The Szeged District Heating Company (SZETAV), in Hungary, provides heating and hot water services to 27,256 apartments and 433 public buildings in Szeged, Hungary, a city with 162,593 inhabitants, located near three border areas: Hungary, Serbia and Romania. Since 2018, the company and its partners have been implementing the largest geothermal renovation of a district heating system in Europe, with the aim of reducing pollution, localizing energy supply and increasing operational efficiency.

As part of the Szeged project, 27 thermal wells were drilled to a depth of 1,700-2,000 meters in different parts of the city. The project design includes extraction wells (9) and injection wells (18), contributing to a more sustainable energy infrastructure for the city. Each production well extracts 70 m³/h of geothermal water at 90°C, providing around 3 MWh of thermal energy. However, despite the success in transforming the heating system, meeting the growing demand for cooling remains a challenge. Cooling is still managed individually in each building connected to the grid. The Danube GeoHeCo project aims to solve this problem by testing a geothermal district cooling system in the company’s headquarters. The headquarters is located in a non-thermally insulated building in the Severni Grad district of the city, has 40 employees and an annual energy consumption of 768,815 GJ for heating and 9 MWh for cooling. The building is connected to the district heating network, and the adjacent Severni 1/A heating plant provides geothermal heating and domestic hot water (DHW) to the surrounding areas.

The geothermal water enters the heating plant at a temperature of 94°C and is re-injected at 40-60°C, with a constant thermal water flow of about 10 m³/h. In order to optimize the use of geothermal energy and solve the cooling need, a high-temperature water absorption cooling system will be tested through the Danube GeoHeCo project. This system will provide 35 kW of cooling for the company’s headquarters, using waste heat and reducing the need for additional energy consumption, thereby minimizing CO2 emissions. The system will be powered by solar photovoltaic panels, ensuring a sustainable energy source.

This innovative project offers significant potential as a “living laboratory”, providing an excellent opportunity for local education on renewable energy sources. It will also serve as a research center for students, graduates and young researchers from the University of Szeged. Through the reuse of waste heat for cooling, the Danube GeoHeCo project helps to optimize energy use, reduce CO2 emissions and further develop the city’s commitment to sustainable energy solutions.