Retrofitting of historical buildings for carbon emission reduction: A case study in Utrecht, the Netherlands

Buildings are responsible for a total of 40% energy consumption and cause 32% of total carbon emissions in the European Union. The emissions caused by the building sector are partly responsible for the increasing global temperature over the last decades. A reduction of emissions related to buildings has the potential to mitigate climate change. Historical buildings play an important role and should be included to reach this goal. The aim of this study is to identify retrofitting measures which are the most optimal within the frame of carbon emissions and economic concerns by taking into account the impact on the heritage value of a historical building. For this purpose, an energy building simulation was conducted as a case study for a historical building in Utrecht the Netherlands. First a literature review was executed to determine which retrofits are the most appropriate to conserve the inherent value of a building in the Netherlands. The outcome shows that a variety of options are able to preserve the building’s character. The best options for the case study were interior insulation for walls, roofs and floors, replacement of the lighting system, the application of a groundwater or ground heat pump, photovoltaics, and construction overhauls. The next step was to test the previously identified options. Data concerning building envelope, technical installations and building schedules was collected to determine the energy demand for heating, cooling, and electricity. The total annual energy demand of the old train workshop is 2454 GJ. After the initial simulation as the base case, several measures and packaged measures were tested to conclude which carbon conservation techniques are the most effective. Each simulation is followed by a cost analysis to show the simple payback period, the costs per unit of conserved carbon and a sensitivity analysis with regards to important parameters. The results showed a great potential for several retrofitting measures. The individual measures with the best outcomes were roof insulation, LED lighting, groundwater heat pump, and photovoltaics. The percentages of potential carbon conservation were 11.61%, 15.84%, 28.46%, and 48.53% respectively. An assemblage of the aforementioned individual measures to a retrofitting package can lower the energy demand by 85.50% and the emitted carbon emissions by 68.65%. The total investment costs of the package are € 360831 with a simple payback period of 7.37 years. The related cost per conserved carbon calculation reveals a cost-effective result