Energy demands and potential savings in European office buildings: Case studies based on EnergyPlus simulations

•The use of lighting controls is recommendable in European office buildings.•Office buildings located in warmer climates can increase their cooling demand if the insulation of the envelop is not appropriate.•Orientation of the building plays a significant role in its energy demand during the use stage. This article presents key energy use figures and explores the energy saving potentials in office buildings across Europe by simulating several currently available scenarios. The information provided in this research work is based on a review of relevant literature and the results of EnergyPlus simulations of a reference office building that can be considered as a representative office building across Europe. Three locations were selected to represent the three climate zones in which Europe was divided. Lighting has been pointed out as an area with significant improvement potentials. These improvements have been investigated by using two scenarios with different lighting control systems. In both cases and regardless of the location of the office building, the energy savings were achieved with already existing technology and will bring important reductions in the overall energy bill. Two further aspects were investigated in this work: the first one is an improvement of the insulation of the windows and the external walls (U-value) and the second one the orientation of the building. Unlikely to the lighting improvements, the location of the buildings highly influences the amount of energy required by HVAC systems. It is observed that higher insulation factors are recommended in cold and medium climate zones while they should be carefully chosen in the warmer climate zones. Office buildings constructed in warm climate zones are subjected to higher heat gains that cannot be easily released from buildings within a well-insulated envelope. Consequently, the energy demand for cooling purposes is increased, affecting the overall energy consumption and the economic performance of the building.