Abstract

This study presents field measurements and analysis of small-scale solar water heating (SWH) systems installed in urban residential areas of Tehran, Iran. Over a 12-month period from January to December 2024, data were collected from 10 residential units equipped with flat-plate collectors and thermosyphon systems. Key performance indicators, including thermal efficiency, solar fraction, and energy savings, were evaluated under varying urban conditions such as shading from high-rise buildings and ambient temperatures ranging from -5°C to 40°C. Results indicate an average annual thermal efficiency of 58%, with peak efficiencies reaching 75% during summer months. The systems provided up to 70% of hot water needs, reducing fossil fuel consumption by approximately 2,500 kWh per household annually. Economic analysis shows a payback period of 5-7 years, considering local subsidies. Challenges like dust accumulation and urban heat island effects were quantified, leading to recommendations for optimized designs in dense urban environments.

Keywords

  • Solar water heating
  • field measurement
  • urban residential
  • thermal efficiency
  • solar fraction
  • energy savings.

References

  1. 1. Assessment of Solar Heater Installations in Urban and Rural Settings. ResearchGate, 2024.
  2. 2. Experimental analysis of a solar heating system with seasonal thermal energy storage built in North China. ScienceDirect, 2015.
  3. 3. Control and Managing of Individual Solar Water Heating Systems in Multi-Apartment Buildings. MDPI, 2024.
  4. 4. Methodology for estimation of potential for solar water heating in a target area. ScienceDirect, 2006.
  5. 5. Solar Energy Utilization Potential in Urban Residential Blocks: A Case Study of Hangzhou, China. MDPI, 2023.
  6. 6. The Photovoltaic Heat Island Effect: Larger solar power plants increase local temperatures. Nature, 2016.
  7. 7. A review on solar water heating technology: Impacts of parameters and techno-economic studies. Springer, 2024.
  8. 8. Recent Progress and Challenges in Microscale Urban Heat Environments. ASME, 2023.
  9. 9. A Review of Multi-Domain Urban Energy Modelling Data. SciePublish, 2024.
  10. 10. Solar Water Heating. WBDG, 2023.
  11. 11. Heat Storage in Urban Areas: Local-Scale Observations and Instrument Comparison. AMS, 1999.
  12. 12. Modeling the economic viability and performance of solar home systems: A roadmap towards clean energy for environmental pathway. PMC, 2022.
  13. 13. Future compatibility of district heating in urban areas — a case study analysis in the context of small towns and rural areas. BioMed Central, 2019.
  14. 14. Cost-benefit analysis of solar energy integration in buildings: A case study of residential buildings in India. Frontiers, 2023.
  15. 15. Optimization of Solar Water Heating System in High-rise Residential Buildings. JESTR, 2022.
  16. 16. Technical, Environmental, and Energy Analysis of Solar Water Heaters. Northumbria, 2021.
  17. 17. Feasibility analysis of solar water heating system in rural areas. ResearchGate, 2017.
  18. 18. Solar neighborhoods: the impact of urban layout on a large-scale solar energy system. Nature, 2023.
  19. 19. District heating. Wikipedia, 2024.
  20. 20. Solar Futures Study. DOE, 2021.
  21. 21. A categorical review of advancements, efficiency, and sustainability in solar water heating systems. Springer, 2025.
  22. 22. Thermal and Environmental Analysis Solar Water Heater System for Residential Buildings. Wiley, 2021.
  23. 23. Solar water heating system integrated design in high-rise apartment in China. ScienceDirect, 2012.
  24. 24. Analysis and Optimization Design of a Solar Water Heating System Based on Life Cycle Cost Using a Genetic Algorithm. MDPI, 2015.
  25. 25. Domestic solar hot water systems: Developments, evaluations and essentials for “viability” with a special reference to India. ScienceDirect, 2011.
  26. 26. Performance Studies and Energy-Saving Analysis of a Solar Water-Heating System. MDPI, 2021.
  27. 27. Design & Performance Analysis of Portable Solar Water Heating System for Rural Areas: Himalayan Regions, India. ResearchGate, 2013.