Assessment of The Coherence Between District Heating Design Parameters and Low-To-Medium Temperature Geothermal Resources In Central and Eastern Europe

Central and Eastern Europe is a region where many district heating networks operate. Most of them were designed and run on energy derived from conventional fuels, mostly hard coal and natural gas. The current policy trends in Europe follow climate neutrality and the decentralisation of energy sources. This puts intense pressure on energy suppliers. From the point of view of cooperation with a geothermal energy source, the problem for current DH installations is serious, due to former design standards. Especially urban, extensive district heating systems were designed for high temperatures. In general, it can be stated that with the increase in the network size and the number of connected consumers, the requirements it puts on the high supply temperature and relatively high return temperature increase. For example, in large heating networks in Poland, the parameters 110/70°C, or even 130/70°C, are standard. For example, geothermal resources available in Poland and Slovakia rarely exceed 80°C, while those with a temperature range of 60-80°C are common. Due to the lack of dependence on weather conditions, geothermal energy is an attractive and stable renewable energy carrier, and the existing heating networks are an ally for its effective use. In the case of the direct use of geothermal energy, it can be said that its economic profitability can be achieved only in cooperation with a heating network. Unfortunately, the maximum temperature that can be delivered by a geothermal heat source poses a severe technical problem. Heat pumps have become devices that transform geothermal energy into higher temperatures used in heating plants. Heat pumps are used willingly, despite relatively high investment costs. A significant disadvantage of heat pumps is the consumption of high-quality driving energy. Often it is either high-temperature thermal energy or electricity. In Eastern and Central Europe, these types of energy are produced based on conventional fuels. On the other hand, the already available and commonly used solutions in decentralised heating make it possible to reduce the required operating parameters of heating systems significantly. This allows for a significant improvement in the efficiency of geothermal use and extends the group of its recipients. The article presents the preliminary results of an assessment aimed at popularising the use of solutions to reduce the requirements set by the recipient on a geothermal heat source. Of course, these changes are not easy to implement. However, it is essential to pay attention to them and present their potential benefits. The article presents the preliminary results of the project "Improving the energy efficiency of geothermal energy utilisation by adjusting the user characteristics" (User4GeoEnergy, No. 2018-1-0502) funded by Iceland, Liechtenstein, and Norway through the EEA and Norway Grants Fund for Regional Cooperation.