Energy audit of a residential building renovated for 2050

Abstract: The largest contributing factor for human impact on global warming is the emission of greenhouse gasses, of which carbon dioxide (CO­2) has the greatest consequences for the climate. Energy use in buildings is closely related to CO2 emissions from electricity and heat generation. An improvement of the energy efficiency of buildings would therefore have great impact on slowing down climate change and could also be economically beneficial for facility owners. In its Europe 2020 Strategy, the European Union has set itself three priorities for the year 2020; Smart, Sustainable and Inclusive growth, where sustainability addresses the issues of energy efficiency. The target is to reduce greenhouse gas emissions by at least 20% compared to 1990 levels; increase the share of renewable energy sources in our final energy consumption to 20%; and a 20% increase in energy efficiency. To promote energy-saving, cost-effective building solutions and attain a higher energy efficiency the European Union has created the Energy Performance of Buildings Directive (EPBD) and the Energy Efficiency Directive (EED), which both have been interpreted and incorporated into national legislation by the different member states of the EU. These directives and Swedish interpretations thereof are studied to investigate what impact they have on buildings in Sweden. Next, an Energy Performance Audit of the residential building Landsfogden 6 in the south of Stockholm was carried out. The results of that is that the energy performance of the building is 126 kWh/m2, which was surprising, given the recently executed substantial renovations, aiming at a 50% reduction in energy need. The only technical building system that has not been updated to a modern standard is the district heating substation. The system is old and oversized, both heat exchangers and pumps and valves, and the analysis shows that there is much to gain by installing a new substation. Fitted with an online control system and correctly adjusted, the energy use could decrease by 110 to 170 MWh/year, with the investment paid back in 2,5 years. Landsfogden 6 has been impacted by the Energy efficiency directive and the Energy performance of buildings directive as the decisions leading up to the renovations were directly connected first to the 20/20 goals of the Europe 2020 Strategy, but then decided upon aiming for the (possibly coming) Swedish goal for 2050, 50% higher energy efficiency.