Comparison of Multi and Single-Zone Modelling for Estimation of Energy Use in an Office Building

Building simulation programs are powerful tools to predict the thermal climate and the energy use in buildings. However, simulations for estimating the energy use are rarely used by consultants. This paper describes two ways of modelling an office building. A case building has been monitored for energy use over a year, and the measurements are used to calibrate two simulation models. The first model simulates a single-zone and takes into account only the adjacent rooms. The cell is further modified to cover all room types in the building. The other model is a full-building model. The objective of this study is to find whether the single-zone modelling approach is appropriate for energy use estimations. Results from the simulations show that it is possible to come very close to measured values with the full-building model. The single-zone tends to over-estimate the need for heating of ventilation air. This must be taken into consideration if such an approach is chosen.