Impact of load structure variation and solar thermal energy integration on an existing district heating network

A model for district heating and cooling networks was developed. It was designed for the hydraulic and thermal simulation of networks with multiple loop topologies. The network description is based on a graph-theoretical method and the Newton algorithm was used for solving the system of nonlinear equations. To validate the model and to demonstrate structural improvement potentials, a case study for a biomass powered district heating network in Scharnhauser Park, Germany was carried out. Taking into account the existing network topology, the consumer stations were redistributed in the model in order to obtain four different load repartitions. By means of three quality indicators (the primary energy factor PEF, the relative importance of losses RiL and the CO2 emissions) it could be shown that the different geographical distributions of consumers within the network have a slight impact on the primary energy use and on the CO2 emissions of the system. The network model was also used to analyse different solar thermal energy supply strategies. It is concluded that the existing collector area can maximally contribute to 0.3% of the total heating energy demand. (C) 2011 Elsevier Ltd. All rights reserved.