"Dörrofen" a Device to Parch Food




About: Hi, my name is John. My hobby is to solve problems from other people and creating nice and functional stuff out of trash. I'm living in Germany so excuse my not so fluent English (some technical terms are ha...

In later days fruits and other stuff got parched to create long storable food.

Some generations before my family could have done something like that due to the family name. So my goal was to go back to the roots and create a device to parch everything.

PS. we have an word for that: "Dörrofen"

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Step 1: Initial Plan and Cutting of the Boards

For such a project it is required to draw down all the stuff. This is the only way to order the right amount of boards.

Furthermore this way I force myself to think before.

Step 2: Heat Bridge for the Alternative Heat Source

Beside the sun, I also wanted to use an alternative heat source. Therefore I've used a steel rod to implement a heat bridge. For what... will be followed later.

Step 3: Assemble the Boards

I've screwed everything together.

Please notice, that the two boards at the button are mounted the wrong way, I've noticed that at the and and had to do that again. The heat bridge should be faced downwards.

Step 4: Fan for the Better Airflow

To increase the airflow I've added a fan which will later be controlled by a micro controller. This will be a update

Step 5: Solar Heater - Pipes

To collect a huge amount of solar energy I've build pipes out of old cans and painted them black.

I've noticed several things while creating the collector.

One: Only three cans can be placed in the PMMA tub

Two: the area is to small for central Europe

Step 6: Solar Heater - Housing

The pipes got a special housing, which I've found in the basement. It is a PMMA tub for aquariums.

Step 7: Solar Heater - Assemble

The solar collector got a customized inlet in the box.

Step 8: Assemble the Solar Collector

... And Pint everything black.

Step 9: The Fire Bucket

As mentioned before. I want to use several heat sources (actually two). The alternative to the sun is to use a fire. The heat bridge got two steel tubes. Furthermore I've found a stainless steel bucket (It's from a industrial coffee machine ). To allow a slight airflow through the bucket I've used a grinder to add some slots.

Step 10: RECAP

The final project looks... OK but It has several downsides:

- as mentioned, the area for the solar collector is to small

- The convection current is to low,

- These two points are responsible for a to cold (51°C on the hottest days) slow airflow

Planed Updates:

- Implement the fan and the micro controller

- Increase the collector area

Wood Contest 2016

Participated in the
Wood Contest 2016

Maker Olympics Contest 2016

Participated in the
Maker Olympics Contest 2016



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    5 Discussions


    2 years ago

    I wonder if the black pipes actually need any glas. Yes, most people do it, but the important thing is that the sun heats the cans and that the air rises to the oven itself

    1 reply
    Layer 8diy_bloke

    Reply 2 years ago

    I've only used the window because otherwise I had to use it in another Project.

    I'm planing an update with a much larger solar collector, made of black bubble wrap.


    2 years ago

    Dörrofen, drying oven, Have used those too, to dry fruit and stuff. I had not made the entry as long as you do. I guess that would work very well.
    I made one with about 50 cm of inlet and additionally a glass panel under about 52 degrees to let in some more heat.
    taking what Beachsidehank said in account, yes mine were made from natural wood
    Nevertheless yours looks great. Curious abt yr gas detection numbers


    3 years ago

    I've seen solar driven dehydrators and they are simple to construct and easly work well, but those have all used natural wood in the construction. I'd have some serious reservation about using composition board like you show for drying edibles simply because of the outgassing of components like formaldehyde used in it's construction.

    1 reply
    Layer 8BeachsideHank

    Reply 3 years ago

    I've didn't thought about that. Luckily I have the possibility to use a device to measure the gas composition. I'll add the numbers here.

    But thanks for the note.