Best-Ever Solar Food Dehydrator Plans: 12 Simple Steps To Completion

Categories: DIY

Nearly two decades of expert testing and experimentation have gone into producing these solar food dehydrator plans. The resulting food dryer isn’t just efficient and off-grid — it’s also highly cost-effective for anyone wanting to preserve large amounts of food at home.

By Dennis Scanlin

For nearly 20 years, I’ve led research teams as founder and coordinator of the Appropriate Technology Program at Appalachian State University. We’ve conducted many original experiments to produce a design for the best food dehydrator you’re likely to find anywhere. Yes, this dryer is supersized — about 6 feet tall and 7 feet long — but it’s on wheels and thus moves easily, can dry large amounts of food quickly and is a must-have for off-grid living. If you have a big garden or buy bulk produce, this solar dehydrator will help you keep up with food preservation all summer and into fall. If you live in a cloudy or humid region, you can add heat from light bulbs to improve its operation. Anyone with basic woodworking skills can tackle these plans. Here you’ll find complete lists of materials and tools, plus step-by-step instructions.  

How It Works

 Drying is an excellent way to preserve produce, but exposing fruits and vegetables to direct light can cause vitamin loss. This design relies on indirect solar power, meaning the drying food is not exposed to the sun but instead to solar-heated air. Our dryer takes advantage of the natural process of rising hot air to operate efficiently without any electric fans.

As you can see in the detailed drawing, the design includes a long, angled wooden box covered with clear plastic glazing and an open bottom end for air intake. Inside, the box holds diagonal layers of black metal screen. The vertical drying chamber on top has a back door to access food-drying trays inside.

The sun’s radiation passes through the plastic top of the collector box to the absorber screens, which retain heat. Air entering through the intake is warmed as it passes over the absorber screens, and then flows into the drying chamber. There, the heated air draws out the food’s moisture before exiting through vents just below the roof. The rising warm air creates negative pressure at the bottom of the collector box, which draws in more outside air to replace the air that left through the top vents. Air will continue to heat and rise, passing through the collector box and into the drying chamber, as long as the sun is shining or the dryer has access to another source of heat. 

The drying chamber of this dehydrator supports 11 trays to hold up to 10 pounds of thinly sliced food — about 35 to 40 medium-sized apples, for reference. It can dry this amount of food in two sunny days, or about half this amount of food in one sunny day because of better ventilation and reduced food mass. The temperature inside the chamber can easily soar to more than 140 degrees Fahrenheit.

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