Preserve your fruits and vegetables with a homemade solar dehydrator

Anyone who grows their own fruits and vegetables will be faced with this problem: what to do when seasonal production exceeds consumption? One possibility to store the product and use it throughout the year is to dehydrate it, an option that helps maintain nutrients. An alternative to be able to apply this technique without having to invest in equipment on the market or to increase the consumption of electricity is to manufacture a dehydrator that also works with the energy captured by the sun.

The concept is simpler than it looks: circulating hot air over thinly sliced ​​food. The warmer the air, the more efficient the system will be at removing moisture from fruits or vegetables. Now be careful, because too much air can end up taking you where you don’t want to; the temperature drops and the system is inoperative. Therefore, if you follow these steps, you will get exactly what you need to dehydrate your food quickly and efficiently.

Materials and tools to build a solar dehydrator.

To get started, make sure your tools include a soldering iron, hacksaw, wood saw, pair of scissors, yardstick, framing square, drill, and utility knife or box cutter.

Once you have all of that, the materials you will need are as follows:

  • About 12 meters of square tube.
  • A metal sheet about five meters long and a little less than one meter wide.
  • One 0.6 x 2.4 meter polycarbonate greenhouse panel.
  • A pair of hinges.
  • A closing.
  • Silicone.
  • 11 wooden planks 2.4 meters long.
  • A screen for securing food approximately 5 meters long by 0.6 wide.
  • Two fine wooden molds.
  • Wood screws and tapping screws for metal.

Instructions.

First step: build the frame.

The size of the frame will be whatever you decide, although in this example we’ve chosen one that’s a little over a meter long (1.2) and a little less than half a meter wide ( 0.48).

Following these measurements, for the horizontal structure cut three pieces of square tube of 1.1 meters and two others, in this case a little longer, of 1.2. For his part, for the vertical, he extracts four other pieces from the tube, two of 0.8 meters and two others of about half a meter.

At this point, assembly will begin. To do this, place the two 0.8 pieces on a flat surface. Mark each of them, first three inches from the bottom, then about 25 from the top. Now between the two bars and just at the first mark (the 7.5cm) place one of the ones you had 1.2meters tall and solder them. Repeat, now at the top end. With this you will have the structure before.

Then you will have to weld the two bars of half a meter between the other two (those of 1.1 meters) to form a rectangle; with the short pieces to the side and the long pieces perpendicular. With this step, you will shape the back.

Now is the time to work on the sides. Place the back panel vertically and cut two more pieces of tubing about half a yard to join one of them on either side of the back frame. It also positions the front part vertically and fixes two panels with a clamp so that they remain in this position. Then square the lower pieces to the side and make sure they are attached.

You will still need two more pieces of bar connecting the panels at the top. As the front is higher, in this case the bars will be tilted. Make sure the parts are exactly sized to fit and that they are the same. If so, attach them to both panels, and once everything is square, weld the pieces.

To complete the structure, only the lower part will remain. Lay it with the front part on the floor and insert the 1 meter piece that was left at the bottom, about 10 centimeters from the front panel.

Second step: make the door.

Take the square tube again and cut two pieces of about 1.2 meters and two more of half a meter. Check that the size is correct for your front panel and if so, solder the frame. The idea is that the door fits perfectly and overlaps the front frame. Then cut a 1’2 × 2’5 sheet to fix it to the structure you just created for your door and thus be covered.

Step 3: Create the cover.

Before you start doubling, it is best to fix the supports on which the trays will rest later. To do this, cut ten pieces of wood half a meter long. At the back, make the marks at the same distance to place five supports. Once you have them, attach the pieces to the sides.

To absorb the heat, cut a 1.2 meter piece of sheet metal about half a meter and place it on the lower panel on the sides and the bottom tube of the door. Once it is tight, screw the part.

At this point, it’s time to start with the deck. To do this, cut the polycarbonate panel in half and fix it on the frame, one part on the top strip and another on the back. Secure the panel to the frame with the tapping screws. To do this, you will need to drill several holes around the perimeter.

To cover the sides and bottom, cut pieces of sheet metal according to size. Remember to leave a space of 10 centimeters on the underside of the door, to serve as ventilation. With two more pieces of foil you need to cover the lower and upper part of the door, leaving spaces for ventilation. Finally, with two other parts of the leaf, you will prevent insects from sneaking through the ventilation inlets and outlets.

At this point, cut four strips of mold, one of 1’2 and the other of 1’1 meter. Staple the 1’2 to the screen and, using small screws, secure it to the polycarbonate panel at its lower end. The idea is that the screen is suspended from the central part. Make sure it is held on the sides, also by screws.

Now move on to place the other part, part 1’1, in this case between the upper part of the front panel and towards the center of the sheet, in its upper part. Screw it on and staple the free spaces in the sheet.

Then secure the lower screen to the sidebars using several screws, so that the screen remains. Also screw the metal parts at the bottom and around the door opening. Finally, apply silicone to the edges of the panel and sheet.

The last step before finalizing the cover will be to paint the interior black and, most importantly, the sides and the heat collector.

Step 4: Activate the food trays.

An important step remains to prepare your solar dehydrator: create the trays in which you will place the food. To do this, cut eight pieces of wood of about 1.1 meters, and 12 more, now just over half a meter. Glue and screw the pieces in order to create rectangles which, in addition, must have a support in the central part.

Now get four 1.3 × 0.7 meter screen pieces. Fold the edges and staple them to the rectangular pieces of wood, if possible so that it is stretched well.

Finally, add two screws to the bottom of each tray, one on each side. It is important that they are about an inch from the end of the table top and also that you do not screw them in completely, but let a little more than an inch stick out. With this, sliding the tray will be much easier.

Fifth step: everything is ready to dehydrate your food.

Before finishing, do not forget to equip the door with hinges and a latch. With this, you will have your home solar dehydration equipment ready. Before you get to work, place it in the sun and wait several days to get rid of the paint and silicone residue.

With this, everything will be ready to test your equipment. If you want to control the temperature, you can place a thermometer inside. As a guide, the ideal is to keep it at around 54 degrees Celsius so that the fruits and vegetables dehydrate quickly and efficiently.

Original project in Instructables.