pumping can be selected to be constituted by two unidirectional fluid pumps having different pumping direction in series connection to constitute the function of fluid bidirectional pumping device 123 fig7 is the second schematic view showing structure principles of the single flow circuit heat exchange device having the fluid bidirectional pumping device 123 being constituted by two unidirectional fluid pumps at different flow pumping directions wherein the fluid inside the heat exchanger inside heat exchange device or full heat exchange device is operatively controlled for periodically alternative pumping directional change such as that as shown in fig7 for the example of the heat exchange device for indoor outdoor air change in cold winter times wherein the indoor higher temperature air flow is pumped to heat exchange device via fluid port a and is discharged to outdoors via fluid port b by the bidirectional pumping device 123 the heat exchanger of the heat exchange device is then gradually formed with a temperature distribution from high temperature at fluid port a to the lower temperature at fluid port b and the pumping direction of the bidirectional pumping device 123 is further operatively controlled manually or by the periodic fluid direction change operative control device 250 to pump the fluid in reverse direction wherein the fluid of outdoor lower temperature fresh air is pumped to.