Experimental Investigation and Performance Analysis of a Flat-Plate Solar Water Heating System for Domestic

Abstract

Solar water heating systems represent one of the most technically mature and economically attractive applications of solar thermal energy, offering significant potential for displacing fossil fuel consumption in the domestic water heating sector — which accounts for approximately 18 percent of total residential energy use in India. This paper presents a comprehensive experimental investigation of a 2 m² flat-plate solar water collector coupled to a 200-litre insulated storage tank, installed at Karad, Maharashtra (latitude 17.27°N), over a twelve-month monitoring period from May 2025 to April 2026. The study systematically evaluates the effect of three collector tilt angles (15°, 30°, and 45° from horizontal) and five mass flow rates (0.010 to 0.060 kg/s) on collector thermal efficiency, useful heat gain, and outlet water temperature. The Hottel-Whillier-Bliss (HWB) model and the F-chart method are applied for theoretical performance prediction and validation against experimental data. Results show that the 30° tilt angle provides maximum annual useful heat gain (4.52 MJ/day annual average, 47.5% collector efficiency) — closely matching the site latitude — and that a mass flow rate of 0.020 kg/s provides the optimal balance of outlet temperature (peak 58.4°C) and system energy delivery. Monthly performance data confirm that the system achieves the target outlet temperature of 55°C on 218 days of the year. Life cycle cost analysis demonstrates a simple payback period of less than one year at current LPG prices, with a benefit-cost ratio of 12.3 over 20 years, establishing strong economic justification for solar water heater adoption in the region.

Cite as:

Rotiwale P. (2026). Experimental Investigation and Performance Analysis of a Flat-Plate Solar Water Heating System for Domestic. Research and Reviews on Experimental and Applied Mechanics, 9(2), 28–37. https://doi.org/10.5281/zenodo.21903927