U.S. patent application number 10/218822 was filed with the patent office on 2004-02-19 for refrigeration system.
This patent application is currently assigned to Delaware Capital Formation, Inc.. Invention is credited to Emerson, Walter H., Martin, Jon Scott, Swofford, Timothy D..
Application Number | 20040031280 10/218822 |
Document ID | / |
Family ID | 31714614 |
Filed Date | 2004-02-19 |
United States Patent
Application |
20040031280 |
Kind Code |
A1 |
Martin, Jon Scott ; et
al. |
February 19, 2004 |
Refrigeration system
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.
Inventors: |
Martin, Jon Scott; (Conyers,
GA) ; Swofford, Timothy D.; (Mechanicsville, VA)
; Emerson, Walter H.; (Mechanicsville, VA) |
Correspondence
Address: |
FOLEY & LARDNER
777 EAST WISCONSIN AVENUE
SUITE 3800
MILWAUKEE
WI
53202-5308
US
|
Assignee: |
Delaware Capital Formation,
Inc.
|
Family ID: |
31714614 |
Appl. No.: |
10/218822 |
Filed: |
August 14, 2002 |
Current U.S.
Class: |
62/246 ; 62/333;
62/434 |
Current CPC
Class: |
F25B 7/00 20130101; A47F
3/0482 20130101; F25B 2400/22 20130101; F25B 25/005 20130101 |
Class at
Publication: |
62/246 ; 62/333;
62/434 |
International
Class: |
A47F 003/04; F25D
017/00; F25D 017/02 |
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.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a refrigeration system. The
present invention relates more particularly to a distributed
refrigeration system.
BACKGROUND
[0002] 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.
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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
[0007] FIG. 1 is a schematic diagram of a conventional
refrigeration system.
[0008] FIG. 2 is a schematic diagram of a distributed refrigeration
system according to a preferred embodiment.
[0009] FIG. 3A is a perspective view of a refrigeration device for
a distributed refrigeration system according to a preferred
embodiment.
[0010] FIG. 3B is a side view of a refrigeration device for a
distributed refrigeration system according to a preferred
embodiment.
[0011] FIG. 4 is a perspective view of a portion of a refrigeration
device for a distributed refrigeration system according to a
preferred embodiment.
[0012] FIG. 5 is a schematic view of an electrical and control
system for a distributed refrigeration system.
SUMMARY
[0013] 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.
[0014] 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.
[0015] 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.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Referring to FIG. 1, a conventional supermarket
refrigeration system is shown. As previously discussed, it is
conventional practice to place the 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).
[0017] Referring to FIG. 2, a distributed refrigeration system is
shown according to a preferred embodiment. Distributed
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.
[0018] Referring to FIGS. 2, 3A and 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.
[0019] The refrigerant piping system contained locally at the
refrigeration system minimizes the amount of refrigerant piping and
corresponding refrigerant required to operate the 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.
[0020] Referring further to FIG. 2, the 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.
[0021] In a particularly preferred embodiment, 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.
[0022] Referring further to FIG. 2, the 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.
[0023] 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,
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.
[0024] Referring to FIG. 5, the electrical and control system
components of the distributed refrigeration system are shown
according to a preferred embodiment. Electrical and 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.
[0025] Referring further to FIG. 5, the electrical and 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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.
* * * * *