We need to focus more on the peak-effects!

February 18, 2014 by Minna G. Lundvall (AF Consult) | 0 comments

Vintersörskog litenWhen we talk about how energy-efficient a building is, it is often the annual energy use that is discussed, since it is directly related to a cost for the owner.

But if we put the energy use in the perspective of the society as a whole, we should rather focus on reducing the peak power needed!

Our production sites and distribution systems have to be sized to handle the maximum needs, even if it only occurs for a few days each year. That makes both systems and buildings more expensive than they would be if we could keep the peak need down.

It also makes us more dependent of non-renewable sources of energy, since a lot of the renewable energy sources are low-temperature and cannot always supply enough power when the need for peak-effects occurs.

The peak effects are an important issue as well for entire urban district heating systems as for the single homeowner with a heat pump.

So what I would like to see and hear more of ahead is Power-Efficient buildings!


What´s about the ecological footprint of a building?

January 24, 2014 by Karl Torghele (Spektrum) | 0 comments

The average lifespan of a residential building is about 80 to 100 years (Central Europe). The efforts for the construction of the building are at the beginning of the observation period. In between efforts for the maintenance and repair must be spent. At the end the lifetime disposal will have to be done.

Most people know the expenses for the operation and heating of their residential building. But only a vew of them have any idea how much energy for the establishment and maintenance or disposal of your building is required.

PEB und HWB Vergleich englScientific calculations show, depending on the material choice and construction design, that there can be very large differences between the ecological efforts for building construction. It is quite surprising that this effort is of the same size as for the heating of the building over the whole lifespan. It means that a sustainable design of a building is not only a building with low heating energy demand, but it is also  necessary to choose the right building materials and construction design.

Great potentials

The optimization potential is thus about 50%, especially for passive houses and Nearly Zero Energy Building of practical relevance. Optimization of ecological footprint deals with the right choice of material and construction design. On the one hand it is important to choose materials with low primary energy input for its production i.e. of renewable or readily available resources, on the other hand the maintenance efforts should be low as well lifetime should be long. It can be shown that the Primary Energy Input for the same service unit (treated living space) could be divided by 2.

Ecological Optimization of buildings is a really complex planning task. Planning tools had been developed the last 20 years and are now available. One of the most common and best etablished in Austria is the Internet-based calculation tool eco2soft. (www.baubook.at/eco2soft)

Eco2soft – calulation and optimization

ECOSOFT is a software for the ecological assessment of building components and buildings. It was developed by the IBO and is available online at baubook Eco2Soft. Thus the ecological impact of new buildings, refurbishments and disposal processes can be quantified easily.

During their life cycle, building materials have a widely differing impact on a wide variety of environmental and health areas. Environmental optimization means finding the best solutions while taking into account as many of these areas and impacts. This affects the life cycle phases of

  • Production,
  • Use
  • Dismantling, recycling and disposal

The choice of environmentally compatible building materials should be made as far as possible on the basis of scientific, or at least reproducible, findings. A good basis for comparing building materials as objectively as possible is a quantitative method, such as that of impact-focused classification, which produces environmental indicators such as greenhouse gas or acidification potential.

Building material characteristics are used for component evaluation and optimization. Components can be joined together forming a whole building. So the ecological footprint of a building can be calculated. Calculations can be performed for new constructions and also for renovations. In the calculation, construction and maintenance costs are measured. At the end you can see the total primary energy input, the greenhouse gas emissions as well as acidification caused by the construction and the maintainance of the whole building but also for parts of the building. You can do an analysis of the most incriminating parts of the building and make comparison of alternative plannings.