US20070089453A1

US20070089453A1 - Refrigeration system with distributed compressors

Info

Publication number: US20070089453A1
Application number: US11/254,617
Authority: US
Inventors: Doron Shapiro
Original assignee: Hussmann Corp
Current assignee: Hussmann Corp
Priority date: 2005-10-20
Filing date: 2005-10-20
Publication date: 2007-04-26

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.

Description

BACKGROUND

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.
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.
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.
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.
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.
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

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.
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.
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.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a first prior art refrigeration system for refrigerating display cases.
FIG. 2 is a schematic view illustrating a second prior art refrigeration system for refrigerating display cases.
FIG. 3 is a schematic view illustrating a refrigeration system according to one embodiment of the present invention.
FIG. 4 is a detailed view of the refrigeration system of FIG. 3.

DETAILED DESCRIPTION

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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Various features and aspects of the invention are set forth in the following claims.

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 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.