English

The aim of the project was to evaluate how the air tightness of buildings changes over time and how the sealing materials are affected during the expected life length of 50 years. The project was divided into two parts were one was laboratory tests of different products with accelerated ageing, and the other part were evaluation of older existing buildings. The laboratory test was conducted in a temporary room with lightweight construction in wood and different sealing products. The room was then heated to 80 °C and had changing relative moisture content in the air.

Nearly all retail locations use ventilation and cooling systems to ensure adequate air exchange for health reasons and indoor comfort temperatures. These systems can run for over 2,000 hours per year and we expect that average operating hours will continue to rise across Europe because of the continued trend towards longer opening hours and increased number of opening days. Shopping malls often enclose large open spaces and atria with high solar and internal gains that can drive ventilative cooling.

Energy performance of mechanical ventilation systems in modern low energy and passive buildings is a crucial factor influencing overall energy performance of building. Energy balance is commonly used tool in evaluation of mechanical ventilation systems. In the case of low energy and passive buildings that tool might be insufficient and should be replaced by exergy analysis taking into account the first and the second Law of Thermodynamics. The paper presents principles of exergy evaluation of mechanical ventilation systems and case study calculations for an office building.

Air tightness is essential to building energy performance, which has been acknowledged for a long time. It plays a significant role in improving building energy efficiency by minimising the heating/cooling loss incurred during unwanted air movement through the building envelope, consequently reducing the building’s energy demand and cutting down carbon emission in the building sector.

A new school building block in Passivehouse standard near Kortrijk (Belgium) is in use since spring 2013. The urban development regulations required that this new building did not influence the incidence of daylight in the adjacent dwellings. This results in an open corridor on the first floor and classrooms with a front door. Draught and increased energy losses are expected. This design choice is contradictory to the basic idea of a passive school that aims to be very airtight and to have very low energy use and excellent thermal comfort.

The future is well-isolated buildings with low heating demand. The first office building in Norway satisfying the passive house standard, the GK environmental house in Oslo, was taken into use in August 2012.

The GK environmental house is the first office building in Norway built according to the passive house concept. In such buildings, it is crucial to develop a ventilation strategy to reduce the energy use outside of the operating time. An optimal operating strategy has been developed for cold days, when the outdoor temperature falls well below 0 °C, which is presented in this paper. Indeed, these conditions correspond to the largest heat loss.

The impact of over-tempered air on the perceived indoor climate was evaluated by questionnaires filled in by the users of the first office building with passive house standard in Norway. In this building, the heating demand is covered entirely by warm air supplied into the rooms through the ventilation system.

The Kindergarten Solhuset is built according to the Active House vision with an emphasize of good daylight conditions and fresh air. The house was completed in 2011, and detailed measurements of the indoor environment have been performed since the completion. The daylight performance is evaluated with daylight factor simulations. The main activity rooms have daylight factors of 7%, while the innermost rooms with only roof windows achieve a high daylight factor of 4%. Electrical light is used frequently in daytime during the winter, but much less frequently during summer.

The present paper addresses experiences with ventilation and thermal comfort in the Active House concept, based on the Active House Specification and realized Active Houses. The Active House Specification is based on a holistic view on buildings including Comfort, Energy and Environment. It uses functional requirements to indoor air quality and thermal comfort. Experiences from realised Active House projects show that better airtightness than nationally required has been achieved.