Experimental Investigation of Using a Novel Insulation Material on the Functioning of a Solar Thermal Collector

This research document presents a new insulation material for solar thermal collectors. Tests were carried out in the laboratory, on an active solar energy demonstration system (ET 200), illuminated with a halogen lamp instead of sun. In this paper, the polystyrene used as insulation in the ET 200 flat plate solar collector was replaced by the cheaper natural material based on clay and straw. The polystyrene in the experimental device is placed under the absorber plate and along the edges of the casing containing the components of the solar collector. In this work, only the polystyrene of the four similar edges was replaced by the composite material. The use of the clay and straw as insulation material instead of polystyrene increased temperature difference (T₂ − T₁) between the inlet and the outlet of the absorber by 0.9±0.14 °C (p < 0.05); thus, increasing the useful power transmitted to water in the solar collector. Compared to polystyrene, tank water was well heated using the proposed material (p < 0.05). This latter also improved the performance of the solar collector by 5.77%. So, it is recommended to use the cheapest nonpolluting material based on clay and straw instead of synthetic insulation to improve the performance of the solar collector.