Europe. Numerous studies have been devoted to the analysis of the physical phenomena related to natural ventilation. These phenomena are very complex and our degree of understanding them often leaves a lot to be desired. Research on this topic within the framework of PASCOOL included experimental and modeling work aiming to fill existing gaps in our knowledge of indoor air conditions in naturally ventilated buildings.

PASSPORT Plus is a new building thermal simulation tool, developed in the framework of PASCOOL. It incorporates new findings from the experimental and theoretical research activities performed in PASCOOL that have been integrated in an original informatic structure. Overall, the emphasis during the development of the program was given on dealing with problem related to cooling of buildings, especially by natural and passive techniques.

Two specific areas are addressed: (1) The necessity for effective estimates of infiltration rates in buildings; and (2) The dependence of vapor compression air conditioning systems on refrigerant charge. It is shown that the estimate of air infiltration rates through simple tests such as "blower-tests" are not applicable. In addition, there may be measurable drops in the capacity of air conditioning systems (on the order of up to 10%) for noni significant variations in the refrigerant charge from the optimum value.

A technically and socially innovative housing project at Hockerton in Nottinghamshire has set out to implement the Agenda 21 principles on a local scale. With a radical approach, impeccable design credentials and committed occupant-owners, the scheme is a striking way forward. It might work for them, but will it work for the rest of us?