Novel dimension scaling for optimal mass flow rate estimation in low temperature flat plate solar collector based on thermal performance parameters

Abstract

Uncomplicated configuration, efficient collection of incident solar radiation and less frequent maintenance issues compared to the other prevalent alternatives enable the flat plate solar collectors to remain relevant in the present age of continuously evolving cutting-edge technologies. However, the quest for energy-efficient and sustainable solutions necessitates resizing of the flat plate collectors to achieve enhanced efficiency. Detailed performance analysis of the collector requires a prohibitively higher number of experimental trials and computationally expensive numerical models. Hence, in this study, a simplified energy equations-based dynamic model is used to develop working relationships for calculating the collector dimensions and the optimum heat transfer fluid (HTF) mass flow rate for achieving a predefined thermal efficiency. The developed formulae can predict the geometrical and operating parameters very accurately, with maximum deviation in estimating the collector channel dimensions being 12.5%. Hence, the formulae can be used as an initial guideline for the design of the collector. The computational results for the geometrical configuration corresponding to an average DNI, calculated from actual solar radiation data, indicate that to achieve a fixed temperature and a collector efficiency, the required HTF mass flow rate increases with increasing level of solar radiation.