The main aim of this study is to design an evacuated tube solar water collector model for the correct prediction of its performance under different climate conditions and materials used for its manufacture. The ultimate objective is to develop a model that can be used to support the local SWH industry to optimise the performance of solar water heater. An experimental rig was set up with the installation requirements in accordance with ISO 9806:2013. The results were recorded over a fortnight, from which a selection of 3 hours was considered for validating a numerical thermal model, which can be adapted to the changing climatic conditions of Mauritius. The Boussinesq’s approximation was employed for developing the numerical thermal model. A close agreement was met for the validation, with only a maximum of 2.06% deviation from experimental data. The temperature contours demonstrated that temperature within the water tank is quite uniform, with 5.0°C increase for each hour. An overall thermal efficiency of 40.39% was noted during the 3-hour solar exposure. It was also observed that the thermal efficiency undergoes very low (if not negligible) increases for solar irradiance values above 75 W/m-2. Furthermore, changes in thermal efficiency were found to follow any drastic fluctuations in solar irradiance, before stabilising around 40.05% again.
Keywords
Solar,evacuated tube,water collector,solar water heater
