By Steffen Petersen, ALECTIA and Technical University of Denmark, Denmark.

Simulation-based support for integrated design of new low-energy office buildings (PhD Thesis)

This thesis reports on four years of research with the aim to contribute to the implementation of low-energy office buildings with high quality of indoor environment and good total economy. The objective was to enable the energy expert of the building design team to generate a useful input to the overall building design process prior to any actual form giving of the building. A workflow operationalised in a building simulation tool was proposed, tested and developed in an iterative manner involving 135 students at DTU. The tool was furthermore used in the early stages of three real building design projects. The end result is a method and tool which evidently enables the energy expert proactively to generate a useful input to the overall building design process.

The tool is called iDbuild ( and is an hourly-based building simulation tool ideal for generating design advice for use in a goal-oriented design processes. The tool is able to illustrate how performance-decisive parameters, and combinations of parameters, affects energy performance, thermal indoor environment, air quality and daylight conditions on room level. This feature is used to illustrate the result of user-defined parameter variations. The variations gives an overview of the consequence of potential design decisions in terms of indoor environment and energy performance prior to any actual form giving of the building. This proactive design advice may facilitate the task of designing low-energy buildings with high quality of indoor environment.

iDbuild is a part of a building simulation program package which also contains BuildingCalc for stand-alone thermal analysis and LightCalc for stand-alone daylight analysis. iDbuild combines the thermal and daylight calculation engines for integrated analysis. In short, this means that the input regarding thermal load from electrical lighting to the thermal calculation is based on hourly weather data-based daylight simulations.

The PhD Thesis can be downloaded at