Integration of a solar thermal system into a district heating system

Apstrakt

The integration of solar thermal systems into district heating networks represents a pivotal step toward sustainable urban energy solutions. This study examines the integration of such a system into the “Toplana Cerak” heating plant, part of Belgrade’s district heating network. The primary aim was to analyze the technical and economic feasibility of transitioning from a conventional natural gas-based heating system to a hybrid model combining solar thermal technology. The proposed system includes solar collectors, a heat exchanger, and a thermal storage unit, ensuring year-round energy delivery. A mathematical model and simulation were employed to optimize critical parameters, including the solar fraction (SF), storage volume, and collector area. Scenarios with varying solar shares (30%-90%) were simulated to identify an optimal configuration. The results revealed that a 70% solar fraction is the most cost-effective and environmentally beneficial, reducing annual CO2 emissions by 31,000 tons and decreasing primary energy use by approximately 70%. Economic analysis using the Sunstore 4 Feasibility Tool showed significant potential savings, with an estimated €3.7 million annually and total savings of up to €162 million over 25 years. Additionally, the levelized cost of heating (LCOH) was halved compared to conventional systems. This study underscores the potential of solar district heating to reduce greenhouse gas emissions, enhance energy independence, and align with EU climate targets. Future recommendations include improving thermal storage design and exploring integrations with other renewable energy sources like biomass or geothermal systems to further enhance efficiency and sustainability.