Energy efficiency of new residential buildings in sweden Design and Modelling Aspects

University dissertation from Östersund : Mid Sweden University

Abstract: Energy security and climate change mitigation have been discussed in Sweden since the oil crisis in the 1970s. Sweden has since then increased its share of renewable energy resources to reach the highest level among the EU member states, but is still among the countries with the highest primary energy use per capita. Not least because of that, increasing energy efficiency is important and it is part of the Swedish long term environmental objectives. Large potential for improving energy efficiency can be found in the building sector, mainly in the existing building stock but also in newly constructed buildingsIn this thesis, criteria for energy efficiency in new residential buildings are studied, several design aspects of residential buildings are examined, and possible further analysis from an energy system perspective discussed. Three case studies of existing residential buildings were analysed, including one detached house and multi-storey apartment buildings. The analysis was based on both energy simulations and measurements in residential buildings.The results show that the calculated specific final energy demand of residential buildings, before they are built, is too rough an indicator to explicitly steer society toward lower final energy use in the building sector. One of the reasons is assumptions made during calculation before the buildings is built. Another reason is the interior building design. A design that includes relatively large areas of heated corridors, service and storage rooms will lower the specific final energy demand without improving the building energy efficiency, which might increase both the total final energy demand and the use of construction materials in the building sector.Efficient thermal envelopes are essential in construction of energy efficient buildings, which include the thermal resistance and also the shape of the building. The shape factor of buildings was found to be an important variable for heat demand in buildings located in temperate and colder climates, particularly if they are exposed to strong winds.From a system perspective, energy efficiency measures and the performance of the end use heating technology in buildings should be evaluated together with the energy supply system, including the dynamic interaction between them.