1 Department of Civil Engineering, Technical University of Denmark2 Section for Building Physics and Services, Department of Civil Engineering, Technical University of Denmark3 unknown
Is a passive house sensible solution for Greenland?
The Arctic is climatically very different from a temperate climate. In the Arctic regions, the ambient temperature reaches extreme values and it has a direct large impact on the heat loss through the building envelope and it creates problems with the foundation due to the permafrost. The solar pattern is completely different due to the limited availability in winter, yet, in summer, the sun is above horizon for 24 hours. Furthermore, the sunrays reach the vertical opaque elements at shallow angles. The great winds and storms have large effects on the infiltration of buildings and they heavily influence the infiltration heat loss through the building envelope. The wind patterns have large influences on the local microclimate around the building and create the snowdrift and problems with thawing, icing and possible condensation in the building envelope. The humidity in the interior is driven out through the building envelope in the winter due to the pressure difference, strong winds and low water ratio in the outdoor air. The Arctic is also defined by different conditions such as building techniques and availability of the materials and energy supply. The passive house uses the basic idea of a super energy efficient house in which the normal hydronic heating system can be omitted. The savings in investment for a traditional hydronic heating system are spent on energy conserving components such as increased insulation in a super airtight building shell, super efficient windows to produce the net positive solar gain, and a ventilation system with very efficient heat recovery. To design a passive house in the way it is defined by Wolfgang Feist, the founder of the Passivhaus Institute, its annual heat demand should not exceed 15 kWh/(m2∙a) and its total primary energy demand should not exceed 120 kWh/(m2∙a) in which the building envelope allows limited air change of 0.6 h-1 at 50 Pa pressurization. The living area of the building is well defined according to the standard conditions as a net area and the heat of 10 W/m2 can just be supplied by post-heating of fresh air after the heat recovery unit which ensures a satisfactory indoor air quality. A passive house also takes advantage of free gains such as solar heat, the heat from its occupants and their activities, and the domestic appliances, and other sources. The hypothesis in this dissertation is testing the possibility of a new usage of an extreme energy efficient building in the Arctic. The purpose of this Ph.D. study is to determine the optimal use of an energy efficient house in the Arctic derived from the fundamental definition of a passive house, investigations of building parameters including the building envelope and systems, and investigations of boundary situations in the Arctic regions. The object of the study is to analyse current passive house standards used in the temperate climate through the energy performance of a passive house in the cold climates. In theory, it is possible to completely fulfil the fundamental definition of a passive house in the Arctic and therefore to save the cost of traditional heating, but that would incur high costs for the building materials and the provision of technical solutions of extremely high standards which would take too many years to pay back in the life time of a building. The fundamental definition which applies to all climates can be realized in the Arctic regions at very high costs using fundamental design values and the building technologies available in the Arctic. Based on the investigations, the optimal energy performing building is derived from a passive house concept. The passive house optimisation follows the main design rule in the Arctic and this is focused on minimizing the heat loss before maximizing the heat gains followed by the optimisation of the essential building elements and the implementation of the necessary equipments in the cold regions such as a highly efficient ventilation system with heat recovery. Furthermore, the implementation of a passive house concept in a cold climate needs to be based on sensible solutions regarding material use, and, on a practical level, using available technologies and resources. The adaptation of a passive house in the Arctic needs to take into account also different socioeconomic conditions, building traditions and use of buildings, survival issue, sustainability and power supply, among others. In the Arctic, the energy efficient house based on a passive house concept offers a sustainable solution to the operation of the building with regarding the heating and the consumption of electricity, but, the energy, money investment and CO2 footprint needed to build such a house would be demanding. Yet, using these energy efficient buildings, there is an opportunity to improve indoor climate, health and security towards extreme climate for the inhabitants in the Arctic areas. Furthermore, the development and usage of extremely energy efficient buildings in the Arctic can lead to new experiences with extremely well-insulating building components, airtight constructions and well-functioning ventilation systems.