Volume 10 Issue 2 ( June 2023 )

The thermal performance of one-ended stainless-steel manifold-based evacuated tubes, solar air collectors, using air as the working fluid, is the subject of an experimental investigation carried out in the winter season at Glocal University, Saharanpur, India [30⁰ 17' (latitude) North and 77⁰ 38' (longitude) East]. Nine evacuated tubes with directed inner tubes of varying diameters are placed in a one-ended stainless-steel manifold to form the solar collector. The input air passes through the directed inner stainless tubes inside the evacuated tubes due to forced convection. In this experiment, hot air is produced in evacuated tubes, gathered in the main header manifold, and released through the output pipe. The airflow velocity, directional stainless steel tube diameter, air mass flow rate, and solar intensity influence the air temperature exiting the outlet. At a solar intensity of 616.2 W/m² , the highest temperature measured is 90.5⁰ C, and the maximum temperature difference between the exit air and the input air was measured to be 62.5⁰ C at a flow rate of 4.58 kg/h in a stainless-steel tube with a 20 mm diameter and 1.27 meters length.

Keywords: evacuated tubes, solar air collector; directional inner stainless-steel tubes; forced convection; airflow; solar intensity, thermal performance