US3599440A - Controllable compressor cooling installation - Google Patents

Controllable compressor cooling installation Download PDF

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Publication number
US3599440A
US3599440A US860309A US3599440DA US3599440A US 3599440 A US3599440 A US 3599440A US 860309 A US860309 A US 860309A US 3599440D A US3599440D A US 3599440DA US 3599440 A US3599440 A US 3599440A
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United States
Prior art keywords
compressor
circulation path
shutoff valve
valve
shutoff
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Expired - Lifetime
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US860309A
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English (en)
Inventor
Ludwig Melion
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Luwa Ltd
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Luwa Ltd
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Classifications

    • 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
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • 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
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control 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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • F25B41/24—Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
    • 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
    • F25B2600/23—Time delays
    • 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
    • F25B2700/19—Pressures
    • F25B2700/197—Pressures of the evaporator
    • 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
    • F25B2700/21171—Temperatures of an evaporator of the fluid cooled by the evaporator

Definitions

  • a check or reliefvalve is provided in the primary coolant circulation path between the branchoff of the auxiliary path and the condenser.
  • both shutoff valves in the primary and in the auxiliary coolant paths can be controlled in a time-delayed fashion with respect to one another by means of a two-stage control process. The control is such that, in each] instance, the shutoff valve in the primary coolant circulation path closes first and, thereafter, the shutoff valve in the auxiliary or secondary coolant circulation path opens.
  • This invention generally relates to cooling installations and particularly concerns a controllable compressor cooling installation of the type which is provided with a primary coolant circulation path from a compressor, through a condenser, a shutoff valve, an expansion valve, an evaporator, and then back to the compressor as well as a secondary or auxiliary coolant circulation path extending from the outlet of the compressor to the evaporator inlet.
  • each and every switching operation creates a peak load in the system.
  • the application range as well as the gradation of the cooling control are fixed by the number of compressors provided, which number normally is relatively low.
  • control over the rotational speeds of the compressor drive motor may be effected to achieve gradation of the cooling output.
  • the low end range of control is severely limited in practice due to the speed characteristics of the electric motor as well as to the characteristics and properties of the control or governor therefor.
  • a further known means to effect control over the cooling output of compressor cooling installations involves constructional modification of the reciprocating compressor so as to reduce the circulation of the coolant.
  • Such techniques comprise lifting of a control valve, opening a bypass valve at individual cylinders of the compressor or changing the dead space or volume therein.
  • the power input requirements of the drive motor for the compressor admittedly are correspondingly reduced.
  • the proportional or relative motor losses actually increase, and the friction losses as well as the compression losses of the unloaded portions of the compressor remain practically the same. So as to remove the relatively increased heat losses generated at the compressor after the condenser, only the reduced flow of coolant is available. Accordingly, the danger of overheating on the pressure side of the compressor is prevalent.
  • the coolant which is mixed with lubricating oil cannot exceed a certain maximum temperature at any point of its circulation as otherwise the chemical stability of the coolant mixture is endangered.
  • a sufficient quantity of coolant must continuously be kept in circulation.
  • the cooling output must not be allowed to decrease below a more or less significant fraction of the full cooling output.
  • a gas bypass conduit is provided between the high pressure side and the low pressure side of the coolant circulation path.
  • a regulating valve such as a so-called output regulator or governor operated by a governor or other control is disposed in the gas bypass conduit.
  • a portion of the coolant flow is diverted through the bypass conduit whereas the remaining portion of the coolant flow circulates in the normal or primary circulation path.
  • such arrangements operate very uneconomically at reduced output, since even when operating at such reduced output, the entire quantity of coolant is always conducted through the compressor or is otherwise compressed.
  • the high pressure side of the compressor is directly connected with its low pressure side, a great danger of overheating exists since a portion of the compressed heating gas is not allowed to cool off in the condenser but again directly reaches the suction side of the compressor.
  • shutoff valve in the auxiliary or secondary circulation path opens.
  • the time-delayed control of the shutoff valves can advantageously be effected by connecting the shutoff valves via control circuits and the like to a governor or like regulating device in which a valve control command time delay is preselected.
  • a governor or like regulating device operating with a time delay can be eliminated and the primary circulation path shutoff valve can be directly controlled by a governor whereas the shutoff valve in the auxiliary or secondary circulation path can be connected via a conductor to a pressure sensor responding to reduced coolant pressure in the evaporator whereby an opening command for the second shutoff valve is generated.
  • the time-delayed switching of the shutoff valves as discussed can occur in direct dependency upon the pressure in the coolant circulation path so as to determine the point and switching time without necessitating the preselection and determination of approximate constant time delays.
  • the novel invention in the preferred embodiment thereof contemplates the utilization of magnetic valves for the shutoff valves of the system.
  • a compressor'l driven by an electric motor 2 suctions or draws in coolant via a conduit 18 running from an evaporator 8.
  • the gaslike compressed chemical coolant leaves the compressor 1 via a hot gas conduit 10 from where such gas passes through a relief or check valve 24 into a conduit 12 and subsequently reaches a condenser'4 whereat the gas is cooled and liquified by cooling water circulation 5.
  • a collector 6 for the liquified coolant can be provided after the condenser 4 or, if desired, the condenser itself can be constructed so as to include a collector. Thereafter, the liquified coolant passes in known manner through an aftercooler (not illustrated) at the condenser 4 or the collector 6, respectively.
  • the liquid coolant then passes through conduit 14 in which a controllable shutoff valve such as a magnetic valve, and an expansion valve 7 are successively provided. Thereafter, the coolant flows through conduit 16 into an evaporator 8 whereat the coolant absorbs heat from the environment by evaporation and thus, the surrounding environment is cooled.
  • a controllable shutoff valve such as a magnetic valve
  • an expansion valve 7 are successively provided.
  • the coolant which is now in vapor or gas form, then passes into compressor 1 and the continuous cycle repeats.
  • an auxiliary or secondary conduit 19 branches off from the hot gas conduit 10.
  • Conduit 19 is provided with a second shutoff valve 22 which may likewise be constructed as a magnetic valve, the auxiliary or secondary conduit leading to conduit 16 which feeds the input to evaporator 8.
  • the operation of the shutoff valves 20 and 22 will be discussed hereinbelow.
  • shutoff valve 20 When it is desired to operate the cooling installation at full cooling output, shutoff valve 20 is opened and shutoff valve 22 is closed. Now, the entire quantity of coolant circulates in known manner in the above-described primary circulation path.
  • Compressor 1 serves to compress the entire flow of coolant and raise the pressure thereof to that required to maintain the circulation, the primary pressurereduction of the coolant occurring at the expansion valve 7.
  • Control over the cooling output in the illustrated inventive embodiment is achieved by means of a two-stage control process wherein the system is repeatedly and reversibly switched between two different operational conditions which,
  • work interval and rest interval respectively.
  • the change or control in the cooling output is achieved by varying the time relationship between the work interval and the rest interval, and, as such, it is possible to achieve a quasi-steady control over the cooling output with due consideration being given of a switching frequency sufficient for the thermal time constant of the embodiment.
  • the range of cooling control will be seen to be disposed between the extreme and opposite conditions of permanent work condition" representing full output and permanent rest condition representing zero output.
  • Control over the cooling output is exclusively achieved by means of an open-close control of both of the shutoff valves 20 and 22 while the compressor 1 continuously operates.
  • the work condition or work interval" corresponds to the abovedescribed normal operation in which shutoff valve 20 is open and shutoff valve 22 is closed. The transition from the work interval" to the rest interval takes place in every instance in a two-stage process and is initiated by closing valve 20. Subsequently, while valve 22 is still in its previously closed condition, compressor 1 suctions the coolant vapor from the evaporator 8 and feeds such vapor via conduit 10 and relief'or check valve 24 to the condenser 4 where such coolant is liquified and stored in collector 6.
  • shutoff valve 22 in the auxiliary or secondary conduit 19 is opened and this constitutes the second state, thereby achieving a rest condition or rest interval." Accordingly, during the rest interval," a circulation path of low flow resistance via the auxiliary or secondary conduit 19, shutoff valve 22, and evaporator 8, exists between the suction conduit 18 and the pressure conduit 10 of the compressor 1. Accordingly, a relatively low-residual quantity of the coolant circulates in the above-mentioned lowpressure circulation path while the major portion of the coolant on the condenser side is maintained between the relief or check valve 24 and the shut-off valve 20.
  • the coolant flow resistances in the low pressure circulation path are maintained low such that compressor 1 is only slightly loaded with the circulation quantity of coolant during the rest interval, such circulation quantity furthermore being strongly reduced.
  • the power draw of the drive motor 2 is thus correspondingly low.
  • This heat loss is discharged to the surrounding environment upon passage of the coolant through the evaporator 8.
  • the residual quantity of coolant permanently remains in a gaslike condition contrary to the normal or primary circulation through condenser 4 with a full output operation. Accordingly, the coolant enters evaporator 8 already in the form of a gas and is not evaporated therein.
  • a zero cooling output of the installation is easily obtained. In fact, the cooling output is even' somewhat negative due to the above-mentioned discharge into the environment of the residual heat loss.
  • the pressure differential which must be produced by com- 1 pressor 1 during the rest interval is determined only by the flow resistances prevalent in the auxiliary or secondary circulation path through valve 22 and evaporator 8. So as to keep these resistances and thus the compression work during the rest interval" to a minimum, the auxiliary or secondary conduit 19 as well as the valve 22 are suitably constructed so as to exhibit large passage cross sections to the extent possible.
  • the residual quantity of coolant which remains in circulation during the rest interval" is dependent and interrelated with its above-described function of removing the slight heat loss from compressor 1.
  • the vapor pressure in the auxiliary or suction-in conduit 19 or in evaporator 8, respectively is a partial measure of this quantity.
  • the pressure in the evaporator during the rest interval is suitably reduced to about 1 ata. as compared to 5 ata. during the work interval" or full cooling output operation. This corresponds to a flow of coolant through the compressor which has been reduced to about 20 percent of its full operational value.
  • the power input to the motor 2 is likewise accordingly reduced by about 80 percent during the rest interval.
  • the novel cooling installation can be economically operated at only a low percentage of its full cooling output capacity even through a long period of time. This is the case since the time average value of the consumed drive power is reduced approximately proportionally to the time average value of the cooling output or load. If the above-mentioned relatively low pressure in the evaporator 8 and in the auxiliary branch stream of the coolant, respectively, is correctly effected, then no danger of coolant overheating results even if the cooling output or load of the installation is completely reduced to zero. 0n the contrary, the gas and motor temperatures drop even below the corresponding values associated with full output operations.
  • control over the cooling output of the installation and of the activation of the shutoff valves and 22, which valves preferably are constructed as magnetic valves, is achieved by means of a twostage governor or control apparatus 30 via control conductors 35 and 36.
  • the nominal or desired value of the cooling output or for the temperature to be maintained by the installation, respectively, is inputted via conductor 32 to the governor or control apparatus 30 whereas the actual value is inputted via conductor 34, such actual value being sensed by a thermal sensing apparatus 33 which determines the cooling temperature as actually obtained in the surrounding environment of evaporator 8.
  • shutoff valve 20 is first closed and that thereafter, shutoff valve 22 is only opened after a certain time delay when the required low pressure in the evaporator 8 has been reached.
  • This time delay can be assumed to at least be approximately constant in every given installation and therefore, such time-delay can be predetermined and preselected in the governor or control device 30.
  • such operation can also be controlled as illustrated by the conductor 38 by means of a pressure sensor 37 disposed at the evaporator. This pressure sensor responds when the evaporator 8 is progressively suctioned empty after the closing of valve 20 to thereby reach the desired value of the low pressure which has been preselected or built into sensor 37.
  • control of the cooling output in the above-described novel compressor cooling installation can be effected over the entire range between the full nominal or theoretical output value and a zero value, all without subjecting the machine or the coolant to deleterious overheating.
  • the particular novel control mode also per mits partial cooling outputs during any desired period of time, all with a high efficiency.
  • the novel control process as described effects no undesirable or impermissible peak loads upon the electrical feed system, and, as should be apparent, the novel arrangement and control technique is equally applicable with installations having either a reciprocating compressor or a turbocompressor.
  • a controllable compressor cooling installation said installation providing a primary coolant circulation path from a compressor, through a condenser, a first shutoff valve, an ex pansion valve, an evaporator, and then back to said compressor; said installation providing a secondary coolant circulation path comprising an auxiliary conduit disposed from the outlet of said compressor to the inlet of said evaporator; check valve means disposed in said primary circulation path between said condenser and the connection branchoff of said auxiliary con duit; a second shutoff valve disposed in said auxiliary conduit; and two-stage time-delay control means for both said first and second shutoff valves, said control means closing said first shutoff valve first and thereafter, opening said second shutoff valve in said auxiliary conduit.
  • a controllable compressor cooling installation said installation providing a primary coolant circulation path from a compressor, through a condenser, a first shutoff valve, an expansion valve, an evaporator, and then back to said compressor; said installation providing a secondary coolant circulation path comprising an auxiliary conduit disposed from the outlet of said compressor to the inlet of said evaporator; check valve means disposed in said primary circulation path between said condenser and the connection branchoff of said auxiliary conduit; a second shutoff valve disposed in said auxiliary conduit; and two-stage time-delay control means for both said first and second shutoff valves, said control means closing said first shutoff valve first and thereafter, opening said second shutoff valve in said auxiliary conduit, said control means for said first and second shutoff valves comprising a governing device for said first shutoff valve in said primary circulation path, and a pressure sensor means and control conductor therefor for said second shutoff valve, said pressure sensor means responding to a reduced coolant pressure in said evaporator so as to generate an opening command for said
  • a controllable compressor cooling installation said in stallation providing a primary coolant circulation path from a compressor, through a condenser, a first shutoff valve, and expansion valve, an evaporator and then back to said compresshutoff valve first and thereafter, opening said second shutoff valve in said auxiliary conduit, said auxiliary conduitdefining a low pressure circulation path for throughflow of a relatively low residual quantity of the coolant through said secondary coolant circulation path while the major portion of the coolant is maintained between said check valve means and said first shutoff valve of said primary circulation path.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
US860309A 1968-09-26 1969-09-23 Controllable compressor cooling installation Expired - Lifetime US3599440A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1436968A CH496931A (de) 1968-09-26 1968-09-26 Regelbare Kompressor-Kälteanlage

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US3599440A true US3599440A (en) 1971-08-17

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US860309A Expired - Lifetime US3599440A (en) 1968-09-26 1969-09-23 Controllable compressor cooling installation

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US (1) US3599440A (enrdf_load_stackoverflow)
AT (1) AT297068B (enrdf_load_stackoverflow)
CH (1) CH496931A (enrdf_load_stackoverflow)
DE (1) DE1948127A1 (enrdf_load_stackoverflow)
FR (1) FR2018930A1 (enrdf_load_stackoverflow)
GB (1) GB1271119A (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4919442A (enrdf_load_stackoverflow) * 1972-05-26 1974-02-20
US4365983A (en) * 1979-07-13 1982-12-28 Tyler Refrigeration Corporation Energy saving refrigeration system
US4827732A (en) * 1987-04-24 1989-05-09 Hoshizaki Denki Kabushiki Kaisha Freezer machine for household use
US4854130A (en) * 1987-09-03 1989-08-08 Hoshizaki Electric Co., Ltd. Refrigerating apparatus
US5105632A (en) * 1989-10-18 1992-04-21 Hoshizaki Denki Kabushiki Kaisha Refrigeration system having liquefied refrigerant control
EP1225402A1 (en) * 2001-01-18 2002-07-24 Fausto Tacconi Refrigeration installation with reduced hysterisis
US6644048B2 (en) * 2001-06-29 2003-11-11 International Business Machines Corporation Method for shutting down a refrigerating unit
US20160273815A1 (en) * 2015-03-19 2016-09-22 Nortek Global Hvac Llc Air conditioning system having actively controlled and stabilized hot gas reheat circuit
CN111271889A (zh) * 2020-03-27 2020-06-12 合肥天鹅制冷科技有限公司 一种带安全泄压功能的水冷冷水机组
US12163526B2 (en) * 2020-11-26 2024-12-10 Atlas Copco Airpower, Naamloze Vennootschap Compressor device and method for controlling such a compressor device

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2497564A1 (fr) * 1981-01-06 1982-07-09 Unite Hermetique Pompe a chaleur
EP0093345A3 (de) * 1982-05-03 1984-07-25 Joh. Vaillant GmbH u. Co. Wärmepumpe
FR2625871B1 (fr) * 1988-01-18 1991-06-14 Prominox Sa Procede et systeme de stockage et de conservation du lait dans une installation de refroidissement a compression de vapeur et a detente directe
EP0904963A3 (en) * 1997-09-26 2001-10-31 Delphi Technologies, Inc. Air conditioning system for a motor vehicle
GB9720385D0 (en) * 1997-09-26 1997-11-26 Gen Motors Corp Air conditioning system for a motor vehicle

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2344215A (en) * 1943-02-26 1944-03-14 York Corp Refrigeration
US3332251A (en) * 1965-10-24 1967-07-25 John E Watkins Refrigeration defrosting system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2344215A (en) * 1943-02-26 1944-03-14 York Corp Refrigeration
US3332251A (en) * 1965-10-24 1967-07-25 John E Watkins Refrigeration defrosting system

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4919442A (enrdf_load_stackoverflow) * 1972-05-26 1974-02-20
US4365983A (en) * 1979-07-13 1982-12-28 Tyler Refrigeration Corporation Energy saving refrigeration system
US4827732A (en) * 1987-04-24 1989-05-09 Hoshizaki Denki Kabushiki Kaisha Freezer machine for household use
US4854130A (en) * 1987-09-03 1989-08-08 Hoshizaki Electric Co., Ltd. Refrigerating apparatus
US5105632A (en) * 1989-10-18 1992-04-21 Hoshizaki Denki Kabushiki Kaisha Refrigeration system having liquefied refrigerant control
EP1225402A1 (en) * 2001-01-18 2002-07-24 Fausto Tacconi Refrigeration installation with reduced hysterisis
US6644048B2 (en) * 2001-06-29 2003-11-11 International Business Machines Corporation Method for shutting down a refrigerating unit
US20160273815A1 (en) * 2015-03-19 2016-09-22 Nortek Global Hvac Llc Air conditioning system having actively controlled and stabilized hot gas reheat circuit
US10066860B2 (en) * 2015-03-19 2018-09-04 Nortek Global Hvac Llc Air conditioning system having actively controlled and stabilized hot gas reheat circuit
CN111271889A (zh) * 2020-03-27 2020-06-12 合肥天鹅制冷科技有限公司 一种带安全泄压功能的水冷冷水机组
US12163526B2 (en) * 2020-11-26 2024-12-10 Atlas Copco Airpower, Naamloze Vennootschap Compressor device and method for controlling such a compressor device

Also Published As

Publication number Publication date
DE1948127A1 (de) 1970-04-02
GB1271119A (en) 1972-04-19
AT297068B (de) 1972-03-10
CH496931A (de) 1970-09-30
FR2018930A1 (enrdf_load_stackoverflow) 1970-06-26

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