Simulation study on the optimization of summer thermal insulation and energy requirements in SBB buildings

The SPF Institute for Solar Technology The HVAC engineering firm Tri Air AG was commissioned by SBB AG Immobilien Bewirtschaftung to carry out a simulation study to examine the need for active cooling and the total energy requirement with different variants.

In the simulation study, which was carried out using the IDA ICE software developed by EQUA Solutions AG, four different variants (actual state plus three further variants) were analyzed and compared with regard to passive and active measures for summer thermal insulation. The overheating potential, the maximum air temperature and the final energy requirement for cooling and heating were determined for each variant.

The simulations made it clear that the holistic view (final energy consumption over the whole year) can in some cases lead to different results than if the analysis is carried out according to standard procedures and regulations.

From the client's point of view, the simulation study brought the following added value:

  • Clarity - The installation of active cooling is necessary, as otherwise comfort in the rooms cannot be guaranteed
  • Reduction in investment costs - It could be shown that passive solar shading prevents direct solar radiation well and that the use of additional solar shading (e.g. heat protection films, blinds) would lead to a higher total energy requirement due to the lower gains in winter
  • Focus of the measures - By replacing the existing windows (reduction of heating requirements) and replacing the gas boiler with a heat pump (reduction of CO2-emissions), the investments would achieve a greater sustainability effect, as the heating requirement is factors greater than the cooling requirement.

Special thanks go to Amina Guliyeva and Igor Bosshard, who were responsible for the simulation work!