U.S. patent application number 15/348593 was filed with the patent office on 2017-03-02 for systems and methods for operating a refrigeration system.
The applicant listed for this patent is PAUL MUELLER COMPANY. Invention is credited to CHRIS ANCIPINK, KEVIN W. BARTHOLOMAUS, KELLY BURGESS, MIKE KELLEY, GRANT WILLIAMS.
Application Number | 20170059240 15/348593 |
Document ID | / |
Family ID | 54010838 |
Filed Date | 2017-03-02 |
United States Patent
Application |
20170059240 |
Kind Code |
A1 |
WILLIAMS; GRANT ; et
al. |
March 2, 2017 |
Systems and Methods for Operating a Refrigeration System
Abstract
Methods and systems for operating a refrigeration system for
refrigerating a product are provided. A first temperature of the
refrigerant downstream of a condenser and upstream of an evaporator
may be obtained. A first pressure of the refrigerant downstream of
the condenser and upstream of the evaporator may be obtained. A
second pressure of the refrigerant downstream of the evaporator and
upstream of a compressor and/or a temperature of the product being
refrigerated may be obtained. A first valve, disposed between the
condenser and the evaporator, may be controlled based on the first
temperature and the first pressure to maintain a pre-determined
cooling set-point for the refrigeration system. A second valve of
the refrigeration system, coupled to the compressor, may be
controlled based on the second pressure or the temperature of the
product to optimize a capacity of a compressor of the refrigeration
system.
Inventors: |
WILLIAMS; GRANT;
(SPRINGFIELD, MO) ; BARTHOLOMAUS; KEVIN W.;
(SPRINGFIELD, MO) ; KELLEY; MIKE; (SPRINGFIELD,
MO) ; BURGESS; KELLY; (SPRINGFIELD, MO) ;
ANCIPINK; CHRIS; (SPRINGFIELD, MO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PAUL MUELLER COMPANY |
SPRINGFIELD |
MO |
US |
|
|
Family ID: |
54010838 |
Appl. No.: |
15/348593 |
Filed: |
November 10, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14461605 |
Aug 18, 2014 |
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15348593 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 49/02 20130101;
F25D 29/001 20130101; F25B 2700/195 20130101; F25B 2600/17
20130101; F25B 2700/21163 20130101; F25D 17/06 20130101; F25B
2600/2513 20130101; F25B 2600/21 20130101; F25B 2700/21175
20130101; F25B 2600/0261 20130101; F25B 2600/19 20130101; F25D
2700/16 20130101; F25D 2700/123 20130101; F25D 2700/121 20130101;
F25B 2700/197 20130101 |
International
Class: |
F25D 29/00 20060101
F25D029/00; F25D 17/06 20060101 F25D017/06; F25B 49/02 20060101
F25B049/02 |
Claims
1. A refrigeration system for refrigerating a product, comprising:
a condenser; an evaporator disposed downstream of the condenser; a
compressor disposed downstream of the evaporator; a first
transducer disposed immediately downstream of the condenser, the
first transducer configured to obtain a first temperature of a
refrigerant downstream of the condenser and upstream of the
evaporator; a second transducer disposed immediately downstream of
the condenser, the second transducer configured to obtain a first
pressure of the refrigerant downstream of the condenser and
upstream of the evaporator; a third transducer disposed immediately
downstream of the evaporator, the third transducer configured to
obtain a second pressure of the refrigerant downstream of the
evaporator and upstream of the compressor or a temperature of the
product being refrigerated; and a controller communicatively
coupled to the first, second, and third transducers, the controller
configured to control a first control valve disposed downstream of
the condenser and upstream of the evaporator based on the obtained
first temperature and the first pressure to maintain a
pre-determined cooling set-point, the controller configured to
control a second control valve coupled to the compressor based on
the obtained second pressure or the temperature of the product to
optimize a capacity of compressor.
2. The refrigeration system of claim 1, wherein the first control
valve comprises an electronic stepper valve configured to reduce
the pressure of the refrigerant.
3. The refrigeration system of claim 1, wherein the second control
valve comprises a solenoid valve configured to load or unload the
compressor.
4. The refrigeration system of claim 1, further comprising: a fan
arranged to pull a refrigeration medium across the condenser; and a
fan drive configured to control a speed of the fan, wherein the
controller is configured to control the fan drive based on the
obtained first pressure.
5. The refrigeration system of claim 1, further comprising a
hand-held device communicatively coupled to the controller, the
hand held device configured to allow a user to remotely monitor the
refrigeration system.
6. The refrigeration system of claim 1, wherein the controller is
configured to calculate a current cooling level of the refrigerant
downstream of the condenser and upstream of the evaporator based on
the obtained first temperature and first pressure, and wherein the
controller is configured to control the first valve of the
refrigeration system based on the calculated cooling level.
7. The refrigeration system of claim 1, wherein the controller is
configured to compare the current cooling level of the refrigerant
with the pre-determined cooling set-point, the pre-determined
cooling set-point being the desired cooling level for the
refrigerant when leaving the condenser, and wherein the controller
is configured to control the first valve of the refrigeration
system based on the comparison.
8. The refrigeration system of claim 1, wherein the controller is
configured to compare the obtained second pressure or temperature
with a pre-determined second pressure or temperature set-point, and
wherein the controller is configured to control the second control
valve of the refrigeration system based on the comparison.
9. The refrigeration system of claim 8, wherein the controller is
configured to energize the solenoid valve when the obtained second
pressure or temperature is less than the pre-determined second
pressure or temperature set-point, and de-energize the solenoid
valve when the obtained second pressure or temperature is greater
than the pre-determined second pressure or temperature set-point.
Description
FIELD OF THE DISCLOSURE
[0001] The present disclosure relates generally to refrigeration
systems and, more specifically, to operating a refrigeration system
in a more efficient manner.
BACKGROUND
[0002] Refrigeration systems are commonly employed to cool,
preserve, and store products such as milk, juice, and fruits.
Conventional refrigeration systems typically utilize a closed-loop
process in which refrigerant is continually circulated through a
condenser, an expansion valve, an evaporator, and a compressor. The
condenser cools and condenses the refrigerant into a saturated
liquid. The saturated liquid refrigerant then travels through the
expansion valve, which reduces the pressure, and, in turn, the
temperature, of the refrigerant. The refrigerant then passes
through the evaporator, at which point the saturated liquid
refrigerant extracts or absorbs heat from an external fluid (e.g.,
milk, air, water), thereby cooling the external fluid. The
extraction or absorption of heat from the external fluid vaporizes
the refrigerant, turning it into a superheated gas refrigerant. The
superheated gas refrigerant then flows into the compressor, which
increases the pressure and the temperature of the refrigerant. The
vapor refrigerant then passes back through the condenser, where the
cycle begins again.
[0003] There are, however, many problems associated with these
conventional refrigeration systems. For example, when these
conventional refrigeration systems experience low flow rates and/or
when the external fluid is to be cooled to a temperature near
freezing, ice may form on the surface of the evaporator. Ice
formation can damages the evaporator, and reduces the cooling
capacity of the system and, in turn, increases energy consumption.
Moreover, the components in these conventional refrigeration
systems are typically cycled, leading to inefficiencies and
increased energy consumption. For example, the compressor typically
cycles on and off based on the temperature of the cooling medium.
This cycling is not only inefficient, but because in practice the
temperature of the cooling medium can be quite unstable, it can
make it quite difficult to maintain the desired product
temperature. Further yet, as the capacity of the condenser depends
on the conditions of the evaporator (e.g., the desired temperature
of the product being cooled), this limits available system capacity
when the temperature of the product being cooled is higher, thus
increasing the duration of the cooling cycle and, in turn,
increasing energy consumption.
SUMMARY
[0004] One aspect of the present disclosure provides a method for
operating a refrigeration system for refrigerating a product. The
refrigeration system includes a condenser, an evaporator downstream
of the condenser, a compressor downstream of the evaporator, and a
refrigerant flowing through the refrigeration system. The method
includes obtaining, from a first transducer coupled to the
refrigeration system, a first temperature of the refrigerant
downstream of the condenser and upstream of the evaporator. The
method includes obtaining, from a second transducer coupled to the
refrigeration system, a first pressure of the refrigerant
downstream of the condenser and upstream of the evaporator. The
method also includes obtaining, from a third transducer coupled to
the refrigeration system, a second pressure of the refrigerant
downstream of the evaporator and upstream of the compressor or a
temperature of the product being refrigerated. The method further
includes controlling, via a processor communicatively coupled to
the refrigeration system, a degree of opening of a first valve of
the refrigeration system disposed between the condenser and the
evaporator, based on the first temperature and the first pressure,
to maintain a pre-determined cooling set-point for the
refrigeration system, and a second valve of the refrigeration
system coupled to the compressor, based on the second pressure or
the temperature of the product, to optimize a capacity of the
compressor.
[0005] Another aspect of the present disclosure provides a
refrigeration system for refrigerating a product. The refrigeration
system includes a condenser, an evaporator disposed downstream of
the condenser, a compressor disposed downstream of the evaporator,
first, second, and third transducers, and a controller. The first
transducer is disposed immediately downstream of the condenser and
is configured to obtain a first temperature of a refrigerant
downstream of the condenser and upstream of the evaporator. The
second transducer is disposed immediately downstream of the
condenser and is configured to obtain a first pressure of the
refrigerant downstream of the condenser and upstream of the
evaporator. The third transducer is disposed immediately downstream
of the evaporator and is configured to obtain a second pressure of
the refrigerant downstream of the evaporator and upstream of the
compressor or a temperature of the product being refrigerated. The
controller is communicatively coupled to the first, second, and
third transducers. The controller is configured to control a first
control valve disposed downstream of the condenser and upstream of
the evaporator based on the obtained first temperature and the
first pressure to maintain a pre-determined cooling set-point, the
controller configured to control a second control valve coupled to
the compressor based on the obtained second pressure or the
temperature of the product to optimize a capacity of
compressor.
[0006] Yet another aspect of the present disclosure provides a
method of operating a refrigeration system for refrigerating a
product, the refrigeration system having a condenser, an evaporator
downstream of the condenser, a compressor downstream of the
evaporator, and a refrigerant flowing through the refrigeration
system. The method includes obtaining, from a first transducer
coupled to the refrigeration system, a first temperature of the
refrigerant downstream of the condenser and upstream of the
evaporator, obtaining, from a second transducer coupled to the
refrigeration system, a first pressure of the refrigerant
downstream of the condenser and upstream of the evaporator, and
obtaining, from a third transducer coupled to the refrigeration
system, a second pressure of the refrigerant downstream of the
evaporator and upstream of the compressor or a temperature of the
product being refrigerated. The method further includes
controlling, via a processor communicatively coupled to the
refrigeration system, a degree of opening of an electronic stepper
valve disposed between the condenser and the evaporator, based on
the temperature and the pressure, to maintain a pre-determined
cooling set-point for the refrigeration system, such that the
evaporator is flooded with liquid refrigerant, or controlling, via
a processor communicatively coupled to the refrigeration system, a
solenoid valve coupled to the compressor, based on the pressure or
the temperature of the product, to optimize a capacity of the
compressor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic diagram of a refrigeration system
assembled in accordance with the teachings of the present
disclosure.
[0008] FIG. 2 is a schematic diagram of an intelligent control
board that can be coupled to the refrigeration system illustrated
in FIG. 1.
[0009] FIG. 3 is a schematic diagram illustrating the intelligent
control board shown in FIG. 2 communicatively coupled to the
refrigeration system shown in FIG. 1.
[0010] FIG. 4 is a process flow chart showing one version of a
method for operating a refrigeration system in accordance with the
present disclosure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] FIG. 1 illustrates a schematic diagram of a refrigeration
system 100 assembled in accordance with the teachings of the
present disclosure. The refrigeration system 100 is a closed-loop
system through which a refrigerant or a coolant is continually
circulated as part of a refrigeration or cooling cycle. The
refrigeration system 100 in this version can located at or on a
dairy farm and is used to refrigerate or cool milk, for example,
but it can instead be used at or in a commercial facility (e.g., at
or in a supermarket), an industrial facility (e.g., at or in a
power plant), or some other location to cool or refrigerate milk
and/or other products (e.g., juice, yogurt, meat, cheese,
etc.).
[0012] The closed-loop refrigeration system 100 generally includes
a condenser 104, a first control valve 108, an evaporator 112, an
accumulator/heat exchanger 116, a second control valve 120, a
compressor 124, and a condenser fan 128. Generally conventional
plumbing 101 extends between each of these components as depicted
and carries a refrigerant, in the conventional manner. The
condenser 104 is generally configured to condense and sub-cool the
refrigerant into a high-pressure liquid. The sub-cooled,
high-pressure liquid flows from the condenser 104 to the first
control valve 108 via a conduit 132 of the plumbing 101. The first
control valve 108, which in this version is an electronic stepper
valve 136 that can move between closed and multiple different open
positions (e.g., 0-2500 different positions) to reduce the pressure
of the refrigerant, converts the refrigerant from a high-pressure
liquid to a low-pressure liquid. The low-pressure liquid
refrigerant then flows from the electronic stepper valve 136 to the
evaporator 112 via a conduit 140 of the plumbing 101. As will be
described in greater detail below, the opening through the first
control valve 108 can be controlled to ensure that the refrigerant
leaving the condenser 104 is sufficiently sub-cooled such that the
evaporator 112 is flooded with liquid refrigerant and, as a result,
a saturated suction is provided.
[0013] As the refrigeration system 100 in the depicted version is
located at or on a dairy farm, the evaporator 112 is mounted in a
milk cooler 114 used to accumulate and cool milk from the milking
process. Thus, when the liquid refrigerant passes through the
evaporator 112, the saturated liquid refrigerant extracts or
absorbs heat from the milk cooler, thereby cooling the milk and
vaporizing the refrigerant. However, unlike conventional
evaporators, which completely vaporize the refrigerant, the
evaporator 112, because it is flooded with liquid refrigerant and a
saturated suction is provided, only partially vaporizes the
refrigerant. Thus, when the refrigerant leaves the evaporator 112,
the refrigerant occupies a partially liquid/partially gaseous
phase.
[0014] To prevent liquid from reaching the compressor 124, the
liquid/gas mixture flows from the evaporator 112 to the
accumulator/heat exchanger 116 via a conduit 144 of the plumbing
101. As shown in FIG. 1, the accumulator/heat exchanger 116 is in
thermal communication with conduit 132 from the condenser, which
carries super cooled refrigerant. The conduit 132 therefore cools
the liquid/vapor mixture carried in conduit 144 and the cooled
liquid falls to the bottom of the accumulator/heat exchanger 116.
The vapor flows onto the compressor 124. At this point, the
refrigerant is in vapor or gaseous form, but is at a lower
superheated temperature (e.g., 1-5.degree. F.) than typically seen
in conventional refrigeration systems. The vapor refrigerant then
flows from the accumulator/heat exchanger 116 to the compressor 124
via a conduit 148 of the plumbing 101. The second control valve
120, which in this version can be a solenoid valve 150, is coupled
to the compressor 124 via conduits 121, 123. The second valve 120
can, when desired, be controlled to unload or load the compressor
124 to vary the capacity of the compressor 124, as will be
described in greater detail below. A benefit of using a solenoid
valve is that solenoid valves are very quick-acting with short
valve member travel distances and times between open and closed
positions.
[0015] The compressor 124 compresses the vapor refrigerant, thereby
increasing its pressure and temperature. The vapor refrigerant then
flows from the compressor 124 back to the condenser 104 via a
conduit 152 of the plumbing 101, at which point the cycle begins
again. The condenser fan 128 is positioned adjacent to or near the
condenser 104 to force a condensing medium (e.g., air) through the
condenser 104, thereby cooling the refrigerant flowing through the
condenser 104. The condenser fan 128 is driven by a condenser fan
motor 156, which is coupled to the condenser fan 128. The condenser
fan motor 156 is itself controlled (e.g., driven) by a fan control
drive 160 communicatively coupled to the fan motor 156. As will be
described in greater detail below, the fan control drive 160 can be
controlled to control the condenser fan motor 156, and thus the
speed of the condenser fan 128, to maintain or achieve a desired
condensing temperature.
[0016] Referring still to FIG. 1, the refrigeration system 100
further includes a plurality of transducers (e.g., sensors)
generally configured to obtain (e.g., detect, sense) data, such as
pressure(s), temperature(s), flow rate(s), etc., indicative of the
operation and performance of the refrigeration system 100. In this
version, the refrigeration system 100 includes a first pressure
transducer 204, a first temperature transducer 208, a second
pressure transducer 212, and a second temperature transducer 216.
It should be understood that the temperature and pressure
transducers 204-216 can generally be any commercially available
sensors such as, for example, the 2CP5 sensor manufactured by
Sensata Technologies, Inc.
[0017] The first pressure transducer 204 is positioned downstream
of the condenser 104 and at or along the conduit 132 between the
condenser 104 and the first control valve 108 (i.e., in a high
pressure area of the system 100). So positioned, the first pressure
transducer 204 is configured to obtain a pressure of the
refrigerant leaving the condenser 104 (referred to herein as a
first pressure of the refrigerant). The first temperature
transducer 208, in the depicted version of the system 100, is also
positioned downstream of the condenser 104 and at or along the
conduit 132 between the condenser 104 and the first control valve
108 (i.e., in the high temperature area of the system 100).
Moreover, in this version, the first temperature transducer 208 is
upstream of the first pressure transducer 204, but in other
versions the transducer 208 can be downstream of the transducer
204. So positioned, the first temperature transducer 208 is
configured to obtain a temperature of the refrigerant leaving the
condenser 104 (referred to herein as a first temperature of the
refrigerant). The second pressure transducer 212 is positioned
downstream of the evaporator 112 and at or along the conduit 144
between the evaporator 112 and the accumulator/heat exchanger 116
(i.e., in a low pressure area of the system 100). So positioned,
the second pressure transducer 212 is configured to obtain a
pressure of the refrigerant leaving the evaporator 112 (referred to
herein as a second pressure of the refrigerant). The second
temperature transducer 216, which is also referred to herein as a
product temperature transducer, is generally positioned near, at,
or in the product to be refrigerated to obtain a temperature of the
product being refrigerated (e.g., milk). Because the refrigeration
system 100 in this version is used to cool milk, the product
temperature transducer 216 in this version is positioned near, on,
or within the milk cooler containing the milk to be cooled.
[0018] It will be appreciated that the refrigeration system 100
illustrated in FIG. 1 can vary and yet still fall within the
principles of the present disclosure. In other versions, the
refrigeration system 100 can include additional, different, or
fewer components than the components described above. The first
control valve 108 can, for example, be an expansion valve or any
other suitable control valve. In some versions, the refrigeration
system 100 can include a conventional evaporator, configured to
produce superheated vapor refrigerant, instead of the evaporator
112 disclosed, which produces a mixed vapor-liquid refrigerant. The
evaporator 112 need not be mounted in the milk cooler 114. Instead,
the evaporator 112 can be mounted to an exterior surface of the
milk cooler 114 or coupled to the milk cooler 114 in a different
manner (e.g., via a conduit or line). When the refrigeration system
100 is used to cool other than or in addition to milk, the
evaporator 112 can be mounted in or coupled to a different external
environment such as, for example, a display case containing one or
more products to be refrigerated. In the versions in which the
refrigeration system 100 includes a conventional evaporator, the
refrigeration system 100 may not include the accumulator/heat
exchanger 116, as the refrigerant would be totally vaporized in the
evaporator prior to reaching the compressor 124. In some versions,
the refrigeration system 100 may not include the second control
valve 120, in which case the refrigeration system 100 would not
permit adjustment of the capacity of the compressor 124. In other
versions, the refrigeration system 100 can include additional,
different, or fewer transducers. As an example, the refrigeration
system 100 may not include both the second pressure transducer 212
and the second temperature transducer 216. As another example, the
refrigeration system 100 can include an additional temperature
transducer disposed adjacent to or near the second pressure
transducer 212. Moreover, any of the transducers 204-216 can be
positioned elsewhere and still perform the intended functionality
described above.
[0019] FIG. 2 illustrates one version of an intelligent control
board 250 that can be communicatively coupled with or connected to
the refrigeration system 100 to improve the performance of the
refrigeration system 100. The intelligent control board 250
generally includes a controller 254 configured to monitor and
control the operation of the refrigeration system 100 and a panel
258 that includes one or more indicators for providing visual
feedback about the operation of the refrigeration system 100.
[0020] As shown in FIG. 2, the controller 254 includes a processor
262, a memory 266, a communications interface 270, and computing
logic 274. The processor 262 can be a general processor, a digital
signal processor, ASIC, field programmable gate array, graphics
processing unit, analog circuit, digital circuit, or any other
known or later developed processor. The processor 262 operates
pursuant to instructions in the memory 266. The memory 266 can be a
volatile memory or a non-volatile memory. The memory 266 can
include one or more of a read-only memory (ROM), random-access
memory (RAM), a flash memory, an electronic erasable program
read-only memory (EEPROM), or other type of memory. The memory 266
can include an optical, magnetic (hard drive), or any other form of
data storage device.
[0021] The communications interface 270 is provided to enable or
facilitate electronic communication between the controller 254 and
the components of the refrigeration system 100. The communications
interface 270 can be or include, for example, one or more universal
serial bus (USB) ports, one or more Ethernet ports, and/or one or
more other ports or interfaces. The electronic communication may
occur via any known communications protocol, including, by way of
example, USB, RS-232, RS-485, WiFi, Bluetooth, and/or any other
suitable communications protocol.
[0022] The logic 274 generally includes one or more control
routines and/or one or more sub-routines embodied as
computer-readable instructions stored on the memory 266. The
control routines and/or sub-routines may perform PID
(proportional-integral-derivative), fuzzy logic, nonlinear, or any
other suitable type of control. The processor 262 generally
executes the logic 274 to perform actions related to the operation
of the refrigeration system 100. The logic 274 may, when executed,
cause the processor 262 to (i) obtain data (e.g., pressure data,
temperature data) from one or more of the transducers 204-216, (ii)
control the first control valve 108 of the refrigeration system 100
based on the obtained data to maintain a pre-determined level of
sub-cooling, (iii) control the second control valve 120 of the
refrigeration system 100 based on the obtained data to optimize a
capacity of the compressor 124, (iv) control the fan control drive
160, and thus the condenser fan 128, based on the obtained data to
adjust a condensing temperature of the condenser 104, (v) detect
fault conditions or errors in the refrigeration system 100, and/or
perform other desired functionality.
[0023] Although not depicted herein, the controller 254 may also
include one or more bit switches that allow a user of the
refrigeration system 100 to select from a number of different
programmed options associated with different features of the
refrigeration system 100. The programmed options may, for example,
include an anti-short cycle that prevents premature cycling of the
compressor 124, and an alarm or fault condition output that
provides visual feedback (e.g., via the panel 258) when alarm or
fault conditions are detected. By selecting the bit (or bits)
corresponding to the desired option(s), the user of the
refrigeration system 100 can trigger (or turn-off) one or more
different features of the refrigeration system 100.
[0024] As shown in FIG. 2, the panel 258 in this version includes
two light-emitting diodes (LEDs) 278, 282 configured to provide
visual feedback about the operation of the refrigeration system
100. The LED 278 emits a red light (i.e., light having a wavelength
in a range of 620-750 nm) through a hole 286 in the control board
250 when the controller 254 detects a fault or alarm condition in
the refrigeration system 100. The LED 278 may emit one red light or
a series of red lights (i.e., flashes of red light) depending upon
the detected fault condition. The LED 278 may, for example, emit
one red light when the fault condition is a bit-switch setting
error, two flashes of red light when the fault condition involves
the transducer 208, three flashes of red light when the fault
condition involves the transducer 212, fourth flashes of red light
when the fault condition involves the temperature transducer 220,
and seven flashes of red light when the fault condition involves
the fan control drive 160. Meanwhile, the LED 282 emits a green
light (i.e., light having a wavelength in a range of between
495-570 nm) through a hole 290 in the control board 250. The LED
282 may emit one green light or a series of green lights (i.e.,
flashes of green light) depending upon the operating conditions.
The LED 282 may, for example, always emit a solid green light so
long as the refrigeration system 100 is on and operating normally,
but emit one flash of green light when the anti-cycle option is
active.
[0025] Though not illustrated herein, the components of the
intelligent control board 250 can be arranged in any known manner.
One of ordinary skill in the art will also appreciate that the
control board 250 can include additional or different components.
The controller 254 can, for example, include additional components,
such as a relay, converter, or gauge, which are not explicitly
depicted herein. The panel 258 can, for example, include more or
less LEDs, LEDs that emit different colors of light, LEDs that emit
different patterns of light (e.g., corresponding to different fault
conditions), different light sources for providing visual feedback,
a user interface, and/or some other means of providing visual
feedback about the operation of the refrigeration system 100.
[0026] FIG. 3 is a schematic diagram that illustrates the
intelligent control board 250 coupled with or connected to the
refrigeration system 100. As illustrated, the control board 250 is
coupled with or connected to the fan control drive 160 via a
communication network 300, the first control valve 108 via a
communication network 304, the second control valve 120 via a
communication network 308, the first pressure transducer 204 via a
communication network 312, the first temperature transducer 208 via
a communication network 316, the second pressure transducer 212 via
a communication network 320, and the second temperature transducer
216 via a communication network 324. As used herein, the phrases
"in communication" and "coupled" are defined to mean directly
connected to or indirectly connected through one or more
intermediate components. Such intermediate components may include
hardware and/or software based components.
[0027] It will be appreciated that the networks 300-324 may be
wireless networks, wired networks, or combinations of a wired and a
wireless network (e.g., a cellular telephone network and/or 802.11x
compliant network), and may include a publicly accessible network,
such as the Internet, a private network, or a combination thereof.
The type and configuration of the networks 300-324 is
implementation dependent, and any type of communications networks
which facilitate the described communications between the
intelligent control board 250 and the components of the
refrigeration system 100, available now or later developed, may be
used.
[0028] With the intelligent control board 250 coupled with or
connected to the refrigeration system 100 in this manner, the
controller 254 is configured to transmit signals (e.g., control
signals, data requests) to and receive signals (e.g., data) from
the fan control drive 160, the first control valve 108, the second
control valve 120, and any of the transducers 204-216. The
controller 254 can thus communicate with the transducers 204-216
and control the fan control drive 160, the first control valve 108,
and the second control valve 120.
[0029] When the refrigeration system 100 is operational and
refrigerant is circulated through the components of the
refrigeration system 100 in the manner described above, the
transducers 204-216 may obtain data associated with and indicative
of the operation of the refrigeration system 100 (i.e., the
refrigeration cycle). Specifically, the first pressure transducer
204 may obtain (e.g., detect, measure) the pressure of the
refrigerant downstream of the condenser 104 but upstream of the
valve 108 (i.e., the first pressure of the refrigerant), the first
temperature transducer 208 may obtain the temperature of the
refrigerant downstream of the condenser 104 but upstream of the
valve 108 (i.e., the first temperature of the refrigerant), the
second pressure transducer 212 may obtain the pressure of the
refrigerant downstream of the evaporator 112 but upstream of the
accumulator/heat exchanger 116 (i.e., the second pressure of the
refrigerant), the second temperature transducer 216 may obtain the
temperature of the product to be cooled, or combinations thereof.
The above-described data may be automatically obtained when the
refrigeration system 100 is operational and/or obtained in response
to a request received from the controller 254. The above-described
data may be obtained simultaneously (e.g., the first temperature
and the first pressure may be obtained at the same time), at
different times, or a combination thereof (e.g., some of the data
can be obtained simultaneously while some data can be obtained at
different times).
[0030] The controller 254 may then obtain the data obtained by one
or more of the transducers 204-216 via the respective networks
312-328. The data may be automatically transmitted to the
controller 254 (i.e., automatically obtained by the controller 254)
and/or transmitted to the controller 254 in response to a request
received from the controller 254. Once obtained, the data may be
stored in the memory 266 or another memory.
[0031] Based on or using the obtained data, the controller 254 may
control (e.g., adjust) components of the refrigeration system 100,
particularly the first control valve 108, the second control valve
120, and/or the fan control drive 160. The controller 254 is
generally configured to control the components of the refrigeration
system 100 such that the refrigeration system 100 operates in the
desired manner discussed herein.
[0032] The controller 254 may control (e.g., close or adjust the
degree of opening of) the first control valve 108, which in the
illustrated version takes the form of the electronic stepper valve
136, based on the first temperature and the first pressure. This is
done to maintain a pre-determined (e.g., factory programmed)
cooling set-point for the refrigeration system 100. The
pre-determined cooling set-point corresponds to the desired
sub-cooling level for the refrigerant when leaving the condenser
104. The desired sub-cooling level corresponds to the sub-cooling
level at which the evaporator 112 is desirably flooded with liquid
refrigerant. Flooding the evaporator 112 in this way provides a
saturated suction leaving the evaporator 112, which results in the
refrigerant leaving the evaporator 112 in a mixed liquid/vapor
state and at a lower temperature than typically seen in
conventional refrigeration systems. Beneficially, this increases
the efficiency of the evaporator 112, keeps the motor of the
compressor 124 cooler, and increases the volumetric efficiency of
the compressor 124.
[0033] To determine whether the refrigeration system 100 is
operating at, below, or above this pre-determined cooling
set-point, the controller 254 can calculate, based on the first
pressure and the first temperature, the current sub-cooling level
of the refrigerant when leaving the condenser 104. In some
versions, the controller 254 can calculate the current sub-cooling
level by correlating the first pressure to an expected temperature
and then comparing the expected temperature with the measured
temperature, the first temperature. The controller 254 may, in
turn, compare the calculated sub-cooling level of the refrigerant
with the pre-determined cooling set-point. When the calculated
sub-cooling level is at least substantially equal (e.g., equal) to
the pre-determined cooling set-point, the controller 254 may
determine that the refrigeration system 100 is substantially
operating at this pre-determined cooling set-point, such that the
controller 254 need not control (e.g., adjust) the first control
valve 108. When, however, the calculated current sub-cooling level
is determined to be less than or greater than the pre-determined
cooling set-point, the controller 254 adjusts (e.g., opens, closes)
the first control valve 108 until the controller 254 determines
that the current sub-cooling level is substantially equal to the
pre-determined cooling set-point (i.e., until the desired level of
sub-cooling has been achieved and maintained). By opening the valve
108 further, more refrigerant will flow through and the sub-cooling
at the condenser 104 will result in a higher temperature
refrigerant. By contrast, closing or reducing the opening of the
valve 108 will reduce flow through the conduit 132, which decreases
the pressure and temperature of the sub-cooled refrigerant exiting
the condenser 104. It will be appreciated that the control of the
first control valve 108 is an iterative and continuous process.
And, in this version, the control valve 108 is or includes the
electronic stepper valve 136, which has 2500 different positions to
facilitate fine-tuned adjustments. Of course, other types of
adjustable port valves could be used.
[0034] The controller 254 may control the second control valve 120,
which in the illustrated version takes the form of the solenoid
valve 150, based on the second pressure and/or the temperature of
the product being refrigerated. This is done to control a capacity
of the compressor 124. As briefly discussed above, when system
capacity is too low (e.g., when the temperature of the product
being cooled is higher than expected), conventional systems
compensate by increasing the duration of the cooling cycle, thereby
increasing energy consumption. Conversely, when system capacity is
too high (e.g., when the temperature of the product being cooled is
lower than expected, under low flow conditions), the product being
cooled may freeze. The system 100 disclosed herein advantageously
prevents either situation by controlling (e.g., adjusting) the
capacity of the compressor 124 in accordance with the operating
conditions of the refrigeration system 100.
[0035] To determine whether the capacity of the compressor 124
needs to be adjusted, the controller 254 can compare the second
pressure (the pressure of the refrigerant when leaving the
evaporator 112) or the product temperature to a pre-determined
(e.g., factory programmed) second pressure set-point or a product
temperature set-point. This pre-determined set-point corresponds to
a desired, if not ideal, capacity for the compressor 124. When the
second pressure or product temperature is substantially equal to
the pre-determined second pressure set-point or product temperature
set-point, the controller 254 may determine that the current
capacity of the compressor 124 is adequate (if not ideal), in which
case the controller 254 does not control the solenoid valve 150.
When, however, the second pressure or product temperature is less
or greater than the pre-determined second pressure or product
temperature set-point, the controller 254 may control the solenoid
valve 150 to provide a controlled reduction or controlled increase
(when the capacity has been previously reduced) of the capacity of
the compressor 124.
[0036] Specifically, when the second pressure or product
temperature is less than the pre-determined second pressure or
product temperature set-point, the controller 254 energizes the
solenoid valve 150, which causes the solenoid valve 150 to open,
thereby unloading and decreasing the capacity of the compressor
124. The controller 254 energizes the solenoid valve 150 for at
least minimum pre-determined amount of time (e.g., 1 second), but
may energize the solenoid valve 150 until the second pressure or
product temperature is greater than the pre-determined second
pressure or product temperature set-point, with the exception that
the controller 254 may, to protect the compressor 124, only
energize the solenoid valve 150 for a maximum pre-determined amount
of time (e.g., 9 seconds). The controller 254 may, when the
solenoid valve 150 is being energized, simultaneously suspend
control of the first control valve 108 and the condenser fan
128.
[0037] Conversely, when the second pressure or product temperature
is greater than the pre-determined second pressure set-point or
product temperature set-point, the controller 254 de-energizes the
solenoid valve 150, which causes the solenoid valve 150 to close,
thereby loading and increasing the capacity of the compressor 124.
The controller 254 de-energizes the solenoid valve 150 for at least
minimum pre-determined amount of time (e.g., 3 seconds), but may
de-energize the solenoid valve 150 until the second pressure or
product temperature is less than the pre-determined second pressure
or product temperature set-point.
[0038] Thus far, the solenoid is described as being energized to
open and, as such, constitutes a naturally closed solenoid. One
advantage of a naturally closed solenoid is that energy is only
required to unload the compressor 124. In other versions, however,
a naturally open solenoid could be used such that it would be
energized to close.
[0039] As with the electronic stepper valve 136, it will be
appreciated that the control of the solenoid valve 150 can be an
iterative and continuous process. In fact, the controller 254 can
self-regulate its control of the solenoid valve 150, provided such
control complies with the above-described minimum and maximum time
periods, based on how fast the second pressure (the pressure
obtained by the second pressure transducer 212) falls when the
compressor 124 is loaded and how fast the second pressure increases
when the compressor 124 is unloaded.
[0040] At least initially (e.g., when the controller 254 first
receives a run signal), the fan control drive 160 operates the
condenser fan 128 at full time for a short period of time (e.g., 3
seconds). Following this short period of time, however, the
controller 254 may control the fan control drive 160 based on the
first pressure to control (e.g., adjust) the speed of the condenser
fan 128. As the first pressure rises up to a pre-determined
pressure point (e.g., 170 psi), the fan control drive 160 can
control the fan 128 such that the fan 128 operates at a
pre-determined minimum speed. When the first pressure rises above
this pre-determined pressure point, and until the first pressure
reaches a pre-determined maximum pressure point (e.g., 230 psi),
the fan control drive 160 can increase the speed of the fan 128.
When the first pressure reaches the pre-determined maximum pressure
point, the fan 128 is operating at full speed, and any pressure
above this pre-determined maximum pressure has no impact on the
speed of the fan 128. Controlling the speed of the fan 128 in this
manner can allow the refrigeration system 100 to operate in a more
stable manner during lower or cooler ambient conditions.
[0041] In this version, the controller 254 may simultaneously
control the electronic stepper valve 136, the solenoid valve 150,
and the fan control drive 160. As such, the controller 254 may open
the electronic stepper valve 136 and, at the same time, energize
the solenoid valve 150. In other versions, however, the controller
254 may only control two or more of the electronic stepper valve
136, the solenoid valve 150, and the fan control drive 160 at
different times. In further versions, the controller 254 may only
control one or two, rather than all, of the electronic stepper
valve 136, the solenoid valve 150, and the fan control drive
160.
[0042] The controller 254 may instruct the panel 258 to provide
visual feedback about the operation of the refrigeration system
100. The controller 254 may instruct the LED 278 of the panel 258
to emit one or a series of lights, as described above, when the
controller 254 detects one or more fault or alarm conditions. In
some cases, the controller 254 may detect one or more fault or
alarm conditions based on the obtained data. The pressure and/or
temperature data may, for example, indicate that the transducer
204, the transducer 208, the transducer 212, and/or the transducer
216 is not functioning properly. The controller 254, by virtue of
its connection with the fan control drive 160, may detect that the
condenser fan 128, the fan motor 132, and/or the fan control drive
160 is not functioning properly. In some cases, the controller 254
may detect a problem with one of the networks 300-324 connecting
the controller 254 to the various components of the refrigeration
system 100. The controller 254 may, alternatively or additionally,
detect that the bit-switches are not functioning properly or were
not properly set. The controller 254 may, alternatively or
additionally, instruct the LED 282 of the panel 258 to emit a solid
green light when the refrigeration system 100 is operating
normally, and instruct the LED 282 of the panel 258 to emit one
flash of green light when the anti-cycle option is active. In turn,
the panel 258 may provide the requested visual feedback via the
LEDs 278, 282, as instructed. Accordingly, a user of the
refrigeration system 100 can easily and quickly identify problems
with the control process for the refrigeration system 100.
[0043] As also illustrated in FIG. 3, in some cases, a hand-held
diagnostic tool 350 can be coupled with or connected to the
intelligent control board 250 via a communication network 354,
which can be a wireless network, a wired network, or a combination
thereof. The hand-held diagnostic tool 350 can include a processor,
a memory, one or more input devices (e.g., a keyboard), a display,
and/or other components, as known in the art. In any event, the
hand-held diagnostic tool 350 allows a user of the refrigeration
system 100 to install the intelligent control board 250, configure
various components of the system 100 (e.g., the controller 254),
and monitor, in real-time, operating conditions of the
refrigeration system 100.
[0044] FIG. 4 illustrates one version of a method or process of
operating the refrigeration system 100 of the present disclosure.
Although the method or process is described below as being
performed by or using the transducers 204-216 and the controller
254, the method or process may, alternatively, be performed by some
other component. The method or process is described as including
various tasks performed in a sequence, but it should be appreciated
that some of the tasks of the method or process can be performed
simultaneously and some or all can be performed in a different
order. In other versions, the method or process may include
additional, fewer, or different tasks, or a different sequence of
tasks. As an example, one or more of the tasks (e.g., the task of
obtaining the first temperature, the task of obtaining the first
pressure, the task of obtaining the second pressure) can be
repeated any number of times.
[0045] In one version, referring to the "blocks" in FIG. 4, the
method includes (i) obtaining, from a first transducer (e.g., the
transducer 208) coupled to the refrigeration system 100, a first
temperature of the refrigerant leaving a condenser (e.g., the
condenser 104) (block 400), (ii) obtaining, from a second
transducer (e.g., the transducer 204) coupled to the refrigeration
system 100, a first pressure of the refrigerant leaving the
condenser (block 404), and (iii) obtaining, from a third transducer
(e.g., the transducer 212 or 216) coupled to the refrigeration
system 100, a second pressure of the refrigerant leaving an
evaporator (e.g., the evaporator 112) or a temperature of the
product being refrigerated (block 408). In some versions, obtaining
the second pressure or the temperature of the product includes
obtaining the second pressure (e.g., via the transducer 212), while
in other versions, obtaining the second pressure or the temperature
of the product includes obtaining the temperature of the product
(e.g., via the transducer 216). In yet another version, obtaining
the second pressure or the temperature of the product can include
obtaining the second pressure and obtaining the temperature of the
product.
[0046] In one version, the method also includes controlling, via a
processor (e.g., the processor 262) communicatively coupled to the
refrigeration system 100, a first valve (e.g., the valve 108) of
the refrigeration system 100 based on the first temperature and the
first pressure to maintain a pre-determined cooling set-point for
the refrigeration system 100 (block 412). In one version, the first
valve can be an electronic stepper valve (e.g., the stepper valve
136) disposed between the condenser and the evaporator. In some
versions, the method further includes calculating, via the
processor, a current cooling level of the refrigerant leaving the
condenser based on the first temperature and the first pressure. In
these versions, controlling the first valve may include controlling
the first valve based on the calculated current cooling level. In
some versions, controlling the first valve includes opening or
closing the first valve when the calculated current cooling level
is different from the pre-determined cooling set-point. In one
version, the method further includes comparing the current cooling
level of the refrigerant with the pre-determined cooling set-point,
the pre-determined cooling set-point being the desired cooling
level for the refrigerant when leaving the condenser. Controlling
the first valve may include controlling the first valve based on
the comparing.
[0047] In one version, the method also includes controlling, via
the processor, a second valve (e.g., the valve 120) of the
refrigeration system 100 based on the second pressure or the
temperature of the product to optimize a capacity of a compressor
(e.g., the compressor 124) of the refrigeration system 100 (block
416). In one version, the second valve can be a solenoid valve
(e.g., the solenoid valve 150) disposed between the evaporator and
the compressor. In some versions, the method further includes
comparing the obtained second pressure or product temperature with
a pre-determined second pressure or product temperature set-point.
In these versions, controlling the second valve of the
refrigeration system may include controlling the second valve based
on the comparing. In some versions, such as when the second valve
is a solenoid valve, controlling the second valve includes
energizing the solenoid valve when the second pressure or product
temperature is less than the pre-determined second pressure or
product temperature set-point, and de-energizing the solenoid valve
when the second pressure or product temperature is greater than the
pre-determined second pressure or product temperature set-point. In
one version, the method further includes suspending control of the
first control valve when the solenoid valve is de-energized.
[0048] Based on the foregoing description, it should be appreciated
that the devices, systems, and methods described herein facilitate
a more efficient refrigeration system for refrigerating a product.
This is accomplished by obtaining data associated with the
operation of the refrigeration system, controlling a first control
valve based on the pressure and temperature of the refrigerant
leaving a condenser of the refrigeration system, and controlling a
second control valve based on the pressure of the refrigerant
leaving an evaporator or based on a temperature of the product
being refrigerated.
[0049] By controlling the first control valve in this manner, a
pre-determined cooling set-point for the refrigeration system can
be maintained. This ensures that the refrigerant leaving the
condenser is sufficiently cooled such that the evaporator is
flooded with liquid refrigerant and, as a result, a saturated
suction is provided. In turn, when exiting the evaporator, the
refrigerant is at a lower superheat than it otherwise would be (in
conventional refrigeration systems), which keeps the motor of the
compressor cooler and increases the volumetric efficiency of the
compressor. By controlling the second control valve in the
above-outlined manner, the capacity of the compressor can be
controlled. Under low-load conditions and/or low set-point
temperatures, the capacity of the compressor can be reduced in a
controlled manner. Such a controlled reduction helps to maintain a
desirable evaporator condition, allowing the product to be cooled
closer to freezing temperatures and reducing the likelihood that
ice will form on the evaporator. When, however, large volumes of
product are to be refrigerated or the desired temperature of the
product is higher, the capacity of the compressor can be increased
in a controlled manner. In this way, the duration of the
refrigeration cycle need not be increased (as in a conventional
refrigeration system), improving product quality and reducing
energy consumption. Additionally, by controlling the capacity of
the compressor in such a controlled manner, the compressor no
longer needs to be cycled on and off, stabilizing the temperature
of the cooling medium for the condenser will be more stable and,
ultimately, making it easier to maintain the desired product
temperature.
[0050] Preferred embodiments of this disclosure are described
herein, including the best mode or modes known to the inventors for
carrying out the disclosure. Although numerous examples are shown
and described herein, those of skill in the art will readily
understand that details of the various embodiments need not be
mutually exclusive. Instead, those of skill in the art upon reading
the teachings herein should be able to combine one or more features
of one embodiment with one or more features of the remaining
embodiments. Further, it also should be understood that the
illustrated embodiments are exemplary only, and should not be taken
as limiting the scope of the disclosure. All methods described
herein can be performed in any suitable order unless otherwise
indicated herein or otherwise clearly contradicted by context. The
use of any and all examples, or exemplary language (e.g., "such
as") provided herein, is intended merely to better illuminate the
aspects of the exemplary embodiment or embodiments of the
disclosure, and do not pose a limitation on the scope of the
disclosure. No language in the specification should be construed as
indicating any non-claimed element as essential to the practice of
the disclosure.
* * * * *