Evaluation of Solar Thermal Potential for Domestic Integrated Water Heating in the South of Western Siberia

Limited adoption of solar energy in the Northwestern region of Russia is associated with insufficient data on annual solar radiation indicators and on the potential of solar collectors for water heating. The study aims to evaluate the potential of solar water heating for domestic use in Northwestern Russia, using Tyumen city as the case. In this region, the number of cloudy days ranges from 5% to 50%, with cloud cover increasing in winter. New data on the total solar radiation, availability duration, and cloud cover have been collected. Solar irradiance could reach 900 MJ/m2 during summer months, while decreasing to 50–150 MJ/m2 significantly in winter. Notably, the solar radiation demonstrates predictable and stable characteristics between the hours of 9 a.m. and 3 p.m. Consequently, the heating system is equipped with a gas-supplied boiler as the primary heat source, with the solar collector being the secondary clean energy source to meet the demand of a residential house. A is designed to compensate for the heat losses in the evening and at night. The results of unmatching energy demand and production highlight the need for a water tank for energy storage to facilitate a wider use of solar power. The peak thermal energy requirement for domestic hot water (DHW) occurs in January, amounting to 6046.8 MJ. In summer, from May to August, the thermal energy produced by solar collectors is not utilized due to the lack of heating load. The annual data indicate that the solar collectors contribute approximately 14% of the total heat required for DHW.