Paper Conference

Proceedings of Building Simulation 2017: 15th Conference of IBPSA


Analysis of Heating Load Diversity and Application in a District Heating System

Claudia Weissmann1, Patrick Wörner 1, Tianzhen Hong 2
1Institute of Concrete and Masonry Structures, Technische Universität Darmstadt, Darmstadt, Germany
2 Building Technology and Urban Systems Division, Lawrence Berkeley National Laboratory, Berkeley CA, United States

Abstract: In Germany, district heating systems for the heat supply of residential districts have become more important in recent years. Still, their efficiency and costs heavily depend on the installed capacity of the central plant, which is designed to be capable of covering the district’s maximum requested heating load at any time. A high diversity of energy demand profiles in the district may balance the impact of individual peak loads and consequently lower the installed capacity. That is why load diversity has already been the focus of previous studies, particularly regarding the electricity demand. However, the influence of single building and occupant related characteristics on diversity respectively the residential district’s overall heat demand profile has not been under further investigation. In order to measure diversity, this paper introduces a peak load ratio (PLR) index that gives the percentage reduction in the district’s peak load compared to the aggregated peak loads of all individual buildings. Based on a definition of building and occupant related boundary conditions, 144 distinct load profiles are created using IDA ICE, a dynamic building simulation software. After that, the PLR index is employed on a fictional test district consisting of these profiles. The example shows that especially after adding buildings with a different occupant behavior the PLR goes up to 15%. In the second part of this paper, the results of the PLR analysis are applied to a district heating simulation model in order to trade off the described benefit of reduced installed capacities against the practical disadvantage of heat distribution losses. Likewise, the influence of load density and the district’s building profile is analyzed. The outcomes show that most notably districts with high load density including buildings constructed according to the latest building energy standards have the potential to take the advantage of load diversity.
Pages: 18 - 27