District heating (DH) systems are considered a viable method for mitigating long-term climate change effects, through reduction of CO2 emissions, their high conversion efficiencies and their ability to be integrated with renewable energy sources (RES). The current evolution towards sustainable DH, e.g. integration of RES, results in increased complexity and diversity during the early-design phase. In the early-design phase of DH systems a feasibility study is conducted to assess if the economic and environmental factors of the project meet the given requirements. This assessment is generally conducted with traditional district heating computational models (DHCM), utilizing a simulation language which limits the evaluation of sustainable DH systems in terms of flexibility and comprehensibility. The need for an alternative language capable of effectively modeling DH systems with integrated RES led to the use of Modelica, which offers improved flexibility, reusability as well as hierarchical and multi-domain modeling. This paper presents a case study, for the evaluation of a new DHCM analyzing its modeling capabilities and system performance, of an educational campus formed by eight institutional buildings connected to a centralized power plant, holding among others a biomass gasifier and a gas boiler. For an optimum utilization of the biomass gasifier, two power plant configurations are assessed: a biomass gasifier system with and without thermal energy storage (TES). The system performance evaluation indicates a significant increase in the utilization of the biomass gasifier with 8.2% (353 hours) compared to results obtained from the traditional DHCM. This deviation is due to a more accurate consideration of the DH thermal capacity and the space heating demand. Furthermore, the models in this DHCM enable assessments of the impact of building retrofits or climate change scenarios. Thus, the increased modeling capabilities and system performance demonstrate that this new DHCM is suitable and beneficial for early-design feasibility studies of innovative RES integrated DH systems.
|Title of host publication||Proceedings of the 9th International Conference on System Simulation in Buildings, December 10-12, 2014, Liege, Belgium|
|Publication status||Published - 2014|
|Event||9th International Conference on System Simulation in Buildings (SSB 2014), December 10-12, 2014, Liege, Belgium - Liege, Belgium|
Duration: 10 Dec 2014 → 12 Dec 2014
|Conference||9th International Conference on System Simulation in Buildings (SSB 2014), December 10-12, 2014, Liege, Belgium|
|Period||10/12/14 → 12/12/14|