvaged and sealing means for sealing the inlet on the bag. After filling, the bags may be transported to a recovery system for recovering refrigerant from the bag so that the refrigerant may be purified and recovered for reuse.

Abstract: A transport refrigeration system which includes a compressor, a condenser, a receiver, an evaporator, an accumulator, and a control valve having cooling and heating output ports which are alternatively connected to first or second refrigerant circuits to initiate cooling and heating cycles, respectively. The heating capacity of a commanded heating cycle is enhanced prior to switching to the heating cycle by connecting the outlet of the receiver to the second refrigerant circuit while maintaining the control valve cooling port active in the first refrigerant circuit for a predetermined time delay. This forces liquid refrigerant in the condenser to flow into the receiver and then into the second refrigerant circuit, making additional liquid refrigerant available to the heating cycle, which is initiated at the end of the predetermined time delay, without introducing liquid refrigerated directly into the accumulator.

Abstract: A refrigeration system including an evaporator. A reservoir is connected to the evaporator at a point intermediate the inlet and the outlet of the evaporator. The reservoir is placed in heat exchange relationship with the suction line near the outlet of the evaporator. In one embodiment a liquid level sensor is provided in the reservoir and the output of the sensor is used to control an expansion valve connected to the inlet of the evaporator. In another embodiment a capillary or fixed orifice device is used as an expression device for the evaporator and the reservoir acts as a refrigerant storage device to accommodate various operating conditions of the refrigeration system.

Abstract: The structure is arranged in such a manner that nonazeotropic mixed refrigerant is enclosed therein and a fractioning/separating device is disposed in a low pressure circuit in the main circuit of refrigerating cycle so as to conduct separation operation, the fraction/separation can be conducted at a low pressure in a separation mode, the specific volume of refrigerant gas generated in a reservoir due to heat supplied from a heater is enlarged, and the velocity of gas which moves upwards in the fractioning/separating device can be increased, causing a gas-liquid contact to be promoted. As a result, high performance separation can be conducted at reduced quantity of heat, causing the density of high boiling point refrigerant reserved to be significantly raised. Thus, the composition in the main circuit becomes a composition enriched with low boiling point refrigerant exhibiting excellent heating performance so as to satisfactorily cope with an increase in the load.

Abstract: The air conditioner is disclosed which determines a stop mode of an outdoor heat exchanger when a difference between a total of a heating power level or levels requested from one or more indoor units and a total of a cooling power level or levels requested from one or more remaining indoor units falls within a predetermined range and, when the stop mode of the outdoor heat exchanger is set, forcedly recovers a regrigerant which is accumulated on the outdoor heat exchanger back to a compressor.

Abstract: The refrigeration or heat pump installation includes a liquid separator that has a vapor chamber having a port connected to the outlet of the evaporator and an outlet connected through a suction conduit to a compressor. The separator also has an intermediate chamber beneath the vapor chamber for receiving liquid from the vapor chamber by the way of a first switching valve, the intermediate chamber being connected to the inlet of the evaporator for the purpose of recirculating liquid. A second switching valve forms part of the expansion apparatus for controlling the flow of fluid either directly to the intermediate chamber or through the first switching valve to the intermediate chamber. The two switching valves are operated to open and closed conditions in the opposite sense for controlling and almost continuous pulsating recirculation of liquid through the evaporator. The expansion apparatus is connected through a condenser to the outlet of the compressor.

Abstract: A liquid line service and process device for use in the liquid line of a refrigeration system comprising a housing respectively including an inlet, a filter core and an outlet forming a refrigerant flow path through the housing. The housing also includes an access port, means for connecting the access port to the refrigerant flow path, a moisture indicator in the refrigerant flow path, and means for controlling the flow of refrigerant in the flow path.

Abstract: A transport refrigeration system having a compressor, condenser, receiver, and evaporator, for controlling the temperature of a served space via hot gas heating and cooling cycles. The receiver is selectively pressurized during a hot gas heating cycle, pressurizing the receiver at low ambient temperatures as sensed by compressor head pressure, and terminating or preventing receiver pressurization above a predetermined head pressure. This is useful for transport refrigeration systems which have a single compartment to condition, and it is even more useful in compartmentalized transport refrigeration systems having two or more compartments to condition.

Abstract: A transport refrigeration system which includes a compressor, a condenser, a receiver, an evaporator, an accumulator, and a control valve which selectively initiates heating and cooling cycles. The heating capacity of a heating cycle is enhanced by connecting the outlet of the receiver to the inlet of the accumulator just prior to each heating cycle, while maintaining the control valve in a cooling position for a predetermined time delay. This forces any liquid refrigerant trapped in the condenser to flow into the receiver, while lower pressure in the accumulator causes liquid refrigerant in the receiver to flow into the accumulator, to provide additional liquid refrigerant in the accumulator at the start of the heating cycle, which is initiated at the end of the predetermined time delay.

Abstract: An air conditioning apparatus comprises a switching valve for switching the flowing direction of a refrigerant discharged from a compressor to carry out either cooling operation, heating operation or defrosting operation; an outdoor heat exchanger for receiving the refrigerant supplied by the compressor through the switching valve to make the refrigerant heat exchange with air to be heat exchanged; an indoor heat exchanger for making the refrigerant heat exchange with a fluid to be heat exchanged; an oil separator which is arranged in a discharging side refrigerant pipe connecting the switching valve and the discharge port of the compressor to separate the refrigerant and a refrigerating machine oil which are discharged from the compressor; a first and second accumulators which are connected in series in an intake side refrigerant pipe connecting the switching valve and the intake port of the compressor; a first bypass passage for connecting the oil separator and the second accumulator through a solenoid valv

Abstract: The automotive air conditioner uses a plurality of groups of coolant having different boiling points. The air conditioner uses both the lower boiling point coolant and the higher boiling point coolant when the air conditioner requires high cooling efficiency. The air conditioner separates the lower boiling point coolant from the higher boiling point coolant when the air conditioner does not require high cooling efficiency. In order to separate the lower boiling point coolant, the air conditioner has a rectifying circuit on which a controlling valve, a first pressure reducing means, a rectifying means, a second pressure reducing means and a heat exchanger is provided. The amount of coolant passing through the rectifying circuit is controlled in accordance with the temperature of the coolant downstream of the heat exchanger.

Abstract: The present invention provides a method and apparatus for recovering and purifying a refrigerant containing lubricant from a refrigerant system. The apparatus includes an evacuation means for evacuating the refrigerant and lubricant from the refrigerant system. A reservoir means receives the evacuated refrigerant and lubricant. A means allows lubricant and refrigerant to exit the apparatus and enter the refrigerant system.

Abstract: An apparatus for the air-conditioning of the interior of automobiles, with a refrigerant circuit, including a low-pressure part and a high-pressure part and in which vaporous refrigerant is drawn off from the evaporator by a compressor and, while experiencing an increase in pressure, the refrigerant is fed to a condenser for cooling and condensation. The condensed refrigerant is collected in a collecting vessel from which it can be diverted via an expansion valve into the evaporator while experiencing a pressure drop and cooling. A pressure-relief valve witha blow-out outlet is proided between the compressor and the condenser in the high-pressure part of the refrigerant circuit. The blow-out outlet of the pressure-relief valve is connected to an intermediate reservoir for the escaping refrigerant.

Abstract: A refrigeration cycle apparatus comprises first and second compressors, a four-way valve, an outdoor heat exchanger, first and second expansion means, at least one indoor heat exchanger, an accumulator, a refrigerant circuit connecting these element in order, a reservoir connected to the accumulator through an overflow pipe and a refrigerant supplying pipe with a first solenoid valve and a feeding pipe with a second solenoid valve for connecting the inlet side of the expansion means to the reservoir, wherein the first and second solenoid valves are opened and closed depending on operational conditions in a refrigeration cycle.

Abstract: Disclosed is a heat pump comprising a main circuit containing a mixture of non-azeotropic refrigerants, the main circuit including a compressor for pressurizing the mixture, a first heat exchanger operating as a heat sink, a second heat exchanger operating as a heat source, and an expansion device connected between the first and second heat exchangers. A portion of the mixture is supplied through a first feed line from a first junction between the expansion valve and the first heat exchanger and vaporized before being fed to a rectifier where it coacts with liquid refrigerant to cause separation of higher pressure refrigerant of the mixture from the lower pressure refrigerant. The separated higher pressure refrigerant is stored in a reservoir in liquid phase and an overflowed portion of the liquid is returned to the rectifier as said coacting liquid.

Abstract: A refrigeration unit comprising a cooling circuit having a compressor, a condenser and an evaporator, and said unit including a hot gas valve and a hot gas bypass passage bypassing the condenser and forming a defrost circuit, so that when the evaporator is frosted upon operation by means of the cooling circuit, constant quantity refrigerant is circulated around the defrost circuit to perform a defrosting operation.

Abstract: A discharge valve and baffle assembly is provided in a refrigeration system having either one or more compressors. The discharge valve and baffle assembly eliminates the effects of an established head upon starting the associated compressor, thereby permitting the compressor to quickly come up to speed for the established head. During compressor operation, the discharge valve and baffle assembly provides a suction force for holding the valve in the open position to prevent bouncing of the valve during part-load conditions and cycling of the valve between the open and closed positions during surge conditions. The assembly prevents backflow of refrigerant through the nonoperating compressor, and also provides a baffle effect to direct the flow of high pressure gaseous refrigerant uniformly into the condenser.

Abstract: A method of obtaining low temperatures comprising pulse-feeding a refrigerant within a step-wise pressure range where boiling occurs, and its vapors are formed at a low pressure. The refrigerant vapors are subsequently compressed and condensed until the formation of a liquid refrigerant. The liquid refrigerant is subcooled and boiled at a low pressure and a temperature out of the boiling temperature step-wise range with the number of steps depending on the final temperature of the refrigerated medium. An apparatus for obtaining low temperatures comprises, successively interconnected in a closed path, an evaporator, a means to separate a liquid refrigerant, associated with at least two differential pressure relays through pressure transducers, a compressor, a condenser, a receiver, a means for pulse feeding of the liquid refrigerant, and a means for uniform distribution of the liquid refrigerant.

Abstract: A refrigeration unit comprising a cooling circuit having a compressor, a condenser and an evaporator, and said unit including a hot gas valve and a hot gas bypass passage bypassing the condenser and forming a defrost circuit, so that when the evaporator is frosted upon operation by means of the cooling circuit, constant quantity refrigerant is circulated around the defrost circuit to perform a defrosting operation.

Abstract: A refrigeration system suitable for use in an air conditioner has a main refrigerant circuit including a compressor, a condenser, a first pressure reducer, a gas-liquid separator, a second pressure reducer and an evaporator connected in series to form a closed loop, and a gas injection passage providing a communication between the gaseous phase part of the gas-liquid separator and a compression chamber of the compressor. A stop valve is disposed in the inlet and outlet pipes of the gas-liquid separator, and a bypass passage is provided for connecting directly the outlet pipe of the condenser to the inlet pipe of the evaporator to bypass the gas-liquid separator.

Abstract: A refrigeration apparatus has a refrigerant circuit which is constituted by a compressor, a condenser, a first pressure reducer, a gas-liquid separator, a second pressure reducer and an evaporator connected to one another in series. The refrigeration apparatus also has a gas injection line connected between a gaseous phase portion of the gas-liquid separator and a compression chamber of the compressor. The improvement comprises a liquid refrigerant extracting passage providing a communication between a portion of the gas-liquid separator at a predetermined level and a portion of the low-pressure side of the refrigerant circuit. With this arrangement, it is possible to stabilize the level of the liquid refrigerant in the gas-liquid separator.

Abstract: The optimum charge in the heating and cooling modes is achieved in a reversible heat pump system by providing a receiver in the indoor section which is sized to store an amount of refrigerant equal to the difference in the optimum charge in each mode. The amount of refrigerant in the receiver is varied in response to the ambient temperature whereby the refrigerant charge is optimized over a range of temperatures.

Abstract: A system for providing a refrigerant to an ice rink, the system including a compressor means for compressing a refrigerant, means for delivering the compressed refrigerant to a low pressure receiver vessel, and means for passing refrigerant condensate from said low pressure vessel to a pair of pumper drum vessels. The rink is provided with a plurality of refrigerant transmitting conduits extending from one end thereof to the other, and with a high pressure header extending across one end of the rink and a low pressure header extending across the opposed end of the rink. The high pressure header is provided with a balance header which couples the opposite free ends of this header element together, and an intermediate line or conduit is also provided which couples the central or mid-portions of the high pressure header and the balance header together.

Abstract: A microcomputer controlled charge control system for modulating charge in a heat pump refrigerant circuit. A charge receiver has its interior in thermal communication with the compressor suction line and has a single charge flow line connected via a charge control valve to the refrigerant circuit at a point intermediate two controllable expansion valves in the high side of the circuit. Super-heating and subcooling strategies are employed to maintain the charge level in the circuit at optimum performance levels, automatically adapting to changes in environmental load conditions on the heat pump heat exchange coils.

Abstract: A refrigerant apparatus having an accumulator for receiving binary refrigerant from the evaporator of the apparatus. An expansion valve is connected in parallel with a capillary duct for increasing the refrigerant delivery from a preselected minimum determined by the capillary tube to controlledly flood the evaporator. The lower boiling point component of the binary refrigerant is caused to be separated in the accumulator for delivery to the compressor during flooded operation of the apparatus so as to increase the proportion of the low boiling point component in the binary refrigerant to provide increased refrigeration capacity to meet the increased demand. Upon decrease in the demand, the accumulated liquid refrigerant in the accumulator is gasified for returning the system to the normal ratio of components of the binary refrigerant. The expansion valve is caused to operate as a function of the temperature of the space refrigerated by the evaporator in effecting the desired flooding operation.

Abstract: A variable capacity binary refrigerant refrigeration apparatus providing improved energy usage efficiency in an operation of a dual evaporator system. One evaporator is used for refrigerating an above-freezing fresh food zone and the other evaporator is used for refrigerating a below-freezing freezer zone. The fluid system includes a rectifier, a separator, and an auxiliary condenser, together with suitable valves for controlling the operation of the apparatus. The system further utilizes control of the cold air circulating fans in effecting the desired improved operation.

Abstract: Adjustments in working fluid mixture composition directly effecting the capacity of an associated vapor compression cycle device are achieved by varying the inventory of mixture stored in a device high-pressure accumulator through the controlled regulation of the accumulator pressure.

Abstract: A device at a heating or cooling unit such as, for example, a heat pump where the energy carrier is a substance, the volume of which varies substantially with the temperature, for example freon.At such a unit, which comprises condenser (1,2), evaporator (1,2) and compressor (3), and where the compressor is driven by an electric motor (18), according to the invention a tank (21) is provided to contain said substance (22) and is connected to the suction side (19) and, respectively, pressure side (20) of the compressor (3) by two respective conduits (23,24), each of which is provided with an electrically controlled valve (25,26) for closing and, respectively, opening the conduit in question.

Abstract: A refrigerant transfer system is provided embodying a pump for controlling the level of liquid refrigerant within a suction header of an evaporator unit. The pump includes a pair of elongated chambers in endwise relation. One chamber has a substantially greater cross-sectional area than the second chamber. Opposite ends of each chamber have port means. A first set of inlet and outlet valve means is connected to the port means at each end of said one chamber. Each inlet valve means is alternately connected to a source of pressurized fluid. A second set of inlet and outlet valve means is connected to the port means at each end of the second chamber. Each inlet valve means of the second set communicates with a lower portion of the evaporator suction header. The heads of a double-headed piston are disposed within the chambers. Control means are operatively connected to the first set of inlet valve means for controlling the direction of movement of the piston heads within the chambers.

Abstract: An air cooled centrifugal water chiller is disclosed which may be operable (1) under conditions of low outdoor ambient temperature, requiring flooding of the air cooled condenser in order to reduce its capacity and maintain proper system operation; or (2) in a heat recovery mode through the provision of a liquid cooled heat recovery condenser which thereby accommodates a portion of or all the condensing load, also requiring reduction in the capacity of the air cooled condenser through flooding. In order to provide sufficient refrigerant within the system to accommodate flooding under the conditions enumerated above, a refrigerant storage vessel is provided in communication with the shell of the evaporator of the system for receiving and storing excess liquid refrigerant during those operating conditions when it is not required in order to flood the air cooled condenser.

Abstract: A vapor compression cycle device is described which includes a multi-component working fluid mixture, and an improved condensing heat exchanger. The vapor compression cycle device includes also a high-pressure liquid accumulator with an associated flow restricting device positioned between the condensing heat exchanger and the evaporating heat exchanger, and a liquid accumulator positioned between the evaporating heat exchanger and the compressor. A method is also described of modulating the capacity of such a device.

Abstract: A vapor compression cycle device is described which includes a multi-component working fluid mixture, a high-pressure liquid accumulator with an associated flow restricting device positioned between the condensing heat exchanger and the evaporating heat exchanger, and a low-pressure liquid accumulator positioned between the evaporating heat exchanger and the compressor. A method is also described of modulating the capacity of such a device.

Abstract: An environmental control system comprises a working gas circuit including a compressor-expander arrangement and first heat exchange means by which the working gas is conditioned before being passed to second heat exchange means connected in the circuit in heat exchange relationship with an environment to be controlled. The working gas is provided with means for regulating the mass of working gas in the circuit in response to the conditioning demand on the system. One such regulating means comprises an inlet path for admitting working gas to the circuit and an outlet path for removing working gas from the circuit.

Abstract: A vapor compression cycle device is described which includes a multi-component working fluid mixture, condensing heat exchanger and an associated vapor-liquid separator connected to the compressor, a high-pressure liquid accumulator connected to the condenser and associated separator, a flow restricting device connected to the condenser and associated separator, an evaporating heat exchanger and associated low-pressure accumulator connected to the flow restricting device, and the evaporating heat exchanger and low-pressure accumulator connected to the compressor. A method is described also to modulating the capacity of such a device.

Abstract: An air conditioning system for an enclosed space employing a unitary compressor and expander of the positive displacement type, each having an inlet port and an outlet port, with a primary heat exchanger connected between the compressor outlet port and the expander inlet port and a secondary heat exchanger connected between the expander outlet port and the compressor inlet port to complete a closed loop having a charge of gas, the gas being non-condensing at the temperatures and pressures encountered in the unit. An accumulator holds an auxiliary charge of the pressurized gas at a pressure which is lower than the pressure existing in the primary heat exchanger and higher than the pressure existing in the secondary heat exchanger. A first intermittently operated valve couples the accumulator to the secondary heat exchanger for injection of auxiliary gas into the closed loop to raise the pressure in the secondary heat exchanger substantially above the atmospheric level to increase the heat rate of the system.

Abstract: A control system for a refrigeration system having an air-cooled condenser exposed to normal year round ambient temperatures. Head pressure is controlled in response to sensed subcooling of the refrigerant in the liquid line near the entrance to the expansion device, so as to prevent the occurrence of flash gas at the expansion device, while still allowing minimum head pressures so as to improve energy efficiency. In alternate embodiments, additional controls are provided for assuring at least a predetermined minimum pressure differential across the thermostatic expansion valve. In one preferred embodiment a two-bulb sensing technique is used for subcooling and pressure differential sensing. Both series and parallel condenser-receiver connection systems are disclosed, as are a number of different subcooling sensing and control embodiments.

Abstract: A compressor, condenser, pressure control valve, condensed liquid receiver, expansion valve and evaporator are arranged in circuit to provide a refrigeration system. The pressure control valve and condensed liquid receiver are bypassed by a pump tank and a pump in circuit between the output of the condenser and the expansion valve. A float switch in the pump tank provides an actuating signal at a predetermined level for condensed liquid in the pump tank, and the actuating signal is coupled to the pump. The pump, when actuated, draws condensed liquid from the pump tank at a free condensation pressure dependent upon ambient temperature at the condenser, and provides high pressure condensed liquid to the expansion valve. An inlet/outlet line between the condensed liquid receiver and the expansion valve allows high pressure condensed liquid which is not passed by the expansion valve to be accumulated in the condensed liquid receiver.

Abstract: The defrost pressure control system for a refrigerator includes a reservoir connected in communication with the evaporator of the refrigerating system. The reservoir is placed in heat exchange relationship with a portion of the refrigerator which remains at a relatively low temperature during defrosting so that a portion of the refrigerant in the system condenses in the reservoir during defrosting, thereby being effectively removed from the refrigerating system. A suitable heat sink may also be employed in the heat exchange relationship with the reservoir. Because of withdrawal of the aforementioned refrigerant, the pressure in the refrigerating system at the end of the defrosting operation is substantially below that which would otherwise be present. As a result the torque required to start the compressor is significantly reduced, thereby insuring effective starting of the compressor even when driven by an electric motor having a relatively low starting torque.

Abstract: A two-temperature refrigerator appliance having a refrigerator unit operated by a single compressor set, a refrigeration loop with two evaporator sections connected in series, one evaporator associated with a cold compartment and the other with a warmer compartment, a control element associated with the colder compartment disposed in the electric circuit of the compressor set, a control element associated with the warmer compartment having a constant switching-on point above the freezing point, several heating elements switched on by said warmer compartment control element with one heating element disposed adjacent a refrigerant collector connected to the refrigeration loop and another element disposed adjacent the sensor of the colder compartment control element, and at least one intermittently operated additional switching element disposed in the electric circuit of the compressor set.

Abstract: A recirculating refrigeration system wherein a screw compressor receives vaporized refrigerant from the evaporators at its low pressure inlet and from a flash tank or receiver at an intermediate pressure inlet. Refrigerant which is not vaporized in the evaporators is trapped in a suction line accumulator from which it flows by gravity into a dump tank. The dump tank has a gas pressure connection to the compressor outlet or to the receiver or flash tank and a control valve is effective to introduce gas under pressure to the dump tank and force the liquid accumulated therein back into a receiver when it has risen to a predetermined level in the dump tank.

Abstract: A refrigerant delivery and separation apparatus and a process for delivering refrigerant at evaporator temperature to an evaporator at a predetermined pressure which is less than the pressure at the receiver, and simultaneously separating refrigerant liquid and vapor which is discharged from the evaporator. The apparatus includes a pair of tanks connected by time operated control members to conventional refrigeration equipment so that one tank is pumping liquid refrigerant to an evaporator at a predetermined pressure while the other tank is separating liquid and vapor refrigerant substantially at evaporator pressure.

Abstract: In a dual temperature refrigerator with a single compressor from which refrigerant flows through a condenser and a capillary tube into a first evaporator, and from the first evaporator through a connecting line into a second evaporator, a refrigerant collector being connected to the condenser at the beginning of the capillary tube, the collector having a volumetric capacity equal to that of the second evaporator and being provided with a heater, a control element in the chamber of the second evaporator intermittently activating the compressor and heater, a suction line from the second evaporator to the compressor, and at least part of the capillary tube in heat-exchange contact with the connecting line. Preferably part of the capillary tube is disposed within the connecting line. Desirably the capillary tube and connecting line are disposed in the insulation of the refrigerator.

Abstract: A refrigeration system incorporating a compressor sub-system which provides a source of higher pressure gaseous refrigerant to force liquid refrigerant into the receiver when condensor pressure is reduced sufficiently below normal to prevent it accomplishing the same purpose. When condensor pressure is insufficient to force liquid refrigerant from a pilot receiver tank to the receiver tank liquid accumulates in the pilot receiver tank to a level where it actuates a control valve, introducing said higher pressure gaseous refrigerant to said pilot tank and forcing liquid out. While condensor pressure is sufficient to the task, as is normally the case, the higher pressure gaseous refrigerant is received directly by the condensor.

Abstract: An absorption refrigerator of natural circulation type employing water as a refrigerant and lithium salt as an absorbing medium, in which a U-tube is disposed in a conduit portion between a condenser and an evaporator and is connected at one end thereof to a separator in addition to the condenser and at the other end thereof to a refrigerant reservoir. A cooling conduit extends into this refrigerant reservoir to maintain substantially constant the internal pressure of the reservoir so that the amount of the refrigerant stored in the reservoir can be controlled depending on the pressure difference between the separator side of the U-tube and the reservoir side of the U-tube. Therefore, the concentration of the lithium salt solution circulating through the refrigeration system can be controlled depending on the temperature of a heating medium supplied to a generator.

Abstract: A refrigerator has a low-temperature cooling compartment and a higher-temperature cooling compartment, and is provided with a cooling system comprised of a cooling-medium flow circuit. The flow circuit includes a compressor, a condenser downstream of the compressor, a flow restrictor downstream of the condenser, a first evaporator section downstream of the flow restrictor and operative for cooling the lower-temperature compartment, and a second evaporator section downstream of the first evaporator section and operative for cooling the higher-temperature compartment. An accumulator communicates with the flow circuit upstream of the flow restrictor. A heater is provided for heating liquid cooling medium in the accumulator to cause evaporation of part of such liquid cooling medium and concomitant pushing of the liquid remainder of the liquid cooling medium in the accumulator out of the accumulator and into the second evaporator section.