I came across the article recently, and if you’re an architect, environmental designer, and/or termite enthusiast you might find it just as fascinating as I did. Apparently, it’s been a topic and biomimetic precedent that has been under investigation for some time. New tools and monitoring techniques have shed some new light recently, however. A more detailed journal article has been published by Hunter Kinga, Samuel Ockob, and L. Mahadevana under the title “Termite mounds harness diurnal temperature oscillations for ventilation” and can be accessed through Penn Franklin.
Worth a read…
Here is a more detailed abstract from that journal:
Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diur-nal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combina-tion of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ven-tilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations.