In this case, tightly fitting dampers are required to prevent reverse thermosiphoning at night, which could freeze water in the heat exchanger coil.

Then, the dynamic heat exchange of a coil heat exchanger was simulated and some conclusions were drawn in terms of its regular laws of heat exchange.

In order to improve the performance of shell-and-tube heat exchanger, a new kind of in-tube heat transfer enhancement technology of twined coil insert is presented.