Describes wind tunnel measurements made on a model of a tall building surrounded by lower buildings under various combination of wind speed, wind angle and air temperature. Gives method for calculation of air infiltration rates and describes the computer program used. Concludes that air infiltration is a strong function of wind direction. Finds that maximum air infiltration was produced by a wind that approached at 0 deg and the minimum air infiltration occurred at 75 deg wind angle.
Describes different types of weatherstrips and reports ageing and deformation test on strips and tests on air tightness and closing force. Concludes that tubular strips provided the highest degree of airtightness in both windows and doors, while angle strips were only slightly inferior in performance. Air leakage was considerably greater for strips of expanded and foam plastics and fibre strips. Tests on ageing properties indicated that special rubber mixtures such as silicone rubber and epdm were preferable to p.v.c.
Suggests many ways of reducing outdoor air admitted to a building. Notes importance of measuring minimum air flow to ensure adequate ventilation. Suggests measuring the concentration of CO2 in indoor atmosphere and using the results to control incoming ventilation. Describes simple and inexpensive implementation of the technique.
Reports measurements of ventilation rate in specially designed low energy office building. Air change rates were measured using sulphur hexafluoride as a tracer gas and air samples were analyzed for carbon dioxide. Gives tables of results. Discusses analysis of ventilation from CO2 data. Concludes that most of the spaces in the building were operating at or above recommended levels.
Stresses importance of building draught-free housing to conserve energy. This poses problems for heating and ventilating engineer. Lists effects on microclimate. Explains interplay between freedom from draughts and ventilation. proposes a list of terms with definitions related to infiltration and draught prevention.
Discusses minimum ventilation necessary for occupied buildings and finds that occupiers minimum needs are based on dilution of body odours and that in Britain a high ventilation rate is necessary to reduce humidity. Describes two electrical solutions to the ventilation problem. The first is a combined ozone and ultra violet irradiation to oxidize the malodours. The second is the application of a heat pump dehumidifier to remove excess moisture in mild weather.
Treats measurements of ventilation rates in a model building and wind tunnel. 2 types of opening, circular holes and model windows were tested under 2 wind cOnditions. one wind condition was selected to give maximum flow through the model; with theother, ventilation was mainly due to turbulent pressure fluctuations. Illustrates different characteristics of theopenings. Draws comparisons between measurements and theoretical predictions. Discusses use of wind tunnels for ventilation studies. NOTES: A further comment on this paper was published in Building and Environment vol.15 no.141.
Reports pressurization tests on eleven schools both with the air handling system on and with it off. Obtains air leakage through components of the building by comparing overall leakage rates before and after sealing each component. Uses leakage rates to calculate air infiltration using a simplified model of a school building. Finds that infiltration caused by stack effect is significant even for a single-storey building.
States that application of further thermal insulation to house structures increases importance of ventilation heat loss, from around 20% to nearly 50% of total design heat requirement. Any further energy savings will be by minimising ventilation components. On basis of British Gas research results and others, illustrates sources and mechanisms of infiltration to give an insight into problems it may cause in future housing. Treatseffect of weather, ventilation rates. Among conclusions states increasing attention will have to be paid in future toinfiltration.
There is at present no analytical step-by-step procedure for calculating air infiltration into houses. Extracts useful house air infiltration data from almost 20 years of scattered research work. 1) Highlights important conclusions of these papers andgives some selected notes on the many variables involved. 2) Reduces this information and summarises it in 2 tables. sets out 2 worked problems using these tables to demonstrate their application.
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