Solar water heating systems for different buildings under a hot climate; parametric optimization and economic analysis

Abstract

Building applied solar thermal systems are considered by different stakeholders an attractive alternative to traditional space and water heating systems. However, their performance depends largely on climatic conditions, water heating needs and operational parameters which, in turn, offer opportunities for performance optimization. The present research attempts to provide architects with a design decision tool that integrates solar thermal collectors efficiently to meet hot water demand for various building types inclusive of residential, commercial and industrial in a hot climate. The analysis is conducted numerically through a thermal model developed and executed in TRNSYS and validated experimentally. The parameters investigated include the collector tilt angle, azimuth angle and collector inlet fluid flow rate. Finally, the collector aperture area required per building foot print area is determined. The research revealed that for a 1000 m2 footprint building area of schools, offices, residential, factories and hospitals would require respectively 8 m2, 10 m2, 14 m2, 24 m2 and 38 m2 of the static collector installed at 24° tilt angle with optimal water flow rate. Additional operational aspects of collector tracking, and solar radiation concentration were investigated and further reduce the required collector area. A simple payback period analysis reveals a return on investment of 2 years applying subsidized tariff rates under the climatic conditions of, or similar to Dubai, in the United Arab Emirates.