This paper compares the conventional exhaust system with a supply-exhaust system with regard to the possible degree of control of the air exchange in the individual rooms. Ventilation efficiency and air exchange efficiency are defined and some examples show the local concentration, mean ventilation efficiency and mean air exchange efficiency for some simple ventilation schemes. Exhaust systems require a very tight building with small make up air openings. The ability of the different systems to avoid leakage out from the building of indoor air is also compared.
In discussion of air infiltration, we must consider air leakage flow, air change, air changes per hour at 50Pa, the surface permeability coefficient, the component permeability coefficient and equivalent leakage area. Air change and air leakage data are given for multiple family houses, single family houses, offices, industrial buildings and single cell elements.
Defines air change and air penetration. Describes the differential pressure method, the infrasound method, qualitative judgement methods, and acoustic measurement devices for determining air penetration. Explains procedures todetermine air change - the rate of decay method, the constant concentration method, and the constant emission method.
Describes three research programmes measuring tightness of components, of specific areas of a building and of complete buildings. Defines the Belgian standards currently applicable. For air tightness, the area or building is depressurized by 5 to 100 Pa and the flow of air that enters is measured. Thenthe components are made air tight one by one, and each time the new flow rate is measured to give values for the different components. The specific area alone can be depressurized, the specific area plus the whole building or just the whole building.
The heating and cooling loads due to air infiltration may be estimated by a mathematical model that requires knowledge of the leakage characteristics of each component of the envelope. To extend the modelisation to the pitched roofs common in Portugal, characteristics of roofs were determined by a differential pressure method.
Studies the direct coupling of ventilation heat and solar gains to increase the performance of passive solar systems. Examples of particularly suitable buildings are described. The thermal model FRED, based on a thermal resistance network representing a three-zone building, is modified to include a simple airflow model driven by wind speed and temperature difference. The simulated building is ascribed symmetric permeabilities, then asymmetric permeabilities.
As more component leakage test data become available, all available data has been merged using the orifice flow equation for a standard pressure differential of 50 Pa existing across the component. All component leakage areas are added to pro
Compares in tables international requirements for housing regarding ventilation requirements of the entire dwelling, plus kitchen, bathrooms and W.C.s, living rooms and bedrooms. Discusses them. Examines the efficiency of ventilation openings and the requirements made on them. Discusses air flow through a house and the effect of wind forces. Notes how effective pressure difference is affected by the distribution of joints and air leaks.
The R-values of permeable insulation systems are generally determined in test apparatus designed to assure one-dimensional heat transfer and to assure no air intrusion effects. Such classical R-values are used to help describe insitu heat-tra
The quantity of air in several rooms lying in a stack connected by means of fresh air and exhaust air ducts is considered as a simple model of amultistorey building. Negative pressures set up within the rooms can be equalised by adjusting the
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