# Build a passive-solar dehydrator



## Auntie (Oct 4, 2014)

I thought some of you that are handy might enjoy this tutorial on building your own "Passive Solar Dehydrator"

Build a passive-solar food dehydrator by Jeffrey Yago, P.E., CEM



> Construction
> 
> I wanted to design a solar-powered dehydrator that would utilize low-cost materials and be very easy for anyone to build using basic hand tools. While you can modify my basic design to accommodate your choice of metal racks, I found some very inexpensive racks at Lowe's that are designed to fit barbeque grills. These racks are made from 12x18-inch perforated aluminum sheets and sold in packages of two for less than $5. Eight racks will cost $20 and since they were designed to cook foods on a grill, they are perfect for our needs. Eight of these racks will easily fit in a dehydrator that is 24 inches high, including extra space at the bottom and top.


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## bigwheel (Sep 22, 2014)

Very cool. Thanks. A bit over my level of mechanical mindness. lol. I may stick with hanging my stuff from a tree with a strip of rawhide. Like the native American ***** Peeples done it. Hey while your digging up useful DIY projects..kindly find one for a simple solar water distiller. I have been saving an old glass double patio door for ten years aiming to build one.


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## darsk20 (Jun 1, 2015)

Like it. Might have to try it.


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## tinkerhell (Oct 8, 2014)

Thank you!

I like their choice for racks.but I wonder if they might have problems with food sticking to them.


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## paraquack (Mar 1, 2013)

Cool, thanks.


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## Auntie (Oct 4, 2014)

You could always purchase the dehydrator screen and put that on the racks. I am not suggesting this particular one it is just an example http://www.amazon.com/LEM-Dehydrato...1439689013&sr=8-5&keywords=dehydrator+screens


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## Kauboy (May 12, 2014)

Nice idea, but I worry about using pine for this project. Unless properly dried, you're inviting a high risk of humidity to build up from that wood excreting its water content into the hot chamber. Perhaps the vents would help, but I'm not sure how much. I'd go with kiln dried if I could find it.


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## Dirk (Mar 4, 2015)

Indeed nice. Would it help to paint the outside black in order to absorb more heat?


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## PaulS (Mar 11, 2013)

For a passive solar dehydrator you want it insulated and vented. Black paint is used on stoves because it not only absorbs heat but also radiates that heat away - it keeps you warm that way. 
A dehydrator should be lined inside with a reflective material (foil?) and the side(s) open to the sun should be double glazed plastic. Glass blocks a lot of infra-red (heat) while the plastic (even if you can't see through it) is clear to the IR.
Most plastics block UV (that is why clear plastic turns white over time) but that shouldn't matter with properly dehydrated foods.
Put adjustable vents on top and bottom and then baffle your platters so the air will circulate. Remember that the food will never get any drier than the humidity level of the air.


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