The wind and buoyancy pressure driving forces for natural ventilation of buildings are very low, typically less than 10 Pa. Depending upon the prevailing climatic and thermal conditions, or even the location of a building on a site in relation to other surrounding buildings and landscape, the predominant pressure force incident on a purpose-provided natural ventilation opening can either be closer to the lower range of pressure differentials (< 2 Pa) or vary over a wider range of higher pressures (2 - 10 Pa).

Ventilation is one of the most important measures to dilute indoor air pollutants. In order to maintain a clean indoor air environment, not only the total ventilation rate of the building but also the distribution of outdoor air to each area must be taken into consideration. A performance evaluation of various ventilation systems, which have different air supply and exhaust equipment, has been made. This investigation was undertaken over a heating period, in a full-scale test house.

Primary energy consumption in Algeria continues to grow, and this is associated with the growth in sale on conventional air conditioning systems. This was a major impact on electricity demand specially for summer cooling purpose for north and south regions of Algeria. This investigation demonstrates that the combination of passively driven air movement and evaporative cooling through wind tower system can be used with success and fulfil comfort requirements of hotel accommodation under constantine climate.

This paper presents results from the first year of monitoring the performance of a laboratory building in the new 14.000m² Torrent Research Centre in Ahmedabad, India. The capital and running costs of air conditioning of non-domestic buildings in northern India are very substantial. while building costs (compared with northern Europe) are low. A cooling technique which maximises reliance on the building fabric and minimises reliance on mechanical equipment is therefore likely to be cost effective. Passive Downdraught Evaporative Cooling (PDEC) represents such a technique.