CA1093328A - Source water cooling in a refrigeration system - Google Patents
Source water cooling in a refrigeration systemInfo
- Publication number
- CA1093328A CA1093328A CA336,003A CA336003A CA1093328A CA 1093328 A CA1093328 A CA 1093328A CA 336003 A CA336003 A CA 336003A CA 1093328 A CA1093328 A CA 1093328A
- Authority
- CA
- Canada
- Prior art keywords
- refrigerant
- condenser
- economizer
- source water
- heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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
- F25B1/00—Compression machines, plants or systems with non-reversible cycle
- F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
-
- 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
- F25B2400/13—Economisers
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Other Air-Conditioning Systems (AREA)
Abstract
Abstract A vapor compression refrigeration system which has an economizer-condenser for recondensing refrigerant gas which is flashed in a flash economizer and a main condenser for condensing gaseous refrigerant to a liquid refrigerant. Source water is circulated through the economizer-condenser to absorb heat from gaseous refrigerant in heat exchange relation therewith. By using source water such as building supply water the low temperature water is utilized to increase the overall efficiency of the refrigeration system.
Description
~3~
S O U R C E W A T E P~ C O O L I N G
I N A R E F R I G E R A _ I ~ N S Y S 'r E M
Il The presen-t invention relates to cooling E:Luid used ¦ within reErigeration systems. More particularly the present invention relates -to the use of source water within a I'lrefrigeration system having both a low temperature condenser and 5 1,l a high -temperature condenser so that the lower temperature source water is used in the low temperature condenser to aid in the overall efficiency of -the reErigeration sys-tem.
¦ Refrigeration systems of the vapor compression type '~ typically employ a compressor to increase the temperature and llpressure of the gaseous refrigerant. Connected thereto is a ,~condenser wherein gaseous refrigerant is cooled to change state to a liquid refrigerant. Thereaf-ter refrigerant May be subcooled lin a flash economizer wherein part of the refrigerant is l¦vaporized absorbing heat from the remaining liquid refrigerant.
,The vaporized refrigerant has typically been drawn into the compressor for recycling to the condenser and the liquid ~ -refrigerant which has nov been cooled passes onto the evapora-tor or chiller. In the chiller the refrigerant is evapora-ted labsorbing heat from the fluid to be cooled, the now gaseous 20 1¦ refrigerant bei.ng drawn into the compressor to complete the ¦cycle. In the above described refrigeration system the compressor is a multistage compressor such -that the flashed ~refrigerant from the flash economi~er may be drawn into the , compressor between the stages allowing the flash economizer to be 25 at an intermediate pressure to the condenser and to the chiller.
Other types Or multistflge compressors have been llsed with various econom:izers. There have been disclosed systems with an evaporator and a condenser wherein the flash economizer is :Located therebetween, the flashed gas being drawn into the second stage o:E a two stage compressor and the liquid refrigerant ~passing through the condellser and to the machine for the cooling o~ the electric motor.
In order to use a flash economizer in a vapor compression system having a single stage compressor it is necessary -that an additional compressor be provided such that the flash gas can be compressed. Thereafter by providing an economizer-condenser this recompressed flashed gas may be condensed to a liquid and may be reflashed to further cool the liquid reErigerant within the Elash economizer. This system is Iparticularly applicable to refrigerants such as R-ll which are ,not adaptable to sensible heat subcooling. Consequently, latent Iheat cooling by means of a change of state is the only practical 'imethod to subcool R-ll and other similar refrigerants.
, Prior refrigeration systems utilizing a flash economizer 20 1I have required a multistage compressor to provide varying pressure "llevels for the flashing to occur. Refrigeration systems with a illsingle stage compressor have previously not been adaptable for retrofit machinery to provide a flash economizing step since the llpressure differential required has not been obtainable. The il refrigera-tion system described hereafter is adaptable -to be ~retrofitted to a single s-tage centriiugal compressor system such l~that a second compressor may be provided to recompress the ¦¦flashed gas from the flash economizer. The provision of an lIeconomizer-condenser which would condense the recompressed ~¦flashed gas aids the overall efficiency of the system.
~33~
Other types of refrigeration systems are also utilized with the low temperature economizer-condenser and the high temperature m~in condenser.
An object of the present invention i5 to pro~ide an efficient refrigeration system.
A more specific object of the present invention is to provide a refrigeration system in which low temperature source water is utilized to increase the efficiency of the system.
Another object of the present invention is to provide source water to a low temperature condenser and then serially to a high tempçrature condenser within a refrigeration system.
A further object of the present invention is to provide low temperature source water to the economizer-condenser such that the gaseous refrigerant may be condensed to a liquid refrigerant at a relatively low temperature.
A yet further object of the present invention is to - provide heated source water from the refrigeration system to the hot water system of a building.
A still further object of the present invention is to utilize the incoming source or building supply water for the removal of heat from the refrigerant notwithstanding of the volume or flow characteristics of the incoming source water.
A further object of the present invention i5 to provide a refrigeration system with a low temperature condenser and a high temperature condenser which may be readily adapted to an existing vapor compression refrigeration system.
: ~ .
~ 2 -___ 3;~
It is another object of the presellt inven-tion to provide for the use of source water within all types of refrigeration systems.
Other objects will be apparent Erom the description to follow and the appended claims.
The preceding ohjects are achieved according to preferred embodiment of the invention by the provision of a flash leconomizer within a single stage vapor compression refrigeration llsystem. Therein the condenser is connected to a compressor, the llcondenser condensing the gaseous refrigeran-t received from the llcompressor to a liquid refrigerant. A flash economizer receives jlthe liquid refrigerant from the condenser and flashes that ~refrigerant by reducing its pressure such -that part of the ilrefrigerant changes state to a gas absorbing heat from -the 15 Ii remaining liquid refrigerant. The liquid refrigerant then travels to the evaporator where it changes state from a liquid to i! a gas absorbing heat from the fluid to be cooled. The gaseous refrigerant from the evaporator is then transported -to the ilcompressor where it is recompressed to start the cycle again.
20 IlThe flashed gas from the flash economizer may be recompressed in ~a second compressor. This recompressed gas is then condensed in an economizer-condenser to a liquid state. This liquid ¦refrigerant is therefrom flashed -through an orifice into the ~Iflash economizer from which the liquid refri.gerant is allowed to 25 1 travel to the evaporator and the gaseous refrigerant is again I conducted to the second compressor. Source water is circulated first through the economizer-condenser and then through the main ¦Icondenser such that the colder temperature source or building ~supply water is utilized within the economizer-condenser to Irecondense the recompressed flashed gaseous refrigerant. The 3~
source water may then be circulated from the economiæer condenser to the main condenser ~or use in condensing the refrigerant from the first compressor, said source water being then circulated as heated water to the building for use therein.
In accordance with one broad aspect, the in~ention relates to a method of increasing the efficiency of a refrigeration circuit having a condenser where the gaseous refrigerant is condensed to a liquid and a low temperature heat exchanger which comprises the steps of conducting liquid refrigerant from the condenser to a lower temperature and pressure heat exchanger wherein a portion of the liquid refrigerant changes state to a gas absorbing heat from the remaining liguid refrigerant to subcool same; and circulating source water in heat exchange relationship with the combination of gaseous and liquid refrigerant in the heat exchanger, the source wâter being at a lower temperature than the refrigerant in the low temperature and pressure heat exchanger and thereby being capable of absorbing heat from the gaseous refrigerant to condense same.
In accordance with another aspect, the invention relates to a refrigeration circuit having an evaporator for cooling a fluid by vaporizing a refrigerant in heat exchange relationship therewith, a condenser wherein heat is removed from the refrigerant so that refrigerant changes state from a gas to a liquid, a flash economizer wherein liquid refrigerant is partially vapoxized, the vaporized refrigerant absorbing heat from the remaininc3 liguid refrigerant, which comprises an economizer-condenser mounted within the economizer in communication with flashed gaseous refrigerant; and means for suppl~ing low temperature source water to the economizer-condenser for absorbing heat from the gaseous refrigerant.
: ~
33;~1 Figure 1 is a schematic diayram of a vapor compression refrigeration system utilizing the present invention.
The embodiment of the invention described below is adapted for use in a vapor compression refrigeration system having a single stage compressor, a condenser, and an evaporator.
It is to be understood that the present invention finds applicability in all types of refrigeration systems includiny absorption refrigeration systems, screw compressor refrigeration systems, and systems using heat pump applications and heat reclaim cycles with various types o~ compression equipment.
The system is also adapted for use with multiple condensers for various purposes.
The source water herein referred to includes any source of low temperature water such as building supply water or city supply water (water which is purchased from the municipal supply source) well water, or other water which is utilized ~for building supply or process utilization, including rainwater, river water, ocean water or underground water among others.
Typically this water is at a fairly low temperature often in the 45 to 50F. range and consequently has the capability for considerable sensible heat subcooling in a heat exchanger.
In many applications such as a hospital or other commercial application the volume of incoming supply water is large and sufficient supply water is available to meet a large portion of the cooling needs of the refrigeration system. This supply water after being circulated through the refrigeration system may then ~ -5a-33Z~
~e utilized within the building for various clornestic purposes.
; The largest energy used within the building in relation to this water is for heating to provide for various hot water purposes such as personal use, sterilization, or kitchen use in a dishwasher and other machinery. By circulating the building supply water through the refrigeration system the water absorbs heat in the process consequently reducing the amount of heat which must thereafter be applied to this source water -to raise it Ito the temperature level necessary .Eor -the various end uses.
l Referring to Figure 1, a schematic diagram of a vapor compression refrigeration system, it can be seen that a dual Ichannel compressor lO is provided having two separate centrifugal ¦Icompressors 11 and 17 loca-ted on a single axis driven by electric 'Imotor 33. The primary compressor 11 has increased temperature lland pressure refrigerant gas exiting therefrom at outlet 14 into line 20. From line 20 the gaseous refrigerant enters condenser 22 wherein it changes state to a liquid refrigerant. Liquid refrigerant is collec-ted in the bottom of condenser 22 and then lltransported through line 24 to ~lash economizer 28. In the flash l¦economizer liquid refrigerant is flashed -through nozzles 26 or llsome other pressure reducing device to a decreased pressure level ¦Isuch that part of the refrigerant changes state to a gas ¦absorbing heat from the remaining liquid refrigerant. Liquid l~refrigerant collects in the bottom of the flash economizer shown l~as reservoir 30. Therefrom via line 32 liquid refrigerant passes through expansion control device 3~ wherein the pressure of the l~`liquid refrigerant is dropped. From the expansion control device ¦¦the liquid refrigeran-t travels to chiller 36 wherein the liquid ¦¦changes state to a gas absorbing heat from the fluid to be cooled 1 as it passes through the chiller. Line 40 then conducts the 3~
gaseous refrigerant from the chi:~Ler to inlet 12, of ~ompressor 11 wherein the gaseolls refrigerant is recompressed to begin the cycle again.
~ ithin chiller 36 is located heat exchanger coil 38 through which refrigerant flows. Water or other fluid to be ,cooled enters chiller 36 through line 64 and flows through coil 3g in heat exchange relationship with the refrigerant in the ~I,chiller. The now cooled water ex:its through line 66 to the fl enclosure to be cooled.
¦ Connected to flash economizer 28 is line 50 which llconducts the Elashed gaseous refrigrant to inlet 15 of compressor 7. Both compressor 11 and compressor 17 are driven by elec-tric ¦l'motor 33. Therein compressor 17 increases the temperature and pressure of the flashed refrigerant gas and delivers the l~recompressed gas to outle-t 18. This recompressed gas -travels iI through line 48 to economizer-condenser 42 wherein -the recompressed gas is recondensed into a liquid. The liquid is collected in reservoir 44 such that it may be flashed from the economizer-condenser to the flash economizer through orifice 46 liwhich ac-ts to create a pressure differential between the 20 1l economizer-condenser and the flash economizer. The flashed ,¦refrigerant from orifice 46 travels upward and is conducted jthrough line 50 back to the second compressor. The remaining liquid refrigerant from orifice 46 is collected in reservoir 30 Iprior to being conducted to chiller 36.
25 ¦ Entering source water travels through line 52 to heat exchanger coil 58 in the economizer-condenser 42 wherein it absorbs heat from the recompressed gaseous refrigerant. The source water exits from coil 58 into line 54. It is then conducted to inlet 84 of double bundle condenser 22. ~ine 54 may ~1 ~ -7-~33~
be connected to the hot water system of the bu:ilding such that the building supply water is circulated only through the economizer-condenser and then immediately into the hot water system of the building. The source water nee~ not ~e routed in-to ~the condenser after flowing through the economizer-condenser but may be conducted back into the builciing water distribution system, pumped into the ground or simply dumped.
In Figure l condenser 22 is shown as a double bundle Icondenser having separate coils for heating and cooling. For a detailed description of the operation of the double bundle ~condenser see United States Patent entitled "Air Conditioning ~System and Control Including Control Method and Means" No.
,l3,628,600 issued to McEarlan. It can be seen in Figure l that Illine 54 is so arranged -that the source water from the economizer-I condenser may be circulated through heating condenser 82 and that ¦a separate source of cooling water is used in cooling condenser ~80 of the double bundle condenser 22. Typically line 54 is so arranged that the source water enters heating condenser 82 lithrough inl.et 84 and is discharged from heating condenser 82 ¦through outlet 86 to the hot water system of the building.
Cooling condenser 80 typically receives cooling water from a l¦cooling tower or other source through inlet 88 and discharges ilsaid water through outle-t 90 back to the cooling tower. Cooling l¦condenser 80 is utilized to absorb sufficient heat from the 1¦ refrigerant to change it from a gaseous state to a liquid state ¦depending upon the capability of the heating condenser for doing ¦the same.
II In the application described the economizer-condenser i typically operates with a refrigerant temperature of approximately 70F. Consequently for the source water to be able 33~:~
to condense the refrigerant therein it must have a temperature lower than 70F. Furthermore a typical operating temperature for double bundle condenser 22 would be in the neighborhood of 105F. Consequently, higher temperature water may be utilized to absorb heat from the gaseous refrigerant therein.
By the provision of the low temperature water being serially connected to flow through the economizer-condenser and the double bindle condenser, water capable of absorbing heat at both temperatures is circulated therethrough. Utilization of this decreased temperature water over the normal condensing water such as cooling tower water at 80 F. aids in the overall efficiency of the refrigeration system as well as having the additional capability of providing heated water to the building.
Should the volume of source water entering a building be insufficient to condense the gaseous refrigerant within the economizer-condenser said refrigerant will merely be recycled through the second compressor such that only a portion of refrigerant is condensed and the remaining gas recycles. This recycling decreases the efficiency of the refrigeration system from the efficiency ~hat is ob~ainable when the economizer-condenser is capable of recondensing all of the gaseous refrigerant, however, any utilization of the economizer-condenser theoretically aids in the overall system efficiency.
In a pure thermal economizer system using only the ~ cold water source for additional condensing, any`additional ; condensing achieved through the economizer-condenser is a pure addition in efficiency to the refrigeration system.
Conse~uently if no cold source water is available, the system will merely operate at the same efficiency as lf it did not have the flash _g _ , . ' :
~ ~D~:3 3~
economizer and the economlzer-condenser. Naturally the Elash econornizer operates at a pressure lower than the primary ~compressor and higher than that of -the chiller. The pressure of the flash economizer is also lower than that of the economizer-condenser such that refrigeran-t condensed therein may be jreflashed to the flash economizer. Within a thermal economized ~system the pressure within -the flash economiæer is the same pressure as the pressure of the economizer~corldenser.
IConsequently, if the economizer-condenser is not capable of condensing the Elashed refrigerant gas there will be no pressure Illdrop therein and the refrigeration system will operate as if there were no f].ash economizer therein.
¦ The preferred embodiment above described has shown an improved vapor compression refrigeration system utilizing ,~'incoming and relatively cool source wa-ter for condensing ,irefrigerant gas within both a low temperature condenser and a high temperatllre condenser. The utilization of this incoming source water essentially provides a free source of relatively llcool fluid since it is being purchased for the building needs in 20 11 any event and creates a cooling sink such -that the overall ,iefficiency of the refrigeration system may be increased without incurring additional operating costs. ~urthermore the efficiency of the refrigeration system will be increased as long as -there is Isome building supply water entering the building notwithstanding 25 1 the volume flow thereof.
The invention has been described in detail with ¦particul.ar reference to the preferred embodiment thereof but it will be understood that variations and modifications can be ~effected within -the spirit and scope of the invention. I
S O U R C E W A T E P~ C O O L I N G
I N A R E F R I G E R A _ I ~ N S Y S 'r E M
Il The presen-t invention relates to cooling E:Luid used ¦ within reErigeration systems. More particularly the present invention relates -to the use of source water within a I'lrefrigeration system having both a low temperature condenser and 5 1,l a high -temperature condenser so that the lower temperature source water is used in the low temperature condenser to aid in the overall efficiency of -the reErigeration sys-tem.
¦ Refrigeration systems of the vapor compression type '~ typically employ a compressor to increase the temperature and llpressure of the gaseous refrigerant. Connected thereto is a ,~condenser wherein gaseous refrigerant is cooled to change state to a liquid refrigerant. Thereaf-ter refrigerant May be subcooled lin a flash economizer wherein part of the refrigerant is l¦vaporized absorbing heat from the remaining liquid refrigerant.
,The vaporized refrigerant has typically been drawn into the compressor for recycling to the condenser and the liquid ~ -refrigerant which has nov been cooled passes onto the evapora-tor or chiller. In the chiller the refrigerant is evapora-ted labsorbing heat from the fluid to be cooled, the now gaseous 20 1¦ refrigerant bei.ng drawn into the compressor to complete the ¦cycle. In the above described refrigeration system the compressor is a multistage compressor such -that the flashed ~refrigerant from the flash economi~er may be drawn into the , compressor between the stages allowing the flash economizer to be 25 at an intermediate pressure to the condenser and to the chiller.
Other types Or multistflge compressors have been llsed with various econom:izers. There have been disclosed systems with an evaporator and a condenser wherein the flash economizer is :Located therebetween, the flashed gas being drawn into the second stage o:E a two stage compressor and the liquid refrigerant ~passing through the condellser and to the machine for the cooling o~ the electric motor.
In order to use a flash economizer in a vapor compression system having a single stage compressor it is necessary -that an additional compressor be provided such that the flash gas can be compressed. Thereafter by providing an economizer-condenser this recompressed flashed gas may be condensed to a liquid and may be reflashed to further cool the liquid reErigerant within the Elash economizer. This system is Iparticularly applicable to refrigerants such as R-ll which are ,not adaptable to sensible heat subcooling. Consequently, latent Iheat cooling by means of a change of state is the only practical 'imethod to subcool R-ll and other similar refrigerants.
, Prior refrigeration systems utilizing a flash economizer 20 1I have required a multistage compressor to provide varying pressure "llevels for the flashing to occur. Refrigeration systems with a illsingle stage compressor have previously not been adaptable for retrofit machinery to provide a flash economizing step since the llpressure differential required has not been obtainable. The il refrigera-tion system described hereafter is adaptable -to be ~retrofitted to a single s-tage centriiugal compressor system such l~that a second compressor may be provided to recompress the ¦¦flashed gas from the flash economizer. The provision of an lIeconomizer-condenser which would condense the recompressed ~¦flashed gas aids the overall efficiency of the system.
~33~
Other types of refrigeration systems are also utilized with the low temperature economizer-condenser and the high temperature m~in condenser.
An object of the present invention i5 to pro~ide an efficient refrigeration system.
A more specific object of the present invention is to provide a refrigeration system in which low temperature source water is utilized to increase the efficiency of the system.
Another object of the present invention is to provide source water to a low temperature condenser and then serially to a high tempçrature condenser within a refrigeration system.
A further object of the present invention is to provide low temperature source water to the economizer-condenser such that the gaseous refrigerant may be condensed to a liquid refrigerant at a relatively low temperature.
A yet further object of the present invention is to - provide heated source water from the refrigeration system to the hot water system of a building.
A still further object of the present invention is to utilize the incoming source or building supply water for the removal of heat from the refrigerant notwithstanding of the volume or flow characteristics of the incoming source water.
A further object of the present invention i5 to provide a refrigeration system with a low temperature condenser and a high temperature condenser which may be readily adapted to an existing vapor compression refrigeration system.
: ~ .
~ 2 -___ 3;~
It is another object of the presellt inven-tion to provide for the use of source water within all types of refrigeration systems.
Other objects will be apparent Erom the description to follow and the appended claims.
The preceding ohjects are achieved according to preferred embodiment of the invention by the provision of a flash leconomizer within a single stage vapor compression refrigeration llsystem. Therein the condenser is connected to a compressor, the llcondenser condensing the gaseous refrigeran-t received from the llcompressor to a liquid refrigerant. A flash economizer receives jlthe liquid refrigerant from the condenser and flashes that ~refrigerant by reducing its pressure such -that part of the ilrefrigerant changes state to a gas absorbing heat from -the 15 Ii remaining liquid refrigerant. The liquid refrigerant then travels to the evaporator where it changes state from a liquid to i! a gas absorbing heat from the fluid to be cooled. The gaseous refrigerant from the evaporator is then transported -to the ilcompressor where it is recompressed to start the cycle again.
20 IlThe flashed gas from the flash economizer may be recompressed in ~a second compressor. This recompressed gas is then condensed in an economizer-condenser to a liquid state. This liquid ¦refrigerant is therefrom flashed -through an orifice into the ~Iflash economizer from which the liquid refri.gerant is allowed to 25 1 travel to the evaporator and the gaseous refrigerant is again I conducted to the second compressor. Source water is circulated first through the economizer-condenser and then through the main ¦Icondenser such that the colder temperature source or building ~supply water is utilized within the economizer-condenser to Irecondense the recompressed flashed gaseous refrigerant. The 3~
source water may then be circulated from the economiæer condenser to the main condenser ~or use in condensing the refrigerant from the first compressor, said source water being then circulated as heated water to the building for use therein.
In accordance with one broad aspect, the in~ention relates to a method of increasing the efficiency of a refrigeration circuit having a condenser where the gaseous refrigerant is condensed to a liquid and a low temperature heat exchanger which comprises the steps of conducting liquid refrigerant from the condenser to a lower temperature and pressure heat exchanger wherein a portion of the liquid refrigerant changes state to a gas absorbing heat from the remaining liguid refrigerant to subcool same; and circulating source water in heat exchange relationship with the combination of gaseous and liquid refrigerant in the heat exchanger, the source wâter being at a lower temperature than the refrigerant in the low temperature and pressure heat exchanger and thereby being capable of absorbing heat from the gaseous refrigerant to condense same.
In accordance with another aspect, the invention relates to a refrigeration circuit having an evaporator for cooling a fluid by vaporizing a refrigerant in heat exchange relationship therewith, a condenser wherein heat is removed from the refrigerant so that refrigerant changes state from a gas to a liquid, a flash economizer wherein liquid refrigerant is partially vapoxized, the vaporized refrigerant absorbing heat from the remaininc3 liguid refrigerant, which comprises an economizer-condenser mounted within the economizer in communication with flashed gaseous refrigerant; and means for suppl~ing low temperature source water to the economizer-condenser for absorbing heat from the gaseous refrigerant.
: ~
33;~1 Figure 1 is a schematic diayram of a vapor compression refrigeration system utilizing the present invention.
The embodiment of the invention described below is adapted for use in a vapor compression refrigeration system having a single stage compressor, a condenser, and an evaporator.
It is to be understood that the present invention finds applicability in all types of refrigeration systems includiny absorption refrigeration systems, screw compressor refrigeration systems, and systems using heat pump applications and heat reclaim cycles with various types o~ compression equipment.
The system is also adapted for use with multiple condensers for various purposes.
The source water herein referred to includes any source of low temperature water such as building supply water or city supply water (water which is purchased from the municipal supply source) well water, or other water which is utilized ~for building supply or process utilization, including rainwater, river water, ocean water or underground water among others.
Typically this water is at a fairly low temperature often in the 45 to 50F. range and consequently has the capability for considerable sensible heat subcooling in a heat exchanger.
In many applications such as a hospital or other commercial application the volume of incoming supply water is large and sufficient supply water is available to meet a large portion of the cooling needs of the refrigeration system. This supply water after being circulated through the refrigeration system may then ~ -5a-33Z~
~e utilized within the building for various clornestic purposes.
; The largest energy used within the building in relation to this water is for heating to provide for various hot water purposes such as personal use, sterilization, or kitchen use in a dishwasher and other machinery. By circulating the building supply water through the refrigeration system the water absorbs heat in the process consequently reducing the amount of heat which must thereafter be applied to this source water -to raise it Ito the temperature level necessary .Eor -the various end uses.
l Referring to Figure 1, a schematic diagram of a vapor compression refrigeration system, it can be seen that a dual Ichannel compressor lO is provided having two separate centrifugal ¦Icompressors 11 and 17 loca-ted on a single axis driven by electric 'Imotor 33. The primary compressor 11 has increased temperature lland pressure refrigerant gas exiting therefrom at outlet 14 into line 20. From line 20 the gaseous refrigerant enters condenser 22 wherein it changes state to a liquid refrigerant. Liquid refrigerant is collec-ted in the bottom of condenser 22 and then lltransported through line 24 to ~lash economizer 28. In the flash l¦economizer liquid refrigerant is flashed -through nozzles 26 or llsome other pressure reducing device to a decreased pressure level ¦Isuch that part of the refrigerant changes state to a gas ¦absorbing heat from the remaining liquid refrigerant. Liquid l~refrigerant collects in the bottom of the flash economizer shown l~as reservoir 30. Therefrom via line 32 liquid refrigerant passes through expansion control device 3~ wherein the pressure of the l~`liquid refrigerant is dropped. From the expansion control device ¦¦the liquid refrigeran-t travels to chiller 36 wherein the liquid ¦¦changes state to a gas absorbing heat from the fluid to be cooled 1 as it passes through the chiller. Line 40 then conducts the 3~
gaseous refrigerant from the chi:~Ler to inlet 12, of ~ompressor 11 wherein the gaseolls refrigerant is recompressed to begin the cycle again.
~ ithin chiller 36 is located heat exchanger coil 38 through which refrigerant flows. Water or other fluid to be ,cooled enters chiller 36 through line 64 and flows through coil 3g in heat exchange relationship with the refrigerant in the ~I,chiller. The now cooled water ex:its through line 66 to the fl enclosure to be cooled.
¦ Connected to flash economizer 28 is line 50 which llconducts the Elashed gaseous refrigrant to inlet 15 of compressor 7. Both compressor 11 and compressor 17 are driven by elec-tric ¦l'motor 33. Therein compressor 17 increases the temperature and pressure of the flashed refrigerant gas and delivers the l~recompressed gas to outle-t 18. This recompressed gas -travels iI through line 48 to economizer-condenser 42 wherein -the recompressed gas is recondensed into a liquid. The liquid is collected in reservoir 44 such that it may be flashed from the economizer-condenser to the flash economizer through orifice 46 liwhich ac-ts to create a pressure differential between the 20 1l economizer-condenser and the flash economizer. The flashed ,¦refrigerant from orifice 46 travels upward and is conducted jthrough line 50 back to the second compressor. The remaining liquid refrigerant from orifice 46 is collected in reservoir 30 Iprior to being conducted to chiller 36.
25 ¦ Entering source water travels through line 52 to heat exchanger coil 58 in the economizer-condenser 42 wherein it absorbs heat from the recompressed gaseous refrigerant. The source water exits from coil 58 into line 54. It is then conducted to inlet 84 of double bundle condenser 22. ~ine 54 may ~1 ~ -7-~33~
be connected to the hot water system of the bu:ilding such that the building supply water is circulated only through the economizer-condenser and then immediately into the hot water system of the building. The source water nee~ not ~e routed in-to ~the condenser after flowing through the economizer-condenser but may be conducted back into the builciing water distribution system, pumped into the ground or simply dumped.
In Figure l condenser 22 is shown as a double bundle Icondenser having separate coils for heating and cooling. For a detailed description of the operation of the double bundle ~condenser see United States Patent entitled "Air Conditioning ~System and Control Including Control Method and Means" No.
,l3,628,600 issued to McEarlan. It can be seen in Figure l that Illine 54 is so arranged -that the source water from the economizer-I condenser may be circulated through heating condenser 82 and that ¦a separate source of cooling water is used in cooling condenser ~80 of the double bundle condenser 22. Typically line 54 is so arranged that the source water enters heating condenser 82 lithrough inl.et 84 and is discharged from heating condenser 82 ¦through outlet 86 to the hot water system of the building.
Cooling condenser 80 typically receives cooling water from a l¦cooling tower or other source through inlet 88 and discharges ilsaid water through outle-t 90 back to the cooling tower. Cooling l¦condenser 80 is utilized to absorb sufficient heat from the 1¦ refrigerant to change it from a gaseous state to a liquid state ¦depending upon the capability of the heating condenser for doing ¦the same.
II In the application described the economizer-condenser i typically operates with a refrigerant temperature of approximately 70F. Consequently for the source water to be able 33~:~
to condense the refrigerant therein it must have a temperature lower than 70F. Furthermore a typical operating temperature for double bundle condenser 22 would be in the neighborhood of 105F. Consequently, higher temperature water may be utilized to absorb heat from the gaseous refrigerant therein.
By the provision of the low temperature water being serially connected to flow through the economizer-condenser and the double bindle condenser, water capable of absorbing heat at both temperatures is circulated therethrough. Utilization of this decreased temperature water over the normal condensing water such as cooling tower water at 80 F. aids in the overall efficiency of the refrigeration system as well as having the additional capability of providing heated water to the building.
Should the volume of source water entering a building be insufficient to condense the gaseous refrigerant within the economizer-condenser said refrigerant will merely be recycled through the second compressor such that only a portion of refrigerant is condensed and the remaining gas recycles. This recycling decreases the efficiency of the refrigeration system from the efficiency ~hat is ob~ainable when the economizer-condenser is capable of recondensing all of the gaseous refrigerant, however, any utilization of the economizer-condenser theoretically aids in the overall system efficiency.
In a pure thermal economizer system using only the ~ cold water source for additional condensing, any`additional ; condensing achieved through the economizer-condenser is a pure addition in efficiency to the refrigeration system.
Conse~uently if no cold source water is available, the system will merely operate at the same efficiency as lf it did not have the flash _g _ , . ' :
~ ~D~:3 3~
economizer and the economlzer-condenser. Naturally the Elash econornizer operates at a pressure lower than the primary ~compressor and higher than that of -the chiller. The pressure of the flash economizer is also lower than that of the economizer-condenser such that refrigeran-t condensed therein may be jreflashed to the flash economizer. Within a thermal economized ~system the pressure within -the flash economiæer is the same pressure as the pressure of the economizer~corldenser.
IConsequently, if the economizer-condenser is not capable of condensing the Elashed refrigerant gas there will be no pressure Illdrop therein and the refrigeration system will operate as if there were no f].ash economizer therein.
¦ The preferred embodiment above described has shown an improved vapor compression refrigeration system utilizing ,~'incoming and relatively cool source wa-ter for condensing ,irefrigerant gas within both a low temperature condenser and a high temperatllre condenser. The utilization of this incoming source water essentially provides a free source of relatively llcool fluid since it is being purchased for the building needs in 20 11 any event and creates a cooling sink such -that the overall ,iefficiency of the refrigeration system may be increased without incurring additional operating costs. ~urthermore the efficiency of the refrigeration system will be increased as long as -there is Isome building supply water entering the building notwithstanding 25 1 the volume flow thereof.
The invention has been described in detail with ¦particul.ar reference to the preferred embodiment thereof but it will be understood that variations and modifications can be ~effected within -the spirit and scope of the invention. I
Claims (10)
1. A method of increasing the efficiency of a refrigeration circuit having a condenser where the gaseous refrigerant is condensed to a liquid and a low temperature heat exchanger which comprises the steps of conducting liquid refrigerant from the condenser to a lower temperature and pressure heat exchanger wherein a portion of the liquid refrigerant changes state to a gas absorbing heat from the remaining liquid refrigerant to subcool same; and circulating source water in heat exchange relationship with the combination of gaseous and liquid refrigerant in the heat exchanger, the source water being at a lower temperature than the refrigerant in the low temperature and pressure heat exchanger and thereby being capable of absorbing heat from the gaseous refrigerant to condense same.
2. The method as set forth in claim 1 wherein the step of circulating includes the heat exchanger having a combination of gaseous and liquid refrigerant therein and further including the step of condensing the gaseous refrigerant to a liquid refrigerant by transferring heat from the gaseous refrigerant to the source water.
3. The method as set forth in claim 1 wherein the step of circulating the source water includes connecting the source water to act as a heat exchange fluid in the condenser after it has been circulated through the low temperature and pressure heat exchanger.
4. The method as set forth in claim 3 and further including the step of supplying cooling water to the condenser for use in absorbing heat from the refrigerant in conjunction with the source water.
5. A method as set forth in claim 4 and further including the step of discharging source water that has been heated within the refrigeration circuit to a hot water system.
6. A refrigeration circuit having an evaporator for cooling a fluid by vaporizing a refrigerant in heat exchange relationship therewith, a condenser wherein heat is removed from the refrigerant so that refrigerant changes state from a gas to a liquid, a flash economizer wherein liquid refrigerant is partially vaporized, the vaporized refrigerant absorbing heat from the remaining liquid refrigerant, which comprises an economizer-condenser mounted within the economizer in communication with flashed gaseous refrigerant; and means for supplying low temperature source water to the economizer-condenser for absorbing heat from the gaseous refrigerant.
7. The invention as set forth in claim 6 and further including means for conducting discharged source water from the economizer-condenser to the condenser wherein heat is absorbed from gaseous refrigerant
8. A refrigeration system having an evaporator for cooling a fluid by vaporizing a refrigerant in heat exchange relationship therewith, a condenser wherein heat is removed from the refrigerant so that the refrigerant changes state from a gas to a liquid, a flash economizer wherein liquid refrigerant is partially vaporized, the vaporized refrigerant absorbing heat from the remaining liquid refrigerant, which comprises a compressor mounted to receive flashed gaseous refrigerant from the economizer and to discharge gaseous refrigerant at a pressure and temperature lower than the pressure and temperature of the refrigerant in the condenser; an economizer-condenser in heat exchange communication with the gaseous refrigerant from the compressor; and means for supplying low temperature source water to the economizer-condenser for absorbing heat from the gaseous refrigerant to condense same.
9. A refrigeration system having an evaporator and a condenser, a supply of low temperature source water and a heat exchanger at a pressure intermediate the evaporator and condenser, the source water being routed to the heat exchanger of the system to absorb heat from gaseous refrigerant at a pressure intermediate to the pressure of the condenser and the evaporator of said circuit, said source water acting to condense said refrigerant from a gas to a liquid and means for routing the source water from the heat exchanger to a water distribution system where the water is utilized for domestic or other purposes.
10. The invention as set forth in claim 9 wherein the heated source water routed from the heat exchanger is utilized for domestic or other purposes in a hot water system.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US95143078A | 1978-10-16 | 1978-10-16 | |
| US951,430 | 1978-10-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1093328A true CA1093328A (en) | 1981-01-13 |
Family
ID=25491676
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA336,003A Expired CA1093328A (en) | 1978-10-16 | 1979-09-20 | Source water cooling in a refrigeration system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1093328A (en) |
-
1979
- 1979-09-20 CA CA336,003A patent/CA1093328A/en not_active Expired
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