Extra ceiling height or solar chimneys create air movement by stack effect; in particular, wind towers are really effective, since they create a breeze and promote cooling by evaporation.
Other techniques
- in Nome (Alaska) the potential for solar heating may be limited, at least when most needed and long-term storage may be difficult or too expensive. Hybrid solutions, such as heat pumps, may be appropriate;
- in Nadi (Fiji Islands) evaporative systems have great potential since there is a great difference between dry bulb and wet bulb temperatures. Mechanical systems have the highest efficiency since they can reduce the air temperature by 70–80% of the DBT–WBT difference; but also, passive techniques give reasonable results.
Radiative cooling towards the clear sky can give considerable dissipation of heat, especially from surfaces with a high sky view factor, such as a roof.
The gain of insulating the roofs for solar protection during the day or for reducing heat losses in cold seasons, is however often greater; finally, there are prototypes for ‘sky coolers’, but they are far too complicated or expensive for practical and low-cost use.