Impact of corrugated duct and heat storage element on the performance of a low-cost solar air heater under forced air circulation: an experimental study.

Abstract

The need to address global warming issues and international policies has placed a greater emphasis on the development of solar energy utilization systems. Intensive study is necessary to expand solar energy applications, as solar energy potential varies widely. This study investigates the thermal and thermohydraulic performance of a modified flat plate solar air heater (FSAH) to assess the effects of using corrugated aluminium duct and sand heat storage elements (HSE) in various combinations. The different arrangements selected for the experimental investigation are the FSAH, FSAH with corrugated aluminium duct (FSAH-C), FSAH with a sand heat storage element (FSAH-S), and FSAH with a combined use of corrugated aluminium duct and a sand heat storage element (FSAH-CS). The materials used for fabrication are low-cost and readily available in the study area. The results indicate that the sand bed enhanced the thermal performance by acting as the thermal heat storage medium, which could also supply heat for a short duration after non-sunny hours, and the corrugated aluminium duct enhanced the surface area and allowed the air to pass twice inside the SAH. We observed that the SAHs with sensible heat storage had a higher top loss compared to the FSAH-S configuration. The average thermal efficiency of the FSAH-CS configuration was 59.17%, which is 8.81%, 5.72%, and 10.95% higher than FSAH-S, FSAH-C, and FSAH, respectively. Furthermore, this configuration achieved an exit temperature of 64.5°C. The proposed system has a thermohydraulic efficiency of 59.14%, which is not significantly different from the average thermal efficiency. Therefore, the suggested system verifies its ability to function without requiring substantial external power.