Non-dimensional graphs for natural ventilation design.

There are certain conditions which are of interest when designing for natural ventilation ofcommercial buildings. These are:- summer cooling- indoor air quality in winter- night-time cooling.For the first two conditions it is necessary to determine the distribution of open areas to givethe desired distribution of flow rates. Since one is dealing with openings whose position andbasic geometry are known, the problem is relatively simple compared to general ventilationproblems. When buoyancy acts alone the position of the neutral layer can be specified andthe size of the openings can be determined explicitly, as described by other authors. Thepaper taltes this explicit approach further.First it is shown how, for the summer and winter design conditions, one non-dimensionalgraph covers the buoyancy alone case with a uniform temperature and then how non-uniformtemperatures can be covered by a few extra graphs. The approach is also extended toinclude the sizing of stacks as distinct from sharp-edged openings.For the winter design condition where the openings are small it is important to estimate theeffects of adventitious openings. It may also be desirable to determine the effects of wind.Suitable procedures and graphs for doing this are described.Finally the possibility of using similar graphs in the evaluation of night-time cooling isbriefly discussed.