A Techno-Economic Feasibility Analysis of Solar Thermal System Installation for Sanitary Hot Water Requirements in a Residential Building

Abstract

Existing studies on solar thermal systems for residential complexes often face challenges in achieving a balance between energy generation, cost-effectiveness, and environmental impact. This paper investigates the feasibility of a solar thermal system for meeting the Sanitary Hot Water (SHW) demand in a residential complex. The study addresses these challenges by evaluating the potential of solar thermal energy in comparison to other renewable energy sources. The analysis focuses on an existing residential complex located at Heriot Watt University, Edinburgh, where the roof space available for solar collectors is limited to 150 m². The proposed system consists of 58 flat-plate vertical collectors, which were selected based on this available area. The system is projected to generate 8,217 kWh in June and 2,193 kWh in November, offsetting the energy demand in June and approximately half of the demand in November. A 30kW auxiliary boiler is proposed to cover the remaining energy deficit in November. The environmental benefits of the system include a reduction of 7.7 tons of CO2 emissions annually, by replacing gas-fired boilers. With an initial investment of £32,000, which includes the cost of collectors, heating system, and installation, the system offers a payback period of 12.5 years when factoring in annual savings from reduced gas consumption.