Theoretical Groundwork for a Database of Building Elements for Use in Renovation to Nearly Zero-energy Buildings

Approximately 80 % of today s building stock will still remain in 2050. With buildings accounting for 40 % of the total energy demand, it is important to continually improve their efficiency in order to meet the goals of minimising the demand for energy from fossil fuel. Some energy efficient building concepts are already defined in Norwegian standards, and passive house buildings have become of increased popularity in recent times. The next concept in line seems to be the near-zero energy buildings, or nZEB for short. This concept has yet to receive an official definition, however some recognised companies have created suggestions for the nZEB concept ion demand from the Norwegian government. This study aims to explore what this concept craves in terms of building constructional methods and energy delivery. Due to most of the buildings of the future already being built, this study will focus on rehabilitation of current buildings. This comes with additional challenges, both legislative and other physical restrictions, which means parameters such as existing building shape needs to be considered. The report presents information on common constructional methods and how to optimise the performance of these. Further exploration of insulation methods, energy production and heat sources are performed in order to study its effect on building energy performance. Through simulation in SIMIEN and THERM, data is gathered and studied in ordered to quantify some suggested restrictions for projects aiming to rehabilitate to nZEB. These results, combined with case- and literature study, provide a basis for reflection on whether nZEB is feasible in building rehabilitation, and if so, what requirements are set for the existing building. The results gathered in this report suggest that nZEB rehabilitation is feasible if certain requirements on building shape and availability of space for both on-site electricity production and a sustainable heat source are met. The study provides groundwork for further investigation of the nZEB concept and possibly the development of a database for building elements