Statistical Analysis of Heat Transfer Effects on Flow Patterns Maps in a Flat-Plate Collector/Evaporator with R600a Under Variable Tilt Angles

This present investigative work proceeds with the statistical study of the heat transfer coefficient (CTC) in the different flow transitions that are formed in a horizontal pipe with variation in the angles of inclination in a collector/evaporator component of a heat pump of solar assisted direct expansion (DX-SAHP) by using R600a refrigerant as working fluid in Quito - Ecuador. The dimensions of the collector/evaporator are 3.8 and 1000 mm inside diameter and length, respectively. To determine the results obtained, five practical tests are carried out with inclination angles of 10, 20, 30, 40 and 45°, with speeds or mass flows that vary between 203.24 and 222.28 kg·m−2·s−1, the heat fluxes reached values between 200.58 and 507.23 W·m−2. The correlations proposed by Kattan, Kundu, and Mohseni, and the experimental data were considered for the analysis of the effects of heat transfer on flow patterns. The results obtained from the investigation show that the maximum CTC is 6163.83 W·m−2·K−1 with an inclination angle of 45°. Statistical analysis was performed considering the direction of Pearson presented results that for the angle of inclination of 10° a greater inverse direction of −0.316 is obtained.