U.S. patent application number 11/254617 was filed with the patent office on 2007-04-26 for refrigeration system with distributed compressors.
This patent application is currently assigned to Hussmann Corporation. Invention is credited to Doron Shapiro.
Application Number | 20070089453 11/254617 |
Document ID | / |
Family ID | 37984066 |
Filed Date | 2007-04-26 |
United States Patent
Application |
20070089453 |
Kind Code |
A1 |
Shapiro; Doron |
April 26, 2007 |
Refrigeration system with distributed compressors
Abstract
A refrigeration system for use with a building. The
refrigeration system can include a plurality of refrigerated
display cases, a condenser, a liquid main and a gas main. Each
refrigerated display case can include an evaporator assembly and a
compressor assembly fluidly coupled to one another. The condenser
can be remotely located from the refrigerated display cases to
reject heat from refrigerant in the system. The liquid main can
fluidly couple an outlet of the condenser with the evaporator
assembly of each refrigerated display case, and the gas main can
fluidly couple the compressor assembly of each refrigerated display
case with an inlet of the condenser. At least a portion of each of
the liquid main and the gas main can be positioned adjacent each
refrigerated display case to allow the refrigerated display cases
to be positioned at a variety of locations within a shopping area
of the building.
Inventors: |
Shapiro; Doron; (St. Louis,
MO) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH, LLP
100 E WISCONSIN AVENUE
Suite 3300
MILWAUKEE
WI
53202
US
|
Assignee: |
Hussmann Corporation
Bridgeton
MO
|
Family ID: |
37984066 |
Appl. No.: |
11/254617 |
Filed: |
October 20, 2005 |
Current U.S.
Class: |
62/434 ;
62/246 |
Current CPC
Class: |
F25B 2400/22 20130101;
F25B 2400/075 20130101; F25B 5/02 20130101; A47F 3/04 20130101 |
Class at
Publication: |
062/434 ;
062/246 |
International
Class: |
F25D 17/02 20060101
F25D017/02; A47F 3/04 20060101 A47F003/04 |
Claims
1. A refrigeration system comprising: a plurality of refrigerated
display cases, each of the plurality of refrigerated display cases
including a dedicated evaporator assembly adapted to cool return
air from the respective refrigerated display case by at least
partially evaporating a refrigerant, and a dedicated compressor
assembly in fluid communication with the dedicated evaporator
assembly to compress evaporated refrigerant from the dedicated
evaporator assembly, the plurality of dedicated compressor
assemblies providing the only source of refrigerant compression in
the refrigeration system; a condenser located remotely from the
plurality of refrigerated display cases to reject heat from the
refrigerant to the environment a gas main fluidly coupling an
outlet of each dedicated compressor assembly to the condenser; a
liquid main fluidly coupling an outlet of the condenser to the
dedicated evaporator assembly in each of the plurality of
refrigerated display cases, the gas main and the liquid main
positioned to allow refrigerant to flow between the condenser and
the plurality of refrigerated display cases without pumping or
compressing the refrigerant as it flows from the gas main, through
the condenser, and into the liquid main.
2. The refrigeration system of claim 1, further comprising a
receiver positioned in fluid communication with the liquid main to
separate liquid and gaseous phases of the refrigerant and to supply
liquid refrigerant to each dedicated evaporator assembly.
3. The refrigeration system of claim 1, wherein each of the
refrigerated display cases includes a receiver in fluid
communication with the liquid main to separate liquid and gaseous
phases of the refrigerant and to supply liquid refrigerant to the
dedicated evaporator assembly of the same refrigerated display
case.
4. The refrigeration system of claim 1, wherein, the dedicated
compressor assembly compresses evaporated refrigerant from the
dedicated evaporator assembly of a single refrigerated display
case.
5. The refrigeration system of claim 1, wherein the plurality of
dedicated evaporator assemblies is connected to the liquid main in
parallel.
6. The refrigeration system of claim 1, wherein the plurality of
dedicated compressor assemblies is connected to the gas main in
parallel.
7. The refrigeration system of claim 1, wherein the condenser
rejects heat from the evaporated refrigerant from each of the
dedicated evaporator assemblies in the system to the
environment.
8. The refrigeration system of claim 1, wherein the dedicated
compressor assembly of each of the plurality of refrigerated
display cases is oil free.
9. The refrigeration system of claim 1, wherein the condenser
includes an air-cooled condenser.
10. The refrigeration system of claim 1, wherein the dedicated
compressor assembly in at least one of the plurality of
refrigerated display cases includes at least two compressors.
11. A refrigeration system for use with a building, the
refrigeration system comprising: a plurality of refrigerated
display cases located throughout a shopping area of the building,
each of the plurality of refrigerated display cases including an
evaporator assembly adapted to cool return air from the
refrigerated display case by at least partially evaporating a
refrigerant, a compressor assembly fluidly connected to the
evaporator assembly to compress evaporated refrigerant from the
evaporator assembly; an air-cooled condenser remotely located from
the shopping area of the building to reject heat from the
refrigerant; a liquid main fluidly connecting an outlet of the
air-cooled condenser with the evaporator assembly of each of the
plurality of refrigerated display cases, the plurality of
evaporator assemblies being connected to the liquid main in
parallel; and a gas main fluidly connecting the compressor assembly
of each of the plurality of refrigerated display cases with an
inlet of the air-cooled condenser, the plurality of compressor
assemblies being connected to the gas main in parallel, the liquid
main and the gas main each having at least a portion positioned
adjacent each of the plurality of refrigerated display cases to
allow the plurality of refrigerated display cases to be positioned
at a variety of locations within the shopping area.
12. The refrigeration system of claim 11, further comprising a
receiver in fluid communication with the outlet of the air-cooled
condenser to separate liquid and gaseous phases of the refrigerant
and direct liquid refrigerant into the liquid main.
13. The refrigeration system of claim 11, wherein the plurality of
compressor assemblies provide the sole source of compression for
the refrigeration system.
14. The refrigeration system of claim 11, wherein the compressor
assembly of each of the plurality of refrigerated display cases is
oil free.
15. The refrigeration system of claim 11, wherein: each of the
plurality of refrigerated display cases is fluidly connected to the
liquid main via a liquid branch line, each of the plurality of
refrigerated display cases is fluidly connected to the gas main via
a gas branch line, and the liquid main and the gas main are
positioned within or just outside the shopping area to minimize the
length of the liquid branch lines and the gas branch lines,
respectively.
16. The refrigeration system of claim 11, wherein the gas main and
the liquid main are positioned to allow refrigerant to flow between
the air-cooled condenser and the plurality of refrigerated display
cases without pumping or compressing the refrigerant as it flows
from the gas main, through the air-cooled condenser, and into the
liquid main.
17. A refrigeration system for use with a building the
refrigeration system comprising: a plurality of refrigerated
display cases positioned in a shopping area of the building, each
of the plurality of refrigerated display cases including a
dedicated evaporator assembly adapted to cool return air from the
respective refrigerated display case by at least partially
evaporating a refrigerant, and a dedicated compressor assembly in
fluid communication with the dedicated evaporator assembly to
compress evaporated refrigerant from the dedicated evaporator
assembly; an air-cooled condenser positioned outside of the
building, the air-cooled condenser positioned to reject heat from
the evaporated refrigerant in the system; a liquid main fluidly
connecting an outlet of the air-cooled condenser with each
dedicated evaporator assembly; and a gas main fluidly connecting an
inlet of the air-cooled condenser with each dedicated compressor
assembly, the liquid main and gas main each having at least a
portion positioned adjacent each of the plurality of refrigerated
display cases to allow the plurality of refrigerated display cases
to be connected to the liquid main and the gas main at a variety of
locations within the shopping area of the building, the liquid main
and the gas main positioned to allow refrigerant to flow between
the condenser and the plurality of refrigerated display cases
without pumping or compressing the refrigerant as it flows from the
gas main, through the air-cooled condenser, and into the liquid
main.
18. The refrigeration system of claim 17, further comprising a
receiver positioned in fluid communication with the liquid main to
separate liquid and gaseous phases of the refrigerant and supply
liquid refrigerant to each dedicated evaporator assembly.
19. The refrigeration system of claim 17, wherein the plurality of
dedicated evaporator assemblies is connected to the liquid main in
parallel.
20. The refrigeration system of claim 17, wherein the plurality of
dedicated compressor assemblies is connected to the gas main in
parallel.
21. The refrigeration system of claim 17, wherein the plurality of
dedicated compressor assemblies provide the only source of
refrigerant compression in the refrigeration system.
Description
BACKGROUND
[0001] The present invention relates to refrigeration systems. More
specifically, the present invention relates to refrigeration
systems for refrigerated display cases for displaying products in a
commercial application.
[0002] A retail store, such as a supermarket, typically contains
many refrigerated display cases for displaying and cooling food
and/or beverage items for sale. Many types of refrigerated display
cases are known in the art, and are in extensive use in retail
locations. Such refrigerated display cases require a refrigeration
system to maintain a temperature within the display case that is
lower than ambient temperature inside the store.
[0003] Refrigeration cycles are well-known in the art and generally
include an evaporator, a compressor, and a condenser. A refrigerant
fluid flows from one component to the next, exchanging heat so as
to absorb heat from a refrigerated area and reject heat at the
condenser, typically experiencing a phase change during the
cycle.
[0004] A first prior art refrigeration system 20 is shown in FIG.
1. The refrigeration system 20 includes refrigeration units 24 that
are each dedicated to a respective refrigerated display case 28.
The refrigeration unit 24 for each refrigerated display case 28
includes a compressor (not shown) and a water-cooled condenser (not
shown). The water-cooled condenser is cooled by a coolant fluid,
typically a water/glycol mixture that is provided by a closed
coolant loop 32 with associated coolant pumps 36. All the
refrigerant for the refrigeration system is contained within the
components of the refrigeration units 24, and a respective
evaporator (not shown) in each refrigerated display case 28.
Refrigerant fluid is heated and expanded in the evaporator as it
removes heat from the refrigerated display case 28. The compressor
compresses the heated refrigerant and forces it to flow to the
water-cooled condenser in the refrigeration unit 24. The
water-cooled condenser transfers heat from the refrigerant fluid to
the coolant fluid, allowing the refrigerant fluid to condense, pass
through an expansion valve, and return to the evaporator to be
heated and expanded in a cyclical manner. The coolant pumps 36 in
the closed coolant loop 32 force the cooling water/glycol mixture
to flow to the water-cooled condenser from a heat exchanger 40
(e.g., an air-cooled fluid cooler), which is typically remotely
located. At the heat exchanger 40, the coolant fluid is cooled and
then returned to the water-cooled condenser to receive heat from
the refrigerant fluid.
[0005] A second prior art refrigeration system 44 is shown in FIG.
2. Each refrigerated display case 52 includes an evaporator 56 for
removing heat from each refrigerated display case 52. Evaporated
refrigerant is routed from the evaporators 56 via a suction header
58 to a local bank of compressors 60 and then through a discharge
header 62 to a remotely located condenser 64 to be condensed.
Condensed refrigerant is routed from the condenser 64 via a liquid
header 57 to the evaporators 56. The local bank of compressors 60
is located either at the end of a group or directly atop a group of
refrigerated display cases 52 and contains several compressors
connected in parallel within a sound-attenuated casing 66. The
suction header 58 and the discharge header 62 are partially located
within the sound-attenuated casing 66. The discharge header 62
establishes fluid communication between the local bank of
compressors 60 and the condenser 64 and is not necessarily
positioned adjacent each refrigerated display case 52. Similarly,
the liquid header 57 establishes fluid communication between the
evaporators 56 and the condenser 64, and is not necessarily
positioned adjacent each refrigerated display case 52. The local
bank of compressors 60 serves to compress heated refrigerant from
several evaporators 56. The remotely located condenser 64 receives
heated refrigerant from a single local bank of compressors 60.
[0006] A third prior art refrigeration system (not shown) is
disclosed in U.S. Pat. No. 4,748,820. The third prior art
refrigeration system includes a bank of centralized compressors
located in an "equipment room" of a building, remotely located from
a group of refrigerated display cases. The bank of centralized
compressors supply compressed heated refrigerant gas via a
discharge line to a condenser typically positioned outside of the
building. From the condenser, cooled liquid refrigerant is routed
via a liquid refrigerant line to evaporators positioned within the
refrigerated display cases to cool a portion of each case. The
evaporated refrigerant gas is then routed to a local booster
compressor and then back to the bank of centralized compressors in
the equipment room via individual suction lines from each
refrigerated display case to repeat the cycle. The individual
suction lines converge prior to the bank of centralized compressors
in an interstage manifold located in the equipment room.
SUMMARY
[0007] Some embodiments of the present invention provide a
refrigeration system including a plurality of refrigerated display
cases. Each refrigerated display case can include a dedicated
evaporator assembly and a dedicated compressor assembly in fluid
communication with each other. Each dedicated evaporator assembly
can be adapted to cool return air from the respective refrigerated
display case by at least partially evaporating a refrigerant, and
each dedicated compressor assembly can compress evaporated
refrigerant from the respective dedicated evaporator assembly. The
dedicated compressor assemblies provide the only source of
refrigerant compression in the refrigeration system. The
refrigeration system can further include a gas main and a liquid
main. The gas main can fluidly couple an outlet of each dedicated
compressor assembly to a condenser, which can be remotely located
from the refrigerated display cases to reject heat from the
refrigerant to the environment. The liquid main can fluidly couple
an outlet of the condenser with each dedicated evaporator assembly.
The gas main and the liquid main can be positioned to allow
refrigerant to flow between the condenser and the plurality of
refrigerated display cases without pumping or compressing the
refrigerant as it flows from the gas main, through the condenser,
and into the liquid main.
[0008] In some embodiments of the present invention, a
refrigeration system for use with a building is provided. The
refrigeration system can include a plurality of refrigerated
display cases located in a shopping area of the building. Each
refrigerated display case can include an evaporator assembly and a
compressor assembly in fluid communication with each other. Each
evaporator assembly can cool return air from the respective
refrigerated display case by at least partially evaporating a
refrigerant. Each compressor assembly can compress evaporated
refrigerant from the respective evaporator assembly. The
refrigeration system can further include an air-cooled condenser
that can be remotely located from the shopping area of the building
to reject heat from the refrigerant. The refrigeration system can
further include a liquid main and a gas main. The liquid main can
fluidly connect an outlet of the air-cooled condenser with the
evaporator assembly of each refrigerated display case. The
plurality of evaporator assemblies can be connected to the liquid
main in parallel. The gas main can fluidly connect the compressor
assembly of each refrigerated display case with an inlet of the
air-cooled condenser. The plurality of compressor assemblies can be
connected to the gas main in parallel. At least a portion of each
of the liquid main and the gas main can be positioned adjacent each
refrigerated display case to allow the plurality of refrigerated
display cases to be positioned at various locations within the
shopping area.
[0009] Some embodiments of the present invention provide a
refrigeration system for use with a building. The refrigeration
system can include a plurality of refrigerated display cases
positioned in a shopping area of the building. Each refrigerated
display case can include a dedicated evaporator assembly and a
dedicated compressor assembly in fluid communication with each
other. The dedicated evaporator assembly can cool return air from
the respective refrigerated display case by at least partially
evaporating a refrigerant. The dedicated compressor assembly can
compress evaporated refrigerant from the respective dedicated
evaporator assembly. The refrigeration system can further include
an air-cooled condenser positioned outside of the building to
reject heat from the evaporated refrigerant in the system. The
refrigeration system can further include a liquid main and a gas
main. The liquid main can fluidly connect an outlet of the
air-cooled condenser with each dedicated evaporator assembly. The
gas main can fluidly connect each dedicated compressor assembly
with an inlet of the air-cooled condenser. At least a portion of
each of the liquid main and the gas main can be positioned adjacent
each of the refrigerated display cases to allow the plurality of
refrigerated display cases to be connected to the liquid main and
the gas main at various locations within the shopping area of the
building. The liquid main and the gas main can be positioned to
allow refrigerant to flow between the condenser and the
refrigerated display cases without pumping or compressing the
refrigerant as it flows from the gas main, through the condenser,
and into the liquid main.
[0010] Other aspects of the invention will become apparent by
consideration of the detailed description and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic view illustrating a first prior art
refrigeration system for refrigerating display cases.
[0012] FIG. 2 is a schematic view illustrating a second prior art
refrigeration system for refrigerating display cases.
[0013] FIG. 3 is a schematic view illustrating a refrigeration
system according to one embodiment of the present invention.
[0014] FIG. 4 is a detailed view of the refrigeration system of
FIG. 3.
DETAILED DESCRIPTION
[0015] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. The use of "including,"
"comprising," or "having" and variations thereof herein is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items. Unless specified or limited otherwise,
the terms "mounted," "connected," "supported," and "coupled" and
variations thereof are used broadly and encompass both direct and
indirect mountings, connections, supports, and couplings. Further,
"connected" and "coupled" are not restricted to physical or
mechanical connections or couplings.
[0016] FIG. 3 illustrates a refrigeration system 100 according to
one embodiment of the present invention for use with a building
120. As illustrated in FIG. 3, the building 120 includes a shopping
area 124. As used herein and in the appended claims, the term
"shopping area" refers to the commonly accessible area of a
supermarket where customers may browse items for sale, and
generally does not include any areas designated as equipment,
storage, or maintenance areas.
[0017] The refrigeration system 100 includes refrigerated display
cases 128. The refrigerated display cases 128 are positioned
throughout the shopping area 124 of the building 120 for housing
and displaying items to be refrigerated. The refrigeration system
100 includes a condenser 132 located outside the building 120
remote from the shopping area 124, a receiver 136, a liquid main
140, and a gas main 144. The condenser 132 may, in some
embodiments, be located inside the building 120 but remote from the
shopping area 124.
[0018] The receiver 136 is in fluid communication between the
condenser 132 and the liquid main 140, and is located substantially
near the condenser 132 outside the building 120. It should be
understood by those of ordinary skill in the art, however, that the
receiver 136 can be located anywhere along the liquid main 140
between the condenser 132 and the refrigerated display cases 128
(e.g., within the building 120) without departing from the scope of
the present invention. Some embodiments may also include individual
receivers located at each compressor unit, rather than one main
receiver. Further, In some embodiments, the refrigeration system
100 does not include a receiver.
[0019] The condenser 132 has an outlet 148 in fluid communication
with the liquid main 140. The condenser 132 also has an inlet 152
in fluid communication with the gas main 144. Each refrigerated
display case 128 is fluidly connected to the liquid main 140 via a
liquid branch line 156. The liquid branch lines 156 are fluidly
connected to the liquid main 140 in parallel with each other.
Similarly, the refrigerated display cases 128 are fluidly connected
to the gas main 144 via gas branch lines 160 in parallel with each
other.
[0020] In some embodiments, the liquid main 140 and the gas main
144 are routed throughout the building 120, such that at least a
portion of the liquid main 140 and at least a portion of the gas
main 144 are positioned adjacent each refrigerated display case 128
of the refrigeration system 100. Positioning at least a portion of
both the liquid main 140 and the gas main 144 adjacent each
refrigerated display case 128 allows the refrigerated display cases
128 to be installed at a variety of locations in the shopping area
124 by tapping into the liquid main 140 and the gas main 144 with a
pair of respective liquid and gas branch lines 156, 160. In some
embodiments, the liquid and gas mains 140, 144 may be outside the
shopping area 124 adjacent a display case 128A that is near an edge
(e.g., a wall) of the shopping area 124. In some embodiments, the
liquid and gas mains 140, 144 may extend out into the shopping area
124 adjacent each of a group of more centrally located display
cases 128B. In still other embodiments, the store may be divided
into "subloop" areas with a liquid and discharge main and
air-cooled condenser for each sub-area of the store. For example
one set of liquid and gas mains with an air-cooled condenser for
the left side of the store and a separate set of liquid and gas
mains and separate air-cooled condenser for the right side of the
store. A further embodiment may use such separate subloops for
different types of refrigerated merchandisers. For example, one set
of liquid and discharge mains for the meat area, one set for the
produce area, etc. Thus, the liquid main 140 and the gas main 144
allow the refrigerated display cases 128 to be positioned
throughout the shopping area 124 of the building 120 in a variety
of configurations, without requiring extensive routing of lengthy
individual liquid and gas branch lines 156, 160, and thereby
minimizing the length of the liquid and gas branch lines 156,
160.
[0021] The arrangement of the liquid main 140 and gas main 144
throughout the building 120 may simplify the installation procedure
of refrigerated display cases 128 or allow for the refrigerated
display cases 128 to be easily moved from one location to another
within the building 120. The liquid and gas mains 140, 144 may be
plumbed into the building 120 (e.g., under the floor or behind
walls of the shopping area 124) before any refrigerated display
cases 128 are installed. When refrigerated display cases 128 are
ready to be installed, they can be added to the refrigeration
system 100 by tapping into the liquid and gas mains 140, 144 at a
location very near the desired location for the refrigerated
display case 128. This eliminates the need for routing lengthy
liquid or gas branch lines 156, 160 between each of the
refrigerated display cases 128 and a centralized location, remote
from the shopping area 124. This also improves the modularity of
the shopping area 124, in that the refrigerated display cases 128
can be reconfigured and moved throughout the shopping area 124
without requiring the cumbersome activity of re-routing lengthy
liquid and gas branch lines 156, 160.
[0022] In the embodiment illustrated in FIG. 4, the refrigerated
display case 128 includes an evaporator assembly 164, a compressor
assembly 168, and a controller 172. (Alternate embodiments may also
include an individual receiver for each compressor unit) The
evaporator assembly 164, compressor assembly 168, and controller
172 are dedicated to operate only for the refrigerated display case
128. Specifically, a dedicated compressor assembly will only
compress refrigerant received from an evaporator assembly of one
refrigerated display case. The evaporator assembly 164 can include
one or more evaporators 173 to meet the cooling requirements of the
refrigerated display case 128. Similarly, the compressor assembly
168 can contain multiple dedicated compressors 174. By way of
example only, the illustrated refrigerated display case 128
includes a compressor assembly 168 having two parallel dedicated
compressors 174, and an evaporator assembly 164 having a single
evaporator 173.
[0023] The liquid branch line 156 connects the liquid main 140 to a
refrigerant inlet 176 of the evaporator assembly 164. Prior to
entering the evaporator assembly 164, the refrigerant will pass
through an expansion valve (not shown). In some embodiments, the
refrigerant passes through a liquid subcooler which cools the
liquid prior to entering the expansion valve. A refrigerant outlet
180 of the evaporator assembly 164 is fluidly connected to an inlet
184 of the compressor assembly 168. In the illustrated embodiment,
the evaporator assembly 164 includes a single dedicated evaporator
173. In embodiments employing more than one evaporator, the
evaporators of the evaporator assembly 164 can be connected in
parallel or series between the liquid branch line 156 and the inlet
184 of the compressor assembly 168.
[0024] The evaporator assembly 164 is located such that air passing
through the evaporator assembly 164 is discharged to a refrigerated
area 198 of the refrigerated display case 128.
[0025] The gas branch line 160 connects an outlet 188 of the
compressor assembly 168 to the gas main 144. The controller 172 in
the refrigerated display case 128 is electrically coupled to the
compressor assembly 168. For example, in some embodiments, one or
more of the dedicated compressors 174 has a variable capacity. The
controller 172 can be electrically coupled to the compressor
assembly 168 to modulate the capacity of the variable capacity
compressor(s) 174 by adjusting, for example, piston stroke or
speed. In such embodiments, the controller 172 can include
automatic feedback control and/or can accept user input (e.g., from
a keypad, a remote control, etc.). In some embodiments, the
controller 172 may be located outside the refrigerated display case
128. In still other embodiments, one controller may serve more then
one display case and compressor unit.
[0026] Refrigerant flows, in liquid phase, from the receiver 136 to
the evaporator assembly 164. At the evaporator assembly 164, heat
is transferred from relatively warm air in the refrigerated area
198 to relatively cool liquid refrigerant, causing the refrigerant
to evaporate into a gas phase. The gaseous refrigerant is
compressed in the compressor assembly 168 as it flows out of the
refrigerated display case 128 to the gas main 144 via the gas
branch line 160. The gas main 144 carries the refrigerant to the
condenser 132.
[0027] As shown in FIG. 3, the condenser 132 is air-cooled. A fan
199 forces cooling air across the condenser 132 to cool the
refrigerant at least partially back to a liquid phase. The receiver
136 separates the liquid and gaseous phases of the refrigerant and
supplies substantially liquid refrigerant to the liquid main 140.
In some embodiments of the present invention, the condenser 132 is
the sole source of heat rejection from the refrigerant in the
refrigeration system 100. In other embodiments, a water cooled
condenser, or evaporative condenser may be used.
[0028] As shown in FIG. 4, the compressor assembly 168 for each
respective refrigerated display case 128 is located within the
refrigerated display case 128. In some embodiments, the compressor
assembly 168 for each respective refrigerated display case 128 is
located adjacent the refrigerated display case 128. In some
embodiments, the compressor assembly 168 and the controller 172 are
positioned adjacent the refrigerated display case 128 in a separate
enclosure. In some embodiments, the compressor assembly 168 and the
controller 172 can be positioned directly adjacent an outer wall of
the refrigerated display case 128.
[0029] In some embodiments, the multiple dedicated compressors 174
located within the compressor assembly 168 (in or adjacent each
respective refrigerated display case 128) are the sole means for
compressing refrigerant in the refrigeration system 100. This
provides a flow path including the gas main, the condenser, and the
liquid main, in which there are no active means for pumping or
compressing the refrigerant. In some embodiments, the multiple
dedicated compressors 174 are oil free thereby doing away with oil
distribution sub-systems and necessary controls.
[0030] In some embodiments, multiple dedicated compressors 174 are
dedicated to the refrigerated display case 128. It should be
understood by those skilled in the art that multiple dedicated
compressors 174 may be arranged in a variety of arrangements (e.g.,
parallel, series, back-up, etc.) while remaining within the scope
of the present invention. When multiple dedicated compressors 174
are used, the multiple compressors 174 can be positioned within the
refrigerated display case 128, adjacent the refrigerated display
case 128, or combinations thereof.
[0031] Various features and aspects of the invention are set forth
in the following claims.
* * * * *