Optimisation of a district energy system with a low temperature network

Low temperature district networks (LTNs) supply both low temperature heat and cooling to multiple buildings. Heat input from renewables and waste heat can be fed into LTNs, and they are often connected to long term thermal storage such as borehole fields. LTNs which include new technologies and topologies need to be evaluated in order to enable their further development and application. The objective of this paper is to evaluate the energy performance of a recently constructed district energy system (DES) with a LTN using a multi-energy network optimisation model. The LTN connects buildings to a borehole field which can be regenerated with heat supply from hybrid solar panels and waste heat from building free-cooling. Monitoring data of heat and free-cooling demand was used as an input to the optimisation model and results were compared with monitoring data of electricity consumption of heat pumps and network pumps. Following validation of the initial model, scenarios with electric storage (batteries) and thermal storage were evaluated. Results from evaluation of scenarios provide insights on how the district energy self-sufficiency can be improved through installation of batteries or by improved use of existing thermal storage. •Optimisation of a low temperature network with bi-directional energy exchange.•Validation of a multi-energy optimisation model using monitoring data.•Scenarios with electric and thermal storage to improve energy self-sufficiency.