Numerical and Experimental analysis of a Solar Air Heater with triangular ducts

The solar air heater is a device that uses the freely available solar energy and converts it to thermal energy using a working fluid like air. These systems can be used in buildings to supplement traditional heating systems and help us reduce energy costs. The shape of the solar air heater cavity can vary depending on the design and purpose of the heater. Some common shapes include rectangular, triangular, circular, semi-circular, etc. The choice of shape can affect the efficiency of the heater and may depend on factors such as available space, desired airflow, and aesthetic considerations. This paper reports the results of a numerical and experimental investigation carried out on the isosceles triangular duct solar air heater (SAH). The parameter varied in the study is the interior angle (θ) of the isosceles triangular duct from 40º to 80º, with an interval of 5° variation. The top absorber plate width (W) is fixed at 160 mm for all duct variants. The height (H) of the duct will vary according to the duct interior angle. The influence of duct interior angle on the heat transfer performance, the bulk temperature of the air, and pressure drop across the solar air heater duct are investigated. The top surface of the duct replicates the absorber plate of the SAH and is subjected to a uniform and constant heat flux value of 1000 W/m². This investigation comprises of both experiments and computational simulations. The numerical problem is modelled and simulated using the commercially available ANSYS Fluent software. The two-equation standard k-epsilon model is engaged to handle the turbulence closure.