Note: Descriptions are shown in the official language in which they were submitted.
~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.
--2--
~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.
--5--
: ~
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
