Design and Performance Evaluation of a Solar Flat Plate Collector for Water Heating Applications

Abstract

This methodology paper presents the design and performance-evaluation procedure for a glazed solar flat-plate collector intended for domestic and low-temperature water-heating applications. The proposed collector uses a blackened metallic absorber, copper riser tubes, a transparent glass cover, rear insulation, a 100 L storage tank, and a controlled water-circulation loop. The evaluation method combines an energy balance with outdoor measurements of solar irradiance, ambient temperature, collector inlet and outlet temperatures, and mass flow rate. Useful heat gain is determined from the water temperature rise, while instantaneous collector efficiency is calculated relative to incident solar energy. The design also permits the conventional efficiency relation between reduced temperature difference and efficiency to be obtained. A representative data set is included only to demonstrate the analysis procedure; it is not presented as a substitute for actual site measurements. Under the illustrative test conditions, useful heat gain and efficiency increased with irradiance and remained strongest near solar noon, while efficiency declined as the collector operating temperature rose above ambient. The proposed methodology is simple, reproducible, and suitable for evaluating design choices, flow rate, heat losses, and storage performance in flat-plate solar water-heating systems.