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For quite a long time energy conservation and energy efficiency were concentrated on a singlebuilding approach. Until 2000 nearly all national building regulations were based on net energybalances (energy needs) comprising transmission losses, ventilation losses, solar gains, internal gains and heating gains. Due to that the development focused on reduced transmission and ventilation losses, and so-called low energy houses or passive houses were designed and demonstrated in pilot projects, at first for new constructions and later on also for refurbishment projects.

The office building belonging to the Remscheider Entsorgungsbetriebe REB (Waste DisposalUnit in Remscheid), which was constructed in 1968, was thoroughly renovated in 2004. Theutilisation quality was greatly improved with a combination of measures including efficientthermal insulation and solar control, fan-controlled ventilation, better use of daylight andactive use of solar energy for domestic hot water - while the energy consumption valueswere reduced appreciably at the same time.A key aspect of the renovation was to improve comfort during summer without applyingactive air-conditioning.

The French regulation on residential building ventilation relies on an overall and continuous airrenewal. The fresh air should enter the building through the habitable rooms while the polluted air isextracted in the service rooms. In this way, internal air is drained from the lowest polluted rooms to thehighest polluted ones. However, internal pressure equilibrium and air movements in buildings resultfrom the combined effects ventilation system and parameters such as wind, temperature difference or doors opening.

The emission from materials is an important source of degradation of our indoor air quality. Toinvestigate this field, it is necessary to determine pollutant concentration inside buildings, based onemission rates and air exchange rate (ventilation + envelope airtightness). This paper presentsdifferent method for such determination and their application to the case of formaldehyde from building materials.

The vortex ventilation system (VV) which uses a rotating finned swirler installed coaxially with the exhaust duct is a very effective local ventilator. VV can enhance the capture depth by a factor of 3-5 compared to the conventional exhaust hood, in the absence of any solid walls nearby. In real situations there may exist ceiling, side wall and floor, all of which can affect the flow field and suction performance by way of the no-slip condition on the walls. 3D CFD simulation was performed in order to see the effect of the floor on the capture performance of the VV.

This paper analyzes some important aspects toward changing energy paradigma in urban area.To that aim it is important to act synergically on three sides of the energy system:- Demand side: by reducing energy demand;- Supply side: by optimizing generation system and transmission of energy and by integrating local renewable energy sources also by distributed (co)generation, where it is possible;- Management side: by implementing advanced management control systems able to reduce energy waste and to combine energy demand and generation in the best way.Actions aiming demand containment can affe

Ventilation is essential for the health and comfort of building occupants. It is particularly required todilute and/or remove pollutants emitted by occupants' metabolism and activities. The concentration of metabolic CO2 is well correlated to metabolic odour intensity. Therefore CO2 concentration can beefficiently chosen as an indoor air quality index when occupants are the main source of pollution inside the buildings.

Energy used for building heating, ventilating and air conditioning contributes to a great share in thetotal energy consumption worldwide. Better understanding and management of energy distribution inthose processes is essential for the improvement of process quality and efficiency of energy use. This paper presents a data-based mechanistic modelling approach to model the dynamic indoortemperature distribution in an imperfectly mixed ventilated airspace based on energy input to thesystem.

For outsiders, a national energy performance (EP) requirement level is quite a black box. Within the EU Asiepi project (www.asiepi.eu) we are developing a methodology to make a comparison of EP requirement levels possible among member states of the EU.An unexpected finding has been that far from all EU countries consider all energy uses in their EP method required by the EPBD (Energy Performance of Buildings Directive). The energy use for fans, domestic hot water and cooling are among the energy uses which are not taken into account by various countries.

Due to the increase in CO2 emissions and the resulting climate change more and more efforts aremade to reduce energy consumption. As a result, the energy demand of buildings is to be reduced by specific measures, for example thermal insulation or intelligent ventilation systems. A demand-based (moisture-controlled) exhaust ventilation system is assessed in comparison to a supply and exhaust ventilation system with heat recovery by means of computational investigations.