defrosting process of evaporator 207 solenoid valve 205 is closed solenoid valve 210 is open to provide passage for refrigerant then secondary compressor 214 starts operating and sending heated refrigerant to defrost condenser 211 through solenoid valve 210 then the heat from defrost condenser 211 is used to heat up evaporator 207 by heat conducting means such as fan or direct contact the refrigerant in defrost condenser 211 flows through expansion valve 216 then the refrigerant from expansion valve 216 enters heat exchanger 215 to absorb heat from the refrigerant in primary heat pump then the refrigerant returns to secondary compressor 214 fig3 is an exemplary working procedure table of the present invention as explained in fig1 when defrosting is required when evaporator 107 requires defrosting evaporator 107 stops operating and evaporator 106 continues operating to provide heat energy that defrost condenser 111 required to defrost evaporator 107 after a preset time has reached or if sensor not shown has detected no further defrosting is necessary defrost condenser 111 stops defrosting and evaporator 107 starts working when evaporator 106 requires defrosting evaporator 106 stops operating and evaporator 107 continues operating to provide heat energy that defrost condenser 109 required to defrost evaporator 106 after a preset time has reached or if sensor has detected no further defrosting is necessary defrost condenser 109 stops defrosting and evaporator 106 starts working when both of evaporator 106 and evaporator 107 can operate without frosting both of them can uninterruptedly operate under severe working condition.