File:Food dehydrator (hybrid).png

English: Schematic of a food dehydrator designed by KVDP, based mainly on Peter Murphy's food dehydrator.

Peter's dehydrator was modified significantly by changing the dimensions (currently 45 cm long X 70 cm high X 35 cm wide -instead 29,5" X 38" X 15" in Peter's design), eliminating the metal heat spreaders, the chimney (replacing it with a simple air outlet hole in the middle of the top wooden panel (marked with L) and by adding a solar thermal collector (similar to other indirect solar dehydrators). The top hole can also be partly closed -this is accomplished by a wooden block that has been given a nut/bolt in one corner, allowing it to swivel opn/closed^[1]). Inlet air holes are made in the solar thermal collector.

The design of this solar thermal collector is similar to other indirect solar collectors -so just a basic flat panel solar thermal collector consisting of glass, an open wooden box and a flat, black sheet of metal. Special about this solar collector however is the addition of a fine wire heat exchanger (marked with D2) attached to the back of the flat, black sheet of metal (marked with B). This heat exchanger comes to outside the wooden box, allowing to be heated by an oil burner (marked with D1). The solar thermal collector is also fitted with 2 nuts and bolts (marked with C), allowing it to be rotated for optimal efficiency for your location/time of the year. See http://www.appropedia.org/File:Solar_energy_harvester_orientation.png

The solar thermal collector goes into a wooden box (marked with G) at the bottom of the dehydrator. This box is made of 4 wooden panels, of which the top wooden panel is perforated, and a single hole is made in the bottom panel to allow the insertion of the solar thermal collector, while also allowing it to rotate a bit (so the hole is larger than what it needs to be). The box makes the bottom panel of the dehydrator redundant, so this was left out. The excess opening can be sealed by means of a rubber seal.

Another major change is the door; this is no longer attached using hinges, but is now a sliding door (marked with J), being slided in from the top. 2 angle plates hold the door in place (hence function as a "rail"). They're marked with E. The door can be made to close more tightly by using 2 or 4 screw tighteners between the angle plates and the door (made of a threated plate and a bolt). Another special addition is a stop beam, marked with F; this beam makes sure the sliding door doesn't fall through downwards.

Then the rest of the parts:

• K: back wooden panel
• H: metal mesh (note that these are not complete trays, so not framed), food comes on top of this. There is about 10 cm space in between the metal meshes
• I: wooden strip, for metal meshes to rest on

Note that no metal heat spreaders are necessary as space is left on both the front as the back of the metal mesh (the metal mesh is much less long as the wooden strips they rest on), creating a more equal heat spread throughout the entire dehydrator (see air circulation schematic). In Peter's design, this was an issue, and to counter this problem he advised to continuously rotate the position of the trays. This is however cumbersome and might no longer be needed with the current design (although the top trays will probably still get more heat than the bottom ones). If this still remains a bit of a problem, try using 2 types of food, the top food trays then being used for food that needs more dehydration than the food placed on the bottom trays. Another option is to simply not fill it completely (using only the bottom or top trays instead) or to build a less high version of this dehydrator (with less trays). In many cases, you'll probably want to use timber you allready have, reuse old existing cabinets, ... so you'll probably end up making a custom version of this dehydrator anyway.