Natural ventilation and the role of passive stack chimneys in traditional excavated and surface dwellings in Santorini.

This paper considers the role of passive stack chimneys in controlling indoor thermalconditions in the vernmlar houses on the volcanic island of Santorini . The quality of theenvironment within these dwellings is disputable, mainly because of the high humidity levels.A monitoring study was carried out in four actual dwellings in Santorini, two built on thesurface and two excavated into the soft volcanic rock. The temperature and relative humidztyof their main space and their chimneys were monitored and compared to the simultaneousexternal conditions. The results of this study were then used in a computer simulation package, modelling the performance of the dwellings and the chimneys in terms of air movement and air change rates. This showed that in most cases, chimneys proved to be efficient, establishing continuous air movement if located correctly, i.e. in the space where ventilation is mostly needed. The air flow characteristics of the chimneys seemed to be based on a diurnal cycle related to the external temperature fluctuation, but with a time lag. By designing a chimney carefully and using the materials in an appropriate way, the ventilation problems of these dwellings can be solved at low cost, both in terms of running costs and energy consumption. In the last few years, natural ventilation has been adopted by many European designers, as the importance of energy conservation is increasingly realized. The study of the role of passive stack chimneys in natural ventilation can not only be useful for the restoration of such vernacular dwellings, but can also be used in the design of new, environmentally friendly, buildings.