Compact heat exchangers: A review and future applications for a new generation of high temperature solar receivers

This paper gives a review on performances of compact heat exchangers (CHEs), including well-established devices, some relative newcomers to the market and also designs still being tested in the laboratory. The structures of the CHEs are briefly introduced, and their heat transfer enhancement mechanisms, as well as their advantages and limitations, are summarized. Then, different heat transfer enhancement technologies in CHEs are compared and their thermo-hydraulic performances are analyzed on the basis of available correlations for heat transfer and friction factor developed by various investigators quoted in the open literature. Finally, the technologies that may fit the specifications for a new generation of solar receiver, which is a critical component of the Concentrated Solar Power (CSP) system, are proposed. It is concluded, among others in the review, that solar receivers based upon CHE technology have been rarely reported, and therefore, more work is needed in this field for a comprehensive understanding and to improve the uses of new energy sources and contribute to sustainability.