Abstract: A hot gas defrost refrigeration system has a compressor, a condenser, and an evaporator, interconnected by fluid passage means and incorporating valve means to cause refrigerant to flow sequentially through the compressor, condenser, and evaporator to the compressor during the refrigeration cycle. Refrigerant flow during the defrost cycle is from compressor to evaporator through the condenser to the compressor. The refrigeration system includes defrost passage means, including valve means, connecting the evaporator outlet to the condenser inlet and connecting the condenser outlet to the compressor inlet. A vessel is provided which combines the functions of receiver during refrigeration and superheater during defrost. During refrigeration liquid refrigerant flows from the condenser through the superheater/receiver to the evaporator. During defrost, the defrost passage means directs vaporous refrigerant from the evaporator through the superheater/receiver to the compressor.

Abstract: A refrigerating circuit apparatus includes a two stage compressor having an upper stage compressing cylinder and a lower stage compressing cylinder, a heat stage tank, an upper stage side variable opening expansion valve and a lower stage side variable opening expansion valve. The upper stage side variable opening expansion valve is controlled toward its closed position for executing a heat storing operation wherein heat is discharged from refrigerant to the heat storage tank. The upper stage side variable opening expansion valve is opened and the lower stage side variable opening expansion valve is closed for carrying out a defrosting operation. Heat stored in the heat storage tank is used in the defrosting operation for removing frost accumulated on an external heat-exchanger during the heating operation.

Abstract: The refrigeration system disclosed herein operates at least one evaporator in a low temperature environment. A condenser is provided for rejecting heat into the environment. Refrigerant from the condenser is provided to a refrigerant processing vessel which allows a mixture of gas and liquid phase refrigerant to separate. A heat exchanging conduit is submerged in the liquid phase refrigerant in the lower portion of the processing vessel and the outlet of a compressor serving the low temperature evaporators is connected to the inlet end of that conduit. Liquid phase refrigerant from the processing vessel is provided to the low temperature evaporators. An intake is provided in the upper portion of the processing vessel for drawing off gas phase refrigerant and that intake and the outlet end of the heat exchanging conduit are connected together and to the inlet side of a compressor driving refrigerant through the condenser.

Abstract: An air conditioning device comprising: a single outdoor unit including a compressor, a four port valve, an outdoor heat exchanger, an accumulator and the like; a plurality of indoor units connected in parallel to the outdoor unit through a first refrigerant-carrying means and a second refrigerant-carrying means; switching valves for selectively connecting one end of the indoor units to either the first refrigerant-carrying means or the second refrigerant-carrying means; and a third refrigerant-carrying means having one end connected to the other end of the indoor units through first flow controllers, and the other end connected to the first refrigerant-carrying means through a second flow controller.

Abstract: A hot gas defrost type refrigeration system in which refrigerant used to defrost is returned to the system's refrigerant circuit after being collected and reduced in pressure, as by expansion valve means, to a pressure below the pressure in the system's return suction header, then heated as by means involving heat exchange with the system's high pressure refrigerant, the refrigerant used to defrost thus being in a superheated gaseous state and returned to the system's return suction header in such state without risk of introduction of liquid refrigerant to the system's compressor(s).

Abstract: A refrigerating circuit apparatus includes a two stage compressor having an upper stage compressing cylinder and a lower stage compressing cylinder, a heat storage tank, an upper stage side variable opening expansion valve and a lower stage side variable opening expansion valve. The upper stage side variable opening expansion valve is controlled toward its closed position for executing a heat storing operation wherein heat is discharged from refrigerant to the heat storage tank. The upper stage side variable opening expansion valve is opened and the lower stage side variable opening expansion valve is closed for carrying out a defrosting operation. Heat stored in the heat storage tank is used in the defrosting operation for removing frost accumulated on an external heat-exchanger during the heating operation.

Abstract: The invention provides a refrigeration system employing hot compressed gas from the compressor to defrost the cooling coil or coils. In prior systems this is accomplished by diverting part of the hot compressed gas to flow through the cooling coil, while the remainder continues to flow through the condensing coil to avoid overload of the compressor. It is found that as the ambient temperature of the condenser coil decreases the compressor output pressure also decreases, decreasing the amount of hot gas available for defrost, so that the period required for adequate defrost also varies. It is therefore necessary either to adjust the length of the defrost period with this ambient temperature, or make the period sufficiently long to ensure defrost at all times, the latter resulting in inefficient operation.

Abstract: The refrigeration system disclosed herein operates evaporators in both moderate and low temperature environments, respective compressors being associated with each type of evaporator. A condenser is provided for rejecting heat into the environment. Refrigerant from the condenser is provided both to the moderate temperature evaporators and to a refrigerant processing vessel which can allow a mixture of gas and liquid phase refrigerant to separate. A heat exchanging conduit is submerged in the liquid phase refrigerant in the lower portion of the processing vessel and the outlets of the compressors serving the low temperature evaporators are connected to the inlet end of that conduit. Liquid phase refrigerant from the processing vessel is provided to the low temperature evaporators.

Abstract: A method of defrosting a refrigerating circuit for use in cooling a vehicular chamber comprises two steps. In a first step a frost formed at an outer surface of an evaporator of a cooling unit is defrosted by directly leading discharged gas to the evaporator. In a second step a frost formed at elements of the cooling unit except the evaporator is defrosted by making air in the vehicular chamber pass through the heated evaporator. In this manner, the cooling down characteristic in the vehicular chamber is improved and compressor durability is preserved.

Abstract: The invention relates to a method and a device for compression of gases, in particular of air, within a compressed air piping system. The air drawn in for the compressor is cooled below 0.degree. C. within a freeze-dehumidifer in a cooling channel. The supply of undercooled refrigerant into the freeze-dehumidifier is interrupted during the defrosting of the freeze-dehumidifier situated within the cooling channel for the air drawn in towards the compressor. The condensate appearing in the form of ice on the freeze-dehumidifer is separated thereby. The defrosting operation is terminated after a pressure of the refrigerant corresponding to a positive temperature of the freeze-dehumidifier is exceeded, or after a presettable period has elapsed. The pressure of the refrigerant is monitored in the suction pipe and if appropriate in the delivery or pressure pipe of the refrigerant compressor.

Abstract: To prevent defrost melt from refreezing during a defrost cycle, the hot gas bypass line is branched to heat the metal plate across which the defrost melt flows as well as the drain pan.

Abstract: An air conditioning apparatus includes two different refrigerating circuits in one central unit for supplying a conditioned air into a defined space through an air duct. Each refrigerating circuit has an air exhausting damper for exhausting internal air from the defined space, and an external air intake damper for taking the external air into the defined space through the central unit. One of the refrigerating circuits forcibly carries out the heating operation, and the external air intake damper thereof is maintained in a closed state while the other refrigerating circuit carries out the defrosting operation to prevent temperature of the conditioned air fed from the central unit into the defined space from decreasing below a desirable level.

Abstract: This invention is associated with my prior invention of a full flow vaporizer for use in a refrigeration system employing hot gas from the compressor to periodically defrost the cooling coil, or coils where multiple coils are employed. The vaporizer usually consists of three concentric circular cross-section tubes. The inner tube receives the fluid from the coil and is provided in its wall with a plurality of fine bores directing the fluid forcefully radially outwards against the inner wall of the middle tube, which is heated by the hot gas. The flow capacities of the passages and the bores are chosen to be in a specific range of flow capacities relative to one another, so that when not in use the vaporizer has no appreciable effect on the remainder of the system. An orifice or restriction is provided at the outlet for the hot gas from the third annular passage and increases the back-pressure applied to the compressor, rendering the device self-balancing to prevent compressor motor overload.

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 ice making system having a compressor, a condenser and an evaporator, and having freeze and harvest cycles. During the harvest cycle, vaporous refrigerant is circulated from the compressor to the evaporator through a discharge line, and is thereafter returned to the compressor through a supply line. A predetermined amount of refrigerant is condensed in a reservoir during the freeze cycle and expelled therefrom during the harvest cycle to augment the amount of refrigerant circulating in the system.

Abstract: A transport refrigeration system, and method of operating same, in which a maximum operating pressure expansion valve and a secondary condenser are used to enhance hot gas heating cycles initiated to hold a predetermined temperature set point, and hot gas defrost cycles. The secondary condenser is disposed in an evaporator section of the refrigeration system, with hot discharge gas from a compressor being directed to the secondary condenser during heating and defrost cycles. A sufficient supply of refrigerant for heating and defrost cycles is ensured by injecting refrigerant from a receiver and condenser into an active heat cycle refrigerant circuit, when the active refrigerant is insufficient to build the pressure on the low pressure side of the refrigeration system to a value sufficient to close the maximum operating pressure expansion valve and the compressor suction pressure is less than the receiver/condenser pressure.

Abstract: A method for controlling an air-conditioning apparatus in terms of execution of the defrosting mode. The apparatus basically includes a variable-frequency compressor, a room heat-exchanger for performing heat-exchange with a room fan, and an outdoor heat-exchanger provided at the outside of the room, which are circularly coupled to each other to establish a refrigerating cycle. Also included in the air conditioning apparatus are a bypass circuit provided between a first line for effecting a connection between an outlet side of the compressor and the room heat-exchanger and a second line for effecting a connection between an inlet side of the compressor and the outdoor heat-exchanger and a restriction device arranged to allow a change of its restriction amount and provided between the two heat-exchanger. The bypass circuit has an opening and closing valve for shutting off the bypass circuit.

Abstract: An ice making system having a compressor, a condenser and an evaporator, and having freeze and harvest cycles. During the harvest cycle, vaporous refrigerant is circulated from the compressor to the evaporator through a discharge line, and is thereafter returned to the compressor through a supply line. A predetermined amount of refrigerant is condensed in a reservoir during the freeze cycle and expelled therefrom during the harvest cycle to augment the amount of refrigerant circulating in the system.

Abstract: A valve for closing a main fluid flow through a main flow passage having a valve stem with a valve head for engaging a valve seat to close the passage, the valve stem carrying at the end remote from the valve head a piston which can be actuated by a closing fluid against spring action to move the valve head (48) into closed position, the valve stem being hollow and is open at the valve head end and at the opposite end has openings opening into the interior of the hollow valve stem, and the piston is mounted for axial movement on the valve stem to allow further movement towards the valve seat against spring action when the valve head has engaged the valve seat and the valve stem has come to a halt, said further movement relative to the valve stem opening a passage into the openings in the valve stem, whereby closing fluid will be injected into the main flow passage at one side of the valve seat through the valve stem.

Abstract: A refrigerating apparatus comprises a compressor, a condenser, an expansion valve and a evaporator which are interconnected serially through a pipeline to form a closed circulation circuit. A check valve allowing a coolant flow only toward the condenser is provided between the discharge port of the compressor and the condenser. A hot gas bypass circuit is connected at one end to a junction between the compressor and the check valve and at the other end to a junction between the expansion valve and the evaporator. The check valve serves to prevent backflow of coolant to the hot gas bypass circuit during the hot gas operation mode without hindering the flow of the coolant gas through the closed circulation circuit during the normal refrigerating operation.

Abstract: A refrigeration system, and method of operating same, in which an economizer heat exchanger, normally used in conjunction with an intermediate port of a refrigerant compressor to cool the main refrigerant flow from a receiver to an evaporator to enhance the refrigerant cooling cycle, is caused to function as an evaporator during a hot gas heating cycle. The economizer heat exchanger is caused to function as an evaporator by adding heat thereto during a heating cycle, and by establishing an alternate liquid line, effective during a heating cycle, which includes the economizer heat exchanger. When the compressor is driven by an internal combustion engine, engine coolant may be used to add the necessary heat to the economizer heat exchanger during a heating cycle.

Abstract: A method and apparatus for air conditioning parked aircraft is disclosed in which air at a temperature below the freezing point of water is provided under pressure to the aircraft. The use of sub-freezing air enables a reduction in air flow rate over prior art systems. This results in less power consumption for cooling and pressurizing the air and also results in less cabin noise. Further, the air entering the cabin is very low in humidity, which enhances passenger comfort. Several cooling system mechanizations are presented which include provisions for automatic frost removal.

Abstract: A refrigerating system comprising a compressor, a condenser communicated with the discharge port of the compressor, an evaporator communicated with the suction port of the compressor, a decompression or expansion device inserted in a line intercommunicating the condenser and the evaporator, a heat accumulator interposed between the discharge port of the compressor and the condenser and a bypass line whose one end is communicated with a line intercommunicating the compressor and the decompression device and whose other end is communicated through the heat accumulator to a line intercommunicating the decompression device and the evaporator.

Abstract: A refrigeration system comprises a plurality of evaporators and a plurality of conduits for feeding cooling-medium vapor evaporated in the evaporators to a plurality of compressors having a common outlet header for compression therein. Conduits extends between the common outlet header of the compressors and the inlets of the evaporators to feed the heated cooling-medium vapor produced by the compressors to one, several or all of the evaporators for defrosting the same.

Abstract: The invention provides a full flow vaporizer for use in a refrigeration system employing hot gas from the compressor to periodically defrost the cooling coil, or coils where multiple coils are employed. The vaporizer usually consists of three concentric circular cross-section tubes forming a first inner passage, a concentric second annular passage, and a concentric third annular passage. The inner tube receives the fluid from the coil and has one end blocked. It is provided in its wall with a plurality of fine bores directing the fluid forcefully radially outwards under the action of the high velocity gas component of the fluid against the inner wall of the middle tube, which is heated by the hot gas that is passed through the third annular passage before being fed to the coil to perform the defrost function. The flow capacities of the passages and the bores are chosen to be in a specific range of flow capacities relative to one another, usually in the range 0.5 to 1.5, preferably in the range 0.9 to 1.

Abstract: The invention provides a full flow vaporizer for use in a refrigeration system employing hot gas from the compressor to periodically defrost the cooling coil, or coils where multiple coils are employed. The hot gas cooled in the defrosting coil produces liquid refrigerant droplets that may damage the expensive compressor. The vaporizer usually consists of three concentric circular cross-section tubes forming a first inner passage, a concentric second annular passage, and a concentric third annular passage. The inner tube receives the fluid from the coil and has one end blocked. It is provided in its wall with a plurality of fine bores directing the fluid forcefully radially outwards under the action of the high velocity gas component of the fluid against the inner wall of the middle tube, which is heated by the hot gas that is passd through the third annular passage before being fed to the coil to perform the defrost function.

Abstract: A refrigeration cycle of an air conditioner includes a variable-capacity compressor which has a predetermined maximum capacity. A thermal storage tank filled with a regenerative material is connected between the discharge side of the compressor and an indoor heat exchanger. In a regenerating operation of the refrigeration cycle, the regenerative material deprives the heat of a refrigerant discharged from the compressor and stores it. At this time, the compressor is driven within a capacity range having a maximum value lower than the predetermined maximum capacity, and an indoor fan for delivering air to the indoor heat exchanger is stopped.

Abstract: A refrigerating apparatus for individually refrigerating a plurality of chambers by a single compressor is disclosed. The refrigerating apparatus includes a plurality of evaporators which are disposed one in each of the respective chambers, and are coupled with each other in parallel. An electromagnetic valve is coupled to each evaporator in series to control the flow of refrigerant, and an expansion valve such as a capillary tube also is coupled to each evaporator in series, to thereby form a plurality of electromagnetic valve-expansion valve-evaporator combinations. An additional heat exchanger is disposed in the refrigerating circuit in parallel with the parallel electromagnetic valve-expansion valve-evaporator combinations through a valve device. The valve device allows adjustment of the flow of refrigerant to the evaporators and the additional heat exchanger to maintain the chambers at their desired temperature without varying the capacity of the compressor.

Abstract: An air conditioner having a defrosting mode of operation is disclosed, in which an outdoor heat exchanger is divided into two heat exchanger units juxtaposed in tandem with each other along the direction of air passage. In defrosting mode, a part of the refrigerant from the compressor is supplied to the upstream outdoor heat exchanger unit deposited with frost, and the rest of the high-temperature high-pressure refrigerant is supplied to the indoor heat exchanger to maintain the room temperature.

Abstract: An ice making system having a compressor, a condenser and an evaporator, and having freeze and harvest cycles. During the harvest cycle, hot vaporous refrigerant is circulated from the compressor to the evaporator through a discharge line. The refrigerant is thereafter returned to the compressor through a supply line. To ensure that a predetermined amount of refrigerant is circulated between the compressor and the evaporator during the harvest cycle, a harvest pressure regulating valve automatically adds vaporous refrigerant to the supply line from the condenser when the pressure therein falls below a predetermined level.

Abstract: An air conditioner includes a compressor, a four-way valve, an indoor heat exchanger, an expansion valve, an outdoor heat exchanger which are connected via pipings to form a heat pump type refrigerant circuit, the four-way valve being switched over to select a heating or cooling mode of operation. This air conditioner is further provided with a first and second branch pipes which extend from an outlet conduit of the compressor, the first branch pipe forming a first bypass pipe connected to an inlet conduit of the compressor. The first and second branch pipes have first and second valves, respectively. The air conditioner is also provided with a microcomputer for selectively opening and closing the second valve in response to the degree of superheating of discharged gaseous refrigerant after the first valve has been opened so that the discharged gaseous refrigerant is supplied to the outdoor heat exchanger to effect a defrosting operation while a heating operation is continued.

Abstract: An integrated heat pump and hot water system including a water to refrigerant heat exchanger having a refrigerant evaporating circuit and a refrigerant condensing circuit that are in heat transfer relation with the water circuit. A bi-flow expansion valve with a positive shut off feature is mounted in the refrigerant liquid line connecting the indoor and outdoor coil of the heat pump. The refrigerant evaporator circuit is connected between the inlet of the compressor and the liquid line by an evaporator line that enters the liquid line between the bi-flow expansion valve and the outdoor coil. A solenoid actuated metering valve is placed in the evaporator line to control the flow of refrigerant passing through the evaporator circuit. The condensing circuit of the heat exchanger is connected directly to the discharge line of the compressor so that the refrigerant discharged from the compressor passes through the condensing circuit.

Abstract: A transport refrigeration system 10, and method of operating same, which includes a compressor 14, a receiver 26, an evaporator 42, an accumulator 44, and valve means 18 which initiates heating and cooling modes or cycles which utilize hot compressor gas. Instead of pressurizing receiver 26 at the start of a heating cycle, which traps refrigerant in condenser 24, the heating capacity of a heating cycle is enhanced by connecting the outlet of receiver 26 and the inlet of accumulator 44 in direct fluid flow communication during a heating cycle. Lower pressure in accumulator 44 allows liquid refrigerant in receiver 26 to be directed into accumulator 44, while permitting refrigerant in condenser 24 to drain into receiver 26, to make additional liquid refrigerant available during the heating cycle.

Abstract: A refrigerated display case with multiple air curtains and a refrigerating system for refrigerating circulation air is disclosed. The refrigerating system includes a compressor, a condenser and two evaporators. One terminal port of both evaporators, positioned on the bottom portion of each evaporator, is alternately and selectively connected with the discharge side of the condenser or the suction port of the compressor through a four-way valve. The other terminal ports of both evaporators, positioned on the upper portion of each evaporator, are connected to each other through communicating lines. The communicating lines are connected to each other by a connecting line. A connecting line also connects a point between the two four-way valves to one of the communicating lines. The two communicating lines and the connecting lines are provided with at least one expansion valve and a plurality of electromagnetic valves and check valves.

Abstract: A method and apparatus for providing optimum control of a refrigeration system during both its cooling cycle and its defrost cycle. During the cooling cycle, the control system maintains operation of a fan for a predetermined period of time sufficient to fully evaporate the liquid refrigerant in the refrigeration system's evaporator coil. The control system initiates the defrost cycle only when the actual system parameters indicate the need to defrost. In the defrost cycle, the flow of hot gas and refrigerant is coordinated in a manner to minimize the amount of energy expended and to reduce thermal shock to the system, thereby eliminating unnecessary wear on the system components.

Abstract: An air conditioner for an auxiliary heating apparatus performs an auxiliary heating of a refrigerant flowing through a refrigerant circuit. The air conditioner is provided with a first auxiliary heat exchanger having a built-in first hydrogen-occluding alloy and hydrogen and a second auxiliary heat exchanger having a built-in second hydrogen-occluding alloy and hydrogen, wherein a temperature/hydrogen pressure characteristic of the second hydrogen-occluding alloy is different from that of the first hydrogen-occluding alloy. The air conditioner is further provided with hydrogen piping for circulating hydrogen between the first auxiliary heat exchanger and the second auxiliary heat exchanger, and a fan for heating the second auxiliary heat exchanger. Selector valves are also provided for circulating the refrigerant discharged from a compressor, when the axuiliary heating of the refrigerant is not performed.

Abstract: An integrated heat pump and hot water system having a refrigerant to water heat exchanger that includes first and second refrigerant circuits in heat transfer relation with a hot water circuit for circulating water from a storage tank through the heat exchanger. One refrigerant circuit is connected between the discharge side of the refrigerant compressor and the heat pump reversing valve. The second circuit is connected between the suction side of the compressor and the indoor coil side of the heat pump expansion device. A pair of control valves are positioned to provide for water heating when the heat pump is in either a heating or cooling mode of operation or, alternatively, when the heat pump is not required to provide air conditioning. In addition, energy in the hot water on the water side of the system is used to evaporate refrigerant in a novel defrost cycle.

Abstract: A method of enhancing the defrost and heating cycles of a transport refrigeration system for a straight truck, which refrigeration system includes a single refrigeration circuit selectively connectible to a compressor driven by the truck engine, or to a stand-by compressor driven by a motor connected to a stand-by source of electrical potential. The enhancement is achieved by slowly but continuously storing heat in an accumulator from the truck electrical system, or from the stand-by source of electrical potential, such that liquified refrigerant introduced into the accumulator during a defrost or heating cycle is immmediately vaporized. The slow but continuous rate of heat storage accumulates the requisite heat without unduly loading the truck electrical system or the truck engine.

Abstract: A reverse cycle defrost refrigeration system including a compressor, an air cooled condenser, an evaporator having surfaces for forming ice thereon during a freezing cycle and arranged to discharge the ice therefrom during a defrost cycle, and a defrost cycle arrangement to supply hot gaseous refrigerant to the evaporator during the defrost cycle including a defrost conduit connected to the condenser for releasing flash gas to the evaporator at the time the defrost cycle begins. A liquid separator surge tank is provided to condition warm defrost gaseous refrigerant which passes back through the defrost conduit to the evaporator at the beginning of the defrost cycle from carrying slugs of liquid refrigerant that may be in the condenser into the evaporator, having an inlet conduit connected to the top of the tank and an outlet conduit exiting from the tank neat the bottom thereof to separate and accumulate any slugs of liquid refrigerant or oil that may be entrained with the flash gas.

Abstract: A compact refrigeration heat exchanger comprising coiled tubing wrapped around a cylindrical chamber having input and output ports for preheating the evaporatior output to superheat liquid refrigerant prior to the compressor inlet by passing hot gas from the compressor output back through the coil while low pressure refrigerant flows through the chamber. The heat exchanger enables a refrigeration system to be defrosted without liquid refrigerant flood back to the compressor. Any liquid remaining accumulates in the heat exchanger due to the different lengths of the tubing in the heat exchanger.

Abstract: An air conditioning apparatus comprises a refrigerant circuit in which a compressor, a four-way valve, a room side heat exchanger, a pressure-reducing device and an outdoor side heat exchanger are connected in this order, wherein there is provided with a refrigerant temperature detector provided at a pipe line near the outdoor side heat exchanger, a room temperature detector for detecting temperature of a room and a controlling device which is electrically connected to the refrigerant temperature detector and the room temperature detector, said controlling device controlling operations for room-warming and defrosting based on inputs from the detectors.

Abstract: A compartmentalized transport refrigeration system, and method of operating same, in which a host refrigeration unit controls the temperature of the air in a front compartment of a trailer, and a remote evaporator unit controls the temperature of the air in a rear compartment. In order to increase the heating and cooling capacity of the remote evaportor, the host unit is prevented from going into a heating mode in response to predetermined conditions, and more, or all in certain instances, of the discharge gas from the host compressor is made available for the remote evaporator.

Abstract: A refrigerated display case with multiple air curtains and a refrigerating apparatus for refrigerating circulating air. The refrigerating apparatus includes a compressor, a condenser and two evaporators. The suction sides of both evaporators are connected with one another by a first passage line which includes first and second compression device with check valves in series, this line being connected to the compressor through valve devices. The discharge sides of both evaporators are also connected with one another by a second passage line which includes a pair of check valves, this second line being connected to the compressor through valve devices, respectively. The first and second passage lines are connected with one another and connected to the condenser through a valve device whereby both evaporators are parallel or serial connected with one another due to operation of the valve devices to accomplish the refrigerating mode or refrigerating and defrosting mode of the refrigerating means.

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 heat pump system in which a by-passing passage is provided for connecting a high pressure segment of a primary refrigerant passage with a low pressure segment of the primary refrigerant passage, a secondary pressure reduction means is disposed in the by-passing passage to produce two phases of the refrigerant (gas-liquid state) and the pressure of the refrigerant is continuously detected by sensing saturated temperatures of the two phases both upstream and downstream of the secondary pressure reduction means for controlling the operation of the system.

Abstract: A refrigeration system, and a method for operating the system, having a two-stage compressor for supplying refrigerant to a cooling coil, and having a desuperheater unit disposed between the two compressor stages. This desuperheater unit includes a container having heat exchange fluid therein and a coil, disposed in the heat exchange fluid, through which the refrigerant passes. During normal operation of the refrigeration system, both compressors are running. The desuperheater unit between the two compressor stages reduces the temperature of the compressed refrigerant before it reaches the second stage. The temperature of the heat exchange fluid is correspondingly increased in the course of the heat exchange. Also during normal operation, frost accumulates on the cooling coil, which is removed by a control device initiating a defrost cycle. When the defrost cycle begins, the first stage compressor is turned off while the second stage compressor continues to run.

Abstract: A transport refrigeration system using a three-way valve 14 for either cooling mode operation and defrost and/or heating mode operation is provided with a thermal storage sink 28 having first and second heat exchangers 26 and 52 and a heat exchange medium 30 therein which serves to sub-cool refrigerant in its passage to the evaporator 36 in a cooling mode, and which serves to evaporate refrigerant in heat exchanger 52 in a defrost mode after the refrigerant has passed through the defrost heat exchanger 42 for defrosting evaporator 36. The stored heat in the medium 30 in the sink serves to hasten the defrost cycle.

Abstract: A refrigerated display cabinet with multiple air curtains has refrigerating apparatus for refrigerating circulating air. The refrigerating apparatus comprises a compressor, a condenser and two evaporators. The suction sides of both evaporators are connected with one another by a first passage line which includes first and second decompression devices with check valves in series, this line being communicated with the compressor through valve devices. The discharge sides of both evaporators are also connected with one another by a second passage line which includes a pair of check valves, this second line being connected to the compressor through valve devices, respectively. The first and second passage lines are connected with one another and connected to the condenser through a valve device whereby the flow path of the refrigerant can be selectively controlled by operation of the valve devices.

Abstract: In a process of defrosting an evaporator of a refrigeration system used for refrigeration or as a heat pump, the refrigerant circuit leading from the compressor to the condenser and from the latter through a throttle valve and the evaporator back to the compressor is altered and the refrigerant delivered by the compressor is supplied to the evaporator and caused to by-pass the condenser. The refrigerant is used as a heat source for a heat accumulator during normal operation and the heat accumulator is used as a heat source for the refrigerant during a defrosting operation.

Abstract: An improved air-cooled heat pump type refrigerating apparatus having a refrigerant circuit reversible into a heating mode and a cooling mode, comprising a series of elements connected by piping means, which include a compressor, a four-way valve, an indoor heat exchanger, a capillary tube for cooling having first check valve connected in parallel therewith, a capillary tube for heating having second check valve connected in parallel therewith and an outdoor heat exchanger. The circuit, by switching the four-way valve, is capable of providing a heating operating mode, a cooling operation mode or a defrosting operation mode. The apparatus is constructed such that a branch tube branching off from a discharge tube of the compressor is provided and midway thereon with a solenoid valve and has a plurality of capillary tubes connected to the other end the branch tube through a distributor. The capillary tubes are connected respectively to heat transfer tubes of the outdoor heat exchanger at points midway thereon.