For more than four years air infiltration measurements have been made on two nearly identical side-by-side test houses in Gaithersburg, Maryland, USA. This testing of the complete seasonal weather influence on air infiltration has, in the past two years, included constant concentration tracer gas measurements (CCTG). These multizone air infiltration measurements have added further detail on the response of air infiltration into the house to weather changes and the variation of air infiltration between different house locations.
The need for reduced energy consumption has led to an overall decrease of air infiltration rates in buildings. particularly in dwellings. Unfortunately. this has given rise to a significant number of problems involving condensation. with resulting damage to the structure and contents of affected buildings. Various means of condensation control are available. The use of a passive ventilation system to achieve this aim has several attractions. not the least of which is that the occupants of houses fitted with such a system need little. if any, knowledge of the principles involved.
Within the framework of the national research project "Ventilationin Housing Construction", studies on occupants ' ventilation behaviour were conducted in a demonstration building in Duisburg- Neumuhl (Federal Rep. of Germany) which also formed part of the project . Analyses were based on values measured from Jan, 1 - Dec. 31, 1984 in 24 flats with identical ground plans, all of which were equipped with mechanical ventilation systems.
Existing models for predicting air infiltration account for three dominant variables, namely envelope leakage characteristics, indoor-outdoor temperature difference and wind speed. Building shape, wind direction and sheltering, also influence the wind induced component of air infiltration. In this report, these variables are examined analytically and experimentally using wind tunnel data and field infiltration measurements. A sensitivity analysis of a power law infiltration relationship reveals that these factors are most significant at small temperature differences.
States that with improved thermal insulation, ventilation heat losses are becoming increasingly important for the total heat demand of a building, particularly multistorey buildings. Explains how the ventilation heat loss of individual rooms
Gives detailed results of an extensive programme of wind tunnel testing of a standard scale model of a one-room, flat-roofed building. A major requirement was coverage of those characteristics of window openings or window accessories which were known (or which appeared) to have a significant effect on indoor air flow.
Wind tunnel tests were carried out using models of fallout shelters to determine correlations between shelter ventilation rate, area and distribution of wall openings, and wind speed and its direction relative to the orientation of the shelter. Models of bermed shelters with five different opening configurations were used in these tests. A simple correlation was formulated between the shelter ventilation rate, the total area of windward openings, the ratio of leeward to windward opening areas, and the velocity of the approach wind.
Login