Evaluation of thermo-hydraulic performance of solar air heater integrated with hexagonal baffles: a numerical investigation
摘要
Solar air heater is a promising solar energy harnessing device that helps increase air temperature, making it suitable for low- and moderate-temperature applications. Although the solar air heater is a mature technology and simple in construction, due to its poor energy conversion, it requires special attention to improve thermal delivery performance. Considering this in the present work, hexagonal baffles with two different configurations integrated into a flat and v-grooved single-pass airflow solar air heater are numerically investigated with an aim to enhance the heat transfer parameters. The solar air heater performance is analyzed using ANSYS Fluent computer codes, wherein the area of the flat and v-grooved absorber plate is 2 and 2.24 m2. Parameters like average outlet air temperature, Nusselt number, thermal efficiency, thermal enhancement factor, etc., are evaluated and illustrated to study the heat transfer behavior of the system. The results indicate that the maximum thermal efficiency was 54.95% for v-grooved solar air heater configuration 1 at a flow rate of 0.06 kg s−1. However, a maximum outlet air temperature of 332 and 342 K was obtained with a flat and v-grooved absorber plate with configuration 1 at a flow rate of 0.01 kg s−1. It is seen that the Nusselt number increases with an increase in flow rate with simultaneous drop in velocity. Hence, the integration of hexagonal baffles tends to improve the thermal performance with the thermal enhancement factor ranging from 1.26 to 2.28.