Cross-reverse type air-conditioning system
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.
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.
The present invention can be applied on residential, agriculture, and industrial purposes.
BACKGROUND OF THE INVENTIONThe 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.”
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.
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.
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.
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.
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 INVENTION1. 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.
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.
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.
The first embodiment of present invention is shown in
Now referring to
Now referring to
Now referring to
As shown in
As shown in
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
As shown in
As shown in
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.
A construction scheme is shown in
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.
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.
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
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.
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.
Type: Application
Filed: Mar 16, 2009
Publication Date: Jul 9, 2009
Inventor: Lung-Tan Hu (Aldergrove)
Application Number: 12/381,658
International Classification: F25D 21/06 (20060101); F25B 1/00 (20060101); F25B 7/00 (20060101);