US20040031280A1

US20040031280A1 - Refrigeration system

Info

Publication number: US20040031280A1
Application number: US10/218,822
Authority: US
Inventors: Jon Martin; Timothy Swofford; Walter Emerson
Original assignee: Delaware Capital Formation Inc
Current assignee: Dover Systems Inc
Priority date: 2002-08-14
Filing date: 2002-08-14
Publication date: 2004-02-19

Abstract

A distributed refrigeration system has a temperature controlled case configured to store and display objects in a facility, a first coolant adapted to cool the objects and circulate through a first cooling system configured to operate with the case, and a second cooling system communicating with the first cooling system to receive a second coolant for removing heat from the first coolant. A method of providing a distributed refrigeration system for delivery to a facility includes providing a temperature-controlled case to store and display objects within a facility, assembling a self-contained first cooling system with the case to circulate a first coolant to cool the objects, and providing a second cooling system communicating with the first cooling system, the second cooling system having a supply connection and a return connection to circulate a second coolant to remove heat from the first coolant.

Description

FIELD OF THE INVENTION

The present invention relates to a refrigeration system. The present invention relates more particularly to a distributed refrigeration system.

BACKGROUND

It is generally known to provide refrigeration systems for commercial or institutional food sales or food service facilities such as supermarkets, grocery stores, cafeterias, etc. These refrigeration systems operate with refrigeration or cooling devices such as temperature controlled cases (individually or in groups) that use air-cooled or water-cooled condensers supplied by a rack of compressors. For example, modern supermarket applications typically have many individual or grouped refrigeration devices located throughout the shopping or display area of the supermarket. Each refrigeration device is provided with a cooling interface such as an evaporator or cooling coil that receives refrigerant from the refrigeration system in a closed loop configuration where the refrigerant is expanded to a low pressure and temperature state for circulation through the cooling interface to cool the space and objects within the refrigeration device. In such applications, one or more condensers are typically located either outside, on the roof, or in a machine room or back room adjacent to the shopping or display area where the refrigeration devices are located and are used to cool the refrigerant that is distributed to all or a group of these refrigeration devices.

In such known refrigeration systems, extensive networks of refrigerant piping are often required to interconnect the remotely located condensers to the cooling interfaces of the various refrigeration devices. These networks of refrigerant piping are often expensive to construct and maintain and are usually coordinated with the construction of the facility since the piping is often insulated and concealed by routing through the floors, ceilings, or walls of the facility to avoid exposure within the shopping area of the facility. Such known systems require numerous joints and other connections that are typically field run, installed and tested, and are subject to potential leakage concerns. Such extensive networks of refrigerant piping also require large quantities of refrigerant that must be charged after piping installation in order to properly operate in a closed loop manner over the extended distances of the network. Generally, the longer the piping network, the more refrigerant required and the greater the potential for leakage which creates adverse environmental concerns within the facilities. The concealed nature of the networks provides further difficulty in maintaining the systems due to the difficulty of locating, accessing and repairing piping leaks. Such refrigerant networks also complicate replacement and relocation of the refrigeration devices within the facility due to the substantially permanent routing of the refrigerant piping and its integration within the facility.

Efforts have previously been made to address these deficiencies. For example, modular refrigeration systems are generally known, such as those described in U.S. Pat. No. 5,743,102 titled “Strategic Modular Secondary Refrigeration” issued on Apr. 28, 1998. Such modular systems typically provide a single rack unit having compressors and a condenser having a smaller piping network for connection to a group of refrigeration devices (for example, five (5) or six (6) located in a particular zone of the facility). In such modular systems, a secondary coolant may be circulated through a second, non-refrigerant piping system having a coolant such as water or a propylene glycol mixture to transfer heat from the local condenser to a remotely located chiller unit. Such known modular refrigeration systems also require field run and assembled refrigerant piping along with the corresponding additional fittings and connections necessary for supplying multiple refrigeration devices. Further, such conventional and modular systems often require separately wiring the various components of the refrigeration device upon installation in the facility, such as wiring for compressor power, control devices, lights, electric defrosting heaters, etc. As recognized in the 5,743,102 patent, it generally has not been considered feasible to provide self-contained refrigerated devices or merchandisers for stand-alone operation in a supermarket or other setting for reasons, among others, including high cost, low energy efficiency, and an unacceptably high noise volume from the compressors.

Accordingly, it would be advantageous to provide a distributed refrigeration system having a stand-alone refrigeration device with a self-contained refrigeration system that is suitably efficient for commercial viability. It would be further advantageous to provide a distributed refrigeration system having a sufficiently low noise level for use in supermarkets or other consumer-oriented facilities. It would also be advantageous to provide a distributed refrigeration system that reduces the amount of refrigerant and refrigerant piping within a facility to reduce environmental hazards and to reduce installation costs, complexity, maintenance and repair time. It would also be advantageous to provide a distributed refrigeration system having a refrigerant piping system limited to a particular refrigeration device and capable of having all refrigerant piping installation and connections made and pre-charged in a factory setting to minimize installation time and complexity, and to improve flexibility in retrofit applications. It would be further advantageous to provide a distributed refrigeration system having a central electrical unit in which all electrical functions of the distributed refrigeration unit are pre-wired at the factory and require only a single electrical power hook up when installed at a facility.

Accordingly, it would be advantageous to provide a distributed refrigeration system having any one or more of these or other advantageous features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a conventional refrigeration system. [0007]
FIG. 2 is a schematic diagram of a distributed refrigeration system according to a preferred embodiment. [0008]
FIG. 3A is a perspective view of a refrigeration device for a distributed refrigeration system according to a preferred embodiment. [0009]
FIG. 3B is a side view of a refrigeration device for a distributed refrigeration system according to a preferred embodiment. [0010]
FIG. 4 is a perspective view of a portion of a refrigeration device for a distributed refrigeration system according to a preferred embodiment. [0011]
FIG. 5 is a schematic view of an electrical and control system for a distributed refrigeration system.[0012]

SUMMARY

The present invention relates to a distributed refrigeration system and includes a temperature-controlled case configured to store and display objects in a facility, a first coolant adapted to cool the objects and circulate through a first cooling system configured to operate with the temperature controlled case, and a second cooling system in thermal communication with the first cooling system, where the second cooling system is adapted to receive a second coolant for removing heat from the first coolant. [0013]
The present invention also relates to a method of providing a distributed refrigeration system for delivery to a facility and includes providing a temperature controlled case adapted to store and display objects within a facility, assembling a self-contained first cooling system with the temperature controlled case, the first cooling system adapted to circulate a first coolant to cool the objects, and providing a second cooling system in thermal communication with the first cooling system, where the second cooling system has a supply connection and a return connection to circulate a second coolant to remove heat from the first coolant. [0014]
The present invention further relates to a stand-alone temperature controlled case for a supermarket and includes an enclosure for storing and displaying objects, a self-contained first cooling system having a first coolant, where the first cooling system is coupled to the enclosure and adapted for exclusive use with the enclosure, and a second cooling system coupled in thermal communication to the first cooling system and adapted to receive a second coolant from a second coolant supply source for removing heat from the first coolant. [0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a conventional supermarket refrigeration system is shown. As previously discussed, it is conventional practice to place the [0016] compressors 10 and the condenser 12 in a location remote from the refrigeration or cooling devices 16. In this conventional arrangement, the compressors 10 are configured in a parallel bank located in an equipment room or on the roof or other remote area of the facility separate from the shopping or display area. The compressors supply a relatively large condenser 12, which may be air or water cooled. The condenser 12 supplies liquid refrigerant to a receiver 14, which provides a condensed refrigerant reservoir for supplying liquid refrigerant to the individual refrigeration devices located throughout a shopping or display area within the facility through a refrigerant piping supply network 20. The refrigerant is expanded in an expansion device (not shown) and directed through an evaporator 18 in each of the refrigeration devices 16, where the refrigerant vaporizes as it receives heat from the space and any objects within the refrigeration device. The compressors extract the refrigerant vapor by suction through a refrigerant return piping network 22, and compress the refrigerant back to a liquid state where it is then cooled in condenser 12, whereupon the cycle continues. The refrigerant supply and return piping networks 20, 22 are field-run and often routed at least partially through concealed areas of the facility such as floors, walls, ceilings, etc. and have numerous joints, couplings, fittings and other connections (not shown).
Referring to FIG. 2, a distributed refrigeration system is shown according to a preferred embodiment. Distributed [0017] refrigeration system 30 may be provided for a single cooling device 32 or may include multiple cooling devices or temperature controlled cases (shown schematically as a low temperature cooling device 34 such as a freezer unit and a medium temperature cooling device 36 such a refrigeration unit) located in a shopping or display area 52 of a facility 50 (e.g. supermarket, grocery store, hotel, restaurant, cafeteria, etc.). In a particularly preferred embodiment, each cooling device includes an enclosure for storing or displaying objects in a spaced that is cooled by a direct expansion refrigeration system having an expansion device 38, a cooling interface 40 (e.g. heat exchanger, evaporator, platform with coolant flow passages, etc.) a compressor 42, and a condenser 44. The refrigeration system is provided as a self-contained unit for exclusive use with a particular cooling device 32, where cooling interface 40 and expansion device 38 are provided within cooling device 32 and compressor 42 and condenser 44 are mounted on or externally to cooling device 32 (shown schematically, for example, as mounted on a top portion of the cooling device). The condenser of cooling device 32 is cooled by a secondary coolant loop 60 using a liquid coolant, such as mixture of water and inhibited propylene glycol. The secondary coolant loop 60 communicates with a remotely located cooling device, shown schematically as a chiller 62, located away from the cooling devices in a remote area 54 (e.g. equipment room, machine room, roof top, etc.). An electrical system, as shown in FIG. 5, is provided to operate and control the various electrical components of the distributed refrigeration system and includes, among others, a controller, solenoid valves, temperature sensors, switches, compressor motor and control relays and contactors, cabinet lighting within the cooled space of the cooling device, timers, fan motors and control switches, anti-sweat heaters and electric defrost heating elements. In an alternative embodiment, the compressor and condenser may be mounted in a lower portion of the cooling device, such as on a slide-out unit for ease of access and maintenance.
Referring to FIGS. 2, 3A and [0018] 3B, the refrigeration system 30 is provided as a self-contained unit for exclusive use with each cooling device. The expansion device 38 and cooling interface 40 may be located in any advantageous location within cooling device 32 for communication with the space and objects or products (not shown) to be cooled and the compressor 42 and condenser 44 are provided in a location that does not interfere with the space or cooling functions of cooling device 32. In a particularly preferred embodiment, the expansion device 38 and cooling interface 40 are located in a lower portion of cooling device 32 and compressor 42 and condenser 44 are located on a top panel 46 of cooling device 32. Fans (not shown) may be provided near cooling interface 40 to distribute cooled air from cooling interface 40 within cooling device 32. The expansion device 38, cooling interface 40, compressor 42 and condenser 44 are interconnected in a closed loop configuration by a local refrigerant piping system 48 to form a primary cooling loop. In a particularly preferred embodiment, the expansion device 38, cooling interface 40, compressor 42 and condenser 44 and piping system 48 are pre-assembled and installed on cooling device 32 in a factory setting for shipment as a stand-alone unit to facility 50. In an alternative embodiment, the cooling system components and piping may be custom configured and installed at the facility to suit customer preferences.
The refrigerant piping system contained locally at the refrigeration system minimizes the amount of refrigerant piping and corresponding refrigerant required to operate the [0019] cooling device 32, and minimizes the number of joints or connections in piping system 48. Further, the ability to pre-assemble, pre-test and pre-charge the relatively smaller piping system 48 and components in a factory setting tends to improve the quality and integrity of the joints to minimize future potential refrigerant leakage. The location of the refrigerant piping solely at cooling device 32 also helps to improve the ability to locate any leakage that may develop within piping system 48 and the accessibility of the piping improves the ability to repair such local leakage quickly and cost-effectively. In conventional back-room or modular refrigeration piping networks the amount of refrigerant necessary to charge and operate the systems is substantially greater than the amount of refrigerant required by the distributed refrigeration system. Accordingly, substantial leakage in conventional systems may occur before being detected, whereas the smaller amount of refrigerant used by the distributed refrigeration system results in both a smaller quantity of refrigerant available for loss by leakage and the may increase the likelihood that leakage would be more readily detectable due to its more rapid impact on the performance of cooling device 32, thereby reducing the effects of any leakage associated with the distributed refrigeration system.
Referring further to FIG. 2, the [0020] compressors 42 at both the low temperature cooling device 34 and the medium temperature cooling device 36 are each sized correspondingly smaller than compressors used with conventional back-rom or modular systems due to the reduced cooling demand dictated by the standalone nature of the distributed refrigeration system. Such smaller compressor sizes may operate at lower efficiencies than the larger compressors of the more conventional systems. However, the smaller compressors 42 of the distributed refrigeration system are capable of operating with a lower refrigerant condensing temperature than the refrigerant condensing temperatures of the conventional systems. In a particularly preferred embodiment, the refrigerant condensing temperature at condenser 44 is in the range of approximately fifty (50) degrees F. to sixty (60) degrees F. (however, other suitable temperature ranges may be used in alternative embodiments). This lower condensing temperature, relative to conventional systems, provides for the use of relatively warmer secondary coolant temperatures at the condenser than are typically considered feasible for conventional low temperature refrigeration devices. In a particularly preferred embodiment, the lower refrigerant condensing temperature associated with the smaller compressor size of the distributed refrigeration system corresponds to a secondary coolant temperature (supplied by another cooling device, such as chiller 62) at the condenser 44 in the range of approximately twenty (20) degrees F. to fifty (50) degrees F. (however, other suitable temperature ranges may be used in alternative embodiments). This temperature requirement is within the operational range of conventional water-glycol solutions for applications below thirty (30) degrees F. and conventional water coolant for applications above thirty (30) degrees F. to provide an alternative to the use of chemicals such as potassium acetate or potassium formate that are often required in conventional systems having lower coolant temperature design requirements. The chiller may be an existing chiller already existing at the facility for use with medium temperature units, or alternatively, may be a custom-sized chiller designed for use with multiple distributed refrigeration systems intended for use at the facility.
In a particularly preferred embodiment, [0021] condenser 44 is a shell and coil type condenser that reduces the required amount of refrigerant charge and the amount of refrigerant flashing, and also preferably avoids the need for a receiver. Since refrigerant contained in the receiver of a conventional system tends to gain heat from the surrounding ambient environment, the additional heat tends to reduce the efficiency of conventional systems. Accordingly, in a particularly preferred embodiment, the absence of a receiver from the distributed refrigeration system tends to improve the comparative efficiency of the distributed refrigeration system. In addition, the lower condensing temperature of the distributed refrigeration system provides efficiency gains over the conventional systems having higher condensing temperatures. These collective efficiency gains help to offset efficiency losses that may result from the use of a relatively smaller compressor 42 in the distributed refrigeration system.
Referring further to FIG. 2, the [0022] secondary coolant system 60 for the distributed refrigeration system is shown according to a preferred embodiment. Secondary cooling system 60 includes chiller 62, which is shown located away from the shopping or display area 52, such as in a remote area 54, such as an equipment room, machine room, roof top location or other convenient location. The chiller 62 provides a source of chilled coolant to remove the heat load from condenser 44 at cooling device 32. The secondary cooling loop 60 has a supply side 64 and a return side 66. The supply and return side may have a single branch directing secondary coolant to and from a single cooling device, or may have multiple parallel branches for directing secondary coolant to multiple cooling devices (shown schematically for example as two branches and refrigeration devices in FIG. 2). The branch lines may be routed to the distributed refrigeration system in any convenient manner and connected to corresponding inlet location 45 and outlet location 47 (shown schematically on FIG. 4) to condenser 44. In a particularly preferred embodiment, flexible hoses are used to connect the secondary coolant supply and return lines to the inlet and outlet of condenser 44. Accordingly, the distributed refrigeration system provides a self-contained direct expansion refrigeration system in a stand-alone cooling device that may be located at any convenient location within a facility and requires only the routing of a secondary coolant supply and return line to the condenser and connection of electrical power. In an alternative embodiment, conventional piping (e.g. copper, PVC, etc.) may be used in place of the flexible hoses to connect the secondary coolant supply and return lines to the inlet and outlet of condenser.
Referring to FIG. 4, the condenser and compressor assembly for the distributed refrigeration system is shown according to a preferred embodiment. In a particularly preferred embodiment, [0023] compressor 42 is a semi-hermetic type compressor such as those commercially available from Copeland Corporation of Sidney, Ohio. The compressor 42 provides a suction source for removing the refrigerant from cooling interface 40. The compressor 42 includes a high pressure switch 86 and a low pressure switch 88 (shown schematically in FIG. 5) that operate to stop compressor 42 when the refrigerant pressure is above a predetermined set point indicative of an overload condition, and when the refrigerant pressure is below another predetermined set point indicative of a vacuum condition. The condenser 44 is preferably a shell and coil type condenser such as those commercially available from the Standard Refrigeration Company of Melrose Park, Ill. The condenser 44 cools the compressed refrigerant to a temperature within the range of approximately forty-five (45) to fifty (50) degrees F. A regulating valve 68 senses the pressure of the refrigerant in the compressor and regulates the secondary coolant flow through condenser 44 according to compressor demand to maintain the condensed refrigerant within the desired temperature range. In a particularly preferred embodiment, valve 68 is a pressure actuated coolant regulating valve, model V46AC-1 of a type commercially available from Penn/Johnson Controls. A compressor refrigerant suction valve 84 (such as a manual shut-off valve) is provided for use in activities such as charging the refrigerant piping system 48. In an alternative embodiment, a balancing valve may be used to control the coolant flow. In other alternative embodiments, other components or component types such as a scroll-type compressor, or other condensed refrigerant temperature ranges may be used having suitable characteristics for operating as a stand-alone distributed refrigeration system.
Referring to FIG. 5, the electrical and control system components of the distributed refrigeration system are shown according to a preferred embodiment. Electrical and [0024] control system 70 includes compressor motor controls, relays, switches, contactors, transformers, defrost devices (e.g. electric heating elements, etc.), lights, compressor motor wiring, solenoid valves, sensors, etc. In a particularly preferred embodiment, the electrical and control system components are pre-wired in a central electrical and control unit configured for a single electrical power supply connection during installation at the facility. The electrical system may be configured to receive any conventional power supply at a facility such as 208 volt, three (3) phase electrical power. In an alternative embodiment, the electrical and control components may be individually connected or wired during installation at the facility to suit customer preference. The electrical and control system 70 includes an electrical system 72 having a central electrical unit 74 that receives a source of electrical power from a conventional electrical power source at facility 50. Central electrical unit 74 includes the necessary conventional distribution and switching apparatus, such as transformers, breakers, contactors, switches, relays, overload protectors, etc. of a standard and commercially available type for operating the motors associated with compressor 44 and the fan 76, the defrosting elements 78, cooling device case lights 80, the anti-sweat heaters 82 and the compressor high and low temperature switches 86 and 88. Anti-sweat heaters 82 may be provided on any surface of the low temperature cooling device 34 or medium temperature cooling device 36 that may be subject to condensation, including, but not limited to, doors, windows, walls, panels, air-flow ducts, housings, etc. In an alternative embodiment, the compressor motor may be supplied by a separate power supply and may also be provided with a separate compressor control module including devices such as contactors, etc. for operation of the compressor motor. The compressor control module may be separately mounted or may be included as a component within the central electrical unit.
Referring further to FIG. 5, the electrical and [0025] control system 70 also includes a control system 100 for controlling the operation of cooling device 32. Control system 100 has a control module 102 that receives electrical power from central electrical unit 74. In a particularly preferred embodiment, control module 102 includes a microprocessor having software that may be custom developed in-house or may be commercially developed according to specifications by a commercial supplier such as Danfoss Inc. of Baltimore, Md. A variety of sensors may be provided with the distributed refrigeration system including, among others, a cooling interface inlet air temperature sensor 110, a cooling interface outlet air temperature sensor 112, a cooling interface surface temperature sensor 114, cooling interface refrigerant pressure sensor 116, a simulated product temperature sensor 118, and a cooling device air temperature sensor 120. Sensors 110, 112, 114, 118 and 120 may be thermocouples, thermistors or resistance temperature devices (RTDs) and suited for use with control system 100. The simulated product temperature sensor 118 is provided in a material having the typical mass and thermal inertia characteristics of the products intended for storage or display in cooling device 32 and may be used during either or both of initial testing operation or commercial operation to provide an indication of actual product temperature within cooling device 32. In a particularly preferred embodiment, control module 102 receives a signal representative of temperature from one or more of sensors 110, 112, 114, 118 and 120 and provides an output signal to control operation of compressor 42, fan 76 and defrosting elements 78. Control system 100 includes a timer 104 for initiating a defrost mode of operation on a predetermined frequency (e.g. once per day) where the electric defrosting heater elements 78 are energized and compressor 42 is temporarily stopped. The duration of the defrost mode of operation is terminated by either of a signal representative of defrosted condition temperature from cooling interface surface temperature sensor 114 or on a predetermined elapsed shut-off time from timer 104 which acts as a backup device to reinitiate the cooling mode of operation (e.g. by shutting off electric defrost heaters 78 and restarting compressor 42) in the event of failure of sensor 114. In an alternative embodiment, the control module software may be developed in-house and the control module may be configured to receive and send other control signals to control the operation of the distributed refrigeration system. In another alternative embodiment, the defrost mode of operation may be initiated without the use of a timer and may be based upon a signal representative of refrigerant pressure within the cooling interface. In a further alternative embodiment, the defrost mode may be controlled by any of the sensors that provide an indication of the cooling performance of the cooling interface.
According to any preferred embodiment, the distributed refrigeration system provides a stand-alone cooling device with a self-contained refrigeration system that is intended to reduce installation time, ownership costs and improve retrofitting flexibility by providing a pre-assembled unit that eliminates the need for a refrigerant piping network external to the cooling device and the corresponding additional amount of refrigerant necessary in such conventional systems with refrigerant networks. The distributed refrigeration system also gains efficiency from avoidance of a receiver and by using lower condensing temperatures compared to conventional supermarket refrigeration systems. The distributed refrigeration system further minimizes the potential for future refrigerant leakage by providing factory installed piping and connections and piping leakage detection and repair is more readily addressed by the location, limitation and accessibility of the refrigerant piping. The distributed refrigerant system also provides for multiple cooling devices having different temperature applications (e.g. low temperature and medium temperature devices) to be cooled by a common secondary coolant and chiller loop. [0026]
According to alternative embodiments, the distributed refrigeration system may include a medium temperature cooling device such as a refrigerator, a cold storage room, etc. of a low temperature cooling device such as a freezer case, walk-in freezer, etc. In further alternative embodiments, the cooling system may be an open storage or display device such as “reach-in” coolers that may have a fan, airflow passages or other devices for creating an “air curtain” of cooled air that creates a boundary between warmer ambient air and the cooled space in which the objects are stored and/or displayed. [0027]
It is important to note that the construction and arrangement of the elements of the distributed refrigeration system provided herein are illustrative only. Although only a few exemplary embodiments of the present invention have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible in these embodiments (such as variations in features such as components, coolant compositions, heat removal sources, defrosting devices, orientation and configuration cooling interfaces, location of components and sensors of the cooling and control systems; variations in sizes, structures, shapes, dimensions and proportions of the components of the system, use of materials, colors, combinations of shapes, etc.) without materially departing from the novel teachings and advantages of the invention. For example, closed or open space refrigeration systems may be used having either horizontal or vertical access openings, and cooling interfaces may be provided in any number, size, orientation and arrangement to suit a particular refrigeration system. According to other alternative embodiments, the distributed refrigeration system may be used with any cooling device using a direct expansion refrigerant or other coolant for transferring heat from one space to be cooled to another space or source designed to receive the rejected heat and may include commercial, institutional or industrial refrigeration devices. According to further alternative embodiments, the defrosting of the cooling interface may be provided by warm air circulation, hot gas (i.e. refrigerant) circulation, or circulation of a liquid coolant. Further, it is readily apparent that variations of the distributed refrigeration system and its components and elements may be provided in a wide variety of types, shapes, sizes and performance characteristics, or provided in locations external or partially external to the refrigeration system. Accordingly, all such modifications are intended to be within the scope of the inventions. [0028]
The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the inventions as expressed in the appended claims. [0029]

Claims

What is claimed is:

1. A distributed refrigeration system, comprising:

a temperature controlled case configured to store and display objects in a facility;

a first coolant adapted to cool the objects and circulate through a first cooling system configured to operate with the temperature controlled case; and

a second cooling system in thermal communication with the first cooling system, the second cooling system adapted to receive a second coolant for removing heat from the first coolant.

2. The distributed refrigeration of claim 1, wherein the facility is one of a supermarket, grocery store, convenience store, cafeteria, hotel or restaurant.

3. The distributed refrigeration system of claim 1, wherein the first coolant is a vapor expansion refrigerant and the second coolant is one of water and a solution of water and propylene glycol.

4. The distributed refrigeration system of claim 1, wherein the first cooling system is a vapor expansion refrigeration system configured to operate exclusively with the temperature controlled case.

5. The distributed refrigeration system of claim 4, wherein the first cooling system is a closed loop system coupled to the temperature controlled case in a stand-alone configuration.

6. The distributed refrigeration system of claim 5, wherein the first cooling system is pre-assembled with the temperature controlled case for delivery to the facility.

7. The distributed refrigeration system of claim 6, wherein the first cooling system is pre-charged and pre-tested for delivery to the facility.

8. The distributed refrigeration system of claim 1, further comprising a central electrical unit coupled to the temperature controlled case and adapted to receive a single electrical supply connection at the facility.

9. The distributed refrigeration system of claim 1, wherein the secondary cooling system further comprises a supply connection and a return connection adapted to couple the secondary cooling system to a secondary coolant supply source at the facility.

10. The distributed refrigeration system of claim 9, wherein the supply connection and the return connection are flexible hoses.

11. The distributed refrigeration system of claim 3, wherein the first cooling system includes a compressor, a condenser, an expansion device and a cooling interface.

12. The distributed refrigeration system of claim 11, wherein the refrigerant has a condensing temperature in the condenser generally within the range of fifty degrees F. to sixty degrees F.

13. The distributed refrigeration system of claim 12, wherein the second coolant has a supply temperature at the condenser generally within the range of twenty degrees F. to fifty degrees F.

14. A method of providing a distributed refrigeration system for delivery to a facility, comprising:

providing a temperature controlled case adapted to store and display objects within a facility;

assembling a self-contained first cooling system with the temperature controlled case, the first cooling system adapted to circulate a first coolant to cool the objects; and

providing a second cooling system in thermal communication with the first cooling system, the second cooling system having a supply connection and a return connection adapted to circulate a second coolant to remove heat from the first coolant.

15. The method of claim 14, wherein the facility is one of a supermarket, grocery store, convenience store, cafeteria, hotel or restaurant.

16. The method of claim 14, further comprising providing a control system to regulate operation of the temperature controlled case in an operating mode and a defrost mode.

17. The method of claim 14, further comprising pre-testing the first coolant system.

18. The method of claim 14, wherein the first coolant is a refrigerant and pre-charging the first cooling system with the refrigerant.

19. The method of claim 14, further comprising providing a central electrical unit that is pre-wired to the temperature controlled case and to the first coolant system and adapted to receive an electrical supply connection at the facility.

20. The method of claim 15, wherein the second coolant is a propylene glycol solution provided by a second coolant supply at the facility.

21. A stand-alone temperature controlled case for a supermarket, comprising:

an enclosure for storing and displaying objects;

a self-contained first cooling system having a first coolant, the first cooling system coupled to the enclosure and adapted for exclusive use with the enclosure; and

a second cooling system coupled in thermal communication to the first cooling system and adapted to receive a second coolant from a second coolant supply source for removing heat from the first coolant.

22. The stand-alone temperature controlled case of claim 21, further comprising a central electrical unit coupled to the enclosure and adapted to receive a single electrical connection at the supermarket.

23. The stand-alone temperature controlled case of claim 21, wherein the first cooling system includes a compressor and a condenser.

24. The stand-alone temperature controlled case of claim 23, wherein the compressor is a semi-hermetic compressor and the condenser is a shell-and-coil type condenser.

25. The stand-alone temperature controlled case of claim 21, wherein the first cooling system is pre-assembled and pre-tested in a factory.

26. The stand-alone temperature controlled case of claim 23, wherein the first coolant is a vapor-expansion refrigerant having a condensing temperature in the condenser generally in the range of fifty degrees F. to sixty degrees F.

27. The stand-alone temperature controlled case of claim 21, wherein the second coolant is a propylene glycol solution having a supply temperature at the condenser generally within the range of twenty degrees F. to forty-five degrees F.