Experimental investigation of thermo-hydraulic efficiency and performance characteristics of an impinging jet-finned type solar air heater

Abstract

The current experimental study aimed to assess the overall performance of a sustainable design solar air heater (SAH). The investigated design comprise of mutual combination of jet impingement technique and application of fins. The array of longitudinal and continuos fins extends the rear side of the absorber and just below to it a jet plate is also encapsulated which consist of inline pattern of holes. For experimentation and testing natural climatic conditions were considered under specific range of design parameters enlisted in Table.1. The influence of the listed parameters is investigated on effective efficiency, outlet air temperature and friction factor respectively. The results are compared with the similar literature available. The outlet air temperature is enhanced while increasing the solar intensity values in comparison to the smooth duct. The maximum effective efficiency obtained is 82.5% for X/Dh = 0.46 respectively. With an increase in the values of Re friction factor decreases and the maximum friction factor has been observed at stream wise pitch ratio of 0.46, jet diameter ratio of 0.046 and least fin spacing of 0.23 yields low values of friction factor. The maximum efficiency in case of impinging jet with fins type design (IJWFSAH) obtained is 84% with 6% and 16% enhancement as compared to simple impinging (IJSAH) and smooth configuration. On the basis of comparative analysis between the theoretical and experimental results of thermal efficiency for IJSAH and IJWFSAH. An average deviation of ± 2% for (Re < 9000) and ± 2.2–3% for (Re > 9000) has been reported for IJWFSAH. The average deviation noted for IJSAH is ± 1.5% for (Re < 9000) and ± 2–3% for (Re > 9000) respectively. The data of comparative analysis shows a good agreement between the experimentally evaluated and theoretically calculated values.