U.S. patent application number 12/381658 was filed with the patent office on 2009-07-09 for cross-reverse type air-conditioning system.
Invention is credited to Lung-Tan Hu.
Application Number | 20090173092 12/381658 |
Document ID | / |
Family ID | 37876968 |
Filed Date | 2009-07-09 |
United States Patent
Application |
20090173092 |
Kind Code |
A1 |
Hu; Lung-Tan |
July 9, 2009 |
Cross-reverse type air-conditioning system
Abstract
The present invention provides an air-conditioning system
capable of continuous heating operation over an outdoor temperature
range of 20 degree to negative 40 degree Celsius. The present
invention utilizes at least two sets of the evaporators capable of
cross-reverse refrigerant circulation and cross-air defrosting
process, which alternately generates the heat energy required for
the defrosting process and the air-conditioning, and said
air-conditioning system can apply a combination of the two defrost
methods to raise overall heating efficiency.
Inventors: |
Hu; Lung-Tan; (Aldergrove,
CA) |
Correspondence
Address: |
Hu Lung-Tan
25755 48th Avenue
Aldergrove
BC
V4W1J6
CA
|
Family ID: |
37876968 |
Appl. No.: |
12/381658 |
Filed: |
March 16, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11311085 |
Dec 20, 2005 |
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12381658 |
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Current U.S.
Class: |
62/151 ; 62/278;
62/335; 62/498 |
Current CPC
Class: |
F25B 2400/04 20130101;
F25B 47/022 20130101; F25B 29/003 20130101; F25B 5/02 20130101 |
Class at
Publication: |
62/151 ; 62/498;
62/335; 62/278 |
International
Class: |
F25D 21/06 20060101
F25D021/06; F25B 1/00 20060101 F25B001/00; F25B 7/00 20060101
F25B007/00 |
Claims
1. A cross-reverse type air-conditioning system comprising: a) a
main refrigeration circuit for the air-conditioning, said main
refrigeration circuit consisting a main compressor for pressurizing
refrigerant, a main condenser for condensing refrigerant and
releasing heat, at least two evaporators for evaporating
refrigerant and absorbing heat energy, a main expansion valve for
regulating the refrigerant pressure difference between said main
condenser and said two evaporators; b) each of said two evaporators
including flow control means for disabling the evaporation process
individually by blocking the refrigerant passage from said main
expansion valve; c) each of said two evaporators including flow
control means for providing a refrigerant passage from said main
compressor to said two evaporators individually; d) each of said
two evaporators including a heat insulated space, and said heat
insulated space including individual outdoor-air-intake means; e) a
control system for selecting defrosting methods and controlling all
said flow control means and outdoor-air-intake means; f) said
multi-range cross-reverse air-conditioning system is capable of
defrosting each evaporator by a defrost-cycle of the cross-reverse
defrosting process, wherein each of said evaporator will
alternately operate with the cross-reverse defrosting process and
the refrigerant evaporation process.
2. A cross-reverse type air-conditioning system as defined in claim
1, wherein; during the full capacity heating operation, all said
evaporators will operate with the evaporation process; all
refrigerant passages from said main compressor to each evaporator
will be blocked to disable the refrigerant-flow associated with the
cross-reverse defrosting process; a controlled flow of outdoor air
is admitted into the heat insulated space of each evaporator by its
associated outdoor-air-intake means.
3. A cross-reverse type air-conditioning system as defined in claim
1, wherein; during the cross-reverse defrosting process of each
evaporator, said outdoor-air-intake means will stop inhaling
outdoor air into the heat insulated space of the evaporator that is
defrosting; a controlled amount of the pressurized refrigerant will
be distributed into the evaporator that is defrosting, the
accumulated frost on said evaporator will be melt by the heat
generated from the condensation process; the other evaporator will
continue the evaporation process with a flow of outdoor air, the
main compressor and the main condenser will continue their
operation to generate the heat energy for the air-conditioning.
4. A cross-reverse type air-conditioning system as defined in claim
1, which further comprises additional evaporators; wherein each of
said additional evaporators includes individual flow control means
for commencing the cross-reverse defrosting process; during the
defrost-cycle of the cross-reverse defrosting process, the
evaporator that is defrosting will receive a portion of the
pressurized refrigerant from the main compressor, said evaporator
will defrost with the heat energy generated by the condensation
process therein.
5. A cross-reverse type air-conditioning system as defined in claim
1, wherein; the evaporator that is defrosting with the
cross-reverse defrosting process will receive a flow of pressurized
refrigerant from the main compressor, and said flow of pressurized
refrigerant will condense in said evaporator and exit through its
associated pressure regulating means into other evaporator that is
operating with the evaporation process.
6. A cross-reverse type air-conditioning system as defined in claim
1, wherein; each evaporator can further comprise sensor means for
detecting the progress of the cross-reverse defrosting process; and
said control system can adjust the defrost-cycle accordingly for
optimum heating efficiency.
7. A cross-reverse type air-conditioning system as defined in claim
1, wherein; said control system is capable to commencing a
defrost-cycle of the cross-air defrosting process, wherein each of
said evaporator will alternately operate with the cross-air
defrosting process and the refrigerant evaporation process.
8. A cross-reverse type air-conditioning system comprising: a) a
refrigeration circuit comprising of four sections, which are a
refrigerant-compressing section, a refrigerant-condensing section,
a refrigerant-evaporating section, and a cross-reverse section;
said refrigerant-compressing section provides a flow of
pressurized-refrigerant to said refrigerant-condensing section and
said cross-reverse section; said refrigerant-condensing section
will condense said flow of pressurized-refrigerant therein, and
release the heat energy for air-conditioning; said
refrigerant-condensing section will provide a flow of refrigerant
to said refrigerant-evaporating section; said
refrigerant-evaporating section absorbs heat from the outdoor
environment and evaporates said flow of refrigerant therein, and
then produces a flow of evaporated-refrigerant into said
refrigerant-compressing section; b) said refrigerant-compressing
section comprises at least one compressor (101); c) said
refrigerant-condensing section comprises at least one main
condenser (102); d) said refrigerant-evaporating section comprises
at least two evaporator units, which are first-evaporator (121) and
second-evaporator (122); each of said evaporator units has an
individual heat insulated space and outdoor-air-intake; e) flow
control means for independently controlling a refrigerant passage
from said refrigerant-compressing section to said first-evaporator
(121); f) flow control means for independently controlling a
refrigerant passage from said refrigerant-compressing section to
said second-evaporator (122); g) said cross-reverse section
comprises a controlled refrigerant passage to each of said
evaporator in said refrigerant-evaporating section; a first
reverse-flow valve (151) for distributing a flow of pressurized
refrigerant to said first evaporator (121) during the cross-reverse
defrosting process of said first evaporator (121); a second
reverse-flow valve (152) for distributing a flow of pressurized
refrigerant to said second evaporator (122) during the
cross-reverse defrosting process of said second evaporator (122);
h) a control system for commencing the cross-reverse defrosting
method and the cross-air defrosting method by controlling all said
flow control means and outdoor-air-intake means; i) said
multi-range cross-reverse air-conditioning system is capable of
defrosting each evaporator by a defrost-cycle of the cross-reverse
defrosting process, wherein each of said evaporator will
alternately operate with the cross-reverse defrosting process and
the refrigerant evaporation process.
9. A cross-reverse type air-conditioning system as defined in claim
8, wherein; during the full capacity heating operation, all said
evaporators will operate with the evaporation process; said
cross-reverse section will be disabled by shutting said first
reverse-flow valve (151) and said second reverse-flow valve (152);
a controlled flow of outdoor air is admitted into the heat
insulated space of said first evaporator (121) and the heat
insulated space of said second evaporator (122) by their associated
outdoor-air-intake means.
10. A cross-reverse type air-conditioning system as defined in
claim 8, wherein; during the cross-reverse defrosting process of
said first evaporator (121), the refrigerant passage of said first
evaporator (121) will be separated from said
refrigerant-evaporating section by its associated flow control
means, and first reverse-flow valve (151) will open to provide a
flow of pressurized refrigerant into said first evaporator (121),
therefore, the accumulated frost on said first evaporator (121)
will melt by the heat energy generated by the condensation process
therein, meanwhile said second evaporator (122) will operate with
the evaporation process by absorbing the heat of the
outdoor-air-flow, said main compressor (101) and said main
condenser (102) will continue operation for the
air-conditioning.
12. A cross-reverse type air-conditioning system as defined in
claim 8, wherein; during the cross-reverse defrosting process of
said second evaporator (122), the refrigerant passage of said
second evaporator (121) will be separated from said
refrigerant-evaporating section by its associated flow control
means, and second reverse-flow valve (152) will open to provide a
flow of pressurized refrigerant into said second evaporator (122),
therefore, the accumulated frost on said second evaporator (122)
will melt by the heat energy generated by the condensation process
therein, meanwhile said first evaporator (121) will operate with
the evaporation process by absorbing the heat of the
outdoor-air-flow, said main compressor (101) and said main
condenser (102) will continue operation for the
air-conditioning.
13. A cross-reverse type air-conditioning system as defined in
claim 8, which can further comprises additional evaporators;
wherein each of said additional evaporators comprises individual
flow control means and reverse-flow and outdoor-air-intake means
for commencing the cross-reverse defrosting process.
14. A cross-reverse type air-conditioning system as defined in
claim 8, wherein; said control system can employ a combination of
the cross-reverse defrosting process and the cross-air defrosting
process to maximize the heating efficiency of the
air-conditioning.
15. A cross-reverse type air-conditioning system as defined in
claim 8, wherein; each evaporator can further comprise sensor means
for detecting the progress of the cross-reverse defrosting process;
and said control system can adjust the defrost-cycle accordingly
for optimum heating efficiency.
16. A cross-reverse type air-conditioning system as defined in
claim 8, wherein; said control system will employ a defrost-cycle
of the cross-reverse defrosting process when the outdoor
temperature is within the range of 10 degree Celsius to negative 40
degree Celsius.
17. A forced-air-defrost type air-conditioning system as defined in
claim 8, wherein; said control system will employ a defrost-cycle
of the cross-air defrosting process when the outdoor temperature is
within the range of 20 degree Celsius to 0 degree Celsius.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a forced-air-defrost type
air-conditioning system, more particularly to a cross-reverse type
air-conditioning system capable of the cross-reverse defrosting
process and the cross-air defrosting process.
[0002] The present invention can be applied on residential,
agriculture, and industrial purposes.
BACKGROUND OF THE INVENTION
[0003] The present invention is a divisional application of the
patent application No. 20070137238 filed on Dec. 20, 2005, entitled
"Multi-range cross defrosting heat pump system and humidity control
system."
[0004] Current available heat pump requires different types of
compressors for different range of working environment temperature;
therefore, the user may need to install multiple air-conditioning
systems such as a combination of a heat pump and a gas heater for
different range of working temperature. One of the reasons is the
low efficiency of the heat pump under low working temperature;
another reason is the need for interrupting operation due to the
frost conditions on evaporators.
[0005] The current defrosting methods such as electrical defrost
system and reverse-circulation defrost system require the heat pump
to stop operation while defrosting. Therefore, it is one objective
of the present invention to provide an air-condition heat pump
capable of uninterrupted operation during system defrosting
process.
[0006] Another objective of the present invention is to provide the
most efficient control methods for cross defrosting heat pump
system under different temperature and humidity conditions; most
heat pumps require the heat energy from other source to maintain
the heating efficiency while the present invention defrosts with
the heat energy absorbed from the environment and the heat energy
generated by the compressor.
[0007] Current compressors have very low efficiency under low
temperature range, the current two-stage compressors utilize two
compression strokes to increase system efficiency, however, the
current two-stage compressors can not operate under different
temperature range, in other words, the two-stage compressor can not
operate under the environment that does not require pressure
boosting; therefore it is another objective of the present
invention to provide a multi-stage pressure boosting heat pump
system capable of adjusting the level of pressure boosting in order
to operate under a wide range of working environment
temperature.
[0008] In general, current heat pump system has very limited range
of working temperatures due to the limitation and the operation
efficiency of the compressor; however, in many circumstances, the
environment temperature may vary from negative 40 degree to 20
degree Celsius, therefore it is main objective of the present
invention to provide a multi-range cross defrosting heat pump
capable of operating under a wide range of working environment
temperature at high efficiency.
SUMMARY OF THE INVENTION
[0009] 1. It is the primary objective of the present invention to
provide a cross-reverse type air-conditioning system capable of
defrosting with cross-reverse refrigerant circulation and cross-air
defrosting process.
[0010] 2. It is the secondary objective of the present invention to
provide the control method for the cross-reverse type
air-conditioning system to prevent the evaporators from
malfunctioning.
[0011] 3. It is the third objective of the present invention to
provide a cross-reverse type air-conditioning system capable for
frost-prevention over an outdoor temperature range 20 degree
Celsius to negative 40 degree Celsius.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1A to FIG. 1I are the illustrative diagrams of the
cross-reverse type air-conditioning system. The control logic table
of cross-reverse type air-conditioning system is provided in Table.
1 as a reference to FIG. 1A to FIG. 1E.
[0013] FIG. 1F is an exemplary construction scheme of the
cross-reverse type air-conditioning system utilizing rotary
valves.
[0014] FIG. 1H and FIG. 1J are construction schemes of the
cross-reverse type air-conditioning system utilizing more than two
evaporators.
[0015] FIG. 1I is another possible modified construction scheme
based on the cross-reverse type air-conditioning system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The first embodiment of present invention is shown in FIG.
1A to FIG. 1F and the table 1 is used as a reference to understand
the control method of the present invention. As shown in the table
1, the present invention includes a combination of the two
defrosting methods, the first defrosting method can be applied to
the operation environment where the outdoor temperature is from 20
degree Celsius to 0 degree Celsius, the second defrosting method
can be applied to the operation environment where the outdoor
temperature is from 10 degree to negative 40 degree Celsius; the
threshold of switching the system from the first defrosting method
to the second defrosting method can be adjusted according to the
operating condition. However, for the ease of comprehension, the
following embodiments will be explained with a threshold of 5
degree Celsius for the system to switch from the first defrosting
method to the second defrosting method.
[0017] Now referring to FIG. 1A and the table 1, the cross-reverse
type air-conditioning system comprising the following basic
components: main compressor 101, main condenser 102, first
evaporator 121, second evaporator 122, main expansion valve 103,
first upper-flow control valve 131, second upper-flow control valve
132, first lower-flow control valve 171, second lower-flow control
valve 172, first reverse-flow control valve 151, second
reverse-flow control valve 152, first expansion valve 141, second
expansion valve 142, first one-way valve 161, second one-way valve
162, first venting fan (not shown), second venting fan (not shown),
separate insulation means (not shown) for each evaporator.
[0018] Now referring to FIG. 1A for the full capacity heating
operation of the cross-reverse type air-conditioning system; the
refrigerant-flow of the first evaporator 121 and the
refrigerant-flow of the second evaporator 122 are enabled, so that
both the first evaporator 121 and the second evaporator 122 are
absorbing the heat from the outdoor-air-flow for the evaporating
process therein; the first upper-flow control valve 131 and the
first lower-flow control valve 171 are open to enable the
refrigerant-flow of the first evaporator 121; the second upper-flow
control valve 132 and the second lower-flow control valve 172 are
open to enable the refrigerant flow of the second evaporator 122;
all the control valves for cross-reverse refrigerant circulation
are shut to disable the hot refrigerant flow from the main
compressor 101 to the first evaporator 121 and the second
evaporator 122; the first reverse-flow control valve 151 and second
reverse-flow control valve 152 are shut. The refrigerant in said
two evaporators absorbs heat from the outdoor-air-flow and next,
the evaporated refrigerant is pressurized in main compressor 101,
and next the main condenser 102 releases the heat energy for the
air-conditioning.
[0019] Now referring to FIG. 1B and FIG. 1C for the first
defrosting method of the cross-reverse type air-conditioning
system, said first defrosting method can also be called as
cross-air defrosting process; when the first defrosting method is
employed, said system operates with a defrost-cycle which is
depending on the outdoor temperature and the humidity. An exemplary
defrost-cycle is provided as follow; the first evaporator 121 and
the second evaporator 122 operate with the evaporation process for
5 minutes as shown in FIG. 1A, and next the first evaporator 121
defrosts with the first defrosting method as shown in FIG. 1B, and
next the second evaporator 122 defrosts with the first defrosting
method as shown in FIG. 1C, and then said system repeats the
defrost-cycle until further change in the outdoor temperature is
detected.
[0020] As shown in FIG. 1B, the first evaporator is defrosting with
the first defrosting method; the refrigerant flow of the first
evaporator 121 is disabled by the first upper-flow control valve
131 and first lower-flow control valve 171, the first venting fan
will operate at full speed to draw the outdoor air through the
first evaporator 121 to melt the frost thereon; the second
evaporator 122 will continue the evaporation process to provide a
sufficient refrigerant flow to the main compressor 101, the main
condenser 102 will continue to generate the heat energy required
for the air-conditioning.
[0021] As shown in FIG. 1C, the second evaporator is defrosting
with the first defrosting method, the refrigerant flow of the
second evaporator 122 is disabled by the second upper-flow control
valve 132 and the second lower-flow control valve 172, the second
venting fan will operate at full speed to draw the outdoor air
through the second evaporator 122 to melt the frost thereon; the
first evaporator 121 will continue the evaporation process to
provide a sufficient refrigerant flow to the main compressor 101,
the main condenser 102 will continue to generate the heat energy
required for the air-conditioning.
[0022] When the outdoor temperature reaches the threshold, at which
the first defrosting method cannot provide enough heat energy with
the outdoor air, the system can switch to the second defrosting
method as shown in FIG. 1D and FIG. 1E, and said second defrosting
method is also called as the cross-reverse defrosting process. The
cross-reverse defrosting process also operate in a similar
defrost-cycle as the first defrosting method, an exemplary
defrost-cycle is provided as follows; the first evaporator 121 and
the second evaporator 122 together operate to generate heat energy
as shown in FIG. 1A for 10 minute, and next the first evaporator
121 defrosts with the cross-reverse defrosting process as shown in
FIG. 1D for 3 minute, and next the second evaporator 122 defrosts
with the cross-reverse defrosting process as shown in FIG. 1E for 3
minute, and next the system repeats the cycle until further change
in the outdoor environment is detected.
[0023] As shown in FIG. 1D, the first evaporator 121 is defrosting
with the second defrosting method, the cross-reverse defrosting
process; the first evaporator 121 will stop the evaporation process
and disable the refrigerant-flow from the main expansion valve 103
by shutting the first upper-flow control valve 131 and first
lower-flow control valve 171. The cross-reverse refrigerant
circulation will be initiated by opening the first reverse-flow
control valve 151, providing a refrigerant passage from the main
compressor 101 to the first evaporator 121, so the pressurized
refrigerant from the discharge port of the main compressor 101 will
now flow to the main condenser 102 and the first evaporator 121;
said pressurized refrigerant will condense in the first evaporator
121 to heat up and melt the accumulated ice on the first evaporator
121, and said refrigerant-flow of the first evaporator 121 will
exit through the first expansion valve 141 and the first one-way
valve into the second evaporator 122; the second evaporator 122
will now receive both the refrigerant-flow from the main expansion
valve 103 and the refrigerant-flow from the first one-way valve
161; in other words, the main condenser 102 and the first
evaporator 121 will be condensing refrigerant to generate heat
energy for the air-conditioning and the cross-reverse defrosting
process respectively, while the second evaporator 122 will be
evaporating the refrigerant by absorbing the heat from the
outdoor-air-flow; the first venting fan will stop or spin slowly to
conserve the heat energy in the first evaporator 121, the second
venting fan will be operating at full speed to provide a sufficient
flow of the outdoor air for the evaporating process of the second
evaporator 122.
[0024] As shown in FIG. 1E, the second evaporator 122 is defrosting
with the second defrosting method, the cross-reverse defrosting
process; the second evaporator 122 will stop the evaporation
process and disable the refrigerant-flow from the main expansion
valve 103 by shutting the second upper-flow control valve 132 and
second lower-flow control valve 172. The cross-reverse refrigerant
circulation will be initiated by opening the second reverse-flow
control valve 152, providing a refrigerant passage from the main
compressor 101 to the second evaporator 122, so the pressurized
refrigerant from the discharge port of the main compressor 101 will
now flow to the main condenser 102 and the second evaporator 122;
said pressurized refrigerant will condense in the second evaporator
122 to heat up and melt the accumulated ice on the second
evaporator 122, and said refrigerant-flow of the second evaporator
122 will exit through the second expansion valve 142 and the second
one-way valve 162 into the first evaporator 121; the first
evaporator 121 will now receive both the refrigerant-flow from the
main expansion valve 103 and the refrigerant-flow from the second
one-way valve 162; in other words, the main condenser 102 and the
second evaporator 122 will be condensing refrigerant to generate
heat energy for the air-conditioning and the cross-reverse
defrosting process respectively, while the first evaporator 121
will be evaporating refrigerant by absorbing the heat from the
outdoor-air-flow; the first venting fan will stop or spin slow to
conserve the heat energy in the second evaporator 122, the first
venting fan will be operating at full speed to provide a sufficient
flow of the outdoor air for the evaporating process of the first
evaporator 121.
[0025] Under the operating condition where the outdoor temperature
is below 0 degree Celsius, the cross-reverse type air-conditioning
system has to continue the cross-reverse refrigerant circulation at
an appropriate time interval to prevent any of the evaporators from
being completely frosted; in order to maximize the efficiency of
heat absorption, the cross-reverse defrosting air-condition system
can employed more than 2 evaporators for reducing the time required
for each defrosting process intervals; in other words, for a
cross-reverse type air-conditioning system with three evaporators,
the first evaporator will defrost with the cross-reverse defrosting
process while the second evaporator and the third evaporator are
continuing the evaporating process for a time interval, and next
the second evaporator will defrost with the cross-reverse
defrosting process while the first evaporator and the third
evaporator are continuing the evaporating process for a time
interval, and next the third evaporator will defrost with the
cross-reverse defrosting process while the first evaporator and the
second evaporator are continuing the evaporating process for a time
interval. Various time schedule can be used to maximize the heating
efficiency of the present invention, however, it should be noted
that the time interval for switching between the defrosting process
of each evaporator should not be overestimated to cause all the
evaporators being heavily frosted at the same time because the
present invention is mostly used in the cold region, and the
malfunction of the indoor heating can be fatal for the residential
use in the crucial weather.
[0026] A construction scheme is shown in FIG. 1H for the
cross-reverse type air-conditioning system with more than two
evaporators. When each evaporator is defrosting with first
defrosting method, that evaporator stops its refrigerant-flow by
shutting its associated upper-flow control valve and lower-flow
control valve, and its associated venting fan is operating at full
speed to defrost with the outdoor-air-flow. A construction scheme
is shown in FIG. 1.J for the cross-reverse type air-conditioning
system with four evaporators and the cross-reverse refrigerant
circuit.
[0027] When each evaporator is defrosting with second defrosting
method, its associated upper-flow control valve and lower-flow
control valve are shut, and its reverse-flow control valve is open
to provide direct passage between that evaporator and discharge
port of the main compressor; its associated venting fan will stop
or spin slowly to conserve the heat within the heat insulated space
of that evaporator. The second defrosting method utilizes the heat
absorbed from the other evaporators and the heat generated from the
main compressor to melt the ice on the evaporator that is
defrosting.
[0028] An exemplary defrost-cycle is provide for the cross-reverse
type air-conditioning system with 3 evaporators; all evaporators
are evaporating refrigerant at full capacity for 5 minutes, then
the first evaporator defrosts for 5 minute, and next the second
evaporator defrosts for 5 minute, and next the third evaporator
defrosts for 5 minutes, thus completed one cycle and the system
will detect if the outdoor temperature has raised or decreased over
the threshold for switching to another defrost method.
[0029] For easier maintenance, most control valves can be combined
into one single rotary valve or other multi-port control valve
means. A control valve construction scheme of the cross-reverse
type air-conditioning system with rotary valves is provided in FIG.
1F, wherein first reverse-flow control valve 151 and first
upper-flow control valve 131 are replaced with first rotary
upper-flow control valve 131 capable of same functions, first
lower-flow control valve 171 and first one-way valve 161 can be
replaced with first rotary lower-flow control valve 171 capable of
same functions. Another construction scheme is provided in FIG. 1I,
wherein the pressurized refrigerant enters the defrosting
evaporator from the discharge port of the defrosting evaporator
during the cross-reverse defrosting process. Many other
construction schemes and control valve means are possible to
perform the same task based on the present invention and should be
considered within the scope of the present invention.
[0030] The system can also further employ a defrosting process
sensor means to detect if the evaporator has melted all the ice
thereon, if no further defrosting is required, the system will
reset to the next step of the defrost-cycle. The defrosting process
sensor means can be a refrigerant pressure or refrigerant
temperature sensor.
TABLE-US-00001 TABLE 1 Control logics of Cross-reverse type
air-conditioning system Full capacity Cross-air defrosting
Cross-air defrosting Cross-reverse defrosting Cross-reverse
defrosting Heating process of process of process of process of
Label Component Name Operation First evaporator Second evaporator
First evaporator Second evaporator 102 Main condenser Condensation
Condensation Condensation Condensation Condensation Process Process
Process Process Process 121 First evaporator Evaporation Defrosting
with Evaporation Cross Reverse Evaporation Process Outdoor-air-flow
Process Defrosting Process (no refrigerant flow) 122 Second
evaporator Evaporation Evaporation Defrosting with Evaporation
Cross Reverse Process Process Outdoor-air-flow Process Defrosting
(no refrigerant flow) 151 First reverse-flow Closed Closed Closed
Open Closed control valve 152 Second reverse-flow Closed Closed
Closed Closed Open control valve 131 First upper-flow Open Closed
Open Closed Open control valve 171 First lower-flow Open NA Open
Closed Open control valve (preferably closed) 132 Second upper-flow
Open Open Closed Open Closed control valve 172 Second lower-flow
Open Open NA Open Closed control valve (preferably closed) First
venting fan Full speed Full speed Full speed Decreasing speed Full
speed Second venting fan Full speed Full speed Full speed Full
speed Decreasing speed
* * * * *