Energy and exergetic analysis of a solar air heater for enhanced thermohydraulic performance with side wall treatment

This numerical study investigates the performance enhancement of a solar air heater using side wall treatment for a Reynolds numbers range of 3000–24000. Thermal enhancement is evaluated for various kinds of straight and tapered side wall designs. The simulations use a DO radiation model to simulate heat inducement due to solar radiation inside the numerical domain. Notably, at a Re of 24000, the SSW 40 and TSW (40-10) configurations had maximal thermal efficiencies of 89.25 % and 90.62 % respectively. The TSW (40-10) arrangement exhibits the highest exergy efficiency at 4.08 %. Environmental assessments show a CO₂ mitigation rate of 1.06 tCO₂/year and an annual environmental cost of $15.5. Furthermore, the energy payback time is estimated at 2.5 months, but the exergy payback time is more than a decade. Enhanced solar air heater designs increase energy efficiency, making renewable heating systems more viable for both residential and commercial customers. This results in lower CO₂ emissions and faster economic returns, promoting widespread adoption of green technologies.