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 
       [0001]    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. 
         [0002]    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 
       [0003]    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.” 
         [0004]    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 
       [0005]    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. 
         [0006]    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. 
         [0007]    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 
         [0008]      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. 
           [0009]      FIG. 6A  is an operation scheme of the first embodiment, in which all the composite-evaporators are operating with evaporation process. 
           [0010]      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. 
           [0011]      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. 
           [0012]      FIG. 6H  is an alternative construction scheme of the first embodiment with four composite-evaporators. 
           [0013]      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. 
           [0014]      FIG. 2A  is an operation scheme of the second embodiment, in which all the composite-evaporators are operating with evaporation process. 
           [0015]      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. 
           [0016]      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. 
           [0017]      FIG. 2G  is an alternative construction scheme of the second embodiment with four composite-evaporators 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    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 . 
         [0019]    Now referring to  FIG. 6A  to  FIG. 6E  and Table.6 for the first embodiment. 
         [0020]    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. 
         [0021]    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. 
         [0022]    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. 
         [0023]    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. 
         [0024]    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 . 
         [0025]    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 . 
         [0026]    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. 
         [0027]    Now referring to  FIG. 6B  and  FIG. 6C  for the defrost-cycle of the cross-air defrosting process. 
         [0028]    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. 
         [0029]    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. 
         [0030]    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. 
         [0031]    Now referring to  FIG. 6D  and  FIG. 6E  for the defrost-cycle of the cross-fluid defrosting process. 
         [0032]    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. 
         [0033]    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. 
         [0034]    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. 
         [0035]    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. 
         [0036]    A construction scheme of the first embodiment with four composite-evaporators is shown in  FIG. 6H . 
         [0037]    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. 
         [0038]    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. 
         [0039]    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. 
         [0040]    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. 
         [0041]    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. 
         [0042]    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. 
         [0043]    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. 
         [0044]    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. 
         [0045]    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. 
         [0046]    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. 
         [0047]    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. 
         [0048]    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. 
         [0049]    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. 
         [0050]    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 . 
         [0051]    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 . 
         [0052]    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 . 
         [0053]    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. 
         [0054]    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. 
         [0055]    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. 
         [0056]    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. 
         [0000]    
       
         
               
             
               
               
               
               
               
             
               
             
               
               
               
               
               
             
           
               
                 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 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
               
             
               
             
               
               
               
               
               
             
           
               
                 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