Making a food dehydrator - what heat source should I use?

Discussion in 'The Projects Forum' started by RogueRose, Jan 14, 2016.

  1. RogueRose

    Thread Starter Member

    Oct 10, 2014
    So I am making a dehydrator that is going to use a fan and some kind of dessicant cartridge to dry the air before blowing into the heating element (at least that is the plan so far).

    I don't know how much heat is needed for this project. The volume is about 6.33 ft^3 and very well insulated. I would like to have a light in the unit as there will be a glass/plastic window in the front to check on the process. IDK if it matters but the unit is basically a cube shape.

    I was thinking about using a hair dryer, the one I have is 500/1500 watts and high and low speed fan. I'm sure I can alter the length of the heating wire if I wanted less heat. I was thinking about doing something to allow incremental temps 25, 50, 75, 100, 250, 500, 500 and then maybe 2 20-40 watts light bulbs. I could do this with nicrom wire although it would be nice to be able to design something that is automated (comes on when temp hits XXX and off at YYY) or to use something that has an infinite adjustment range (like a dimmer/pot).

    I have read a bit about halogen cookers and they are supposed to be really efficient so that is something that might be of interest.

    Does anyone have suggestions or ideas about this?
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    I would use a a triac dimmer on a fan and heat with one or more incandescent light bulbs on a dimmer.
  3. cmartinez

    AAC Fanatic!

    Jan 17, 2007
    I think you'd also need to use a blower, which might also be controlled by a triac dimmer or a PWM, depending on the blower's motor. The big challenge here, would be to design a proper PID controller that could use humidity and temperature as parameters.

    On the other hand, maybe that would complicate things too much. So yes, I'd start by controlling heat and air flow first. before digging any deeper
  4. wayneh


    Sep 9, 2010
    Forget the desiccant. The airflow will quickly overwhelm the capacity of the desiccant. The heater is there to lower the relative humidity of the air in the chamber.

    My dehydrator has a thermal fuse to protect against overheating. Seems like a good idea.
    cmartinez likes this.