Solar Dehydrator

Alacrates's picture

A few pictures of the solar dehydrator I put together this summer. I didn't get around to experimenting with it too much this season, time got away from me.

I think I'll have to work with an electric dehydrator over the winter, and come back to this again when it warms up again next year.

The basic design has three chambers: the front chamber has the glass allowing light into the area that is painted black (with some layers of metal lath that is painted black as well) to transform solar light into heat, and set up a warm passive air current.

That air rises in the area below the glass, and then falls through the screen-trays, to hold the thin slices of food. The back section then has a chimney area, where the air is pushed out a screened area at the back of the unit.

I'm hoping to make some dehydrated fruit pieces for snacks, some dehydrated vegetables for soups, and maybe some dehydrated meat for jerky.

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Alacrates's picture

View from the side...

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Alacrates's picture

The screen trays, to place the food slices on...

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Alacrates's picture

Inside View #1

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Nice work. I will be interested to hear how it works.

David Trammel's picture

Alacartes, would you consider writing up a longer more detailed post on how you built this to be posted as a guest blog to the main site. As a carpenter myself I can see how you put it together (nice design btw) and could reproduce it, but someone less skilled might not know how.

The over hang in the back, is that to shield the outbound heated air? I can see you have a screen over it to protect from insects but hot air from the front should rise in the food tray area. Should the vent cut on the back wall be at the top?

I didn't get the chance to do any experiments this Summer either. I wanted to try some solar powered wax melting to make candles. Like you I have a electric food dryer, the plastic circular multi tray type and am going to try some food drying soon myself.

BTW: I flipped your last picture.

Alacrates's picture

I could write something up... I've got a few other blog posts on the go at the moment, but I would like to get to this eventually.

I took the basic design from some pictures on a thread at a permaculture forum, then just pieced it together around a screen door window I grabbed out of some scrap. https://permies.com/t/40/3562/kitchen/Solar-Food-Dryers

I was rushing when I made it and didn't think it out as carefully as I would've liked to, its a little bit too large & cumbersome for easy use! The idea with the air flow is that it is drawn from a screened opening under the window, heats up in the black paint and painted black metal lath to create an updraft, is pushed down through the food trays, then is pushed up and out the rectangular chimney in the back. The little cover is to prevent rain getting in the screened opening (not sure if that little piece of plywood would be adequate, I could change it if needed.

Thanks for flipping the picture, haha, I tried uploading it several times, it just wouldn't stay the right way up!

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Alacrates's picture

The way the airflow is supposed to go... now that I think about it, I'm not sure why it needs the chimney at the back, probably could've had the screened exit at the bottom/back underneath the food trays. If the airflow isn't enough for good dehydration, I'll cut in a little electric fan with a small solar collector to increase the airflow.

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David Trammel's picture

That explains it better, thanks.