Radiant Heat Solar Dehydrator

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About: Loo Ly Mun is the technical expert of Ecocentric. He designs and builds our appropriate technology solutions. He enjoys experimenting and innovating to figure out the sustainability solutions for the Malaysi...

Hey there!

I am Lymun- founder of Ecocentric Transitions, an environmental sustainability based organization in Kuala Lumpur, Malaysia.

Nisha (our creative lead) and me co-create sustainable designs through our workshop engagement and have received a lot of requests for different ways to cook food under the sun and preserve its longevity.

While searching on the internet for a solar dehydrators that work in a highly humid environment, I came across this website and have decided to follow their design.

http://www.geopathfinder.com/Solar-Food-Drying.htm...

Sustainability: I mostly try to use materials I already have or scavenge materials from dumpsites.

As this dehydrator is used to dry foods, I made an effort to use stains and finishes that are food safe.

This dehydrator consist of 3 frames; the collector frame, food frame and the reflector frame.

P.S This is my first instructable. So you may need to refer back to the original site for references.

Step 1: What You Need

Materials I used:

1. 3 pcs 2"x2" 8' planed hardwood (may need more depending on your size)

2. Perspex / Acrylic sheet (From an unused old picture frame)

3. Corrugated metal roof sheet (Some leftovers from a construction site)

4. Aluminum metal sheet

5. Stainless steel / aluminum wire mesh

6. 30 x 1/2" roofing screws

7. 32 x 1/2" Aluminum flat head roofing nails

8. Black heat resistant spray paint

9. White spray paint

10. Orange oil wax wood conditioner

11. 2 x 4" T-Hinge. + screws

12. A bunch of 1 1/2" screws (approx.. 40pcs)

13. 1 Length of dowel rod to make dowels

14. Sheet metal cutter

15. Tools for wood working (saw, measuring tape, clamps, pencil, angle ruler, protractor)

16. Coffee

Optional:

17. 100% silicone sealant + caulk gun

Step 2: Building the Frames

Let the fun begin!

First I measure the size of the Perspex sheet and build the frames according to that size. Mine was about 2'x1.5'. So cut 3 sets of 2 x 2' (vertical) and 2 x 1.5' (horizontal)

Make one frame then make 2 more... so you have 3 frames

Joinery:

I used a normal screw in from the side. its strong enough for this purpose. Pocket holes are stronger though.

I also like to hide my screws, so I make short dowels and cover them. glue it in, cut the excess and sand it down after it has dried

Step 3: Paint the Metals

While waiting for the glue in the joints to dry, its time to paint the sheets of metal.

First measure and cut to size the flat aluminum sheet to fit the size of the frame.

Also cut the metal roofs to size. Have at least 2 ridges to fit so that it can support the food frame.

Then paint the flat aluminum sheet with the heat resistant black spray paint on both sides.

Use the white spray paint for the corrugated metal roof. You only need to paint the top part.

I sprayed a few coatings to make sure that the paint is even.

Step 4: Making the Wood Look Good

First, brew yourself a nice cup of coffee and take a break.

Then make more thick coffee to stain your wood (I added more coffee than usual to make it thicker) Wipe excess off and let it dry.

Once the coffee has dried, its then time to rub the orange oil wax in with a piece of cloth/rag to protect the wood and make it look really good.

Here is also when I use the silicone. As I used mostly hand tools, the cuts are not straight and this will make small gaps in between the joints. So I fill those gaps with silicone.

Step 5: Making the Legs

The dehydrator needs to be propped up at a 15 degree angle for airflow (for it to work properly).

I have decided to make cute little legs for them. These will be attached to the lowest frame (collector frame) with the corrugated roof metal sheet attached to it.

To measure the legs:

I have used a free online right angle triangle calculator to determine the length of the legs. Just enter the 15 degree angle and the length of your dehydrator to determine the height of back legs to the base

Then add the height of the front legs to the back legs to determine the overall length of the back legs.

I have attached the legs the front as shown and the hind legs is attached to the inside of the frame.

Details of how I designed the legs is shown in the drawings.

Step 6: Fixing Panes

First we make the top frame, the collector frame

Use the flat head nails to nail in the black aluminum sheet to the bottom of the frame. I bent in the edges inwards so that it is not sharp to touch.

Drill some holes into the Perspex sheet to match the roofing screws. Then turn it over and screw in the Perspex on top with the roofing screws to the frame (which has the black flat aluminum sheet already attached to it)

Second, we make the food frame. Cut the wire mesh to size and fold in the edges. Nail it in on the folds.

Third we screw in the corrugated white metal roof to the base frame with the legs.

Step 7: Putting It All Together

Lastly we attach the T-hinges on the back of the top and lowest frame.

These hinges are the only things holding the 2 frames together (the food frame is braced by the front legs)

Carry the Radiant Heat Solar Dehydrator by the base frame.

Step 8: Reaping the Benefits!

Here are some of the items we dehydrate here in Tropical Malaysia!

We make green teas from leaves, flowers and fruit. Sometimes we dehydrate sated fish and chilies. We have also tried making fruit tape and dry orange peal (which we burn to ward off mosquitoes)

Have fun!

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    3 Discussions

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    jprussack

    4 months ago

    Fantastic!

    1
    None
    Kink Jarfold

    4 months ago on Step 8

    You're doing a great job all the way out there in Kuala Lumpur, Lymun. Keep it going.

    KJ

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    abhinavonowinew

    4 months ago

    Really neat ! Welcome to instructables :) Do tell us about your next build adventure.