Cost Optimization of Cellular Office Buildings based on Building Energy Simulation (Kostenoptimalisatie van kantoorgebouwen met individuele kantoorcellen op basis van gebouwenergiesimulatie)

The overall aims of this research are the definition of the economically optimum officebuilding configuration for a given cellular office building and aquantification of the costs of the measures taken to lower the energy usebeyond this optimum. The research scope is limited to medium-sized cellularoffice buildings in a temperate climate. A bi-dimensional optimization isperformed targeting minimum net present cost from a micro-economic viewpointand minimum annual operating primary energy use. The optimization variables arethe building envelope properties, the lighting system properties and the HVACsystem selection. The primary energy use consists of the heating, cooling,ventilation - and associated auxiliary - and lighting energy use, allcalculated with dynamic simulations. An empirical, building specific model forthe building use incorporating adaptive behaviour is used to establish the internalboundary conditions for the energy calculations. Passive cooling through nightventilation and window operation is included as an option in the optimizationprocess, for which the building design requirements are determined based on anextensive uncertainty analysis. The results show that the minimum net presentcost is found for building designs with an average U-value of 0.60 W/m2Kand measures to limit the solar heat gains. Daylighting, decreasing the averageU-value to 0.35 W/m2K and increasing the air tightness are shown tosignificantly lower the energy use at a limited additional cost.nrpages: 274status: publishe