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.
After discussing briefly the principles of natural ventilation, goes on to describe tracer gas techniques, air movement measurements, and various model techniques including analogues. Advantages and disadvantages of each method are indicated, andtheir suitability for particular applications.
Reports a theoretical study of natural ventilation made jointly by HVRA (UK) and Institute for Public Health Engineering TNO (Netherlands). Uses analogue and digital computers, and results so derived were used to produce a design method suitable for rapid assessment of the natural ventilation of projected buildings. Shows this method to be quicker, cheaper, and more accurate than the crack method (measured leakage at windows and doors) or the air change method.
Points out that ventilation heat loss can account for 50% of total loss in a well-ventilated house. Presents analysis of mechanics of natural ventilation. Describes computer-based model developed by British Gas Corporation for predicting ventilation patterns in houses. Uses calculations applying the method to illustrate basic reasons why natural ventilation is likely to cause problems in heating well-insulated dwellings. Discusses these problems in detail. Treats how ventilation could affect sizing of appliances and indoor thermal environment.
Outlines necessary ventilation rates for an occupied room. Discusses natural ventilation of a room through openings in the ceiling. Discusses natural draught ventilation for single family houses, combined natural draught and mechanical ventilation, mechanical fresh air ventilation based on a central duct, fortuitous ventilation caused by air infiltration and leakage. Compares natural and mechanical ventilation. Considers supplyair systems for single family houses, warm air heating and possibilities for heat recovery.