Broad array of sustainable measures for S43/45 new-build project
While photovoltaic systems and geothermal probe fields are now standard, reducing grey energy is a much more complex task.
Philipp Hodel
19. February 2025
With the S43/45 project, Zug Estates is systematically addressing the topic of grey energy. This accounts for more than half of all emissions by the real estate sector in Switzerland and is increasingly attracting public attention. Having signed the Reuse-Oriented Construction Charter, Zug Estates worked hard on this front in 2023 and was able to incorporate the findings obtained into the S43/45 project.
Significant reduction in grey energy
Analysis and calculation of grey energy, coupled with the action taken, resulted in a significant reduction compared with the initial draft plans. This was achieved by reducing the volume of the underground levels by one third as well as downsizing the glazed area through the incorporation of balustrades. Not least, optimisation of the structural design, coupled with the use of recycled concrete, had a positive impact. Long-term, the buildings’ high flexibility of use will be another important factor in terms of optimising consumption of grey energy.
CO2-free operation remains essential
As with the Suurstoffi site as a whole, Zug Estates is working hard to ensure that the process of constructing the two new S43/45 buildings is as CO2-neutral as possible. To that end, a new geothermal probe field consisting of 84 geothermal probes extending around 280 metres into the ground is being realised. Through integration with the anergy grid, the new geothermal probe field is linked to the existing Suurstoffi energy system, which provides the site with heating and cooling energy. Photovoltaic systems with an installed capacity of nearly 437 kWp are being installed on the two roofs as well as on the façade of the S43 building. These meet the electricity needs of up to 70 single-family homes and will result in a near 30% increase in installed capacity on the site by 2027.
Energy and material-efficient building technology
In conventional ventilation systems, rooms and corridors are connected to ventilation and exhaust air ducts. This requires major installation work on ceilings and takes up considerable space and material. Costly modifications are required every time the rental space is refurbished. With the chosen combinedventilation system, each floor is connected via riser zones ➊ that extend vertically through the entire building. Fresh air reaches the rental space through these riser zones ➋. Where necessary, the fresh air is distributed to individual offices using small ventilators ➌, i.e. without the use of additional ventilation ducts. For cooling purposes, balustrade air conditioners ➍ eare installed along the windows and connected via a raised floor ➎ Exhaust air is transported from the upper part of the office area ➏ into the corridor and ultimately out of the building. The chosen system is highly efficient in terms of energy and materials, and takes up less room within the internal space.
