Long-term thermal performance and techno-economic assessment of a passive solar water heater with a flat-plate PPR-based solar collector
Year: 2026
Type: article
Abstract: Solar water heating systems offer an effective way to reduce residential fossil fuel consumption. However, conventional flat-plate solar collectors typically rely on metallic components and multi-circuit configurations that increase cost and system complexity. This study presents a long-term performance assessment of a passive solar water heater (SWH) equipped with a flat-plate solar collector fabricated from Polypropylene Random Copolymer (PPR) operating under a simplified single-circuit thermosiphon configuration. The proposed design eliminates auxiliary components such as circulation pumps, heat exchangers, and antifreeze loops, enabling a robust and cost-effective system architecture for domestic applications. The system was evaluated through a one-year field case study in a four-person household in Santiago, Chile, a region characterized by high solar resource availability. Results show a 55% reduction in liquefied petroleum gas (LPG) consumption, corresponding to an annual solar fraction of 55% and a system-level solar thermal efficiency of 58.1%. Annual energy savings totalled approximately 2,904 kWh, resulting in an estimated payback period of 4 years at current fuel prices. A sensitivity analysis further indicates that user behavior parameters, such as shower flow rate and duration, significantly influence the effective solar contribution, potentially increasing the solar fraction to above 75% under optimized conditions. Overall, the findings demonstrate that polymer-based passive SWHs with simplified hydraulic configurations can deliver reliable thermal performance and attractive economic returns in regions with high solar irradiance.
Institution: University of Toronto
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,620
OpenAlex ID: W7165007764