Zeolite beads dry the air around crops instead of heating the crops themselves

Plant scientist Kent Bradford of the University of California, Davis believes a simple ceramic bead that sucks moisture out of the air can make agriculture far more energy efficient and much less expensive. The beads are zeolites — porous minerals that readily bind certain molecules — with pores engineered to be just the right size and shape to trap water molecules. They were developed by Rhino Research in Thailand.

In humid tropical countries, where up to a third of crops are lost before reaching consumers, the beads are placed alongside harvested rice or maize seeds in mesh sacks or screened-in compartments. They capture water from the air, significantly reducing the moisture that leads to rot and fungal toxins. Bradford and his collaborators spent several years testing and refining the technology with farmers in Thailand, India, Nepal, Kenya and other tropical nations.

The next target was industrial-scale drying in richer nations for almonds, walnuts, rice and grains. Conventional operations blow hot air through crops in drying towers or silos, which scorches parts of the batch and ruins taste; experiments showed ambient air, first dried by passing through the beads, works just as well. The beads themselves are re-dried in a compact oven for reuse — a far more efficient use of heat than heating moving air.

Selecting pore size for water molecules turns a cheap mineral into a targeted dehumidifier with no power draw of its own.

Drying the air rather than the grain halves the energy in Bradford's estimate and avoids the scorching that hot-air towers cause.

Mesh-sack deployment needs no equipment a smallholder cannot use, which is why field trials ran across Thailand, India, Nepal and Kenya.

Condition the small mass instead of the big one: fixing the air around a product can replace processing the product itself, and the same physics scales from a village sack to an industrial silo.

As of February 2017 the researchers were working to bring the technology to industrial-scale drying in richer nations; the halved-energy figure is Bradford's estimate, and no adoption totals are recorded in the material.