102 and then be discharged from an air exhaust port 109 at the hot current flowpath of the heat exchanging unit 102 electronic control unit 107 constituted by the electromechanical component or the solid state electronic component and or the microprocessor and operation software for receiving the electric energy from the power supply and being set and controlled by an external operation interface 108 to control the operations of the electric heating device 103 the drum drive motor set 105 and the electric fluid pump set 106 and external operation interface 108 constituted by the electromechanical component or the solid state electronic component and or the microprocessor and operation software for receiving manual input to control the operation of the electronic control unit 107 by way of the above devices when the operator turns on the external operation interface 108 for operation the electronic control unit 107 starts the electric fluid pump set 106 the electric heating device 103 and the drum drive motor set 105 at this time the room temperature air flow enters the intake flowpath of the heat exchanging unit 102 through the air inlet port 101 the room temperature air flow passes through the heat exchanging unit 102 for heat exchanging with the discharged hot air and then is discharged by the outlet at the intake flowpath of the heat exchanging unit 102 for further being heated into hot air by the electric heating device 103 and then reenters the drum 104 driven by the drum drive motor set 105 to dry the clothes and then flows into the inlet at the hot current.