Thermal and economical study of a solar collector using natural fibers as thermal insulation

Abstract

ABSTRACT In the present thermal study of three passive flat plate solar air collectors, it was demonstrated that using natural fibers as thermal insulation (fibers/clay, petiole/gypsum) resulted in a significantly higher annual useful power generation by (49.43 and 56.17%) respectively than the synthetic insulation (polystyrene). The results of the study show that the energy efficiencies of solar air collector with natural thermal insulation varied between 42.89 and 45.73%, while the synthetic insulation was 26.50%, their exergy efficiencies varied between 9.07 and 9.19% for solar air collector with natural thermal insulation compared to 4.58% for the synthetic insulation. The economic analysis was based on looking for a monetary optimum for the heating cost. The cost price of the kilowatt-hour (kWh) produced from the conventional collector was 24.47% higher than that produced from fossil fuels. However, by using natural fibers as a thermal insulation, the cost was reduced by 17.49 and 20.91% respectively compared to the one produced from fossil fuels. The return time for these collectors was between 4.08 and 6.47 years. From an environmental point of view, the solar collector has reduced 15.60 to 16.33 tons of carbon dioxide (CO2) which may be produced by electricity.