Monday, 14 November 2011

Assignment no. 1 - Passive Houses: Achievable concepts for low CO2 housing

This paper, entitled " Passive Houses : Achievable concepts for low CO2 housing" was written in January 2006 by Henk. F. Kaan and Bart J. de Boer of the  Energy research centre of the Netherlands. The paper was presented at the ISES conference 2005, Orlando, USA in September 2005.
In January 2005, an EU supported project (involving nine countries) called Promotion of European Passive house(PEP) commenced to promote passive house development based on the German/Austrian model. This paper examines the issues that the PEP project relates to. 
The main points of the paper are:
  • There is a need for more energy efficient buildings because "in the Western world, 40% of all energy consumption is from building".
  • Germany and Austria are the front runners in passive house construction with over 5,000 passive houses  built to date and more to follow.
  • Some European countries are introducing passive house initiatives but shouldn't just copy the German/Austrian model. Climate, building tradition, specific building codes and building details differ from country to country and this affects design and construction.The economics of passive house building vary from country to country.
  • The PEP project must define the term Passive House for each country. The writers inform us that "The energy use in an absolute sense does not by definition tell whether the building is good or not". One must question that achieving a passive house shouldn't in all cases be based on energy usage of 15KWh/m2 but based on different criteria for different countries. For instance in warmer countries in southern Europe, shouldn't energy required for cooling be taken into account?
  • The behaviour of occupants is also a huge factor once the house is built. For example, mis-use of the heating and ventilation system leads to over use of energy. The writers ask should the passive house technology "take over the decisions?" and systems be designed as "fool proof". 
  • While solar energy is important, it is the overall combination of the heating elements in the building that contribute to satisfactory indoor comfort. These heating elements include: air tightness, heat recovery from ventilated air, insulation building type and shape. These elements were found to be the most important when the energy research centre of the Netherlands used the computer program "TRNSYS" to carry out a study on optimum use of solar energy in building.
The paper concludes by the writers assuming that every country has different characteristics. The PEP hopes to look at all the countries involved and find similarities and differences "and show how the countries can learn from each other."
I agree  that every country has different characteristics such as climate, building traditions, access to building materials and passive houses should be defined differently in different regions.
 Also, in countries where the concept of passive house is in the early stages, it is more difficult to obtain the relevant building materials. These may have to be imported and one then has to consider the carbon footprint disadvantage and cost of the passive house option.

Note: Click on this link to go to the PEP website for more information:

Note: Here is a visual presentation showing the basic principles of  Passive House construction