Bachelor's thesis Christian Grozescu


Simulation Models of Building Energy Systems for City District Simulations

In context with the decentralization of energy supply and the development of renewable
energy sources with fluctuating power output it is important to gain information about the
time-dependent energy demand of cities. For this reason city quarter simulations are executed
in which the energy demand of the contained buildings is calculated. Although the
simulations cover a high number of buildings, they have to be done in a realistic amount of
This thesis deals with the simplification of building models for the calculation of heat demand
in city quarter simulations. Therefore, simplification strategies are applied to the model
of a multi-family-dwelling in order to reduce simulation time. On the one hand coupled
sub-models are decoupled and simulated separately.On the other hand, multiple roomswith
similar properties are modelled as one zone. The resultingmodels are simulated with various
parameters and their behavior in the simulations is compared. The goal of the simplifications
is to generate models with reduced simulation times that recreate the thermal behavior and
the heat demand of buildings similar to the unaltered model.
The simplified models show a great reduction in simulation time. Therein the decoupling of
rooms which have lowheat exchange among each other has little effect on the simulated heat
demand of the building. Combining multiple rooms to one zone can also grant significantly
shorter simulation times and has little influence on the result if the rooms have similar
boundary conditions such as solar radiation.