By Dr Maria Wall, Associate Prof., Division of Energy and Building Design, Lund University, Sweden.
The presentation will cover topics as:
– the importance to minimize the energy use for buildings in cold climates, like Sweden
– developments of buildings with a very low energy demand
– the importance of renewable energy supply; solar energy strategies and examples
– concepts to achieve zero-energy buildings, balancing demand and supply
– development needs and strategies ahead.
The development of energy-efficient buildings and sustainable urban areas are increasingly important due to the need of reducing CO2-emissions and to secure renewable energy supply. High environmental goals in many countries are accompanied by directives and stricter regulations but also many voluntary environmental programmes are developed in regions and cities.
In Sweden, we have a long development of reducing energy demand in buildings, which was accelerated due to the oil crises in the 1970s. Owing to the cold climate, a first strategy is to reduce the energy demand for space heating. For a long period, we have built different types of “demonstration buildings” to test improved constructions and mechanical systems, and followed up by measurements. Lessons learnt were useful in developing building concepts, components and systems for buildings. To show in reality how it works is important to convince others to do the same. Property owners and developers have an important role by building their own exemplary buildings. Everyone from carpenters, engineers, architects and property owners learn from this. Today, different types of low-energy building concepts exist, in different countries. This is a very positive development.
Renewable energy supply has become an increasingly important factor. A local renewable energy production is then often seen as important. Solar energy heat and electricity is one key ingredient. Solar energy gives us daylight and reduces electricity for lighting both indoors and in outdoor environments. It is also important for our health. Solar energy can also heat our buildings by passive solar gains through windows. With active solar systems on buildings and in other places, we can produce both renewable heat and electricity, and also solar cooling. However, such strategies need careful planning since buildings and urban planning have a long time horizon. A good planning will increase the potential of using solar energy for a long time ahead, while the lack of taking solar access into planning will instead become a barrier for maybe a hundred years.
Developments of zero-energy/emission buildings and neighborhoods are ongoing. For that, the building itself needs to be very energy-efficient combined with using renewable energy to meet its need in a Swedish/cold climate. Thus, lessons learnt from reducing the energy demand in buildings are very useful as a starting point. A general definition of a zero-energy building is a building that produces as much renewable energy as it needs. Although this may seem simple, many different boundary conditions and definitions exist. The most appropriate strategy and definition for a climate and region/country could be discussed. Concepts with wider perspectives could probably give more sustainable solutions; Instead of sub-optimizing a single building, e.g. a “zero” balance could be defined for a group of buildings, a neighborhood.
New developments are expected and good examples that show not only a verified energy performance but also low environmental impact and good economy are anticipated and needed. Cost-benefit analyses need to include additional benefits as increased productivity, higher revenue, reduced employee turnover and reduced absence. We need to see all the advantages and solve barriers.
Maria Wall is an associate professor at the Division of Energy and Building Design, Lund University, Sweden. She has a MSc in Architecture and a PhD in Engineering. Her research includes different issues related to energy-efficient buildings as well as solar energy strategies. She is the leader of the IEA SHC Task 51 on Solar Energy in Urban Planning that is in its finalizing stage and was former leader of SHC Task 41 on Solar Energy and Architecture. She was the main initiator and developer, and is also the Director of the 2-year international Master’s Programme in Energy-efficient and Environmental Building Design at Lund University. Recently, she started the preparation phase of a new IEA SHC Task on Solar Neighbourhood Planning. This Task will be developed during one year in cooperation with international experts and the project plans to be started in autumn 2019.