Swegon Air Academy seminars in May 20-22 in Nürnberg, Stuttgart and Münich have attracted architects, engineers and many people dealing with new and renovated residential buildings. Our speakers have drawn up a complete story of why there is a need for a mechanical ventilation system in residential buildings.
A very experienced Burkhard Schulze Darup covered many topics including historical overview of building technologies including U-values, overview of buildings standards and many ventilation strategies, both for renovated and new buildings. Darup´s presentation was full of examples of buildings renovation from various levels of energy-efficiency down to passive house standard or nZEB buildings. He focused on development of energy efficiency since 1950-2014 where currently the German buildings consume approximately 280 kWh/(m2.a) for heating, hot water, ventilation and domestic electricity. In 2020 the German standard EnEV2020 will require that all new buildings must be energy-efficient buildings and in order to achieve it Burkhard proposed to use a passive house concept with integrated renewables.
A very knowledgeable Ulrich Zink first shocked people with scary numbers regarding the total CO2 emissions worldwide and then he talked about the current situation of buildings in Germany. Zink presented a great overview of German building typology from 1918 to 2006 where he described building structures and building practices. Part of his presentation was also five wonderful examples of building projects with detailed focus on energy performance of each building including commissioning process afterwards. In every project people had some obstacles to overcome, such as for example a heat recovery unit being too large to fit in a door way and therefore the unit had to be stripped to bare bones to be able to fit through.
A very charismatic Hans Westfeld completed a story on importance of a mechanical ventilation system and showed really good examples why mechanical ventilation is needed in residential buildings. Old buildings are not energy-efficient and are not providing comfort indoor quality for living, and on the other hand new buildings are airtight and insulated and very energy-efficient, but these buildings still have problems with mould growth from humidity produced by humans inside. To get rid of this humidity with only natural ventilation one would need to open the window every 2-3 hours throughout the entire day. The solution is a good and controllable mechanical ventilation system. After each presentation Hans gave a proof how quickly the CO2 levels can increase in a room if mechanical ventilation system is not used. During his presentation he monitored the CO2 levels where in all three seminar rooms the CO2 levels were around 850-1,000 ppm during Hans´ presentation. A half an hour before the end of his presentation, Hans asked for the mechanical ventilation to be switched off and at the end of his presentation he showed that in this half an hour the CO2 level has risen to almost 2,600 ppm (including the temperature rise of several degrees Celsius) in seminar rooms.