People have been drying food ever since ancient times. American Indians hung meat over camp fires. Medieval European households hung bunches of herbs or apple slices from the ceiling where warm air would rise to dry them.
Basically, something becomes dry when dry air moves past it, picks up the moisture and then moves the moisture away. Warm air is the most effective because it will absorb more moisture than cold air will. Standing air, of any temperature, won't carry moisture away and, if it stays in one spot long enough, will cause mold. Therefore, a functional food dehydrator must have a way to keep the air moving, vents to let dry air in and more vents to let wet air out.
The two most popular ways of keeping air moving in commercial dehydrators are fans and the chimney effect. When we started experimenting with dehydrators, we tried fans. In side-by-side tests, most people preferred the non-fan model. So that's what we made. After all, fans frequently pull dust into the machine, fans are noisy and fans use a lot of electricity. And hey, with blackouts threatening, who needs something that takes more power than really necessary?
So how does the chimney effect work? It's like this. Warm air rises naturally. This is why chimneys go up from fire places. The warm smoky air rises upwards and out of the house. In our dehydrator, we have a Warm Air Generator (WAG for short) at the bottom of the dehydrator which gently heats air to just above room temperature so that the air will rise through the food dehydrator, past all of the wet food, pick up the moisture and carry it out of the vent at the top of the dehydrator.
And that's how it works! Simple as that!