In this study, we investigated the indoor air quality (IAQ) in classrooms with exhaustventilation systems and in naturally ventilated classrooms. In the latter, we found peak CO2-concentrations of more than 4000 ppm. 1500 ppm was exceeded during 40 to 86% ofteaching time, dependent on class size. The windows were opened rarely in winter which ledto low mean air exchange rates of 0.20 0.23 h^-1. The operation of mechanical ventilationsystems improved IAQ considerably. Peak CO2-concentrations decreased to less than 2500ppm. 1500 ppm was exceeded for only 7 to 57% of teaching time.
In the recent past new concepts for the building envelope have been developed with theunderlying wish to improve the energy performance of a building as well as comfortconditions in the inner spaces. Examples are: solar walls, high-tech window systems, doublefacades and integration of daylighting systems and of PV-panels. In this paper the doublefacade concept is discussed.This kind of facade is considered as a device to be used for pre-heating the ventilation airduring winter as well as for nocturnal cooling of the building during summer.
Dwellings airtigthness is not well known in practice, in France.When dwellings are equipped with mechanical ventilation systems (which represents about 95% of the new dwellings in France) the airtigthness can strongly influence the performance ofventilation.In the frame of the European Joule Project TIP-VENT (Towards Improved MechanicalVentilation Systems) , measurements of airtightness and underpressures were made onthree multifamily buildings.
In this study a series of parametric laboratory measurements were made of the velocitiesoutside, ve, and inside, vi, a full-scale louver positioned in a rectangular opening located in avertical wall forming part of a 1m x 1m x 2m deep model room. The louver parametersexamined, for external incident wind speeds from 0.6 to 2.5 m/s, included louver blade depth(L), aperture (d) and distance from the louver in to room (Rd). For this initial study the bladesof the louvers for each experiment were horizontal with an inclination angle ? of 0.
This paper presents the results of ventilation measurements taken in a non-occupied one-storey dwelling situated in the countryside. The measurements of the ventilation rates in the different rooms have been obtained by the use of tracer gases with the constant concentration technique. Four configurations of ventilation systems have been tested successively. The ventilation systems tested consist of natural air supply and mechanical exhaust. Both 'normal' air supply grilles and self-regulating grilles have been tested.
In France, the regulation on residential building ventilation is based, since 1969, on a generaland continuous air renewal ; the fresh air comes into habitable rooms by air inlets and thestale air is drawn out to exhaust vents in the service rooms. So the air inters the habitablerooms crosses through the dwelling, is extracted in the service rooms.The Research and Development Division of Gaz de France and the CSTB have studied theneeds in each room of a dwelling (depending on the size and the occupancy) to perform newventilation system(s).
The prediction of energy use, air flows and temperatures in different rooms of a building andat different climatic conditions is very important, especially when evaluating new conceptsfor heating and ventilation systems in combination with different building envelopeconstructions. A thorough system analysis considering coupled air flow and thermalcalculations becomes very complex if e.g. thermal bridges and dynamic conditions areconsidered.
The move towards improving building air-tightness to save energy has increased theincidence of poor indoor air quality and associated problems, such as condensation onwindows, mould, rot and fungus on window frames. Mechanical ventilation heat recoverysystems (MVHR) combined with heat pumps offer a means of significantly improving indoorair quality as well as providing heating and cooling required in buildings.This paper is concerned with the testing and performance of a novel ventilation heat pumpsystem developed for the domestic market (1,2,3).
Within the EC-JOULE project "AIRLIT-PV", a new facade unit, integrating ventilation, daylighting, solar protection, intelligent local control and photovoltaic power, has been developed and is under evaluation by means of performance testing at four different test sites in Europe, both in test cells and in occupied buildings. This paper will summarise an extensive market survey, describe the shape and function of the unit and report on the first findings from the performance testing of the units. The ventilation performance will be emphasised.
Infiltration has traditionally been assumed to affect the energy load of a building byan amount equal to the product of the infiltration flow rate and the sensible enthalpydifference between inside and outside. However, laboratory and simulation research hasindicated that heat transfer between the infiltrating air and walls may be substantial, reducingthe impact of infiltration.