Experimental Performance of a Two-Phase Closed Thermosyphon Charged with Hydrocarbons and Freon Refrigerants for Renewable Energy Applications

Experimental performance investigation of a two-phase closed thermosyphon (TPCT) charged with eight working fluids: R134a, R601, R245fa, R600a, R1234ze, R152a, R245fa/R152a and R601/R245fa has been carried out. The TPCT was made of 3 m long smooth copper pipe with an d(i) of 40 mm. The evaporator section was immersed in the thermostatic water bath and the condenser section was cooled by recycled water. The experimental results show that R245fa/R152a offers the highest heat transfer rate Q, and R600a and R1234ze performance closely to R134a. Cooper and Rohsenow pool boiling HTC correlations were chosen to compare with the experimental results, which have good agreement with the measurements and the average errors are 23.1% and 16.6% respectively. Nusselt and Hashimoto and Kaminaga correlations were chosen to predict the condensation HTCs. Compared with the measurements, both tend to over predict the condensation HTCs in low tb (Q) and under predict the HTCs in high tb (Q). And Hashimoto and Kaminaga correlation offers better agreement. (C) 2017 The Authors. Published by Elsevier Ltd.