Thermal behaviours of vernacular buildings in the Yemen Arab Republic

A simple steady-state mathematical model, describing the average total daily rate of heat loss through the walls, windows and flat roof of a generalised Yemeni building, has been developed. From this, a technique was evolved by which designers can predict approximately the transient rate of heat loss via traditionally employed combinations of indigenous materials, as used in the walls and roof. The principal variable is the ratio of the total glazed area for each storey to the corresponding sum of the surface areas of the solid walls and roof in contact with the ambient environment. The predictions, expressed graphically, enable designers to select the most suitable combination of locally available, indigenous building materials, so that more energy-effective dwellings can be built: these inhibit severely the heat fluxes entering the dwelling during the day-time and leaving at night.