US20050028552A1 - Vapor compression type refrigerating machine - Google Patents

Vapor compression type refrigerating machine Download PDF

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Publication number
US20050028552A1
US20050028552A1 US10/909,547 US90954704A US2005028552A1 US 20050028552 A1 US20050028552 A1 US 20050028552A1 US 90954704 A US90954704 A US 90954704A US 2005028552 A1 US2005028552 A1 US 2005028552A1
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Prior art keywords
refrigerant
pressure
compressors
heat exchanger
side heat
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Abandoned
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US10/909,547
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English (en)
Inventor
Haruyuki Nishijima
Hirotsugu Takeuchi
Toru Ikemoto
Hisatsugu Matsunaga
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Denso Corp
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Denso Corp
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Assigned to DENSO CORPORATION reassignment DENSO CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: IKEMOTO, TORU, MATSUNAGA, HISATSUGU, NISHIJIMA, HARUYUKI, TAKEUCHI, HIROTSUGU
Publication of US20050028552A1 publication Critical patent/US20050028552A1/en
Abandoned legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/002—Lubrication
    • F25B31/004—Lubrication oil recirculating arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2341/00—Details of ejectors not being used as compression device; Details of flow restrictors or expansion valves
    • F25B2341/001—Ejectors not being used as compression device
    • F25B2341/0012—Ejectors with the cooled primary flow at high pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/04—Refrigeration circuit bypassing means
    • F25B2400/0401—Refrigeration circuit bypassing means for the compressor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/07—Details of compressors or related parts
    • F25B2400/075—Details of compressors or related parts with parallel compressors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/23—Separators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/26—Problems to be solved characterised by the startup of the refrigeration cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/27—Problems to be solved characterised by the stop of the refrigeration cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2501—Bypass valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/17—Speeds
    • F25B2700/171—Speeds of the compressor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2117—Temperatures of an evaporator
    • F25B2700/21175—Temperatures of an evaporator of the refrigerant at the outlet of the evaporator

Definitions

  • the present invention relates to, among refrigerating machines in which heat on a low temperature side is moved to a high temperature side, a vapor compression type refrigerating machine having a plurality of compressors which is effective when applied, in particular, to an ejector cycle.
  • the ejector cycle is a cycle used in a vapor compression type refrigerating machine in which the pressure of a refrigerant is reduced by an ejector so that the refrigerant is allowed to expand, vapor-phase refrigerant that has been vaporized by an evaporator is sucked into the ejector, and the suction pressure of the compressor is increased by converting expansion energy into pressure energy (for example, refer to the Japanese Unexamined Patent Publication No. 6-11197).
  • a pressure reducing unit such as an expansion valve (hereinafter, referred to as an expansion valve (hereinafter, referred to as an expansion valve cycle)
  • the refrigerant flowing out from the expansion valve flows into the evaporator
  • the refrigerant flowing out from the ejector flows into a vapor-liquid separator, and a liquid phase refrigerant resulting from separation by the vapor-liquid separator is supplied into the evaporator while a vapor phase refrigerant resulting from separation by the vapor-liquid separator is sucked into the compressor.
  • the expansion valve cycle provides a flow of refrigerant in which the refrigerant circulates from the compressor back to the compressor via the condenser, the expansion valve, and the evaporator sequentially in that order
  • the ejector cycle provides two flows of refrigerant; one is a flow of refrigerant in which the refrigerant circulates from the compressor back to the compressor via the condenser (a high pressure side heat exchanger), the ejector, and the vapor-liquid separator sequentially in that order
  • the other is a flow of refrigerant in which the refrigerant circulates from the vapor-liquid separator back to the vapor-liquid separator via the evaporator and the ejector sequentially in that order.
  • the refrigerating machine oil is a lubricating oil which lubricates sliding parts and bearings within the compressor.
  • the refrigerating machine oil whose kinematic viscosity is larger than the refrigerant adheres to an internal wall of the heat exchanger to thereby decrease the heat exchange efficiency of the heat exchanger.
  • an oil separator for separating the refrigerating machine oil mixed in the refrigerant on a discharge side of the compressor, that is, a refrigerant inlet side of the high pressure side heat exchanger, so that refrigerating machine oil separated by the oil separator is returned to a suction side of the compressor via an oil return circuit which is constituted as a restriction unit such as a capillary tube.
  • check valves 10 c , 10 d are provided, as shown in FIG. 2 , along refrigerant circuits which connect to discharge sides of the respective compressors 10 a , 10 b.
  • the refrigerating machine shown in FIG. 2 that is, the refrigerating machine including the plurality of compressors 10 a , 10 b arranged in parallel relative to the flow of refrigerant for sucking in and compressing a refrigerant, a high pressure side heat exchanger 20 for removing heat from a high pressure refrigerant discharged from the compressors 10 a , 10 b , a low pressure side heat exchanger 30 for vaporizing a low pressure refrigerant and absorbing heat therefrom, an oil separator 70 provided on a refrigerant inlet side of the high pressure side heat exchanger 20 for separating and extracting a refrigerating machine oil mixed in the refrigerant, and an oil return circuit 71 for returning the refrigerating machine oil so separated and extracted by the oil separator 70 to the suction sides of the compressors 10 a , 10 b , a difference in pressure between a pressure remaining on the high pressure side heat exchanger 20 side and a pressure remaining on the low pressure side heat exchange
  • a bypass circuit 80 for establishing a communication between the refrigerant circuit on the high pressure side heat exchanger 20 side and the refrigerant circuit on the low pressure side heat exchanger 30 side and a bypass valve 81 for opening and closing the bypass circuit 80 , whereby, when the plurality of compressors 10 a , 10 b are stopped, the bypass valve 81 is opened.
  • This construction provides, however, another problem as described below.
  • a normally-closed type valve is desirably adopted for the bypass valve 81 .
  • the normally-closed type valve means a valve which closes when not energized and opens when energized.
  • the bypass valve 81 When adopting a normally-opened valve as the bypass valve 81 , however, as the bypass valve 81 needs to be energized until the vapor compression type refrigerating machine is re-activated after it has been stopped, the dark current, that is, the current consumed while the vehicle is stopped increases.
  • the invention was made in view of the situations and a first object thereof is to provide a novel vapor compression type refrigerating machine which is different from conventional ones, and a second object of the invention is to prevent damage to a compressor due to excessive compression when the refrigerating machine is activated.
  • a vapor compression type refrigerating machine for moving heat on a low temperature side to a high temperature side comprising a plurality of compressors ( 10 a , 10 b ) arranged in parallel relative to the flow of a refrigerant for sucking in and compressing a refrigerant, a high-pressure side heat exchanger ( 20 ) for removing heat from a highly pressurized refrigerant discharged from the compressors ( 10 a , 10 b ), a low-pressure side heat exchanger ( 30 ) for absorbing heat by vaporizing a low pressure refrigerant, an oil separator ( 70 ) provided on a refrigerant inlet side of the high-pressure heat exchanger ( 20 ) for separating and extracting a refrigerating machine oil mixed in the refrigerant, an oil return circuit ( 71 ) for returning the refrigerant so separated and extracted by the oil separator ( 70 ) to su
  • the bypass valve ( 81 ) is kept open until the predetermined period of time has elapsed after the compressors ( 10 a , 10 b ) were stopped, so that the pressure of the refrigerant circuit on the high-pressure side heat exchanger ( 20 ) side and the pressure of the refrigerant circuit on the low-pressure side heat exchanger ( 30 ) side are made equal, and after the bypass valve ( 81 ) is closed, the compressor valve ( 90 ) is opened, so that the refrigerant circuit on the high-pressure side heat exchanger ( 20 ) side is made to communicate with the refrigerant circuit on the low-pressure side heat exchanger ( 30 ) side via the compressors ( 10 a , 10 b ).
  • a vapor compression type refrigerating machine comprising a plurality of compressors ( 10 ) arranged in parallel relative to the flow of a refrigerant for sucking in and compressing a refrigerant, a high-pressure side heat exchanger ( 20 ) for removing heat from a highly pressurized refrigerant discharged from the compressors ( 10 a , 10 b ), a low-pressure side heat exchanger ( 30 ) for absorbing heat by vaporizing a low pressure refrigerant, an ejector ( 40 ) having a nozzle ( 41 ) for converting a pressure energy of the highly pressurized refrigerant that flows out from the high-pressure side heat exchanger ( 20 ) into a velocity energy so as to reduce the pressure of the refrigerant for expansion and pressure increasing portions ( 42 , 43 ) for sucking in a vapor-phase refrigerant vaporized by a high-speed flow of refrigerant injected from the nozzle
  • the bypass valve ( 81 ) is kept open until the predetermined period of time has elapsed after the compressors ( 10 a , 10 b ) were stopped, so that the pressure of the refrigerant circuit on the high-pressure side heat exchanger ( 20 ) side and the pressure of the refrigerant circuit on the low-pressure side heat exchanger ( 30 ) side are made equal, and after the bypass valve ( 81 ) is closed, the compressor valve ( 90 ) is opened, so that the refrigerant circuit on the high-pressure side heat exchanger ( 20 ) side is made to communicate with the refrigerant circuit on the low-pressure side heat exchanger ( 30 ) side via the compressors ( 10 a , 10 b ).
  • the compressor valve ( 90 ) opens and closes the refrigerant circuits ( 91 , 92 ) which connect to discharge sides of the compressors ( 10 a , 10 b).
  • FIG. 1 is an exemplary diagram illustrating an ejector cycle according to an embodiment of the invention
  • FIG. 2 is an exemplary diagram illustrating an ejector cycle according to a related art
  • FIG. 3 is an exemplary diagram illustrating an ejector cycle according another related art.
  • FIG. 4 is a graph illustrating pressure behaviors of the ejector cycles according to the related arts.
  • an ejector cycle according to the invention is applied to a vapor compression type refrigerating machine which needs to decrease the temperature in a showcase for preserving foods and drinks in cooled and frozen conditions or a refrigerator of a refrigerated vehicle for transporting foods and drinks that are preserved in cooled and frozen conditions lower than the temperature of an air conditioner.
  • Compressors 10 a , 10 b suck in and compress a refrigerant by obtaining power from an electric motor, and these two compressors 10 a , 10 b are arranged in parallel relative to the flow of a refrigerant. Note that when the compressors 10 a , 10 b are referred to collectively, they are described as the compressor 10 , whereas when the respective compressors need to be described individually, they are described as the compressor 10 a or the compressor 10 b.
  • a condenser 20 is a high-pressure side heat exchanger constituting a radiator for implementing a heat exchange between a high-temperature, high-pressure refrigerant discharged from the compressor 10 and outside air so as to cool and condense the refrigerant
  • an evaporator 30 is a low-pressure side heat exchanger for implementing a heat exchange between air sent into a refrigerator and a low-pressure refrigerant so as to vaporize a liquid-phase refrigerant to thereby exhibit a refrigerating capacity.
  • An ejector 40 is an ejector for sucking in a vapor-phase refrigerant which is vaporized at the evaporator 30 by reducing the pressure of the refrigerant that has flowed out from the condenser 20 for expansion and converting an expansion energy into a pressure energy so as to increase the suction pressure of the compressor 10 .
  • the ejector 40 includes a nozzle 41 for converting the pressure energy of the high-pressure refrigerant that flows thereinto into a velocity energy so as to reduce the pressure of the refrigerant, in an isenthalpic fashion, a fixing portion 42 for sucking in the vapor-phase refrigerant that is vaporized at the evaporator 30 through an entrainment action by a high-speed flow of refrigerant injected from the nozzle 41 for mixing with the flow of refrigerant injected from the nozzle 41 and a diffuser 43 for mixing the refrigerant injected from the nozzle 41 with the refrigerant sucked in from the evaporator 30 so as to convert the velocity energy into a pressure energy to thereby increase the pressure of the refrigerant.
  • the pressure (the static pressure) of the refrigerant is also increased at the mixing portion 42 .
  • the mixing portion 42 and the diffuser 43 are generally referred to as a pressure increasing portion.
  • the vapor-liquid separator 50 is a vapor-liquid separating unit into which the refrigerant that has flowed out from the ejector 40 flows and which is adapted to store the refrigerant that has so flowed in by separating the refrigerant into a vapor-phase refrigerant and a liquid-phase refrigerant, and an outlet for the vapor-phase refrigerant of the vapor-liquid separator 50 is connected to a suction side of the compressor 10 , whereas an outlet for the liquid-phase refrigerant thereof is connected to the evaporator 30 side.
  • a variable restriction unit 60 is an expansion valve which is provided at a position along the refrigerant passageway between the condenser 20 and the ejector 40 , that is, upstream of the nozzle 41 with respect to the flow of refrigerant for reducing the pressure of the highly-pressurized refrigerant that has flowed out from the condenser 20 to a vapor-liquid two-phase area for expansion.
  • This variable restriction unit 60 is such as to control the opening of restriction so that the degree of superheating of refrigerant on the refrigerant outlet side of the evaporator 30 resides within a predetermined range (for example, 0.1 deg to 10 deg) and has a similar construction to that of a known external pressure equalizing type expansion valve.
  • variable restriction unit 60 is such as to include a valve element 61 for varying the opening of the restriction, a film-like diaphragm 63 constituting a back pressure compartment 62 where an internal pressure varies by sensing the refrigerant temperature on the refrigerant outlet side of the evaporator 30 , a connecting rod 64 which connects the valve element 61 to the diaphragm 63 so as to transfer the displacement of the diaphragm 63 , a spring 65 adapted to apply a spring pressure in a direction in which the volume of the back pressure compartment 62 is reduced and an external equalizer pipe 67 for introducing the pressure of the refrigerant on the refrigerant outlet side of the evaporator 30 into a pressure compartment 66 which is situated opposite to the back pressure compartment 62 across the diaphragm 63 .
  • the back pressure compartment 62 communicates with a temperature sensing tube 62 a for sensing the temperature of refrigerant on the refrigerant outlet side of the evaporator 30 , whereby the temperature of refrigerant on the refrigerant outlet side of the evaporator 30 is transmitted to the back pressure compartment 62 via the temperature sensing tube 62 a.
  • variable restriction unit 60 reduces the opening of restriction thereof so as to increase the velocity of the drive flow injected from the nozzle 41 to thereby increase the suction flow or the amount of refrigerant circulating through the evaporator 30 when the pressure in the evaporator 30 , that is, the heat load in the evaporator 30 increases, whereby the degree of superheating of refrigerant on the outlet side of the evaporator 30 increases.
  • variable restriction unit 60 increases the opening of restriction thereof so as to decrease the velocity of the drive flow injected from the nozzle 41 to thereby decrease the amount of refrigerant which circulates through the evaporator 30 .
  • An oil separator 70 is such as to separate and extract a refrigerating machine oil mixed in the refrigerant, and this oil separator 70 is provided on a refrigerant inlet side of the condenser 20 .
  • centrifugal separation method for separating a refrigerating machine oil from a refrigerant by rotating, at high speed, the refrigerant in which the refrigerating machine oil is mixed
  • collision separation method for separating a refrigerating machine oil from a refrigerant by causing the refrigerant in which the refrigerating machine oil is mixed to collide against a wall surface at high speed.
  • the centrifugal separation system is adopted.
  • An oil return circuit 71 is a circuit for returning the refrigerating machine oil separated and extracted by the oil separator 70 to the suction side of the compressor 10 .
  • This oil return circuit 71 is made up of a fixed restriction such as a capillary tube (a fine tube) or an orifice whose restriction opening is fixed, and in this embodiment, a capillary tube is adopted.
  • the oil return circuit 71 is set such that a pressure loss is generated which is substantially equal to a sum of the pressure reduction amount of the nozzle 41 and the pressure reduction amount of the variable restriction unit 60 .
  • a bypass circuit 80 is a refrigerant circuit for establishing a communication between a refrigerant circuit on the condenser 20 side and a refrigerant circuit on the evaporator 30 side, and a bypass valve 81 is a normally-closed electromagnetic valve for opening and closing the bypass circuit 80 .
  • a high-pressure side of the bypass circuit 80 is connected to the refrigerant circuit on the condenser 20 side at a position between the condenser 20 and the oil separator 70
  • a low-pressure side of the bypass circuit 80 is connected to the refrigerant circuit on the evaporator 30 side at a position between the vapor-liquid separator 50 and the evaporator 30 .
  • a three-way valve 90 is a compressor valve for opening and closing refrigerant circuits 91 , 92 which connect to the compressors 10 a , 10 b , respectively.
  • the three-way valve 90 is an electric valve for switching the case where the refrigerant circuit 91 connecting to the compressor 10 a is opened whereas the refrigerant circuit 92 connecting to the compressor 10 b is closed, the case where the refrigerant circuit 91 connecting to the compressor 10 a is closed whereas the refrigerant circuit 92 connecting to the compressor 10 b is opened, and the case where the refrigerant circuits 91 , 92 are both opened.
  • the three-way valve 90 may be disposed on a merging side of the refrigerant circuits 91 , 92 , that is, on discharge sides of the compressors 10 a , 10 b , the three-way valve 90 may be disposed on a branching side of the refrigerant circuits 91 , 92 , that is, the suction sides of the compressors 10 a , 10 b.
  • bypass valve 81 and the three-way valve 90 are controlled by an electronic control unit 100 , and signals from rotational speed sensors 101 , 102 for detecting the rotational speed of the compressors 10 a , 10 b are inputted into the electronic control unit 100 .
  • the electronic control unit 100 detects whether or not the compressors 10 a , 10 b are stopped based on the rotational speeds, of the compressors 10 a , 10 b , that are detected by the rotational speed sensors 101 , 102 .
  • This operation is an operation mode for generating a refrigerating capacity at the compressor 30 .
  • the refrigerant discharged from the compressor 10 is circulated to the condenser 20 side, whereby the pressure of the highly pressurized refrigerant that is cooled at the condenser 20 is reduced in an isenthalpic fashion down to the vapor-liquid two-phase area by the variable restriction unit 60 . Thereafter, the pressure of the refrigerant so reduced in pressure is reduced in an isenthalpic fashion by the nozzle 41 of the ejector 40 so that the refrigerant expands, whereby the refrigerant flows into the mixing portion 42 at faster speed than sonic velocity.
  • the refrigerant is once boiled at the variable restriction unit 60 , and the refrigerant is expanded at an inlet portion of the nozzle 41 so as to restore the pressure, whereby the refrigerant can be boiled at a second-stage nozzle while continuing to generate boiling nucleus.
  • the boiling of refrigerant at the nozzle 41 can be promoted, thereby making it possible to improve the ejector efficiency ⁇ e by making the drops of refrigerant become minute particles.
  • the ejector efficiency ⁇ e is defined by using, as a denominator, a product of the mass flow rate Gn of refrigerant which flows through the condenser 20 and a difference in enthalpy ⁇ ie between the outlet and inlet of the nozzle 41 and putting, as a numerator, a sum of a refrigerant flow rate Gn indicating to what extent the energy is recovered, as work done, by the compressor 10 and the mass flow rate Ge of refrigerant which flows through the evaporator 30 and a pressure recovery ⁇ P at the ejector 40 .
  • chlorofluorocarbon is used as refrigerant
  • the high-pressure side refrigerant pressure that is, the pressure of refrigerant that flows into the nozzle is made to be equal to or less than the critical pressure of the refrigerant.
  • This operation mode is such as to be executed in a case where the two compressors 10 a , 10 b are both stopped.
  • the electronic control unit 100 continues to energize the bypass valve 81 until a predetermined period of time (for example, 30 sec) has elapsed since the compressors 10 a , 10 b were stopped so as to open the bypass circuit 80 , and when the predetermined period of time has elapsed, the electronic control unit 100 cuts off the energization of the bypass valve 81 so as to close the bypass circuit 80 and opens the three-way valve 90 , whereby at least one (for example, the refrigerant circuit 91 ) of the refrigerant circuit 91 connecting to the compressor 10 a and the refrigerant circuit 10 b connecting to the refrigerant circuit 92 is opened.
  • a predetermined period of time for example, 30 sec
  • the bypass valve 81 is opened until the predetermined period of time has elapsed since the compressors 10 a , 10 b were stopped so that the pressure of the refrigerant circuit on the condenser 20 side and the pressure of the refrigerant circuit on the evaporator 30 side are equalized and, after the bypass valve 81 is closed, the three-way valve 90 is opened so as to open at least either of the refrigerant circuit 91 connecting to the compressor 10 a and the refrigerant circuit 92 connecting to the compressor 10 b to thereby establish a communication between the refrigerant circuit on the condenser 20 side and the refrigerant circuit on the evaporator 30 side via the compressor 10 .
  • the embodiment is such that when the compressors 10 a , 10 b are stopped, firstly, the bypass valve 81 is opened so as to equalize the pressure of the refrigerant circuit on the condenser 20 side with the pressure of the refrigerant circuit on the evaporator 30 side, and thereafter, the refrigerant circuit on the condenser 20 side and the refrigerant circuit on the evaporator 30 side are made to communicate with each other via the refrigerant circuits 91 , 92 connecting to compressor 10 , whereby the equalized pressure state is maintained.
  • the invention is not limited thereto, and the compressors 10 a , 10 b may suck in and compress refrigerant by obtaining power from an engine such as an internal combustion engine.
  • the invention is applied to the showcase or the like for preserving foods and drinks in cooled and frozen conditions
  • the application of the invention is not limited thereto, and the invention may be applied to, for example, a vapor compression type refrigerating machine for an air conditioner.
  • variable restriction unit 60 an internal pressure equalizing type temperature expansion valve may be adopted as the variable restriction unit 60 .
  • variable restriction unit 60 and the nozzle 41 are provided separately, the invention is not limited thereto, and for example, the variable restriction unit 60 and the nozzle 41 may be integrated into a single unit.
  • the compressor valve is made up of the three-way valve 90
  • the invention is not limited thereto, and the compressor valve may be made up by disposing an electromagnetic switching valve along the length of, for example, each of the refrigerant circuit 91 connecting to the compressor 10 a and the refrigerant circuit 92 connecting the compressor 10 b.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressor (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
  • Air Conditioning Control Device (AREA)
US10/909,547 2003-08-06 2004-08-03 Vapor compression type refrigerating machine Abandoned US20050028552A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2003287719A JP4023415B2 (ja) 2003-08-06 2003-08-06 蒸気圧縮式冷凍機
JP2003-287719 2003-08-06

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US20050028552A1 true US20050028552A1 (en) 2005-02-10

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US10/909,547 Abandoned US20050028552A1 (en) 2003-08-06 2004-08-03 Vapor compression type refrigerating machine

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US (1) US20050028552A1 (ja)
JP (1) JP4023415B2 (ja)
CN (1) CN100498138C (ja)
DE (1) DE102004036718B4 (ja)

Cited By (19)

* Cited by examiner, † Cited by third party
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US20060254308A1 (en) * 2005-05-16 2006-11-16 Denso Corporation Ejector cycle device
US20090107170A1 (en) * 2007-10-25 2009-04-30 Pil Hyun Yoon Air conditioner
US20100175422A1 (en) * 2009-01-12 2010-07-15 Denso Corporation Evaporator unit
US20110005268A1 (en) * 2008-04-18 2011-01-13 Denso Corporation Ejector-type refrigeration cycle device
US20120103003A1 (en) * 2009-01-27 2012-05-03 Mitsubishi Electric Corporation Air-conditioner and method of returning refrigerator oil
US20120167601A1 (en) * 2011-01-04 2012-07-05 Carrier Corporation Ejector Cycle
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US20210348810A1 (en) * 2020-05-06 2021-11-11 Carrier Corporation Ejector refrigeration circuit
CN114308419A (zh) * 2020-09-30 2022-04-12 中核兰州铀浓缩有限公司 一种离心机冷却系统双回路改单回路运行系统及方法
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