Numerical Investigation of Cover Plate Configurations Effect on Thermal Characteristics of a Polymer Solar Collector

This paper presents numerical analysis on influence of different configurations on thermal performances of a polymer solar collector.In the first step two configurations including single cover plate and honeycomb cover plate are investigated.Results showed that collector with single cover plate is more efficient than collector with honeycomb cover plate at lower reduced temperature values.Honeycomb cover plate behaves like insulator, increasing overall collector top resistance to heat loss which results in higher thermal efficiency at higher reduced temperature values.This also leads to higher temperatures at stagnation regimes.Also, in this paper two passive overheating protection based on natural convection are examined.Channels inside honeycomb cover plate can be connected to channels inside absorber plate allowing for air to flow inside collector.Three different channel widths are considered 4.25, 10, and 20 mm.With such passive method, it is possible to reduce average absorber temperature up to ~20C.Second overheating protection uses additional channel below the absorber plate allowing the flow of ambient air.With this method it is possible to reduce temperatures up to ~50C but it also causes high temperature gradient, 50C/m of collector length which can potentially result in deformation of polymer solar collector.Present work is a part of the research focused at development of a low-cost polymer solar collector that operates in a drain back system.