PR2009

In 2003 the new extension of the German Museum of Technology (Deutsches Technikmuseum, Berlin), which comprises around 12,000 m?? of exhibition space was completed as a low-energy building. Planning and building this construction took almost 20 years (from 1987 to 2003). Validation measurements have been conducted since 2004. The building has been monitored by the Fraunhofer Institute for Building Physics IBP and IBUS (Institut fuer Bau und Umwelt, Berlin) during construction, in the commissioning phase, and during the period of validation measurements.

International building legislation is setting stronger and stronger requirements for the energy performance of buildings. An actual example is the impact of the Energy Performance of Buildings Directive in the European Union (EPBD) on the national requirements in the Member States. The improved energy performance of buildings cant be achieved by additional insulation or more effective buildings systems only. A major influence factor on the energy quality is the ventilation technology and also the airtightness of the building envelope.

There is worldwide plea to reduce carbon emission. Several governments in East Asia recently have responded by setting higher indoor temperatures in summer. But the public need to be convinced that such practice would not sacrifice indoor environmental quality, especially thermal comfort of the occupants. To implement such a measure, suitable ventilation system(s) to work under theunconventional conditions should be identified. Stratum ventilation, a new mode, is proposed for the elevated indoor temperature.

The legal background for the assessment of the energy performance of buildings and energycertificates in Germany will be changed in October 2009. Beside the tightening of the requirements byabout 30%, a significant change will be made at the calculation of residential buildings. Up to now thecalculation has to be performed by using the so-called simple approach (EN 15603) by applying theoutdated European standard EN 832 in combination with the European Standard EN 14335 withnational boundary conditions.

In order to respond to global warming and natural resources depletion challenges, industrials from the building sector need to propose an adequate offer. Energy simulation tools can support this process. Various studies and real cases show that a high performance level, e.g. primary energy consumption below 50 kWh.m-2 per year (including heating, cooling, domestic hot water, lighting and ventilation), can be reached by appropriate architecture combined with high insulation, free cooling and heat recovery on exhaust air.

The Center for Building Performances and Diagnostics of Carnegie Mellon University is experimenting with Hybrid Ventilation in Pittsburgh, Pennsylvania, USA, to evaluate the potential energy savings of this technique in a region where there are many variations in climate throughout any given year. Sharing the results of this experiment aims to increase awareness of this technique in the US and develop its implementation in the future.

In most Dutch classrooms draught results in insufficient ventilation and poor air quality during the heating season, adversely affecting the well being and performance of pupils. Also a considerable part of the year the risk of overheating is high due to the high internal heat load. New analyses show that over 85% of time the heat load and not minimum indoor air quality is the determining factor for the required amount of ventilation. That is if passive cooling is to be preferred above mechanical cooling, with regard to energy conservation.

Due to increasing interest in indoor air quality and demand controlled ventilation in buildings aiming at energy and cost saving, as well as health and comfort aspects, the objective of our work has been the development of a reliable, low cost tool for demand ventilation control. Based on a single microelectromechanical (MEMS) metal oxide semiconductor (MOS) gas sensor VOC detection as close as possible to perceived air quality and additionally, a good correlation with measured CO2 concentrations due to implementation of an empirical data evaluation algorithm has been achieved.

Since the 2002/91/CE EPBD was published, all European countries should making efforts in harmonizing local standards, imposing the assessment of building energy and environmental impact through a common certification procedure. Generally speaking, as a matter of fact, beside the main problem of different methods and tools adopted for evaluating the building energy balance, ventilation is still one of the controversial issues, since each country refers to different local requirements regarding the air-change rate values to be used when performing the calculation.