Quantifying Demand Flexibilities of Buildings for an Optimal Design and Operation of Integrated District Energy Systems

The EU's ambitious climate targets have highlighted the need for novel methodologies in the integrated energy
system planning and the development of sector-coupled operation strategies. In order to balance generation
and consumption in the electricity grid with a high share of renewable energies, energy storage potentials have
to be utilized across all sectors and new demand-side management strategies have to be developed. The
energy storage potentials of buildings could benefit the grid stability and support the exploitation of renewable
energy sources. Still, these potentials are not well quantified and are not considered in today’s planning
methods for district energy systems. This paper presents the derivation of widely applicable linear building
models that capture both detailed demand characteristics and storage characteristics from dynamic building
simulations, while accounting for thermal comfort. These models are integrated into linear energy system
optimization models, enabling the hourly optimization of air source heat pump operation and the heat emittance
into the buildings. The resulting approach allows for the quantification of flexibility indicators and provides
insights into efficient operation strategies for buildings with varying thermal characteristics. The results indicate
that all investigated buildings show economically viable potential for utilizing their thermal flexibility. While well insulated buildings demonstrate higher potential for longer-lasting preheating and storage periods, still
buildings with poor or moderate insulation also offer potential for shorter periods of utilization.