EXPERIMENTAL AND THEORETICAL ANALYSIS OF A HEAT PIPE HEAT EXCHANGER USING HFC-152a AS WORKING FLUID

In the present paper the experimental and theoretical analyses of a 6-row Heat Pipe Finned Heat Exchanger (HPFHE) are reported. By means of a double wind channel the experimental tests were run under the operating conditions typical for air-conditioning in European countries for both the summer and the winter seasons. To evaluate the HPFHE performance as a function of the refrigerant loaded in the heat pipes, different potential fluids were analysed in terms of figure of merit number. Accordingly three different fluids were chosen and experimentally tested: the well-known and commonly used HFC-134a, the new low Global Warming Potential (GWP) HFO-1234ze(E), and the HFC-152a which presents a figure of merit number approximately 63 % greater than that of HFC-134a at 10 °C. HFC-152a was demonstrated to outperform the other refrigerants. The consistency of the experimental results is proved by a comparison with a semiempirical model of the HPFHE based on heat transfer correlations available in the open literature.