One of the main aspects determining the thermal behaviour of buildings concerns the distribution and circulation of air. Experimentation was undertaken in the context of the investigation of a method of measurement of the natural ventilation of large rooms. The first objective was to endeavour to characterise the atmospheric conditions around the building, namely, conditions related to wind factors, but also those concerned with the location of the building in relation to neighbouring obstacles (other buildings, relief of the ground, etc).

Wind towers (scoops situated on the roofs of buildings to catch the wind) have been in use for centuries in the Middle east and Pakistan, to provide ventilation and cooling with minimal mechanical plant. In Europe, the problem of cooling buildings has generally not been significant, but in recent years there has been a trend towards substantial increases in internal heat gains from IT equipment etc., and overheating in summer has become one of our major concerns.

Natural ventilation studies were carried out within the frame of PASCOOL EC Research Project. Research on this topic included experimental and modelling work aiming to fill the existing gaps in our knowledge of indoor air conditions in naturally ventilated buildings. Experiments were carried out in full scale and test cell facilities during the summer period. Single sided and cross ventilation as well as air flow through large internal openings were the basic topics that were studied. Existing models were validated and new ones were developed.

The suitability of night ventilation for cooling for the UK is first assessed by presenting plots of summer weather data on the bioclimatic chart for three locations within the country. These indicate that most of the external weather conditions lie within the thermal mass and ventilation effectiveness areas of the charts. To confirm this, thermal simulations of a typical office module under a variety of internal conditions and summer weather data were performed.