Thermo-Economic Evaluation of a Virtual District Heating Network Using Dynamic Simulation

In the current context of energy transition, district heating systems are considered as a convenient yet efficient solution to reduce both primary energy consumption and greenhouse gases emissions. The use of locally available alternative heat sources, as for example the heat rejected by waste incinerators, constitutes an opportunity to valorize low-grade heat. Despite a higher initial investment cost, waste incinerators present the advantage to have a zero fuel cost that balances this initial capital expense. In the present contribution, a reference case study based on the IEA EBC Annex 60 framework is used as a first attempt to explore dynamic effects related to the distribution of heat through district heating networks. It consists of a small set of reference dwellings with different heating profiles depending on the type of buildings and their level of insulation. The costs for the different operating scenarios and the consequent advantages of a combined heat and power waste incinerator as a heat source are determined. This paper illustrates the use of a plug flow dynamic model intended to predict the heat transport delay, the heat losses and the pumping work due to long piping instead of the classical steady-state approach usually used for district heating networks profitability assessment. A comparative assessment of both the unit cost of heat and CO2 emissions savings is performed for two different heating technologies, namely a combined heat and power waste incinerator combined to backup boilers and a natural gas boiler.