The Effect of Reducing Geometry Complexity on Energy Simulation Results

Accuracy and time are metrics inherently associated with the design process and the energy performance simulation of buildings. The accurate representation of the building is an essential requirement for energy analysis, which comes with the expense of time; however, this is in contrast with the need to minimise the simulation time in order to make it compatible with design times. This is a particularly interesting aspect in the case of complex geometries, which are often simplified for use in building energy performance simulation. The effects of this simplification on the accuracy of simulation results are not usually reported. This paper explored these effects through a systematic analysis of several test cases. The results indicate that the use of orthogonal prisms as simplified surrogates for buildings with complex shapes presents a worst-case scenario that should be avoided where possible. A significant reduction of geometry complexity by at least 50% can also be achieved with negligible effects on simulation results, while minimising the time requirements. Accuracy, however, deteriorates rapidly below a critical threshold.