Optimized use of buildings as decentralized heat storage in the Demand Side Management – Development of a grid-integrated heating system equipped with a thermally activated building system based on model based predictive control of heat pumps

Young Jae Yu
Fraunhofer-Institute for Building Physics
Branch Kassel, Department Energy Systems, Group LowExergy Systems
Phone +49 561 804-7448 – youngjae.yu@ibp.fraunhofer.de

Prof. Dr.-Ing. Anton Maas
University of Kassel, Architecture Urban Planning and Landscape Architecture, Department of Building Physics
Prof. Dr.-Ing. Jens Knissel
University of Kassel, Architecture Urban Planning and Landscape Architecture, Department of Technical Building Services

Short discription of the subject

Background and Motivation
Increasing the share of fluctuating renewable energy requires an efficient form of balance between energy supply and demand. Thereby, Demand Side Management (DSM) and efficient storage technologies are important tools to compensate the fluctuations of renewable energies. Here it is important to interconnect distributed generation and storage units and to control it by means of Demand Side Management.  Especially, in the building sector a short-term surplus electricity from renewable energy sources can be converted into heat energy by heat pumps with DSM and then stored in building thermal mass in dependent of the actual heat demand. Against this background, this study demonstrates how far buildings, especially single family houses, are eligible for use as variable energy consumer and thermal energy storage in DSM.

Research Methods
The main focus of this study is an investigation of grid-integrated heat pump operation that enables energy efficient heating through the use of surplus electricity from renewable energy sources. Thereby, thermally activated building systems (floor, wall, ceiling) are used as thermal storage. The storage efficiency and loft shifting potentials of different thermally activated building systems are evaluated through a thermal dynamic simulation with TNRSYS.

Additionally, control algorithms of heat pumps developed that take into account the thermal behavior of thermal mass in buildings, and dynamic current tariff structure using weather forecast and expected day-ahead price signals in advance. For the evaluation of control algorithms, both energy efficiency of heat pumps and thermal comfort can be used as a basis and this allows a comparison with conventional control strategies. Particularly for the evaluation of the thermal indoor comfort a building model with high complexity is required.

Expected Result
The aim of this study is to develop control algorithms for the grid-integrated heat pump operation that enables an optimum use of thermal mass in buildings for load shifting. Thereby the share of surplus electricity in total energy consumption for heat supply should be maximized, and an interaction between the heat and the electricity sector should be achieved to discharge local power grids from peak loads.

Using buildings as decentralized thermal energy storage for DSM is not only meaningful because of its quantitatively large storage potentials, but also because of the relatively low technical and economic cost of thermal energy storage for grid stabilization compared to using electric storage batteries and fossil power plants.  

Short CV

Since 10.2012Research fellow (Ph.D. Student), Fraunhofer-Institute for Building Physics, Kassel Branch, Group Low Exergy Systems, Department Energy Systems
Since 08.2012Ph.D. Student, University of Kassel, Architecture Urban Planning and Landscape Architecture, Department of Building Physics
04.2010 – 03.2012Master course - Renewable energy and energy efficiency, University of Kassel, Department of Mechanical Engineering
10.2007 – 09.2009 Master course - CLIMADESIGN, Technical University of Munich, Department of Building Climatology and Building Services

Focus of interests and research


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