Environmental Engineering Reference
can be defined for each zone. For the example of the Scharnhauser Park Town Hall,
the building was simulated using three different zones, one of which connects to the
ground. Temperature setpoints, air change rates and internal gains were defined by
schedules. For example, the air change was set at 0.25 h − 1 during weekends and varied
between 0.3 and 0.5 h − 1 depending on the time during weekdays.
The complete model gives a good agreement between heating energy consumption
and simulated demand on a daily basis (see Figure 6.39). Typically the difference
between measured consumption and simulation value is between 10 and 20%. On a
monthly basis, the simulated values overestimate the measured values by 5%. Typical
weekly errors are below 5%, but if weeks with special occupancy occur, the weekly
error is near 10%. The implemented online simulation procedure allows the user to
follow the building's summer and winter performance on a daily evaluation base and to
optimize the performance. Overestimation of the heating energy consumption occurs
on weekdays with less occupancy than usual, which is not yet considered in the model.
More information about the real occupancy of the building adds to the accuracy of the
demand simulation. Currently, work is ongoing to improve the estimation of occupancy
rate using the building's electricity consumption. The measured water consumption
cannot be used for occupancy estimation, as the building operates a fountain in summer,
which distorts the user estimation based on sanitary use (see Figure 6.40). The model
is now used for automated energy control and as a fault detection system in the Town
Hall. The boundary conditions for meteorological data are obtained from a weather
station in the vicinity via the Internet.
Figure 6.39 Measured and simulated heating energy consumption using a simple dynamic model