The Sint-Pieterschurch in the city of Ghent is one of the largest churches of the city. It was built in the 17th century. The city council wants to use the church not only for its religious functions, but also for cultural activities as concerts and exhibitions. To be able to do this the thermal comfort of the visitors has to be guaranteed. At this moment the church has no central heating system. Gas heaters are used during services. Installing a central heating system will influence the humidity and moisture behaviour of the church.

This paper deals with the relevance of Computational Fluids Dynamics (CFD) results confronted tomeasurements carried out under uncontrolled thermal conditions. Experimental tests have been undertaken in a room and in a kitchen of an experimental house. Although the wall surface temperatures and the air intake temperature have not been imposed, the air change rates have been controlled during the measurements. Moreover, since measurements have been carried out in a real environment, air leakage has occurred at the walls.

Local control of ventilation in large buildings is considered to be a main issue in energy savings regarding the huge energy losses that are usually induced by such large volumes. An efficient ventilation system and the development of local control ventilation strategies could prevent large buildings from having an unsuited or overvalued ventilation and reduce significantly the energy consumption.

More than 700 million of measured data, 730 days, 55 dwellings: the HR-VENT hybrid ventilationdemonstration project applied in NANGIS (France) on a set of occupied collective dwellings is closely linked to its stakes. From January 2004 up to December 2005, the values of humidity, temperature, pressure, opening surface and gas appliance operation are saved every minute in all the wet rooms by specifically developed sensors.

For retrofitting as well as for new buildings a good airtightness is an important issue. In Germany, Austria and Switzerland about 1000 persons conduct blower door tests according to EN 13829 in order to characterize the air permeability of buildings. Also, preliminary measurements of the air barrier are made, often by the craftsmen themselves. Early measurements allow to repair leakages more easily than when the building is completed.

The article describes the influence of the supply air devices that are part of hybrid ventilation system which is being developed within a EU funded project RESHYVENT as a part of this project, on thermal comfort in living-room of a three-bedroom apartment. The supply air radiator and the supply air convector are compared. The fresh air is sucked through a supply air convector and supply air radiator respectively and the air leakage through the facade is assumed too. 2 variants, which cover different outdoor temperature and supply air temperature for each device, have been solved.

Our commitment to improve both air quality and energy savings in existing dwellings involves scopemeasurements campaigns. Constraints linked to the use of measurements material in these conditions, the keeping of their reliability all project long and their costs prompted industry to develop special devices for this kind of application. It is the case of this high accuracy manometer required for the wide demonstration project called HR-VENT (Nangis- France).

This paper presents ventilation systems with longitudinal counterflow spiral recuperators. Heat transfer losses in ventilation system can be reduced by increasing the length of the recuperator, but in this case pressure drops increase. These two losses determine exploitation costs. Taking into consideration the results of measurements and calculations the costs for capital expenditure and exploitation of ventilation systems are minimized.

This paper summarizes the work within the EU RESHYVENT project in regard to design parameters for the performance assessment of hybrid ventilation systems. A framework for performance assessment based on simulation was developed. Performance criteria were defined for air flows, indoor air quality, thermal comfort, acoustics, energy, and emissions.

In the scope of the EU supported project RESHYVENT, the possible integration of Renewable Energy Solutions (RES) into hybrid ventilation systems has been analysed. The focus has been on solar and wind applications to substitute the use of fossil fuel. The feasibility of the investigated options depends on the ventilation concept the RES is integrated into, the location of the building geographically, placement of the RES in the building and on the urban environment.