Covering peak loads in district heating networks using ground source heat pumps: potentials and challenges
Decarbonizing the building stock will require a significant increase in district heating, particularly in urban areas. Key challenges for rapid expansion include meeting peak loads with renewable sources and addressing the growing demand for cooling. This project investigates the potentials of decentralized, ground-coupled heat pumps using either geothermal probes or groundwater to address these issues. The simulation-based analysis relies on case studies to derive practical insights for future district heating development. As demonstrated in former research, e.g. the 'HP-source' project the total length of geothermal probes can be significantly reduced when used solely for peak load rather than full load coverage. In residential buildings, the winter peak load often roughly matches summer cooling demand. In this setup, district heating supplies the winter base load, while ground-coupled heat pumps cover peaks. In summer, the heat pump and the probes cover the cooling demand. This paper presents interim results, focusing on two case studies, aiming to initiate discussion on the topic. Case study 1 deals with the integration of decentralized borehole fields in a district-heating-and-cooling network currently under development. It focuses on different topologies and considers existing waste heat sources and demand for heating and cooling. Case study 2 is related to the integration of a borehole field into the existing technical infrastructure of a hospital, currently supplied by district heating. Different integration variants, including system sizing and coverage of summer cooling needs, are analysed.