Cooling principle of traditional paddle is making the paddle be cooled by increase water volume and heat transfer area,while cooling principle of micro water valve is increasing the heat transfer coefficient through designing special channel.

With a project example, presents the heating system design for large space factory buildings with energy efficient hot air furnace as heat source.

The advantage of saving- energy、 the huge potentiality and the existent problems is indicated from the relation of frequency control and the saving-energy of the water pump energy-conservation of the air blower and the protection of environment and the urgency of saving-energy for high voltage auxiliary electromotor in heat-engine plant.