Often called Provence wells
in French, this process involves passing a part of the clean, new air used for ventilation through tubes buried about 1.5 meters deep in the ground.
While our tropical temperatures are relatively high, it remains much cooler underground than in the outside air : this ingenious system uses the relative coolness of the ground to cool the air entering the house. So with an outdoor temperature around 30°C, the air introduced through the heat exchanger can be as low as 22°C.