Summary
Outdoor tests on two identical small model houses compared a reference house with one ventilated by a steel solar chimney coupled to a buried PVC earth-tube heat exchanger. Buoyancy alone produced natural airflow, but adding a small fan to push air through the earth tube gave the strongest cooling, lowering indoor temperature by about 3.6 °C, roughly a third more than other configurations.
Description written by Solar Tower. The original abstract is available from the publisher via the link below.