U.S. patent application number 11/539306 was filed with the patent office on 2008-04-10 for electronic head pressure control.
This patent application is currently assigned to HUSSMANN CORPORATION. Invention is credited to George A. Baker, Norman E. Street, Phil K. Zerbe.
Application Number | 20080083237 11/539306 |
Document ID | / |
Family ID | 38962028 |
Filed Date | 2008-04-10 |
United States Patent
Application |
20080083237 |
Kind Code |
A1 |
Street; Norman E. ; et
al. |
April 10, 2008 |
ELECTRONIC HEAD PRESSURE CONTROL
Abstract
A condenser assembly for use in a refrigeration system to reject
heat from refrigerant to an environment. The condenser assembly
includes first and second condenser modules each having a condenser
coil and valve. Each condenser coil includes an inlet port to
receive a refrigerant and an outlet port to discharge the
refrigerant. The valve is in fluid communication with the
corresponding inlet port and regulates flow of the refrigerant
through the corresponding condenser coil A sensor in communication
with the refrigeration circuit generates a signal indicative of an
inlet pressure of the condenser assembly. A controller is
programmed to actuate the first valve to regulate the flow of the
refrigerant into first condenser coil, and to actuate the second
valve independent of the first valve to regulate the flow of the
refrigerant into the second condenser coil to control condenser
volume based on the signal indicative of the inlet pressure.
Inventors: |
Street; Norman E.;
(O'Fallon, MO) ; Baker; George A.; (Wheaton,
IL) ; Zerbe; Phil K.; (Lombard, IL) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH LLP
100 E WISCONSIN AVENUE, Suite 3300
MILWAUKEE
WI
53202
US
|
Assignee: |
HUSSMANN CORPORATION
Bridgeton
MO
|
Family ID: |
38962028 |
Appl. No.: |
11/539306 |
Filed: |
October 6, 2006 |
Current U.S.
Class: |
62/196.4 |
Current CPC
Class: |
F25B 2700/195 20130101;
F25B 2400/21 20130101; F25B 49/027 20130101 |
Class at
Publication: |
62/196.4 |
International
Class: |
F25B 41/00 20060101
F25B041/00 |
Claims
1. A condenser assembly to condense a refrigerant for use in a
refrigeration system and to reject heat of the refrigerant to
ambient air of the environment, the refrigeration system including
a refrigeration circuit, the condenser assembly comprising: a first
condenser module including a first condenser coil having a first
inlet port to receive the refrigerant and a first outlet port to
discharge the refrigerant, and a first valve in fluid communication
with the first inlet port and actuable to regulate flow of the
refrigerant through the first condenser coil; a second condenser
module including a second condenser coil having a second inlet port
to receive the refrigerant and a second outlet port to discharge
the refrigerant, and a second valve in fluid communication with the
second inlet port and actuable to regulate flow of the refrigerant
through the second condenser coil; and a controller programmed to
selectively actuate the first valve to regulate the flow of
refrigerant into the first condenser coil, and programmed to
actuate the second valve independent of the first valve to regulate
the flow of refrigerant into the second condenser coil to control
condenser volume.
2. The condenser assembly of claim 1, further including a sensor in
communication with the refrigeration circuit and configured to
generate a signal indicative of an inlet pressure of the condenser
assembly, wherein the controller is programmed to actuate the first
valve and the second salve based on the signal indicative of the
inlet pressure.
3. The condenser assembly of claim 1, wherein the first condenser
module includes a first air moving device disposed adjacent the
first condenser coil to draw ambient air over the first condenser
coil to regulate a condenser capacity of the condenser assembly a
first amount, and wherein the second condenser module includes a
second air moving device disposed adjacent the second condenser
coil to draw ambient air over the second condenser coil to regulate
the condenser capacity a second amount.
4. The condenser assembly of claim 3, wherein the controller is
programmed to actuate the first valve to selectively isolate the
first condenser coil from the refrigeration circuit to reduce the
condenser capacity of the condenser assembly when the inlet
pressure is below a predetermined level.
5. The condenser assembly of claim 4, wherein the controller is
programmed to actuate the second valve to selectively isolate the
second condenser coil separate and independent from isolation of
the first condenser coil.
6. The condenser assembly of claim 3, wherein the first air moving
device further includes a first fan and a second fan, and wherein
the controller is programmed to selectively operate the first fan
independent of the second fan to regulate the condenser capacity of
the condenser assembly.
7. The condenser assembly of claim 6, wherein the first condenser
module further includes a baffle disposed between the first fan and
the second fan to compartmentalize the first condenser module.
8. The condenser assembly of claim 4, wherein the first outlet port
is configured to allow refrigerant to drain from the first
condenser coil in response to isolation of the first condenser
coil.
9. The condenser assembly of claim 3, wherein the controller is
programmed to selectively operate the first air moving device, and
wherein the controller is programmed to selectively operate the
second air moving device independent of the first air moving device
to regulate the condenser capacity.
10. The condenser assembly of claim 9, wherein the controller is
programmed to selectively operate the first air moving device
independent of the first valve, and wherein the controller is
programmed to selectively operate the second air moving device
independent of the second valve.
11. The condenser assembly of claim 1, wherein the first condenser
module further includes a first regulator disposed on the first
outlet port to regulate flow of the refrigerant from the first
condenser coil, and wherein the second condenser module further
includes a second regulator disposed on the second outlet port to
regulate flow of refrigerant from the second condenser coil.
12. The condenser assembly of claim 1, wherein the controller is
programmed to actuate the first valve to selectively connect the
first condenser coil with the refrigeration circuit to increase the
condenser volume.
13. The condenser assembly of claim 12, wherein the controller is
programmed to actuate the second valve to selectively connect the
second condenser coil separate and independent from connection of
the first condenser coil to increase the condenser volume.
14. A method of regulating a condenser assembly for a refrigeration
system including a refrigeration circuit having a refrigerant, the
method comprising: providing a first condenser module in the
refrigeration circuit, the first condenser module including a first
condenser coil having a first inlet port and a first outlet port,
and a first valve in fluid communication with the first inlet port;
providing a second condenser module in the refrigeration circuit,
the second condenser module including a second condenser coil
having a second inlet port and a second outlet port, and a second
valve in fluid communication with the second inlet port; regulating
flow of refrigerant into the first condenser coil by actuating the
first valve with a controller, regulating flow of refrigerant into
the second condenser coil by actuating the second valve with the
controller independent of the first valve; and varying a volume of
the condenser assembly.
15. The method claim 14, further comprising generating a signal
indicative of a condenser inlet pressure; and varying a volume of
the condenser assembly based on the signal indicative of the
condenser inlet pressure.
16. The method claim 14, further comprising varying a condenser
capacity of the condenser assembly by selectively drawing ambient
air over the first condenser coil; and varying a condenser capacity
of the condenser assembly by selectively drawing ambient air over
the second condenser coil independent of drawing ambient air over
the first condenser coil.
17. The condenser assembly of claim 16, wherein drawing ambient air
over the first condenser coil further includes selectively
operating the first air moving device and selectively operating the
second air moving device independent of the first air moving
device.
18. The condenser assembly of claim 17, further comprising
selectively operating the first air moving device independent of
actuation of the first valve, and selectively operating the second
air moving device independent of actuation of the second valve.
19. The method of claim 16, wherein drawing ambient air over the
first condenser coil includes operating a first fan of the first
air moving device independent from operating a second fan of the
first air moving device to vary the condenser capacity.
20. The method of claim 14, further comprising reducing the
condenser volume by isolating the first condenser coil from the
refrigeration circuit.
21. The method of claim 20, wherein regulating flow of refrigerant
into the second condenser coil includes selectively isolating the
second condenser coil independent from isolating the first
condenser coil.
22. The condenser assembly of claim 20, wherein isolating the first
condenser coil further includes draining refrigerant from the first
condenser coil.
23. The condenser assembly of claim 14, further comprising
regulating the flow of refrigerant from the first outlet port; and
regulating the flow of the refrigerant from the second outlet
port.
24. The method of claim 14, wherein regulating flow of refrigerant
into the first condenser coil includes connecting the first
condenser coil with the refrigeration circuit and increasing the
condenser volume when the condenser inlet pressure is above a
predetermined level.
25. The method of claim 24, wherein regulating flow of refrigerant
into the second condenser coil includes selectively connecting the
second condenser coil with the refrigeration circuit and increasing
the condenser volume independent from connecting the first
condenser coil.
26. A condenser assembly for a refrigeration system having a
refrigerant circuit circulating a refrigerant, the condenser
assembly comprising: a plurality of condenser modules, each module
including a condenser coil having an inlet port to receive the
refrigerant and an outlet port to discharge the refrigerant, a
valve in fluid communication with the first inlet port and actuable
to regulate flow of the refrigerant through the condenser coil; and
a controller programmed to actuate the valves of the plurality of
condenser modules to fluidly connect the condenser coils of the
plurality of condenser modules to the refrigeration circuit to
define a first condenser volume, and wherein the controller is
programmed to selectively actuate at least one valve of the
plurality of condenser modules independent of at least two other
valves of the remaining plurality of condenser modules to isolate
the corresponding at least one condenser coil from the
refrigeration circuit to define a second condenser volume different
from the first condenser volume.
27. The condenser assembly of claim 26, wherein the second
condenser volume is less than 50% of the first condenser
volume.
28. The condenser assembly of claim 26, wherein the second
condenser volume is more than 50% of the first condenser
volume.
29. The condenser assembly of claim 26, wherein the controller is
programmed to selectively actuate the at least one valve of the
plurality of condenser modules to define the second condenser
volume as one of three possible incremental condenser volumes.
30. The condenser assembly of claim 29, wherein the incremental
volumes are proportional to the number of condenser modules in the
plurality of condenser modules.
31. The condenser assembly of claim 29, wherein the number of
condenser modules equals four and the incremental condenser volumes
equal 75%, 50%, and 25% of the first condenser volume.
32. The condenser assembly of claim 26, wherein the refrigerant is
hindered from flowing into the corresponding at least one condenser
coil in response to isolation of the at least one condenser
coil.
33. The condenser assembly of claim 26, wherein the outlet port is
configured to drain the refrigerant disposed in the at least one
condenser coil in response to isolation of the at least one
condenser coil.
34. A method of regulating a condenser assembly for a refrigeration
system including a refrigeration capacity and a refrigeration
circuit circulating a refrigerant, the method comprising: providing
a plurality of condenser modules, each module including a condenser
coil having an inlet port to receive the refrigerant and an outlet
port to discharge the refrigerant, and a valve in fluid
communication with the first inlet port; actuating the plurality of
valves and fluidly connecting the condenser coils of the plurality
of condenser modules to the refrigeration circuit; defining a first
condenser volume based on connecting the condenser coils of the
plurality of condenser modules to the refrigeration circuit;
selectively actuating at least one valve of the plurality of
condenser modules independent of at least two other valves of the
remaining plurality of condenser modules; isolating the
corresponding at least one condenser coil from the refrigeration
circuit, and defining a second condenser volume different from the
first condenser volume with the at least one condenser coil
isolated.
35. The method of claim 34, wherein defining a second condenser
volume includes defining a second condenser volume that is less
than 50% of the first condenser volume.
36. The method of claim 34, wherein defining a second condenser
volume includes defining a second condenser volume that is more
than 50% of the first condenser volume.
37. The method of claim 34, wherein defining a second condenser
volume includes defining the second condenser volume as one of
three possible incremental condenser volumes.
38. The method of claim 37, wherein defining the second condenser
volume further includes defining incremental volumes that are
proportional to the number of condenser modules in the plurality of
condenser modules.
39. The method of claim 37, wherein providing a plurality of
condenser modules further includes providing four condenser modules
and defining the second condenser volume further includes defining
three incremental condenser volumes equaling 75%, 50%, and 25% of
the first condenser volume.
40. The method of claim 34, wherein isolating the corresponding at
least one condenser coil includes inhibiting flow of refrigerant
into the corresponding at least one condenser coil.
41. The method of claim 34, wherein isolating the corresponding at
least one condenser coil further includes draining the refrigerant
from the at least one condenser coil through the outlet port.
Description
BACKGROUND
[0001] The present invention relates to a condenser assembly for
use in retail store refrigeration systems, and more particularly to
a control of the condenser assembly that regulates condenser volume
in communication with the refrigeration system.
[0002] Typical retail store refrigeration systems often utilize
condenser assemblies including condenser coils to dissipate heat
from refrigerant passing through the condenser coils. In
large-scale retail store refrigeration systems, oftentimes large
conventional condenser assemblies are sized to dissipate, or
reject, an amount of heat equal to the heat load of the
refrigeration system. In other words, the condenser coils are sized
to dissipate the amount of heat in the refrigerant that was
absorbed or generated in other portions of the refrigeration
system.
[0003] Typically, the condenser assemblies are positioned outside
the retail store, such as on a rooftop, to allow heat transfer
between the condenser coil and the outside environment (i.e., to
allow the heat in the refrigerant to dissipate into the outside
environment). A mechanical draft may be provided by a fan to
air-cool the condenser coil.
[0004] Existing condenser assemblies often display poor efficiency
in dissipating heat from the refrigerant. As a result, these
condenser assemblies can be rather large for the amount of heat
being dissipated from the refrigerant, requiring additional space
for the condenser assemblies. Further, larger condenser assemblies
require more refrigerant in the refrigeration system to maintain
adequate operation of the refrigeration system. The refrigeration
systems using these large condenser coils often require excess
refrigerant to be stored in receivers or tanks so that the
condenser coils can be flooded in low ambient temperature
conditions to provide winter operation of the condenser assembly.
The large amount of refrigerant in these systems increases
potential effect to the environment if the refrigerant were
released to the atmosphere.
[0005] Winter operation requires a smaller condenser assembly
capacity to reject heat to the environment as a result of a
decrease in ambient temperature. A decrease in ambient temperature
results in a condenser capacity increase in the condenser. Some
refrigeration systems flood the condenser coils to maintain the
refrigeration capacity in the refrigeration system at operational
levels under low ambient conditions. These refrigeration systems
use mechanical hold-back valves to regulate the refrigerant and to
flood portions of the condenser assembly. These valves are
configured to maintain the head pressure of the system at an
operating pressure sufficient for adequate expansion valve
operation. In low ambient temperature conditions, the mechanical
hold-back valves force more refrigerant into the condenser (i.e.,
flooding) to reduce the heat transfer effectiveness of the
condenser. The excess refrigerant is distributed from a receiver
into the condenser coil to reduce the condenser capacity. In high
ambient temperature conditions, the mechanical hold-back valves
open to reduce flooding of the condenser and to improve the heat
transfer effectiveness of the condenser.
[0006] Some other refrigeration systems isolate fifty percent of
the condenser assembly (e.g., isolation of one condenser slab in a
two-condenser slab assembly) from refrigerant flow due to low
ambient conditions. These condenser slabs extend longitudinally
along the condenser assembly, and can further utilize flooding to
reduce the capacity of the remaining active portion of the
condenser assembly. The isolation of one-half of the condenser
capacity reduces the effectiveness of the condenser assembly to
cool compressed refrigerant. However, these condenser assemblies
operate either at full capacity (i.e., zero-percent reduction) or
at half capacity (i.e., fifty-percent reduction). These condenser
assemblies cannot be isolated to less than fifty percent or more
than fifty percent capacity without: at least partial flooding of
the condenser assembly to accommodate winter operation.
[0007] Typical condenser assemblies include fans that cycle "on"
and "off" to maintain adequate control of the condenser capacity
under low ambient conditions. For example, when first and second
longitudinal condenser slabs of a two-slab assembly are
operational, the two fans farthest from the inlet to the condenser
(i.e., one fan per slab) cycle "off" to provide a first reduction
in condenser capacity. The process continues to cycle two fans
"off" until most, if not all fans in the condenser assembly are
cycled "off." After all the fans are cycled "off," one of the two
condenser slabs is isolated. The remaining condenser slab remains
active to cool the refrigerant in the refrigeration system. The
condenser capacity of the remaining condenser slab is further
reduced by flooding a portion of the remaining active condenser
slab.
SUMMARY
[0008] In one embodiment, the invention provides a condenser
assembly to condense a refrigerant for use in a refrigeration
system having a refrigeration circuit, and to reject heat of the
refrigerant to ambient air of the environment. The condenser
assembly includes first and second condenser modules each having a
condenser coil and valve. Each condenser coil includes an inlet
port to receive a refrigerant and an outlet port to discharge the
refrigerant. The valve is in fluid communication with the
corresponding inlet port and regulates flow of the refrigerant
through the corresponding condenser coil. A sensor in communication
with the refrigeration circuit generates a signal indicative of an
inlet pressure of the condenser assembly. A controller is
programmed to actuate the first valve to regulate the flow of the
refrigerant into first condenser coil, and to actuate the second
valve independent of the first valve to regulate the flow of the
refrigerant into the second condenser coil to control condenser
volume based on the signal indicative of the inlet pressure.
[0009] In another embodiment, the invention provides a method of
regulating a condenser assembly for a refrigeration system that
includes a refrigeration circuit having at refrigerant. The method
includes providing a first condenser module having a first inlet
port and a first outlet port in the refrigeration circuit, and a
first valve in fluid communication with the first inlet port. The
method also includes providing a second condenser module having a
second inlet port and a second outlet port in the refrigeration
circuit, and a second valve in fluid communication with the second
inlet port. The method further includes generating a signal
indicative of a condenser inlet pressure, regulating flow of
refrigerant into the first condenser coil, regulating flow of
refrigerant into the second condenser coil by actuating the second
valve independent of the first valve and varying a volume of the
condenser assembly based on the signal indicative of the condenser
inlet pressure.
[0010] In yet another embodiment, the invention provides a
condenser assembly for a refrigeration system having a refrigerant
circuit that circulates a refrigerant. The condenser assembly
includes a plurality of condenser modules. Each condenser module
includes a condenser coil having an inlet port to receive the
refrigerant and an outlet port to discharge the refrigerant, and a
valve in fluid communication with the first inlet port that
actuates to regulate flow of the refrigerant through the condenser
coil. The condenser assembly further includes a controller
programmed to actuate the valves of the plurality of condenser
modules to fluidly connect the condenser coils of the plurality of
condenser modules to the refrigeration circuit to define a first
condenser volume. The controller is further programmed to
selectively actuate at least one valve of the plurality of
condenser modules independent of at least two other valves of the
remaining plurality of condenser modules to isolate the
corresponding at least one condenser coil from the refrigeration
circuit to define a second condenser volume that is different from
the first condenser volume.
[0011] In yet another embodiment the invention provides a method of
regulating a condenser assembly for a refrigeration system
including a refrigeration circuit that circulates a refrigerant.
The method includes providing a plurality of condenser modules,
each module including a condenser coil having an inlet port to
receive the refrigerant and an outlet port to discharge the
refrigerant, and a valve in fluid communication with the first
inlet port. The method further includes actuating the plurality of
valves and fluidly connecting the condenser coils of the plurality
of condenser modules to the refrigeration circuit and defining a
first condenser volume based on connecting the condenser coils of
the plurality of condenser modules to the refrigeration circuit.
The method further includes selectively actuating at least one
valve of the plurality of condenser modules independent of at least
two other valves of the remaining plurality of condenser modules,
isolating the corresponding at least one condenser coil from the
refrigeration circuit, and defining a second condenser volume
different from the first condenser volume with the at least one
condenser coil isolated.
[0012] Other aspects of the invention will become apparent by
consideration of the detailed description and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a perspective view of a condenser assembly
including four condenser modules.
[0014] FIG. 2 is a perspective view of the condenser modules of
FIG. 1;
[0015] FIG. 3 is a perspective view of the condenser module of FIG.
2, with portions removed to illustrate microchannel condenser
coils;
[0016] FIG. 4 is a cut-away view of one of the microchannel
condenser coils of FIG. 3, exposing multiple microchannels; and
[0017] FIG. 5 is a broken view of the microchannel condenser coil
of FIG. 3.
DETAILED DESCRIPTION
[0018] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. The use of "including,"
"comprising," or "having" and variations thereof herein is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items. Unless specified or limited otherwise,
the terms "mounted," "connected," "supported," and "coupled" and
variations thereof are used broadly and encompass both direct and
indirect mountings, connections, supports, and couplings. Further,
"connected" and "coupled" are not restricted to physical or
mechanical connections or couplings.
[0019] FIG. 1 shows a condenser assembly 10 that may be used in a
large-scale retail store refrigeration system (not shown), such as
that found in many large grocery stores or supermarkets. In such a
refrigeration system, the condenser assembly 10 may be positioned
outside the retail store, such as on the rooftop of the store, as
part of a refrigeration circuit defined by the refrigeration system
to allow heat transfer from the condenser assembly to the outside
environment. The role of the condenser assembly 10 in the
refrigeration system is to receive compressed, gaseous refrigerant
from one or more compressors (not shown), condense the gaseous
refrigerant back into its liquid form, and discharge the liquid
refrigerant to one or more evaporators (not shown) located inside
the store. The liquid refrigerant is evaporated when it is passed
through the evaporators, and the gaseous refrigerant is drawn into
the one or more compressors for re-processing into the
refrigeration system.
[0020] The condenser assembly 10 includes an inlet line or inlet
header 15, an outlet line or outlet header 20, and a plurality of
condenser modules 25. The inlet header 15 is coupled to the
plurality of condenser modules 25 to receive refrigerant from the
one or more compressors and to distribute the compressed, gaseous
refrigerant to the plurality of condenser modules 25. In the
illustrated embodiment, an inlet 26 is disposed adjacent an end of
the condenser assembly 10. Refrigerant from the one or more
compressors is delivered to the inlet header 15 through the inlet
26 at the end of the condenser assembly 10 in the direction of
arrow 27. In other embodiments, the inlet 26 may be disposed in
other locations, such as adjacent a middle of the condenser
assembly 10 where the refrigerant from the compressors may be
delivered to the inlet header 15 at a location between an
approximately equal number of condenser modules 25.
[0021] The outlet header 20 is coupled to the plurality of
condenser modules 25 adjacent a bottom of the condenser assembly 10
to receive the cooled, liquid refrigerant from the plurality of
condenser modules 25 and to send the refrigerant to the one or more
evaporators. In some embodiments, the outlet header 20 may include
space to store liquid refrigerant condensed by the condenser
assembly 10 to eliminate a separate, dedicated receiver tank in the
refrigeration system.
[0022] An outlet 28 is disposed adjacent an end of the condenser
assembly 10. Refrigerant from the condenser modules 25 is delivered
from the outlet header 20 through the outlet 28 to the one or more
evaporators from the end of the condenser assembly 10 in the
direction of arrow 29. In other embodiments, the outlet 28 may be
disposed in other locations, such as adjacent a middle of the
condenser assembly 10 where the refrigerant from the condenser
modules 25 may be delivered from the outlet header 20 at a location
between an approximately equal number of condenser modules 25.
[0023] The plurality of condenser modules 25 are supported by a
frame 30. The frame 30 provides support to the plurality of
condenser modules 25 to adequately support the condenser assembly
10 on a surface (not shown). The frame 30 may be a freestanding
structure as shown in FIG. 1. However, the frame 30 may comprise
any number of different designs other than that shown in FIG. 1. As
such, the illustrated frame 30 of FIG. 1 is intended for
illustrative purposes only.
[0024] FIG. 1 illustrates the condenser assembly 10 including four
condenser modules 25. The condenser modules 25 are arranged such
that each module 25 is in parallel with the other modules 25. In
addition, each module 25 extends along a lateral direction of the
condenser assembly 10 rather than along a longitudinal direction.
One of the condenser modules 25 is located adjacent the inlet 26,
such that the one condenser module 25 is closer to the inlet than
the remaining condenser modules 25. Other embodiments may include
less than four or more than four condenser modules 25. If a
relatively large heat load must be satisfied, a relatively large
condenser assembly 10 having a plurality of condenser modules may
be used. However, if a relatively small heat load must be
dissipated a relatively small condenser assembly 10 having only one
or two condenser modules may be required.
[0025] As shown in FIG. 1, each condenser module 25 includes two
condenser coils 35, an air moving device 40 having two fans 100,
105, an inlet line or distributor 45, and an outlet regulator or
valve 55. In the illustrated embodiment of the condenser assembly
10, each condenser module 25 further includes an inlet regulator or
valve 50, with the exception of the condenser module 25 closest to
the inlet to the condenser assembly 10. In other embodiments, the
inlet valve 50 may be included on each condenser module 25 in the
condenser assembly 10.
[0026] FIGS. 2 and 3 show one of the plurality of condenser modules
25. Although the illustrated condenser module 25 includes two
condenser coils 35, other embodiments of the condenser module 25
may include one condenser coil 35 or more than two condenser coils
35 connected in parallel or in series. Each condenser coil 35 is
inclined with respect to horizontal such that the footprint of the
condenser module 25 is reduced. The illustrated condenser module 25
shown includes two microchannel condenser coils 35 as disclosed in
U.S. Pat. No. 6,988,538 (assigned to Hussmann Corporation). In
other embodiments, the condenser coil 35 may be a fin-and-tube
condenser coil inclined with respect to horizontal. Still other
embodiments may include a condenser coil that is substantially
horizontal.
[0027] Each condenser coil 35 includes a first inlet port 60, a
second inlet port 65, an outlet port 70, an inlet manifold 75, a
receiver manifold 80, and an outlet manifold 85. The first inlet
port 60 is coupled to the condenser coil 35 adjacent an upper end
of the inlet manifold 75 to receive a portion of the refrigerant
from the inlet header 15 through the inlet distributor 45. The
second inlet port 65 is coupled to the condenser coil 35 below the
first inlet port 60 adjacent a lower portion of the inlet manifold
75 to also receive refrigerant from the inlet distributor 45. The
outlet port 70 is coupled to the condenser coil 35 at a lower end
of the outlet manifold 85 to discharge the refrigerant from the
condenser coil 35 into the outlet header 20.
[0028] The inlet manifold 75, the receiver manifold 80, and the
outlet manifold 85 are fluidly connected by a plurality of
microchannels 90 (see FIG. 4). The inlet manifold 75 is coupled to
the first and second inlet ports 60, 65 and to the plurality of
microchannels 90 adjacent the inlet distributor 45 to distribute
refrigerant through the micronchannels 90. The receiver manifold 80
is coupled to a side of the condenser coil 35 that is opposite the
inlet and outlet manifolds 75, 85 to receive refrigerant from the
inlet manifold 75 through a portion of the plurality of
microchannels 90 and to distribute the refrigerant through the
remaining of the plurality of the microchannels 90 to the outlet
manifold 85. The outlet manifold 85 is coupled to the condenser
coil 35 between the outlet port 70 and the remaining of the
plurality of the microchannels to receive cooled refrigerant and to
distribute the refrigerant to the outlet port 70. A barrier or
baffle 95 is disposed between the inlet manifold 75 and the outlet
manifold 85 to inhibit flow of refrigerant from the inlet manifold
75 directly to the outlet manifold 85.
[0029] The air moving device 40 is attached to an upper portion of
the condenser module 25 to draw ambient air over the condenser coil
35. The illustrated embodiment in FIGS. 1-3 shows the air moving
device 40 including a first fan 100 and a second fan 105 (e.g.,
single-speed fans, variable speed fans, etc.). The fans 100, 105
are in fluid communication with separate plenums which are divided
by a baffle 110 (FIG. 3). The first and second fans 100, 105 are
attached to the condenser module 25 and each are supported in a fan
shroud 115 to guide airflow over the microchannels 90. An electric
motor (not shown) is supported by the condenser module 25 to drive
at least one of the first and second fans 100, 105 using either an
AC or DC power source. Some embodiments of the condenser module 25
may include more or less than two fans to generate airflow over the
condenser coil 35.
[0030] The inlet distributor 45 attaches to the condenser module 25
downstream of the inlet header 15 and upstream of the first and
second inlet ports 60, 65 to distribute refrigerant from the inlet
header 15 to the first and second inlet ports 60, 65. On condenser
modules 25 that include the inlet valve 50, the inlet valve 50 is
in fluid communication with the first and second inlet ports 60, 65
and attached to the condenser module 25 adjacent the inlet
distributor 45. The inlet valve 50 includes an open position and a
closed position to regulate flow of refrigerant into the respective
condenser module 25. In the illustrated embodiment, the inlet valve
50 is a solenoid valve, although other valves having open and
closed positions are also considered.
[0031] The outlet valve 55 is disposed on the condenser module 25
adjacent the outlet port 70 to regulate flow of refrigerant between
the condenser coil 35 and the outlet header 20. The outlet valve 55
is a check valve that allows refrigerant to flow from the condenser
coil 35 to the outlet header 20 and inhibits flow of refrigerant
from the outlet header 20 to the condenser coil 35.
[0032] The condenser assembly 10 further includes a sensor 120 and
a controller 125. FIG. 1 shows the sensor 120 in electrical
communication with the controller 125 and attached to the inlet
header 15 adjacent the inlet of the condenser assembly 10. The
sensor 120 includes a pressure transducer or other similar device
to monitor a condenser inlet pressure. In other embodiments, a
sensor may be disposed adjacent an outlet of the condenser assembly
10 to measure a condenser outlet pressure. Still other embodiments
may include a sensor disposed in other portions of the
refrigeration circuit to measure a corresponding pressure. Yet
other embodiments can use sensors that measure the temperature of
the refrigerant in the refrigeration system or that measure the
temperature of the air surrounding or interacting with the
condenser coils, the evaporator coils, or other refrigeration
components.
[0033] FIG. 1 shows the controller 125 in electrical communication
with the first and second fans 100, 105, and the inlet valve 50 of
one condenser module 25. The controller 125 is also in electrical
communication with the first and second fans 100, 105, and the
inlet valves 50 of the remaining condenser modules 25, but is not
shown in FIG. 1 for clarity. The controller 125 is coupled to the
electric motor to selectively operate the first and second tans
100, 105 to controllably draw air over the condenser coils 35 in
response to the condenser inlet pressure. In other embodiments, the
first and second fans 100, 105 can be controlled using other
methods (e.g., inverters, electronic commutation, etc.).
[0034] The controller 125 is coupled to the inlet valve 50 to vary
the inlet valve 50 between the open and closed positions to control
flow of refrigerant into the condenser coil 35 in response to the
condenser inlet pressure. In some embodiments, the controller 125,
or portions thereof, may be in electrical communication with the
outlet valve 55, as well as other components of the refrigeration
system (e.g., compressors, evaporators, thermal expansion valves,
etc.). In other embodiments, the controller 125 can base control on
other parameters, such as the temperature of the refrigerant in the
refrigeration system and the temperature of the air surrounding or
interacting with the condenser coils, the evaporator coils, or
other refrigeration components. Still other embodiments may include
a controller that controls the valve 50 based on a pressure of the
refrigeration system other than the condenser inlet pressure, such
as a compressor outlet pressure or a compressor inlet pressure.
[0035] During operation of the refrigeration system utilizing the
condenser assembly 10 the compressed, gaseous refrigerant is
directed into the inlet header 15 and through the condenser modules
25 where the heat transfer between the airflow passing over each
condenser coil 35 causes the gaseous refrigerant to at least
partially condense. The refrigerant flows from the first and second
inlet ports 60, 65 into the inlet manifold 75 and through the
portion of the condenser coil 35. The refrigerant collects in the
receiver manifold 80 and is distributed through the remaining
portion of the condenser coil 35 to further discharge heat from the
refrigerant into the atmosphere. The cooled, substantially liquid
refrigerant flows through the outlet port 70 into the outlet header
20 from the outlet manifold 85. The first and second fans 100, 105
may be activated by the controller to provide and/or enhance the
airflow through the condenser coil 35 and to further enhance
refrigerant cooling.
[0036] The condenser assembly 10 includes a capacity that is
indicative of the ability of the condenser assembly 10 to
effectively reject heat from refrigerant in the refrigeration
circuit to the atmosphere. The condenser capacity varies based on
the overall surface area of the condenser assembly 10 that is
available to provide heat transfer between the condenser assembly
10 and the atmosphere, and may be affected by ambient temperatures
of a surrounding environment or atmosphere. In high ambient air
temperature conditions (i.e., summer operation), the condenser
capacity to cool refrigerant is relatively low. The high ambient
conditions require a high condenser volume to achieve adequate
rejection of heat from refrigerant to the atmosphere. In low
ambient air temperature conditions (i.e., winter operation), the
condenser capacity is relatively high and must be reduced to
maintain the condenser inlet pressure due to an increase in heat
transfer effectiveness between the condenser assembly 10 and the
relatively cool atmosphere. Reduction in heat transfer surface area
by decreasing a volume of the condenser during winter operation
maintains an effective and efficient refrigeration system.
[0037] Winter operation of the condenser assembly 10 requires less
condenser capacity to adequately cool refrigerant due to low
ambient temperatures. The low ambient temperatures cause
refrigerant pressure at the inlet of the condenser assembly 10 to
lower and allow less condenser capacity to adequately cool
refrigerant flowing through the assembly 10. Likewise, relatively
high ambient temperatures cause refrigerant pressure at the inlet
of the condenser assembly to increase and cause a need for a higher
condenser capacity.
[0038] The condenser capacity is at least partially defined by a
condenser volume available to reject heat from refrigerant to the
atmosphere. The condenser assembly 10 defines a first condenser
volume that is indicative of a first condenser capacity when the
all inlet valves are open and the plurality of condenser coils 35
are connected to the refrigeration circuit. The refrigerant flows
through all available condenser modules 25 to provide adequate
cooling for the refrigerant. When the inlet refrigerant pressure
drops below the predetermined level, the controller 125 selectively
actuates at least one inlet salve 50 independent of the remaining
inlet valves 50 to isolate the corresponding condenser module 25
from the refrigeration circuit and to reduce the condenser capacity
a first amount.
[0039] The condenser assembly 10 defines a second condenser volume
that is indicative of a second condenser capacity that is different
from the first condenser volume when at least one condenser module
25 is isolated from the refrigeration circuit. The second condenser
volume can be more than fifty percent of the first condenser volume
by isolating less than one-half of the available condenser modules
25. Alternatively, the second condenser volume can be less than
fifty percent of the first condenser volume by isolating more than
one-half of the available condenser modules 25. In the condenser
assembly 10 shown in FIG. 1, the controller may isolate up to three
of the four condenser modules 25 to reduce the condenser capacity.
For example, when three of the four condenser modules 25 are
isolated from the refrigeration circuit, the second condenser
volume is approximately twenty-five percent of the first condenser
volume. Inversely, isolation of three of the four condenser modules
25 results in a seventy-five percent reduction of the first
condenser volume.
[0040] The controller 125 provides effective refrigeration
management for the refrigeration system by regulating the condenser
capacity. The controller 125 independently operates and controls
each condenser module 25 in the condenser assembly 10 and
selectively isolates or connects each condenser module 25 with the
refrigeration circuit.
[0041] The air moving device 40 generates airflow over the
condenser coil 35 to regulate the condenser capacity of the
condenser assembly 10. The first and second fans 100, 105 are
cycled between "on" and "off" conditions to vary the condenser
capacity based on the condenser inlet pressure of the condenser
assembly 10. Cycling the first and second fans 100, 105 between
"on" and "off" conditions varies the condenser capacity of the
condenser assembly 10 by adjusting ambient airflow passing over the
condenser coils 35. The first and second fans 100, 105 are cycled
"off" in response to a low condenser inlet pressure to reduce the
condenser capacity. Similarly, the first and second fans 100, 105
are cycled "on" in response to a high condenser inlet pressure to
increase the condenser capacity. At least one of the first and
second fans 100, 105 remains "on" when refrigerant flows through
the corresponding condenser coil 35 of the condenser module 25 that
includes those fans 100, 105. The controller selectively cycles at
least one of the first fan 100 and the second fan 105 independent
of the other of the first fan 100 and the second fan 105 to vary
the condenser capacity. In other embodiments, the controller
simultaneously cycles the first and second fans 100, 105 between
"on" and "off" conditions to vary the condenser capacity. In still
other embodiments, the first and second tans 100, 105 can be cycled
or controlled by other methods as described above.
[0042] The controller 125 also operates the inlet valve 50 to
regulate the condenser capacity. The controller 125 manages the
refrigeration system by varying the inlet valve 50 between the open
and closed positions to isolate the condenser module 25 from the
refrigeration circuit. Isolation of the condenser module 25 closes
off the condenser coil 35 from refrigerant flowing through the
refrigeration circuit. Each inlet valve 50 is operated by the
controller 125 independent of the remaining plurality of inlet
valves 50 to isolate the corresponding condenser module 25 from the
remaining plurality of condenser modules 25. In the illustrated
embodiment, the controller is configured to selectively isolate the
condenser modules 25 that include the inlet valves 50 without
shutting down the condenser assembly 10. Refrigerant continues to
flow through the condenser module 25 that is nearest the inlet 26
(i.e., the condenser module 25 without the inlet valve 50), due to
the lack of the inlet valve 50 on that condenser module 25. The
condenser module 25 without the inlet valve 50 cannot be isolated
until the condenser assembly 10 is completely shutdown. In
embodiments that include the inlet valve 50 on each condenser
module 25, the controller 125 can move the inlet valve 50 on the
condenser module 25 that is nearest the inlet 26 to isolate the
condenser assembly 10 so that maintenance can be performed on the
condenser assembly 10.
[0043] If the pressure of the refrigerant at the inlet to the
condenser assembly 10 is below a predetermined level, the
controller 125 first cycles "off" at least one of the first and
second fans 100, 105 of one of the condenser modules 25 to decrease
the condenser capacity. The controller 125 cycles "off" the
remaining fans 100, 105 as needed to vary the condenser capacity
and to maintain adequate refrigerant pressure at the inlet to the
condenser assembly 10.
[0044] The controller 125 simultaneously cycles "off" any of the
first and second fans 100, 105 that are "on" when the corresponding
inlet valve 50 is moved to the closed position. There is no need
for the first and second fans 100, 105 to operate when the inlet
valve 50 is closed because no refrigerant flows through the
condenser coil 35 of the respective isolated condenser module 25.
In the illustrated embodiment, the controller 125 moves the inlet
valve 50 of the condenser module 25 farthest from the inlet of the
condenser assembly 10 to the closed position to further decrease
the condenser capacity by reducing the condenser volume in response
to the condenser inlet pressure below the predetermined level. The
controller 125 continues to reduce condenser capacity by closing
each of the remaining inlet valves 50 as needed to isolate the
remaining condenser modules 25.
[0045] In embodiments that include the inlet 26 and/or outlet 28 of
the condenser assembly 10 adjacent the middle of the condenser
assembly 10, the sequence of shutdown of the condenser modules 25
begins with the condenser module 25 that is farthest from the
condenser module 25 that is the last to be shutdown or isolated
prior to shutdown of the condenser assembly 10. In the illustrated
embodiment, the condenser module 25 that is the last to be
deactivated corresponds to the condenser module 25 that is without
the inlet valve 50 adjacent the end of the condenser assembly 10.
The sequence of isolation moves from the condenser modules 25
located farthest from the condenser module 25 without the inlet
valve 50 toward the condenser module 25 without the inlet valve 50,
such that the condenser modules 25 that are closest to the
condenser module 25 without the inlet valve 50 are the last to be
isolated. In other words, the condenser module 25 that is closest
to the inlet 26 and/or outlet 28 of the condenser assembly 10 is
the last to be deactivated.
[0046] The refrigeration management provided by the controller 125
allows precise control of the condenser volume to maintain an
adequate condenser inlet pressure. The sequence of isolation of the
condenser modules 25 generally begins with the condenser module 25
farthest from the inlet to the condenser assembly 10. The
controller 125 isolates the next-farthest condenser module 25 each
time the condenser volume must be reduced. When the condenser
volume must increase to compensate for an increased condenser inlet
pressure, the sequence is reversed. Specifically, the controller
125 opens the inlet valve 50 of the previously-isolated condenser
module 25 that is closest to the inlet of the condenser assembly
10. As the condenser inlet pressure increases and there is a need
for more condenser volume, the controller 125 opens the inlet valve
50 of the condenser module 25 that is the next-closest to the inlet
of the condenser assembly 10. The process continues until there is
adequate condenser volume to reject heat from refrigerant to the
surrounding environment.
[0047] The amount of refrigerant in the refrigeration circuit
remains constant during summer and winter operation and reduces the
need for large receivers to store refrigerant. Isolation of the
condenser module 25 from the refrigeration circuit by the
controller 125 limits flow of refrigerant through a portion of the
condenser assembly 10. After isolation of the condenser module 25,
the outlet valve 55 allows refrigerant within the condenser coil 35
to drain into the outlet header 20. The outlet valve 55 inhibits
flow of refrigerant from the outlet header 20 into the condenser
coil 35 and isolates the coil 35 from the refrigeration circuit.
Draining the refrigerant from the isolated condenser coil 35
maintains the condenser inlet pressure at the predetermined level
without the need for a receiver to store excess refrigerant.
[0048] When the sensor 120 indicates an increase in the inlet
refrigerant pressure above the predetermined level, the controller
125 actuates the inlet valve 50 of at least one condenser module 25
to allow refrigerant to flow into the corresponding condenser coil
35. The controller 125 connects each isolated condenser module 25
one at a time to the refrigeration circuit. If the condenser
capacity remains inadequate to cool the refrigerant and to maintain
the inlet pressure at about the predetermined level, one or both of
the first and second fans 100, 105 may be activated to draw ambient
air over the condenser coil 35 of the respective condenser module
25 to improve the condenser capacity. The controller 125 connects
enough of the condenser modules 25 to the refrigeration circuit to
maintain the inlet condenser pressure at about the predetermined
level.
[0049] Thus, the invention provides, among other things, an
electronic control to regulate condenser capacity and refrigerant
charge of a condenser assembly. Various features and advantages of
the invention are set forth in the following claims.
* * * * *