Multi-range composite-evaporator type cross-defrosting system

Abstract

The present invention provides a multi-range composite-evaporator type cross-defrosting system for continuous heating operation under an environment temperature range from 20 degree to negative 40 degree Celsius. Said system employs a combination of two defrosting methods under different temperature and humidity conditions; the first defrosting method is used for the outdoor temperature range of 20 degree Celsius to 0 degree Celsius, the second defrosting method is used in the outdoor temperature range of 10 degree Celsius to negative 40 degree Celsius, and a control system will adjust the appropriate threshold for switching between the two defrosting methods.

Description

FIELD OF THE INVENTION

The present invention relates to a multi-range composite-evaporator type cross-defrosting system, more particularly to a heating or air-conditioning system that is capable of continuous operation under the outdoor temperature range of 20 degree Celsius to negative 40 degree Celsius.

The present invention can be applied on the fields of residential, agriculture, and industrial; more particularly, the present invention can be used on heating and air-conditioning purpose.

BACKGROUND OF THE INVENTION

The present invention is a divisional application of the patent application No. 20070137238 filed on Dec. 20^th 2005, entitled “Multi-range cross defrosting heat pump system and humidity control system.”

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

1. It is a primary object of the present invention to provide a multi-range composite-evaporator type cross-defrosting system capable of continuous operation under various ranges of temperature.

2. It is a second object of the present invention to provide a multi-range composite-evaporator type cross-defrosting system capable of continuous operation during the defrosting process.

3. It is another object of the present invention to provide an efficient defrosting control method of the multi-range composite-evaporator type cross-defrosting system, which is capable of cross-defrosting with the heat energy absorbed from the outdoor-air-flow and the heat energy generated from the compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 6A to FIG. 6E are the illustrative diagrams of the composite-evaporator type cross-defrosting system constructed of fluid-defrost type composite-evaporators; the control logics of said system is provided in Table.6 as a reference. FIG. 6G is a demonstrative diagram of the composite-evaporators.

FIG. 6A is an operation scheme of the first embodiment, in which all the composite-evaporators are operating with evaporation process.

FIG. 6B and FIG. 6C are the operation schemes of the first defrosting method of the first embodiment, which is also called as the cross-air defrosting process.

FIG. 6D and FIG. 6E are the operation schemes of the second defrosting method of the first embodiment, which is also called as the cross-fluid defrosting process.

FIG. 6H is an alternative construction scheme of the first embodiment with four composite-evaporators.

FIG. 2A to FIG. 2E are the illustrative diagrams of the composite-evaporator type cross-defrosting system constructed of refrigerant-defrost type composite-evaporators; the control logics of said system is provided in Table.2 as a reference.

FIG. 2A is an operation scheme of the second embodiment, in which all the composite-evaporators are operating with evaporation process.

FIG. 2B and FIG. 2C are the operation schemes of the first defrosting method of the second embodiment, which is also called as the cross-air defrosting process.

FIG. 2D and FIG. 2E are the operation schemes of the second defrosting method of the second embodiment, which is also called as the cross-refrigeration defrosting process.

FIG. 2G is an alternative construction scheme of the second embodiment with four composite-evaporators

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention includes two main embodiments, the first embodiment is the composite-evaporator type cross-defrosting system constructed of fluid-defrost type composite-evaporators as shown in FIG. 6A, the second embodiment is the composite-evaporator type cross-defrosting system constructed of refrigerant-defrost type composite-evaporator as shown in FIG. 2A.

Now referring to FIG. 6A to FIG. 6E and Table.6 for the first embodiment.

The basic operation scheme is shown in FIG. 6A to FIG. 6E, the composite-evaporator type cross-defrosting system operates with a control system that change the defrosting methods according to the outdoor temperature and humidity; when the outdoor temperature is in the range of 20 degree Celsius to 0 degree Celsius, the control system can apply the first defrosting method, which is also called as the cross-air defrosting process; when the outdoor temperature is in the range of 10 degree to negative 40 degree, the control system can apply the second defrosting method, which is also called as the cross-fluid defrosting process; the threshold at which the control system switch between the first defrosting method and the second defrosting method can be adjust at any point between 10 degree Celsius to 0 degree Celsius.

As shown in FIG. 6A, the composite-evaporator type cross-defrosting system comprising the following basic components: main compressor 601, main condenser 602, main heat exchanger 603, main expansion valve 604, first composite-evaporator 611, second composite-evaporator 612, first defrost-pump 631, second defrost-pump 632, first control valve 621, second control valve 622, first venting fan (not shown), second venting fan (not shown), separate heat insulation for each evaporator (not shown), outdoor temperature sensor (not shown), a control system for controlling and commencing the defrost-cycle.

The composite-evaporator type cross-defrosting system comprises a refrigerant-circulation for the evaporation process and the condensation process and an anti-freeze-fluid-circulation for the cross-fluid defrosting process; the anti-freeze-fluid basically refers to a compound fluid of water and chemical that has a lower freezing point than 0 degree Celsius.

The main heat exchanger has two separate pipelines for the refrigerant-circulation and the anti-freeze-fluid-circulation; the first pipeline will receive a flow of pressurized refrigerant from the main compressor 101, the second pipeline will receive the anti-freeze fluid from the first composite-evaporator 611 and the second composite-evaporator 612; the main heat exchanger 603 will transfer the heat energy from the first pipeline to the second pipeline during the defrost-cycle of the cross-fluid defrosting process.

The first composite-evaporator 611 has one set of evaporation coil and one set of anti-freeze-fluid pipeline, said evaporation coil and said anti-freeze-fluid pipeline will share the radiator fins as shown in FIG. 6G; said anti-freeze-fluid pipe will receive a flow of hot anti-freeze-fluid from the first defrost-pump 631 during the cross-fluid defrosting process of the first composite-evaporator 611.

The second composite-evaporator 612 has one set of evaporation coil and one set of anti-freeze-fluid pipeline, said evaporation coil and said anti-freeze-fluid pipeline will share the radiator fins as shown in FIG. 6G; said anti-freeze-fluid pipe will receive a flow of hot anti-freeze-fluid from the second defrost-pump 632 during the cross-fluid defrosting process of the second composite-evaporator 612.

Now referring to FIG. 6A for the full capacity heating operation of the first embodiment; the first composite-evaporator 611 and the second composite-evaporator 612 are operating with evaporation process by absorbing the heat energy of the outdoor-air; the anti-freeze-fluid-circulations of both the first composite evaporator 611 and the second composite-evaporator 612 are disabled by stopping the first defrost-pump 631 and the second defrost-pump 632; the refrigerant-circulations of both the first composite evaporator 611 and the second composite-evaporator 612 are enabled by opening the first control valve 621 and the second control valve 622; now the refrigerant is circulating as follows, the refrigerant is pressurized in the main compressor 601 and condensed in the main condenser 602, and next the first composite-evaporator 611 and the second composite-evaporator 612 will be evaporating the refrigerant inside their evaporation coil.

Now referring to FIG. 6B and FIG. 6C for the defrost-cycle of the cross-air defrosting process.

The basic concept of the cross-air defrosting process is to disable the refrigerant-flow of the frosted composite-evaporator, and a controlled amount of the outdoor air will flow through that frosted composite-evaporator to heat up the frost thereon, while the other composite evaporator will operate with the evaporation process to provide the evaporated refrigerant to the main compressor 601 for the pressurization process, the main condenser 602 will carry on the condensation process for the air-conditioning or heating; the cross-air defrosting process requires a defrost-cycle of alternating operation, a defrost cycle is demonstrated as follows, the first composite-evaporator 611 defrosts with cross-air defrosting process for 5 minute as in FIG. 6B, and next the second composite-evaporator 612 defrosts with the cross-air defrosting process for 5 minute as in FIG. 6C, and next the first composite-evaporator 611 and the second composite-evaporator 612 all resume the evaporation process for 10 minute as in FIG. 6A, and next the control system repeats the defrost cycle or switch to another defrosting method if a change in the outdoor temperature is detected. The time interval of the defrost cycle can be adjusted according to the outdoor temperature and humidity.

As shown in FIG. 6B is the cross-air defrosting process of the first composite-evaporator 611; the refrigerant-flow of the first composite-evaporator 611 is disabled by shutting the first control valve 621; the first venting fan will operate at full speed to draw the outdoor air through the first composite-evaporator 611 to melt the frost thereon; the refrigerant-flow of the second-composite evaporator 612 is enabled by opening the second control valve 622, so that the second composite-evaporator 622 will operate with the evaporation process to provide a sufficient refrigerant-flow to the main compressor 601, the main condenser 602 will continue to generate the heat energy required for the air-conditioning.

As shown in FIG. 6C is the cross-air defrosting process of the second composite-evaporator 612; the refrigerant-flow of the second composite-evaporator 612 is disabled by shutting the second control valve 622; the second venting fan will operate at full speed to draw the outdoor air through the second composite-evaporator 612 to melt the frost thereon; the refrigerant-flow of the first-composite evaporator 611 is enabled by opening the first control valve 621, so that the first composite-evaporator 621 will operate with the evaporation process to provide a sufficient refrigerant-flow to the main compressor 601, the main condenser 602 will continue to generate the heat energy required for the air-conditioning.

Now referring to FIG. 6D and FIG. 6E for the defrost-cycle of the cross-fluid defrosting process.

The basic concept of the cross-fluid defrosting process is to disable the evaporation coil of the frosted composite-evaporator, and a controlled flow of hot anti-freeze-fluid will be distributed to the anti-freeze-fluid pipeline of said frosted composite-evaporator to conduct heat current through the radiator fins; while the other composite evaporator will operate with the evaporation process to provide the evaporated refrigerant to the main compressor 601 for the pressurization process, the main condenser 602 will carry on the condensation process for the air-conditioning or heating; the cross-fluid defrosting process requires a defrost-cycle of alternating operation, a defrost cycle is demonstrated as follows, the first composite-evaporator 611 defrosts with the cross-fluid defrosting process for 5 minute as in FIG. 6D, and next the second composite-evaporator 612 defrosts with the cross-fluid defrosting process for 5 minute as in FIG. 6E, and next the first composite-evaporator 611 and the second composite-evaporator 612 all resume the evaporation process for 10 minute as in FIG. 6A, and next the control system repeats the defrost cycle or switch to another defrosting method if a change in the outdoor temperature is detected. The time interval of the defrost cycle can be adjusted according to the outdoor temperature and humidity.

As shown in FIG. 6D, when the first composite-evaporator 611 is defrosting with the cross-fluid defrosting process, the refrigerant-flow of the first composite-evaporator 611 is disabled by shutting the first control valve 621; the anti-freeze-fluid circulation is initiated by enabling the first defrost-pump 631, so that the anti-freeze-fluid will circulate from the main heat exchanger 603 to the anti-freeze-fluid pipeline of the first composite-evaporator 611, and the heat energy will be transferred through the radiator fins of the first composite-evaporator 611 to defrost the accumulated frost thereon; the first venting fan will decrease speed or stop to prevent heat from escaping out of the heat insulated space of first composite-evaporator 611, thus creating a hot environment inside the heat insulated space of the first composite-evaporator 611; the first composite-evaporator 611 will now be defrosting with the heat energy of the condensation process from the main heat exchanger 603, while the second composite-evaporator 612 will be operating with the evaporation process by absorbing the heat from the outdoor-air.

As shown in FIG. 6E, when the second composite-evaporator 612 is defrosting with the cross-fluid defrosting process, the refrigerant-flow of the second composite-evaporator 612 is disabled by shutting the second control valve 622; the anti-freeze-fluid circulation is initiated by enabling the second defrost-pump 632, so that the anti-freeze-fluid will circulate from the main heat exchanger 603 to the anti-freeze-fluid pipeline of the second composite-evaporator 612, and the heat energy will be transferred through the radiator fins of the second composite-evaporator 612 to defrost the accumulated frost thereon; the second venting fan will decrease speed or stop to prevent heat from escaping out of the heat insulated space of second composite-evaporator 612, thus creating a hot environment inside the heat insulated space of the second composite-evaporator 612; the second composite-evaporator 612 will now be defrosting with the heat energy of the condensation process from the main heat exchanger 603, while the first composite-evaporator 611 will be operating with the evaporation process by absorbing the heat from the outdoor-air.

The first embodiment of the present invention can be further extended with additional composite evaporators, and the control system can adjust accordingly to the basic concept of the present invention; when one of the composite evaporators is frosted and requires to defrost with the second defrosting method, said frosted evaporator will disable its associated evaporation coil and enable a fluid passage between the main heat exchanger and the associated anti-freeze-fluid pipeline of said frosted evaporator, and the heat insulated space of said frosted evaporator will control the speed of its associated venting fan to minimize the heat loss, at the same time all other evaporators can continue the evaporation process to absorb heat energy from the outdoor-air, the main compressor and the main condenser will continue their operation for the air-conditioning or heating; the control system will also operate in a defrost-cycle demonstrated as follows, all the composite-evaporators will operate with the evaporation process for 10 minute, and next the first composite-evaporator will defrost for 2 minute with the cross-fluid defrosting process, next the second composite evaporator will defrost for 2 minute with the cross-fluid defrosting process, and next the third composite-evaporator will defrost for 2 minute with the cross-fluid defrosting process, and next the fourth composite-evaporator defrosts for 2 minute with the cross-fluid defrosting process, and next the control system repeats the defrost-cycle or adjust its operation if further change in the outdoor temperature is detected.

A construction scheme of the first embodiment with four composite-evaporators is shown in FIG. 6H.

For easier maintenance, most control valves can be combined into one single rotary valve or other multi-port control valve means. An alternative scheme of the control valve means is provided as follows, wherein the first control valve 621 and the second control valve 622 are replaced with a single rotary valve or other multi-port control valve with the same functionality.

Another alternative scheme is provided for simplifying and reducing the cost as follows, the first defrost-pump 631 and the second defrost-pump 632 are replaced with a main defrost-pump and a multi-port control valve with the same functionality.

Many other alternative construction schemes and control valve means are possible to perform the same task based on the principle and the claims of present invention and should be considered within the scope of the present invention.

Now referring to FIG. 2A to FIG. 2E and Table.2 for the second embodiment, which is the composite-evaporator type cross-defrosting system constructed of refrigerant-defrost type composite-evaporators; the control logics of said system is provided in Table.2 as a reference.

The second embodiment also operate with a control system that changes the defrosting methods according to the outdoor temperature and humidity; when the outdoor temperature is in the range of 20 degree Celsius to 0 degree Celsius, the control system can apply the first defrosting method, which is also called as the cross-air defrosting process; when the outdoor temperature is in the range of 10 degree to negative 40 degree, the control system can apply the second defrosting method, which is also called as the cross-refrigeration defrosting process; the threshold at which the control system switches between the cross-air defrosting process and the cross-refrigeration defrosting process can be adjust at any point between 10 degree Celsius to 0 degree Celsius.

The second embodiment as shown in FIG. 2A, the composite-evaporator type cross-defrosting system comprising the following basic components: main compressor 201, main condenser 202, first composite-evaporator 203, second composite-evaporator 204, main expansion valve 207, first control valve 212, second control valve 211, first defrost-flow valve 214, second defrost-flow valve 213, first expansion valve 221, second expansion valve 222, first venting fan (not shown), second venting fan (not shown), outdoor temperature sensor (not shown), separate heat insulation means for each of said composite-evaporators, a control system for selecting and commencing the defrost-cycles of the cross-air defrosting process and the cross-refrigeration defrosting process.

The first composite-evaporator 203 is constructed of one set of evaporation coil and one set of defrost-condensation coil 205, said evaporation coil and said defrost-condensation coil 205 will share the radiator fins so that the heat energy can be transferred from said defrost-condensation coil to said evaporation coil during the cross-refrigeration defrosting process of the first composite-evaporator 203; the defrost-condensation coil 205 of the first composite-evaporator 203 will be referred as the first defrost-condenser 205 for the ease of comprehension.

The second composite-evaporator 204 is constructed of one set of evaporation coil and one set of defrost-condensation coil 206, said evaporation coil and said defrost-condensation coil 206 will share the radiator fins so that the heat energy can be transferred from said defrost-condensation coil to said evaporation coil during the cross-refrigeration defrosting process of the second composite-evaporator 204; the defrost-condensation coil 206 of the first composite-evaporator 204 will be referred as the first defrost-condenser 206 for the ease of comprehension.

Now referring to FIG. 2A for the full capacity heating operation when both the first composite-evaporator 203 and second composite-evaporator 204 are operating with the evaporation process; the evaporation coil of the first composite-evaporator 203 and the evaporation coil of the second composite-evaporator 222 are enabled by opening the first control valve 212 and second control valve 211; the first defrost-condenser 205 and the second defrost-condenser 206 are disabled by shutting the first defrost-flow valve 214 and the second defrost-flow valve 213; the first venting fan and the second venting fan will be operating to provide the outdoor-air into the heat insulated space of the first composite evaporator 203 and the heat insulated space of the second composite-evaporator 204; the main compressor 201 and the main condenser 202 will be operating with the pressurization process and the condensation process respectively to provide the heat energy for the air-conditioning or heating.

Now referring to FIG. 2B and FIG. 2C for the cross-air defrosting process of the second embodiment; the control system can employ said cross-air defrosting process when the outdoor temperature is between 20 degree Celsius and 0 degree Celsius; during the defrost-cycle of the cross-air defrosting process, the control system will defrost each evaporator with a defrost-cycle as follows; the first composite-evaporator 203 defrosts with the cross-air defrosting process for 5 minute as shown in FIG. 2B, and next the second evaporator 222 defrosts with the cross-air defrosting process for 5 minute as shown in FIG. 2C, and next the first evaporator 221 and the second evaporator 222 will resume the evaporation process as shown in FIG. 2A or repeat the defrost-cycle if the condition required.

As shown in FIG. 2B, the first composite-evaporator 203 is defrosting with the cross-air defrosting process; the evaporation coil of the first composite-evaporator 203 is disabled, and the outdoor-air will be drawn into the heat insulated space of the first composite-evaporator 203 to melt the accumulated frost on the first composite-evaporator 203; the second composite-evaporator 204 will operate with the evaporation process to provide the evaporated refrigerant to the main compressor 201; the main compressor 201 and the main condenser 202 will continue the pressurization process and the condensation process respectively for the air-conditioning; the first defrost-condenser 205 and the second defrost-condenser 205 will remain disabled during the defrost cycle of the cross-air defrosting process.

As shown in FIG. 2C, the second composite-evaporator 204 is defrosting with the cross-air defrosting process; the evaporation coil of the second composite-evaporator 204 is disabled, and the outdoor-air will be drawn into the heat insulated space of the second composite-evaporator 204 to melt the accumulated frost on the second composite-evaporator 204; the first composite-evaporator 203 will operate with the evaporation process to provide the evaporated refrigerant to the main compressor 201; the main compressor 201 and the main condenser 202 will continue the pressurization process and the condensation process respectively for the air-conditioning; the first defrost-condenser 205 and the second defrost-condenser 205 will remain disabled during the defrost cycle of the cross-air defrosting process.

Now referring to FIG. 2D and FIG. 2E for the second defrosting method; when the outdoor temperature drops below the threshold for initiating the cross-refrigeration defrosting process, the control system will commence a defrost-cycle as follows; the first composite-evaporator 203 and the second evaporator 204 operate with the evaporation process as shown in FIG. 2A for 10 minute, and next the first composite-evaporator 203 defrosts with the cross-refrigeration defrosting process as shown in FIG. 2D for 2 minute, and next the second composite evaporator 204 defrosts with the cross-refrigeration defrosting process as shown in FIG. 2E for 2 minute, and next the control system will repeat the defrost-cycle until further change in the outdoor environment is detected.

The basic concept of the cross-refrigeration defrosting process is to distribute a controlled flow of the pressurized refrigerant into the defrost-condensation coil of the composite-evaporator that is defrosting, so that the accumulated frost on said composite-evaporator will melt by the heat energy transferred from its associated defrost-condenser, therefore, the required time for the defrosting process will be greatly shortened; the other evaporator of the system will continue the evaporation process with its associated evaporation coil, the main compressor and the main condenser will also continue their operation to generate the heat energy for the air-conditioning. The defrost-cycle of the cross-refrigeration defrosting process requires each evaporator to alternate its operation at a time interval, and the detailed control scheme is provide in FIG. 2D and FIG. 2E.

As shown in FIG. 2D, the first composite-evaporator 203 is defrosting with the cross-refrigeration defrosting process; the first composite-evaporator 203 will disable its associated evaporation coil and enable the first defrost-condenser 205 by opening the first defrost-flow valve 214; a controlled flow of pressurized refrigerant is distributed from the main compressor 201 to the first defrost-condenser 205, and said flow of pressurized refrigerant will release heat energy in the first defrost-condenser 205 to transfer a heat current to the evaporation coil of the first composite-evaporator 203, and next the first defrost-condenser 203 will transfer the refrigerant therein to the evaporation coil of the second composite-evaporator 204 via the first expansion valve 221; the first venting fan will decrease speed or stop to conserve the heat inside the heat insulated space of the first composite-evaporator 203, thus creating a hot environment; the second composite-evaporator 204 will receive the refrigerant-flow from the main expansion valve 207 and the refrigerant-flow from the first expansion valve 221; in other words, the main condenser 202 and the first defrost-condenser 223 will be condensing refrigerant to generate heat energy for the air-conditioning and the cross-refrigeration defrosting process respectively, while the second composite-evaporator 204 will be operating with the evaporation process by absorbing the heat from the outdoor-air; the second defrost-condenser 206 is disabled by shutting the second defrost-flow valve 213.

As shown in FIG. 2E, the second composite-evaporator 204 is defrosting with the cross-refrigeration defrosting process; the second composite-evaporator 204 will disable its associated evaporation coil and enable the second defrost-condenser 206 by opening the second defrost-flow valve 213; a controlled flow of pressurized refrigerant is distributed from the main compressor 201 to the second defrost-condenser 206, and said flow of pressurized refrigerant will release heat energy in the second defrost-condenser 206 to transfer a heat current to the evaporation coil of the second composite-evaporator 204, and next the second defrost-condenser 204 will transfer the refrigerant therein to the evaporation coil of the first composite-evaporator 203 via the second expansion valve 222; the second venting fan will decrease speed or stop to conserve the heat inside the heat insulated space of the second composite-evaporator 204, thus creating a hot environment; the first composite-evaporator 203 will receive the refrigerant-flow from the main expansion valve 207 and the refrigerant-flow from the second expansion valve 222; in other words, the main condenser 202 and the second defrost-condenser 206 will be condensing refrigerant to generate heat energy for the air-conditioning and the cross-refrigeration defrosting process respectively, while the first composite-evaporator 203 will be operating with the evaporation process by absorbing the heat from the outdoor-air; the first defrost-condenser 205 is disabled by shutting the first defrost-flow valve 214.

The second embodiment of the present invention can be further extended with additional composite evaporators, and the control system can adjust accordingly to the basic concept of the present invention; when one of the evaporators is frosted and requires to defrost with the cross-refrigeration defrosting process, said frosted composite-evaporator will disable its associated evaporation coil and enable its associated defrost-condenser to initiate a controlled flow of pressurized refrigerant from the main compressor, said defrost condenser will conduct a heat current through its radiator fins to said frosted composite-evaporator, and the heat insulated space of said frosted evaporator will control the operation speed of its associated venting fan to conserve the heat energy therein, meanwhile, all other composite-evaporators can continue the evaporation process with their associated evaporation coils to absorb heat energy from the outdoor-air, the main compressor and the main condenser will continue their operation for the air-conditioning; the control system will also operate with a defrost-cycle, wherein each evaporator will take turns to operate with the cross-refrigeration defrosting process; an example of the defrost cycle is demonstrated as follows, all composite-evaporators operate with the evaporation process for 10 minute, and next the first composite-evaporator defrosts for 2 minute, next the second composite-evaporator defrosts for 2 minute, and next the third composite-evaporator defrosts for 2 minute, and next the fourth composite-evaporator defrosts for 2 minute, and next the control system repeats the defrost-cycle or adjust its operation if further change in the outdoor temperature is detected. A construction scheme is provided in FIG. 2G for the second embodiment that constructed with four composite evaporators.

For easier maintenance, most control valves can be combined into one single rotary valve or other multi-port control valve means, for instance, the first defrost-flow valve 214 and the second defrost-flow valve 213 can be constructed with one multi-port control valve of the identical functionality, and the first control valve 212 and second control valve 211 can also be constructed with one multi-port control valve of the identical functionality.

The control system can further employ the sensor means for the progress of the defrosting process to detect if the composite-evaporator has melted all the frost thereon, if the frost is completely melted, the control system can be reset to the next step of the defrost-cycle; said sensor means can be a pressure or temperature sensor in the composite evaporator.

It should be understood that the threshold temperatures for initiating each defrosting method are different for other regions in the world, where the humidity and frosting condition are the main factor deciding which defrosting method to apply at different temperature range.

TABLE 2
Control logics of the second embodiment
Part. 1
			Cross-air defrosting process	Cross-air defrosting process
		Full capacity heating	of	of
Label	Component Name	operation	first composite evaporator	Second composite evaporator
202	Main condenser	Condensation Process	Condensation Process	Condensation Process
203	First composite-evaporator	Evaporation Process	Defrosting with	Evaporation Process
		(evaporation coil enabled)	outdoor-air	(evaporation coil enabled)
			(evaporation coil disabled)
204	Second composite-evaporator	Evaporation Process	Evaporation Process	Defrosting with
		(evaporation coil enabled)	(evaporation coil enabled)	outdoor-air
				(evaporation coil disabled)
214	First defrost-flow valve	Closed	Closed	Closed
213	Second defrost-flow valve	Closed	Closed	Closed
212	First control valve	Open	Closed	Open
205	First defrost-condenser	No refrigerant-flow	No refrigerant-flow	No refrigerant-flow
211	Second control valve	Open	Open	Closed
206	Second defrost-condenser	No refrigerant-flow	No refrigerant-flow	No refrigerant-flow
	First venting fan	Full speed	Full speed	Full speed
	Second venting fan	Full speed	Full speed	Full speed
Part. 2
			Cross-refrigerant defrosting	Cross-refrigerant defrosting
		Full capacity heating	process of	process of
Label	Component Name	operation	first composite evaporator	second composite evaporator
202	Main condenser	Condensation Process	Condensation Process	Condensation Process
203	First composite-evaporator	Evaporation Process	Defrosting by	Evaporation Process
		(evaporation coil enabled)	first defrost-condenser	(evaporation coil enabled)
			(evaporation coil disabled)
204	Second composite-evaporator	Evaporation Process	Evaporation Process	Defrosting by
		(evaporation coil enabled)	(evaporation coil enabled)	second defrost-condenser
				(evaporation coil disabled)
214	First defrost-flow valve	Closed	Open	Closed
213	Second defrost-flow valve	Closed	Closed	Open
212	First control valve	Open	Closed	Open
205	First defrost-condenser	No refrigerant-flow	Condensation Process	No refrigerant-flow
211	Second control valve	Open	Open	Closed
206	Second defrost-condenser	No refrigerant-flow	No refrigerant flow	Condensation Process
	First venting fan	Full speed	Decreasing speed or stop	Full speed
			to conserve heat
	Second venting fan	Full speed	Full speed	Decreasing speed or stop
				to conserve heat

TABLE 6
Control logics of the first embodiment
Part. 1
			Cross-air defrosting process	Cross-air defrosting process
		Full capacity heating	of	of
Label	Component Name	operation	First composite-evaporator	Second composite-evaporator
602	Main condenser	Condensation Process	Condensation Process	Condensation Process
603	Main heat-exchanger	No heat transferred	No heat transferred	No heat transferred
		(Fluid circulation disabled)	(Fluid circulation disabled)	(Fluid circulation disabled)
611	First composite-evaporator	Evaporation Process	Defrosting with outdoor air	Evaporation Process
		(evaporation coil enabled)	(evaporation coil disabled)	(evaporation coil enabled)
		(fluid pipeline disabled)	(fluid pipeline disabled)	(fluid pipeline disabled)
612	Second composite-evaporator	Evaporation Process	Evaporation Process	Defrosting with outdoor air
		(evaporation coil enabled)	(evaporation coil enabled)	(evaporation coil disabled)
		(fluid pipeline disabled)	(fluid pipeline disabled)	(fluid pipeline disabled)
621	First control valve	Open	Closed	Open
631	First defrost-pump	No pumping	No pumping	No pumping
622	Second control valve	Open	Open	Closed
632	Second defrost-pump	No pumping	No pumping	No pumping
	First venting fan	Full speed	Full speed	Full speed
	Second venting fan	Full speed	Full speed	Full speed
Part. 2
			Cross-fluid defrosting process	Cross-fluid defrosting process
		Full capacity heating	of	of
Label	Component Name	operation	First composite-evaporator	Second composite-evaporator
602	Main condenser	Condensation Process	Condensation Process	Condensation Process
603	Main heat-exchanger	No heat transferred	Heat transferring	Heat transferring
		(Fluid circulation disabled)	(Fluid circulation enabled)	(Fluid circulation enabled)
611	First composite-evaporator	Evaporation Process	Defrosting by hot anti-freeze	Evaporation Process
		(evaporation coil enabled)	(evaporation coil disabled)	(evaporation coil enabled)
		(fluid pipeline disabled)	fluid (fluid pipeline enabled)	(fluid pipeline disabled)
612	Second composite-evaporator	Evaporation Process	Evaporation Process	Defrosting by hot anti-freeze fluid
		(evaporation coil enabled)	(evaporation coil enabled)	(evaporation coil disabled)
		(fluid pipeline disabled)	(fluid pipeline disabled)	(fluid pipeline enabled)
621	First control valve	Open	Closed	Open
631	First defrost-pump	No pumping	Pumping	No pumping
622	Second control valve	Open	Open	Closed
632	Second defrost-pump	No pumping	No pumping	Pumping
	First venting fan	Full speed	Decreasing speed or stop	Full speed
			to conserve heat
	Second venting fan	Full speed	Full speed	Decreasing speed or stop
				to conserve heat

Claims

1. A multi-range composite-evaporator type cross-defrosting 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 heat-exchanging section; said refrigerant-compressing section provides a flow of pressurized-refrigerant to said refrigerant-condensing section and said heat-exchanging section; said refrigerant-condensing section will condense said flow of pressurized-refrigerant therein, and release the heat energy for air-conditioning or heating purpose; said refrigerant-condensing section provides 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 (601);c) said refrigerant-condensing section comprises at least one main condenser (602);d) said refrigerant-evaporating section comprises at least two units of composite-evaporator, which are first composite-evaporator (611) and second composite-evaporator (612); each of said composite-evaporators consists of one set of evaporation coil and one set of anti-freeze-fluid pipeline;e) flow control means for independently controlling a refrigerant passage from said refrigerant-condensing section to the evaporation coil of said first composite-evaporator (611);f) flow control means for independently controlling a refrigerant passage from said refrigerant-condensing section to the evaporation coil of said second composite-evaporator (612);g) said heat-exchanging section comprises a main heat-exchanger (603); said main heat-exchanger (603) consists of a refrigerant-pipeline and a fluid-pipeline, said refrigerant-pipeline will receive a controlled flow of pressurized refrigerant from said refrigerant-compressing section, and the heat energy will be transferred to said fluid-pipeline to heat up the anti-freeze-fluid therein;h) fluid pumping means for controlling a flow of hot anti-freeze-fluid from said heat-exchanging section to the anti-freeze-fluid pipeline of said first composite-evaporator (611);i) fluid pumping means for controlling a flow of hot anti-freeze-fluid from said heat-exchanging section to the anti-freeze-fluid pipeline of said second composite-evaporator (612);j) a control system for commencing a defrost cycle of cross-fluid defrosting process and cross-air defrosting process by controlling said flow control means and outdoor-air-intake means and fluid pumping means;k) said multi-range defrost-condenser type air-conditioning system is capable of defrosting each of said composite-evaporators by a defrost-cycle of cross-fluid defrosting process, wherein each of said composite-evaporator will alternately operate with cross-fluid defrosting process and the refrigerant evaporation process.

2. A multi-range composite-evaporator type cross-defrosting system as defined in claim 1, wherein; during the full capacity operation, all said composite-evaporators will operate with the evaporation process to absorb heat from the outdoor-air; said heat-exchanging section will be disabled by stop providing hot anti-freeze-fluid with said pumping means.

3. A multi-range composite-evaporator type cross-defrosting system as defined in claim 1, wherein; during the defrost-cycle of cross-fluid defrosting process, said heat-exchanger will receive a flow of pressurized refrigerant from said refrigerant-compressing section to heat up the anti-freeze-fluid in said fluid-pipeline of said heat-exchanger, one of the frosted composite-evaporator will disable its associated evaporation coil and enable a fluid circulation of hot anti-freeze-fluid in its associated anti-freeze-fluid pipeline with said pumping means, meanwhile, the other composite-evaporator will operate with evaporation process to absorb heat energy from the outdoor-air.

4. multi-range composite-evaporator type cross-defrosting system as defined in claim 1, wherein; when said first composite-evaporator (611) is defrosting with cross-fluid defrosting process, said first composite-evaporator will disable its associated evaporation coil with its associated flow control means (611), said pumping means (631) will initiate a flow of hot anti-freeze-fluid from said heat-exchanger to the anti-freeze-pipeline of said first composite-evaporator (611), the accumulated frost on said first composite-evaporator (611) will melt by the heat energy of said flow of hot anti-freeze-fluid, said second composite-evaporator (612) will operate with the evaporation process to provide a flow of evaporated refrigerant to said main compressor (601), while said main compressor (601) and said main condenser (602) will continue the pressurization process and the condensation process.

5. A multi-range composite-evaporator type cross-defrosting system as defined in claim 1, wherein; when said second composite-evaporator (612) is defrosting with cross-fluid defrosting process, said second composite-evaporator will disable its associated evaporation coil with its associated flow control means (612), said pumping means (632) will initiate a flow of hot anti-freeze-fluid from said heat-exchanger to the anti-freeze-pipeline of said second composite-evaporator (612), the accumulated frost on said second composite-evaporator (612) will melt by the heat energy of said flow of hot anti-freeze-fluid, said first composite-evaporator (611) will operate with the evaporation process to provide a flow of evaporated refrigerant to said main compressor (601), while said main compressor (601) and said main condenser (602) will continue the pressurization process and the condensation process.

6. A multi-range composite-evaporator type cross-defrosting system as defined in claim 1, which can further comprises additional composite-evaporators; wherein each of said additional composite-evaporators comprises individual flow control means for its associated evaporation coil and pumping means for its associated anti-freeze-fluid pipeline.

7. A multi-range composite-evaporator type cross-defrosting system as defined in claim 1, wherein; each of said composite-evaporators can further comprise sensor means for detecting the progress of the defrosting process; and said control system can adjust the defrost-cycle accordingly for optimum heating efficiency.

8. A multi-range composite-evaporator type cross-defrosting system comprising; a) a main compressor (601);b) a main condenser (602) for air-conditioning or heating purpose;c) at least two composite-evaporator units, which are the first composite-evaporator (611) and the second composite-evaporator (612); each of said composite-evaporator consists of one set of evaporation coil and one set of anti-freeze-fluid pipeline; each of said composite-evaporator units consists of individual heat insulation and independent intake means for outdoor-air;d) a main heat-exchanger consisting of a refrigerant pipeline and a fluid pipeline, said refrigerant pipeline will receive a flow of pressurized refrigerant from said main compressor (601) to heat up said fluid pipeline; said fluid pipeline will distribute a flow of hot anti-freeze-fluid to the anti-freeze-fluid pipeline of said first composite evaporator (611) when said first composite-evaporator (611) is defrosting with cross-fluid defrosting process; said fluid pipeline will distribute a flow of hot anti-freeze-fluid to the anti-freeze-fluid pipeline of said second composite evaporator (612) when said second composite-evaporator (612) is defrosting with cross-fluid defrosting process;e) flow control means for individually controlling the refrigerant passage from said main compressor (601) to the evaporation coils of each said composite-evaporators;f) a control system for commencing a defrost-cycle of cross-fluid defrosting process by controlling all said flow control means and intake means; during said defrost-cycle of cross-fluid defrosting process, each of said composite evaporator will alternately operate with the evaporation process and cross-fluid defrosting process.

9. A multi-range composite-evaporator type cross-defrosting system as defined in claim 8, which can further comprises additional composite-evaporators; wherein each of said additional composite-evaporators comprises individual flow control means for its associated evaporation coil and pumping means for its associated anti-freeze-fluid pipeline.

10. A multi-range composite-evaporator type cross-defrosting system as defined in claim 8, wherein; each of said composite-evaporators can further comprise sensor means for detecting the progress of the defrosting process; and said control system can adjust the defrost-cycle accordingly for optimum heating efficiency.

11. A multi-range composite-evaporator type cross-defrosting system as defined in claim 8, wherein; said control system can further employ a combination of cross-air defrosting process and cross-fluid defrosting process to raise the energy efficiency.

12. A multi-range composite-evaporator type cross-defrosting system as defined in claim 11, wherein; said control system can employ a defrost cycle of cross-air defrosting process when the outdoor temperature is from 20 degree to 0 degree Celsius, and said control system can employ a defrost-cycle of cross-fluid defrosting process when the outdoor temperature is from 10 degree to negative 40 degree Celsius; the threshold at which said control system switch from cross-air defrosting process to cross-fluid defrosting process can be automatically adjusted according to the humidity condition.

13. A multi-range composite-evaporator type cross-defrosting system as defined in claim 8, wherein; said control system will decrease the flow of outdoor air through the composite-evaporator which is defrosting with cross-fluid defrosting process, thus creating a hot environment inside the heat insulated space of the composite-evaporator.

14. A multi-range composite-evaporator type cross-defrosting 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-defrosting section; said refrigerant-compressing section provides a flow of pressurized-refrigerant to said refrigerant-condensing section and said cross-defrosting 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 provides 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 (201);c) said refrigerant-condensing section comprises at least one main condenser (202);d) said refrigerant-evaporating section comprises at least two composite-evaporator units, which are first composite-evaporator (203) and second composite-evaporator (204); each of said composite-evaporator consists of one set of evaporation coil and one set of defrost-condensation coil;e) said cross-defrosting section comprises one refrigerant passage from said main compressor (201) to the defrost-condensation coil (205) of first composite-evaporator (203) and one refrigerant passage from said main compressor (201) to the defrost-condensation coil (206) of second composite-evaporator (206);f) flow control means for independently initiating a flow of pressurized refrigerant from said refrigerant-compressing section to the defrost-condensation coil (205) of said first composite-evaporator (203) during cross-refrigerant defrosting process of said first composite-evaporator (203);g) flow control means for independently initiating a flow of pressurized refrigerant from said refrigerant-compressing section to the defrost-condensation coil (206) of said second composite-evaporator (204) during cross-refrigerant defrosting process of said second composite-evaporator (204);h) flow control means for independently blocking the refrigerant passage from said main compressing section to the evaporation coil of first composite-evaporator (203) during the cross-air defrosting process of first composite-evaporator (203) and the cross-refrigerant defrosting process of first composite-evaporator (203);i) flow control means for independently blocking the refrigerant passage from said main compressing section to the evaporation coil of second composite-evaporator (204) during the cross-air defrosting process of second composite-evaporator (204) and the cross-refrigerant defrosting process of second composite-evaporator (204);j) a control system for commencing a defrost-cycle of cross-refrigerant defrosting process by controlling said flow control means and outdoor-air-intake means.

15. A multi-range composite-evaporator type cross-defrosting system as defined in claim 14, wherein; each composite-evaporator units includes individual heat insulation, and each said outdoor-air-intake means will decrease the rate of venting during the cross-refrigerant defrosting process of its associated composite-evaporator.

16. A multi-range composite-evaporator type cross-defrosting system as defined in claim 14 further comprising: a) additional composite-evaporators, which includes one set of evaporation coil and one set of defrost-condensation coil;b) flow control means and refrigerant-passages for said additional composite-evaporators to commence the cross-refrigerant defrosting process;c) refrigerant passages for collecting the refrigerant from each of said defrost-condensation coils.

17. A multi-range composite-evaporator type cross-defrosting system as defined in claim 16, wherein; when one of said composite-evaporators is defrosting with the cross-refrigerant defrosting process, this defrosting composite-evaporator will disable its associated evaporation coil and enable its associated defrost-condensation coil, and this defrost-condensation coil will generate a flow of refrigerant to the evaporation coil of other composite evaporators.

18. A multi-range composite-evaporator type cross-defrosting system as defined in claim 16; said control system will employ a defrost-cycle of the cross-refrigerant defrosting process when the outdoor temperature is from 10 degree Celsius to negative 40 degree Celsius.

19. A multi-range composite-evaporator type cross-defrosting system as defined in claim 16, wherein; said control system will employ a defrost-cycle of the cross-air defrosting process when the outdoor temperature is from 20 degree Celsius to 0 degree Celsius.

20. A multi-range composite-evaporator type cross-defrosting system as defined in claim 16, wherein; each of said composite-evaporators can further comprise sensor means for detecting the progress of the defrosting process; and said control system can adjust the defrost-cycle accordingly for optimum heating efficiency.