Prosumers and district heating: Experimental validation of strategies to improve thermal energy production and consumption

The European Union targets a 55 % reduction in greenhouse gas emissions by 2030 and climate neutrality by 2050, emphasizing decarbonisation in energy sectors. District Heating Networks with thermal prosumers and bidirectional substations are critical to decarbonize the heating sector by integrating renewable energy sources. The paper analyses how to enhance the share of renewable energy sources used by a thermal prosumer. Various strategies, including heat pump integration, are experimentally studied to improve the prosumer's energy self-consumption in a district heating network operating at two temperature levels (80/50 °C and 60/30 °C for supply and return), utilizing the hardware-in-the-loop technique to couple the substation in real-time with data-driven profiles for thermal loads (multi-family residential buildings) and production (solar panels). Energy flows are analysed for representative days and then extrapolated to calculate yearly results. The implemented strategies were found to be effective in terms of user's self-sufficiency: the energy produced by solar panels and used to cover the thermal demand increased across all case studies i.e., from 8 % to 27 % for non-renovated buildings operating with high-temperature network, from 14 % to 26 % for renovated buildings with low-temperature network. The share of self-consumption increased from 13 % to 30 %, and from 10 % to 15 % respectively, and the production from renewable sources was enhanced (up to 39 %). With net metering, local energy surplus can be utilized beyond production periods, achieving 58 % self-consumption when integrating a heat pump. The results can support stakeholders in developing efficient district heating systems, particularly in the context of potential thermal energy communities.