Heat exchanger made of heat pipes with round cross section (Known as round heat pipe heat exchanger) has been widely used in China. But some further improvements are greatly desired both in design and in operation. The two main performance parameters of heat exchanger are its heat transfer coefficient and flow resistance, which often affect each other. For example, the maximum permissible pressure drop which is propotional to the flow resistance limits heat transfer coefficient, especially for the round heat pipe heat exchangers. The self-clean ability of the exchanger is also affected negatively when heat transfer ability is too low.
These problems are well solved by a newly developed heat exchanger made of heat pipes with elliptic cross section (Known as elliptic heat exchanger). It is shown that the performances of elliptic heat pipe heat exchanger are much higher than those of round one. The details will are presented and discussed in the following sections. It is believed that the use of elliptic heat pipe heat exchangers indicates a way for further application of heat pipe heat exchangers.