Abstract: Methods of sequencing parallel units in HVAC systems are described to improve overall system operating efficiency. The improved method is applicable for sequencing parallel centrifugal pumps in a variable flow hydronic system, parallel fans in a variable air-flow system, and centrifugal chillers in an HVAC system having a plurality of variable speed drive centrifugal chillers arrange in parallel. The method calls for determining an operating point of the on-line units, comparing the current operating point to a natural curve of maximum efficiency, and adding or shedding units as required to move closest to an operating curve of optimal efficiency, without direct regard to actual loading. Natural operating curves relate head pressure and operating speed rather than load. Control logic that implements such operating characteristics often will result in operating more parallel units on-line that would be required by prior art to meet the load.

Abstract: A refrigerating system has a condenser, an evaporator, and a two-stage centrifugal compressor assembly with an electric motor provided with a cooling system. A condenser inlet is connected to a compressor assembly outlet, while a condenser outlet is connected via first and second choke elements to an inlet of the evaporator and to the cooling system. The evaporator outlet communicates with the compressor assembly inlet, and the cooling system outlet communicates with the inlet of the second stage of the assembly. The cooling system is provide with a cooling skirt having a cavity of the cooling system lying between a stator and a housing. The refrigerating system has a separator vessel, a recuperative heat exchanger, and a heat-regulating valve controlled by the coolant pressure and temperature at the cooling skirt inlet, and also fitted in series with the separator vessel in the line connecting the condenser inlet to the evaporator. The separator vessel is connected by a gas phase to the coolant feed duct.

Abstract: A blast furnace (1) is supplied with a flow of optionally oxygen-enriched air coming from an isothermal compressor (3) or a (radial) centrifugal compressor (11).

Abstract: An air conditioning apparatus includes a first, second and third internal devices, and an external device which is provided with a plurality of separately operable units.

Abstract: An air conditioning equipment is provided with an oil level equalizing system, which includes a plurality of low-pressure shell-type compressors communicating with a suction line through a plurality of branch portions, a plurality of connecting lines each communicating with a corresponding compressor shell at a location adjacent to a normal oil level in the shell, and an oil level equalizing line communicating with the plurality of connecting lines. The oil level equalizing system also includes a communication line, through which the suction line communicates with the oil level equalizing line at a location upstream of the plurality of branch portions with respect to a direction of flow of a refrigerant. This arrangement functions to increase the pressure within the oil level equalizing line to a value higher than that within the shell of each compressor.

Abstract: A parallel type refrigerator provided with a plurality of condensing chambers which are formed by partitioning the inside of a shell of a condenser by partition plates so that a cooling medium flows through tubes respectively provided in the plurality of condensing chambers in sequence, and further provided with a plurality of evaporating chambers which are formed by partitioning the inside of a shell of an evaporator by partition plates so that a cooled medium flows through tubes respectively provided in the plurality of evaporating chambers in sequence.

Abstract: The present invention discloses an air conditioning system including at least first and second compressors, at least first and second heat exchangers associated respectively with the at least first and second compressors, at least third and fourth heat exchangers in refrigerant fluid communication respectively with the at least first and second heat exchangers, the at least third and fourth heat exchangers also being in heat exchange communication with a stream of air to be conditioned, an air flow pathway arranged to receive the stream of air downstream of the third and fourth heat exchangers and to direct it to a plurality of enclosures via a plurality of air outlets, and a control system operative to selectably operate the at least first and second compressors, such that none, all or some of the at least first and second compressors operate at a given time.

Abstract: A boosted air source heat pump system is presented having a primary compressor, a booster compressor and an economizer. On activation of the heat pump system, the primary compressor is operated. When the primary compressor cannot meet the demand, the booster compressor is activated, but only upon receipt of a signal enabling the operation of the booster compressor. The booster compressor is preferably a variable speed booster, and its speed is controlled to be at or between an absolute minimum speed and an absolute maximum speed. The booster may be on the low side or the high side of the primary compressor. The operation of the economizer may be modulated to meet the demand on the system.

Abstract: A compound refrigeration system is provided for use with a thermal storage system. A water chiller and a brine chiller are provided, with a primary compressor pulling refrigerant through the water chiller and a booster compressor pulling refrigerant through the brine chiller and applying the refrigerant to the inlet of the primary compressor. The high pressure stage compressor and the low pressure stage booster compressor operate simultaneously during nighttime hours, chilling both water for air conditioning and brine for making ice. Only the high pressure stage compressor operates during daylight hours, chilling water which is further chilled by heat exchange with the ice formed during the night.

Abstract: An air-conditioning apparatus forms a refrigerating cycle with a refrigerant heater and a compressor having two cylinders. The apparatus simultaneously carries out a refrigerant heating operation and a heat pump operation when a required heating capacity is high, and when the required heating capacity is low, only the heat pump operation. This operation technique helps reduce the size of the apparatus and expand a variable width of heating capacity. The apparatus also has a defrosting unit for defrosting an outdoor heat exchanger during the heat pump operation.

Abstract: A system and method of applying dual centrifugal compressors to a single evaporator and a single condenser in a refrigeration chiller unit. The condenser is split into two chambers by a divider having the same cross-sectional shape as the condenser and having holes provided through which the tubing provided in the condenser passes. The condenser includes a valve in fluid communication with both chambers of the compressor, for selectively equalizing or separating the pressures within the respective chambers. One or both compressors can be operated, according to the load. An independent condenser pressure can be provided for each centrifugal compressor, and thus the problems encountered by the conventional parallel-compressor refrigeration system can be avoided. With the invention, the refrigeration chiller capacity can be maximized and also adjusted to accommodate variable load requirements.

Abstract: A primary compressor and a booster compressor connected in series is presented. A first conduit connects the low side of a heating/cooling or refrigeration system to the inlet of the booster compressor, the outlet of the booster compressor and the inlet of the primary compressor. A second conduit connects the outlet of the primary compressor to the high side of the system. The first conduit includes a check valve for closing or opening the connection between the first conduit and the outlet of the booster compressor. A sump conduit is positioned near the bottom of the primary and booster compressors to allow lubricant to flow from the booster compressor to the primary compressor.

Abstract: In an air conditioner in which plural outdoor units are connected to plural indoor units, at least one outdoor unit is provided with a compressor having a power control mechanism for inhibiting a part of a compression work, and the power of the compressor is made variable by controlling the power control mechanism. The outdoor unit is provided with two heat exchangers which are designed in a substantially U-shaped form, and disposed in a main body of the outdoor unit so that the opening sides thereof are confronted to each other, and the refrigerating elements which constitutes a refrigerant circuit and contains at least the compressor, an accumulator, etc. are disposed in a space which is surrounded by the two heat exchangers.

Abstract: The invention relates to a compression apparatus (10) comprising a turbocompressor (1) with a plurality of compression stages (1a, 1b, 1c, 1d) as well as infeed flows (5b, 5c, 5d), where the compression apparatus (10) serves for operating a refrigerant circuit, especially with a hydrocarbon gas such as propane, ethylene, methane, or a mixture thereof, wherein a mixer device (8a, 8b, 8c) is arranged outside the turbocompressor (1) and wherein a preceding and a succeeding compression stage (1a, 1b, 1c, 1d) are connected to one another via the mixer device (8a, 8b, 8c) in such a manner that the infeed flow (5b, 5c, 5d) provided for the succeeding compression stage (1b, 1c, 1d) opens into the mixer device (8a, 8b, 8c) in order to mix the infeed flow (5b, 5c, 5d) with a main flow (6a, 6b, 6c) of the preceding compression stage (1a, 1b, 1c).

Abstract: A distributed cooling system for environmentally testing products comprises at least two insulated chambers, at least three cooling compressors and a computer control. A first one of the compressors is permanently allocated to a first one of the chambers, a second one of the compressors is permanently allocated to a second one of the chambers. The control selectively allocates the remaining compressor(s) to either of the chambers to meet a cooling requirement of a batch. Consequently, the compressors are allocated where needed such that the total number of compressors provided for the entire system is minimized.

Abstract: A highly reliable air conditioning system which can be operated by commonly available compressors and produce a higher energy utilization efficiency in desiccant assisted air conditioning process while offering an economical cost of purchase as well as operation is disclosed. The air conditioning system is made by combining a desiccant assisted air conditioner with a plurality of vapor compression refrigeration circulation units, each unit having a compressor, an evaporator and a condenser. The circulation units are arranged so that the evaporators and the condensers are disposed in a last-come-first manner in relation to an order between a process air passage and a regeneration air passage.

Abstract: Unit for distribution and/or collection of cold and/or of heat, including: (a) a main exchanger (1) of heat between a refrigerant fluid (2, 21, 22) and a heat transfer fluid (3); (b) a means for producing cold with a means for heat exchange with the heat transfer fluid; (c) a closed main circuit (3) for continuous free circulation of the heat transfer fluid; (d) at least one heat transfer fluid drawing loop (7 to 11); characterized in that the flow cross-section of the main circuit (3), the maximum refrigerating power of the means for producing cold, Pmax, expressed in W, and the main heat exchanger (1) are sized relative to one another in order to satisfy, in operation, approximately the relationship: P.sub.Max =f.sub.m .times.c.times..DELTA.T, in which: f.sub.m is the mass flow rate of the heat transfer fluid, expressed in kg/s; c is the mass heat of the heat transfer fluid, in liquid form, expressed in J/kg/.degree.K.; .DELTA.

Abstract: An oil separator for a refrigeration system having two inlets for receiving two streams of a mixture of oil and refrigerant for separation. One inlet is on each side of the oil separator. This allows for a separator with a smaller diameter to be used to achieve the same preferred speed of travel of the oil-refrigerant mixture.

Abstract: A scroll compressor having injection ports 70A and 70B opened to operating chambers Vc during a predetermined period of a complete compression cycle, so that a part of the refrigerant circulating in a refrigerating system is injected into the compression chambers from the injection ports. The injection ports are opened to an intermediate pressure chamber, which is at a pressure between the pressure of the refrigerant sucked into the compressor and the pressure of the refrigerant discharged from the compressor. The intermediate pressure chamber is arranged so as to eliminate pressure pulsations therein. Check valves 72A and 72B are provided in an end plate 54 of a stationary scroll member 50. Furthermore, relief valves may also be provided in the end plate for releasing the pressure of the operating chambers to a low pressure side of the refrigerating system.

Abstract: In a refrigerating apparatus having a compression mechanism (21), an outdoor heat exchanger (24), an outdoor motor-operated expansion valve (25) and an indoor heat exchanger (32), the compression mechanism (21) is so composed that two compressors (2a, 2b) are connected in parallel with each other. Each compressor (2a, 2b) is provided with an oil discharge mechanism (40) for discharging, when lubricating oil stored in its casing exceeds a set amount, the lubricating oil.

Abstract: Apparatus to condition air comprising a blower to effect a flow of air to be conditioned in a path of travel from a first location to a second location; a cooling member along the path of travel adjacent to the first location adapted to initially cool the air flowing therepast, the cooling means having, in association therewith, pipes for circulating a cooling fluid between the cooling member whereat thermal energy is added to the cooling fluid and a location outside the path of travel whereat thermal energy is removed from the first cooling fluid; a condenser along the path of travel adjacent to the second location adapted to reheat the air flowing therepast; an evaporator within the path of travel between the cooling member means and the condenser adapted to further cool the air flowing therepast; a compressor; piping coupling the evaporator, condenser and compressor for circulating cooling fluid therebetween.

Abstract: A refrigeration system, particularly for controlling the temperature of an environment, and presenting a compressor; a condenser; a laminating thermostatic valve; an evaporator; an evaporation pressure control valve interposed between the outlet of the evaporator and an inlet of the compressor; an economizer in turn presenting a laminating orifice downstream from the condenser, and a flash tank with an inlet communicating with the orifice, a liquid-phase outlet connected to the thermostatic valve, and a gaseous-phase outlet connected to an intermediate inlet of the compressor; and a tapping valve interposed between the outlet of the compressor and the flash tank, and which is opened when the pressure in the flash tank falls below a predetermined threshold value.

Abstract: Each compressor in a circuit has an oil pump with excess capacity relative to lubrication requirements of the respective compressor. Excess capacity is diverted to a common line which connects to each of the compressors in the circuit through a float valve. Each float valve is operated responsive to the oil level in the associated compressor such that oil diverted as excess capacity is supplied to any compressor in the circuit short of oil.

Abstract: In a positive displacement compressor having a plurality of banks, operation can be multi-staged or single staged. Single stage operation can be of a single bank or plural banks in parallel. Switch-over between modes of operation is under the control of a microprocessor responsive to sensed inputs.

Abstract: In a system having low and high stage compressors with an oil separator downstream of each stage there can be a tendency for oil from the first stage to collect in the second stage. So, responsive to a low level of oil in the first stage oil system, oil is supplied from the second stage oil system to the first stage oil system.

Abstract: A lightweight, heavy duty, large volume centrifugal compressor for use in mechanical vapor compression systems, especially water vapor compression systems in heat pump installations, said compressor comprising a shaft driven propeller-like rotary member consisting of a frusto-conical hub and a plurality of curved blades made of a lightweight material, each being secured to said hub along a longitudinal curved line and radially extending therefrom; each pair of adjacent blades being interconnected by a bridging membrane member of a lightweight material curvingly extending from the roots of the leading edges of said adjacent blades to the tips of the rear edges of the blades; said rotary member being encompassed within a closely fitting shroud, so that curved vapor flow channels are defined between each said pair of blades, their associated membrane member, and the shroud.

Abstract: Two outdoor units (2A, 2B) are connected to liquid lines (5A, 5B), respectively, and connected to gas lines (6A, 6B), respectively. Each of the gas lines (6A, 6B) is branched to a high-pressure passage (65, 66) and a low-pressure passage (67, 68). The liquid lines (5A, 5B), the high-pressure passages (65, 66) and the low-pressure passage (67, 68) are connected to a main liquid line (4L), a main high-pressure gas line (4H) and a main low-pressure gas line (4W), respectively, in such a manner that the outdoor units (2A, 2B) are arranged in parallel with each other. Three user units (3, 3, 3) are each connected at an end thereof to the main liquid line (4L) and each connected to the main high-pressure gas line (4H) and the main low-pressure gas line (4W) so as to be switchable between the gas lines (4H, 4W).

Abstract: A commercial refrigeration network including refrigeration system units constructed and arranged for placement in strategic proximity to corresponding product cooling zones within the shopping arena of a food store, each refrigeration unit having a condensing unit rack configured to accommodate the maximum refrigeration loads of its associated zone with an optimum floor space footprint in the shopping arena, and the condensing unit rack including a plurality of multiplexed compressors, condenser and associated high side and low side refrigerant delivery and suction conduits operatively connected to evaporators for cooling the corresponding zone, and the network also including another cooling source remote from said modular refrigeration units and constructed and arranged for circulating a fluid coolant in heat exchange relationship with the condenser to obtain optimum condensing and efficiency of said evaporators in cooling the corresponding zone.

Abstract: A thermomechanically integrated distillation column and method for the separation of ethylene from ethane and other close-boiling light hydrocarbons. The column has a plurality of sections operated at successively lower pressures from a high pressure subcritical section to a superatmosphere bottoms product zone. Bottoms liquid from the high pressure and intermediate sections are flashed in respective cooling loops to about the pressure of the section of next lower pressure, vaporized in heat exchange with an overhead condensing zone and introduced to the top stage of next lower pressure section. Vapor from the intermediate sections and the bottoms product zone are compressed in respective compression loops and fed to the bottom stage of the section of the next higher pressure. External refrigerant can be supplied to the overhead condensing zone for trim as needed for control purposes.

Abstract: A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein.

Abstract: An environmental control system includes a refrigeration loop including a two-stage variable speed centrifugal compressor having a low pressure compressor in flow communication with a high pressure compressor and having an inlet and an outlet, a condenser having an inlet connected with the compressor outlet and an outlet, an evaporator having an inlet connected with the condenser outlet and an outlet connected with the compressor inlet and an expansion valve connected between the condenser outlet and the evaporator inlet, and a selectively operative bypass valve in flow communication with the low pressure compressor discharge and the compressor inlet for partially recirculating a portion of the low pressure compressor discharge back to the compressor inlet to regulate compressor flow balance.

Abstract: Actual thermodynamic processes occurring in a system such as a heat pump or refrigeration plant are made to approach theoretical ideal processes, e.g. an isothermal (T.sub.o), by use of a multistage gear machine as compressor and/or expander in the system, and conditioning, such as cooling, the system working fluid between successive stages in the machine. The individual stages of the gear machine each include a pair of meshing gears, preferably cylindrical spur gears of equal diameter and diminishing width from stage-to-stage.

Abstract: An air conditioning apparatus apparatus equipped with a cooling and heating cycle utilizing a refrigerant and equipped with an improved ice storage therein. The air conditioning apparatus includes a thermal storage tank for storing heat of refrigerant circulating in the cooling cycle; thermal storage refrigerant positioned parallel to an indoor heat exchanger; an auxiliary compressing unit provided in the thermal storage refrigerant pipe; an expansion unit for controlling expansion of the refrigerant. An method for the air conditioning apparatus. The method includes the steps of providing an auxiliary compressor; cooling a gaseous refrigerant from the auxiliary compressor; heat-exchanging the gaseous refrigerant; condensing the refrigerant; sending the condensed refrigerant to the indoor heat exchanger; evaporating the condensed refrigerant; and sending the evaporated refrigerant back to the auxiliary compressor.

Abstract: An air conditioner in which, when a first compressor is being operated and a second compressor is being stopped, liquid refrigerant does not flow into the second compressor even in a state of wet vapor suction, a decrease in lubricating oil in the second compressor or a decline in its concentration are not experienced, and breakage of the second compressor does not occur owing to faulty lubrication when the second compressor is started. In addition, to obtain an air conditioner which does not lapse into a wasteful shortage of cooling and heating capabilities when the air conditioner is not in the state of wet vapor suction, by reliably detecting the presence or absence of the state of wet vapor suction. In the air conditioner, the first compressor and the second compressor are connected together by an equalizing pipe. A bypass passage which connects together a discharge pipe and a suction pipe of the second compressor is provided.

Abstract: A multistage centrifugal compressor, comprising a casing having an inlet portion and a compression portion. The inlet portion has an inlet opening gaseously coupled to an evaporator so as to receive a gaseous refrigerant. The inlet and compression portions each have a plurality of gas passages therethrough. The compression portion has an outlet opening that is located at the end of the casing which is opposite the end of the casing having the inlet opening. An electric motor assembly is positioned within the inlet portion of the casing so as to provide a transfer of heat dissipated by the motor assembly to the gaseous refrigerant entering through the inlet opening. The gaseous refrigerant flowing in the inlet opening passes through and about the motor assembly so as to cool the motor assembly.

Abstract: The present inventions are intended to improve heat efficiency of a refrigeration system having plural refrigerating cycles of different evaporating or condensing temperatures typically used in breweries. Each of main lines of different evaporating temperatures are connected with each of suction lines to a compressor respectively, to enable the system to save energy and to establish a back-up system of compressors. A different condensing temperature system having a common refrigerant source is provided with refrigerant transferring means to transfer refrigerant from an refrigerant excess cycle to an refrigerant insufficiency cycle.

Abstract: The present inventions are intended to improve heat efficiency of a refrigeration system having plural refrigerating cycles of different evaporating or condensing temperatures typically used in breweries. Each of main lines of different evaporating temperatures are connected with each of suction lines to a compressor respectively, to enable the system to save energy and to establish a back-up system of compressors. A different condensing temperature system having a common refrigerant source is provided with refrigerant transferring means to transfer refrigerant from an refrigerant excess cycle to an refrigerant insufficiency cycle.

Abstract: A multi-stage compressor assembly including an arrangement for controlling the oil level having first and second capillary tubes. First capillary tube connects between the second stage high pressure housing at a level above the normal oil sump level to the first stage low pressure housing. The second capillary tube connects from the first stage housing at a point above the normal sump level to a point on the second stage suction tube. The oil level is automatically self compensating by the location of the capillary tube inlets and by differential housing pressure urging oil migration through the capillary tubes.

Abstract: A refrigeration system for refrigerators having two or more compartments maintained at different temperatures comprises separate cycles for each compartment, each cycle in turn comprising separate evaporator means, heat exchanger means and compressor. To provide for cycle separation, the condenser may be split into separate units, connected by phase separators where appropriate. The system is particularly designed for use in connection with mixed, nonazeotropic refrigerants.

Abstract: A method of staging and modulating compressors in a multi-circuited refrigeration system including a plurality of condensing heat exchange circuits where each condensing heat exchange circuit includes a plurality of compressors. The method comprises the steps of: accumulating a first operative condition for each compressor; accumulating a second operative condition for each compressor; determining the status of each compressor in each circuit and designating therefrom a first list of circuits having compressors available to be turned on and a second list of circuits having compressors available to be turned off.

Abstract: A scroll type compressor having a pair of scroll type compression units which are encased in the same casing so as to make a common use of a lubricating oil reservoir provided in the casing, wherein the compression units have compression elements, drive shafts, driving motors and other components which are of the same constructions and specifications, and wherein each of the compression units are adapted to be driven selectively by commercial electrical power or through a frequency-variable inverter so as to operate at different speeds. Since both compression units can be made up from the same components such as the compression elements, loads in the production, service and administration, are greatly reduced contributing to a reduction in the labor and cost, while eliminating any mounting error.

Abstract: A household refrigerator includes a refrigerant circuit having a compressor, a condenser receiving refrigerant from the compressor and a phase separator receiving refrigerant from the condenser. The liquid refrigerant containing portion of the phase separator is connected to the inlet of the freezer evaporator, the outlet of which is connected to the compressor. The vapor refrigerant containing portion of the phase separator is connected to the compressor. The fresh food evaporator is connected to the phase separator to receive liquid refrigerant from the phase separator and to return vapor refrigerant to the phase separator.

Abstract: A heat exchanger includes a rotary compressor having two compression pumps and a motor for driving the compressor pumps, a condenser connected to the rotary compressor, a regulator connected to the condenser and with an evaporator connected to the regulator. An electric power is supplied from an inverter circuit to the motor of the rotary compressor. The output frequency of the inverter circuit is controlled by a frequency controlling device according to a heat load of a heat exchange circuit subjected. The rotary compressor is operated according to a parallel operation pattern in which the two compression pumps are actuated or a single operation pattern in which a single compression pump is actuated. Either one of the two operation patterns is selected by a selecting device according to the operational condition of the heat exchanger. The switching between the single operation and the parallel operation is performed by a switching device according to the output signal of the selecting device.

Abstract: A system and process of parallel compressors for compressing fluids miscible with oil. The present invention utilizes parallel-coupled compressors, wherein each compressor comprises a crankcase chamber, discharge chamber, suction chamber, and ejector which operate independent of one another. Means are provided for coupling the ejector in the return of the lubrication pump oil within the crankcase chamber and the maintenance of that oil level in all the crankcase chambers regardless of each compressor capacity and quantity with which they are operating or are not operating. The transference of suction chamber oil to crankcase chamber is performed by the ejector via energy from the lubrication pump contained within each crankcase chamber. Further, transference of oil from suction chamber to crankcase chamber via an ejector performs all necessary equalization functions.

Abstract: Unitized air conditioning apparatus for conditioning air for an enclosed space may include: an inlet chamber through which air may be drawn; first and second selectively operable air handling units by which air may be drawn through the inlet chamber and refrigeration apparatus for circulating refrigerant through the air handling units for heat exchange with air prior to discharge into the enclosed space. Air dampers are provided for isolating one of the air handling units, when not operating, from the other air handling unit when it is operating.

Abstract: An excess liquid refrigerant accumulator for multievaporator refrigeration systems is provided. Under some operating conditions, the lowest temperature evaporator of a multievaporator system may discharge some liquid refrigerant rather than only vapor refrigerant. This liquid discharge creates a loss of cooling capacity. A receptacle connected to the exit of the lowest temperature evaporator accumulates the liquid. By locating the receptacle within the cooled compartment, the cooling capacity which would otherwise be lost, is regained.

Abstract: A refrigeration system suitable for use in household refrigerators having a fresh food compartment, a freezer compartment and an intermediate temperature compartment is provided. The system includes a first expansion throttle, a first evaporator for providing cooling to a freezer compartment, first, second and third compressors, a condenser, a second expansion throttle, a second evaporator for providing cooling to a fresh food compartment, a third expansion throttle, and a third evaporator for providing cooling to an intermediate compartment. All the above elements are connected in series, in that order, in a refrigerant flow relationship. A first phase separator connects the second evaporator to the third expansion throttle in a refrigerant flow relationship and provides intercooling between the second and third compressors.

Abstract: A capacity controllable compressor apparatus has a plurality of high-pressure chamber compressors which are connected in parallel to a common refrigerant suction pipe and a common refrigerant discharge pipe, and oil equalizing pipes through which oil sumps of the plurality of compressors are communicated with each other. One of the plurality of compressors is operated with its chamber kept at a higher internal pressure than other compressors.

Abstract: A refrigerating cycle apparatus has, in a sealed casing, a compressor including first and second compressor means driven simultaneously. A refrigerating cycle circuit is constituted by connecting this compressor, a condenser, a pressure-reducing device, and an evaporator. Counterflow checking means is provided on the suction side of the first compressor means, for checking the counterflow of the refrigerant from the first compressor means to the evaporator. Switching means is provided on the discharge side of the second compressor means.

Abstract: A heat transfer system employing a two-stage compressor and a heat recovery system including a flash vapor receiver which pools warm refrigerant from a system condenser, delivering receiver refrigerant vapor to the compressor at its second stage inlet and delivering receiver liquid refrigerant to a system evaporator. The system also employs evaporation, compression and condensation of an oilless refrigerant, or an azeotrope mixture of oilless refrigerants, to reduce compression and resulting power requirements. The system evaporator or evaporators are flooded with refrigerant, with vaporous refrigerant separated and routed to the compressor and liquid refrigerant separated and returned to the evaporators.