Model-based assessment of cost-effective retrofit solutions for a district heating system extension

This contribution aims to investigate the viability of a district heating system (DHS) on the long-term, by studying a method to extend an existing DHS with new buildings while keeping the same generation and distribution facilities. The study is conducted by simulating the DHS. The models are developed in Modelica. Simulation results show that extending a DHS is possible under scenarios. Retrofitting the envelope of some buildings and applying a centralised control over every customer’s thermostat both give satisfying results. On the other hand, decentralised storage manages to improve indoor comfort but slightly increases the energy demand. Centralised storage proves to be very dependent on its sizing and control strategy, and only provides poor results when non-optimal.