Advancements and integration strategies of solar water heaters in buildings: A comprehensive review

Abstract

The integration of renewable energy into buildings is a key strategy to reduce energy consumption and heating costs. This review comprehensively examines solar water heater (SWH) systems, focusing on their major components such as storage tanks, solar collectors (flat plate, evacuated tube, parabolic trough, and others), and heat transfer fluids. Two integration strategies are discussed: building-integrated systems (roof and façade applications) and standalone thermosiphon systems. Recent advancements in SWHs include the use of selective coatings, nanofluids, and phase change materials (PCMs), which significantly enhance thermal efficiency. Key factors influencing performance such as collector orientation, tilt angle, and thermal losses are analyzed. The review concludes with design optimization recommendations and integration strategies that support higher system efficiency and broader adoption in both residential and commercial applications.