Étude Rénovation du campus Pädagogische Hochschule, Schwäbisch Gmünd, Allemagne

The evaluation of the campus of the PH Schwäbisch Gmünd, University of Education, shows that the operation of the buildings causes greenhouse gas emissions that correspond to annual emissions of approx. 1300 tons of CO2. These are primarily caused by the combustion of natural gas and wood pellets and result from the consumption of electrical energy. The aim of the feasibility study was to develop a plan on how to achieve climate neutrality in operations.

To this regard, the potential for reducing energy consumption was examined. Electricity can be saved primarily through efficient lighting. Energy losses through ventilation can be countered by controlled window ventilation or mechanical ventilation with heat recovery, while improved insulation quality can reduce heat losses from the building envelope. Various scenarios were examined for each existing and planned building, based on the minimum
legal requirements (GEG Sanierung), the specifications for financially subsidized measures (BEG EM) and the state's own specifications (BTK Vermögen und Bau). The reduced energy consumption values were determined for the packages of measures and life cycle assessments were prepared in accordance with DIN EN 15978. The reduced CO2e emissions were determined for the operating phase B. In addition to the operating phase, phase C of the partial demolition of building materials and phase A of the new construction or addition of building components were also assessed. It was found that the architectural variant with the lowest building mass is also associated with the lowest CO2e emissions for production and operation. Refurbishment package D (taking into account the state-owned BTK - Vermögen und Bau) can almost halve current CO2e emissions.
Additional compensation must be provided for the remaining emissions. As it was stipulated that the emissions caused by the operation should only be offset by renewable energy generated on site, the only options available were wind power and solar energy use.
The recommendation is to cover all usable roof surfaces with PV, although this is not sufficient even in the best variant. In order to achieve complete neutrality in operation in the annual balance sheet, a parking lot must also be considered.
If the refurbishment measure itself is also included in the balance sheet framework, with the aim of offsetting the carbon footprint for production in addition to operation, further systems for renewable energy generation are required, e.g. through corresponding participation in a wind farm. The variants examined were recorded in a matrix comprising seven criteria, each with a weighting factor. Retaining the buildings and converting the heat supply to a geothermal heat pump is the best option. Only the peak load supply then comes from district heating or a local pellet boiler. This configuration requires the smallest PV area to compensate for the residual energy demand. A life cycle calculation carried out in parallel shows that the same variant is the cheapest, in line with the LCA calculation.