Thermal performance of a solar water heater with internal exchanger using thermosiphon system in Côte d'Ivoire

This study presents a theoretical and experimental analysis of the thermal performance of a solar water heater prototype with an internal exchanger using thermosiphon system. The results focus mainly on the levels of the heat fluxes temperatures recorded, mass flow rate and efficiency of collector. These tests are performed for a sunny day and a cloudy day. The daily solar intensities range from 300 to 1233 W/m2, with the daily ambient temperature ranging between 27 °C and 33 °C. Maximum temperatures at the flat solar collector output are 88 °C and 58 °C for the sunny day and cloudy day, respectively. Maximum instantaneous efficiencies are 68.33% and 50% for the sunny day and the cloudy day, respectively. The values of the thermal performances parameters FR (τα) and FRUL are 0.780 and 4.252 W/m2 °C respectively for the cloudy day and 0.777 and 4.689 W/m2 °C respectively for the sunny day. The coefficient of exchange thermal of heat exchanger Ue found is 149.15 W/(m2 K) when, the average heat exchanger effectiveness obtained is 70%. The experimental results show that mean daily efficiency is near 50%. This reveals a good compatibility of the system to convert solar energy to heat which can be used for heating water.