Effect Of Octagonal Shaped Aperture Area On Optical Performance Of The Simple Flat Plate Solar Reflecting System

Solar flat plate reflectors are less expensive, made from indigenous technology, easier to maintain, and more readily available in the market than its curves counterpart. The impact of switching from a Square Shaped Aperture Area (SAA) reflector configuration to an Octagonal Shaped Aperture Area (OSAA) reflector configuration on the overall performance of the solar reflecting system are studied in the present article. The study is carried out using numerical analysis in a similar manner that is carried out based on an inverted frustum type flat plate solar reflecting system [1]. Four diverge Indian stations are considered for the analysis they are; Delhi, Guwahati, Bengaluru, and Vadodara. For these locations the impact of different sun altitude angles on system performance were investigated. The behavior of the solar beam ray and its interaction with the reflector is mathematically determined and the analysis was performed using a specially written MATLAB Code. Based on its interaction with the reflector the rays are classified into six categories. Despite SAA's concentration ratio being 13% higher than OSAA's, the results show that OSAA has redirected more rays to the bottom receiving surface due to its distinctive reflector configuration. Compared to traditional SAA system, use of OSAA results in successfully converting 23% more number of rays towards bottom reflector which otherwise leave from the top of the system from the top. Moreover, it has been seen that the system's optical performance is much improved at a higher altitude angles of sun, and in the east-west alignment compared to a north-south alignment with the trajectory of the sun. In overall the performance of the OSAA-based sun reflecting system and the accompanying ray distribution profile is around 9% higher than that of the SAA-based solar system, to sum up.