This paper is a general survey of work done on natural ventilation of dwellings. Discusses ventilation of houses with both natural and mechanical ventilation. Reviews experimental investigations, quoting air-change-rates found. Discusses ventilation requirements and methods for investigating different factors. Outlines suggested experimental method for investigating air infiltration of mechanically ventilated houses.
A supply of fresh air is necessary in any dwelling to ensure a comfortable, safe and hygienic environment, but the heat loss to this air, during the heating season, may represent a substantial proportion of the total heat loss. This points to the need forgreater control of domestic ventilation, either by using a mechanical system or by better design for natural ventilation. This paper touches upon both of these possibilities. Gives simple method for assessing approximately the possible reduction in heat loss achieved by the use of a mechanical ventilation system.
Discusses the mechanisms which govern natural ventilation. These are wind speed, flow, characteristics of openings in buildings and pressures generated at building surfaces by wind and temperature difference. Gives formulae for simple cases. Outlines ways of determining natural ventilation rates. Gives brief account of the effect of turbulence and openings in one wall only.
States that to obtain accurate estimates of wind induced natural ventilation of buildings the pressure distribution over the building is required. Reviews the available information for isolated buildings and groups of buildings. Gives the results of wind tunnel measurements made on a cuboid when surrounded by buildings of the same shape. Results are presented statistically and indicate that the pressure distribution on a building can be fairly accurately determined provided the density of the built form and the roughness fetch are known.
Surveys existing studies of natural ventilation which are of two types; full scale studies of small domestic buildings and analogue studies, mainly electronic digital analogues. Gives simple nomograms, deduced from the analogue studies which are useful for estimating gross building infiltration rates underextreme meteorological conditions. States that none of the analogue studies have been carried out in conJunction with simultaneous full scale or model scale studies in order to check their performance.
Describes a computer program written in 1900 fortran which is suitable for computing natural ventilation rates in multi-storey buildings. Lists the assumptions made, the data requirements and output available. Gives a print-out of the program.
Analyses theoretically the natural ventilation of buildings. Derives fundamental formula for the amount of ventilation due to temperature difference from Bernouilli's theorem considering buoyancy. Explains physical meaning of friction loss and theneutral zone, derives pressure distribution due to wind from the shape of buildings and the location of openings. Obtains total expression for amount of ventilation due to both temperature difference and wind.
Describes measurements made to compare ventilation rates in six Belgian houses with both natural and mechanical ventilation systems using O2 and N2O as tracer gases. Ventilation rates were correlated with wind speed. Air leakage across individual components of the house was measured and from this the distribution of leakage areas calculated.
Refers to previous article treating application of theory of graphical representation in building services of calculating natural ventilation rates in buildings. Illustrates technique using examples of several buildings. Concludes that at themoment this approach is too complex and costly for general application except in specialised cases. Considers simplified methods may be developed suitable for general use.