Investigation of Heat Network Optimization Modeling

This study builds on a scenario development method to optimize the operation of a district heat network with 200 residential units. The heat network is based on a combined heat and power system (CHP), which allows comprehensive investigations on adaptation steps for further decarbonization, including centralized and decentralized heat and power generation. The applied methodology contains an expanded scenario transfer for three core and four additional scenarios as well as modeling and optimization of the adaptations for heat and power supply under these scenarios. From possible 5.040 calculations, a subtotal of 384 calculations is evaluated in detail for this paper.
The optimization results are evaluated according to three dimensions: the share of renewable heat in the heat grid, operating expenses for electricity and fuels enhancing revenues and subsidies, and the sum of direct and indirect district-related CO2 emissions. Furthermore, the analysis of the optimization results focuses on the utilization of roof surfaces for solar energy technologies, the choice of the central heat supply system and the impact of the core and additional scenarios on the adaptation steps.
The findings demonstrate that pv systems offer greater cost reductions and a positive impact on CO2 emissions compared to solar thermal systems, making them the preferred choice for rooftop utilization. A correlation is observed between higher renewable energy shares in the heat network and reduced operating expenses, with heat pumps meeting significant heat demand through subsidies and higher efficiency. However, heat pump adaptations do not lead to a complete renewable heat supply due to the natural gas boiler back-up system implemented in every adaptation step. The comparison of the impact of scenario differentiation and the heat generation system reveals, that the scenarios show a significantly lower influence on the results, both costs and RE-share.
Overall, the study provides valuable insights for decision-making and planning processes for the transition of district heat networks, highlighting the importance of renewable energy integration and cost-effective operations to reduce CO2 emissions and enhance sustainability.