Rocket stove/dehydrator question from a lazy newbie...

Hi everybody,my name is Martijn and i'm both a first time poster as wel as total newbie to these forums.
Anyway,to get to the point :
Does anybody here have any experience with combining a rocket mass heater with a diy food dehydrator?
I have no land to grow my own food atm,the weather/climate in the Netherlands is not really conductive to Solar dehydration,but our markets sell produce for a really low price at the end of our market days (wednesdays and saturdays) giving me/us the option to buy fresh produce in bulk (sort of).
Now me and some friends of mine do not really need a rocket mass heater to heat our homes right now,but we would like to be able to dry/dehydrate our food and have long term food storage.
So,using woodscraps and tree clippings instead of electricity or natural gas to make a dehydrator just seems like a smart idea to me,but sofar i've found sweet fa on the concept.

So anybody have any tips or ideas?

my thanks in advance,

Martijn...

Hello, Martijn and welcome to Permies!
I don't know the answer but I know someone on this site can help you with your question.
We will look forward to your participation here.

haven't tried it, but I don't think it would be terribly difficult. how you design it should depend on the volume of food you intend to dehydrate at once, and the particulars of the food in question. dehydrating a couple of pounds of sweet potatoes is going to be substantially different than dehydrating a pallet of pears.

I think I may have a solution here! Dehydrating food is done at a relatively low temperature, correct? (under 200 degrees?). As the RMS heats up, the section closest to the barrel is going to be the hottest, while the tail end is the coolest. Put a thermometer on a container that would fit your food however you arrange it and move the container towards or away from the barrel until you find a spot that maintains the general temperature you would like to use! Keep in mind that the longer you run fire, the hotter the whole bench will get so you'll have to keep adjusting.

That's just a "shoot from the hip" idea, I'm sure there are others and better ones! Best of luck

Thanks Adam that's one worth looking into. but correct me if i'm wrong but isn't there in practice some kind of upper limit to how hot the thermal mass"bench" usually gets?

This might give you some ideas...


http://www.aprovecho.org/public/Publications/Still-The.Winiarski.Wood.Fired.Agricultural.Food.Dryer.pdf

you sir,are a hero...

Glad to help, post details if you build one.

Anything that gets a breeze blowing through the screens will work. The air does not need to be very warm. Do you think a solar chimney of some sort would work?
Even a near-flattened black-painted trash barrel with vents could function to create a breeze, though would only work in sunshine.

Martijn Stokkers : Do a Permies/Google search for - ' Dragon Heaters ' - They have a (proposed) Design gallery, showing a dehydrator/ clothes dryer cabinet
w/out any fans ! I think these sketches are there to gage future interest. But it gives you clear pictures of this drying compartment over top of a set of over -
sized ( My 'personal' opinion, Y.M.M.V. ! )"bells'' !

For the Future good of the Craft ! Be safe, keep warm ! As always/ your comments and questions are solicited and are Welcome ! PYRO-LOGICALLY Big AL !

Bump.

Has anyone built one? I quickly discovered I need something like this for drying acorns, apples, and others if I'm to succeed in my goal of supplying my own livestock feed. The weather in Vermont at harvest time is either gorgeous or ... not. I don't think solar is a great option in this climate.

Build your rocket mass heater in the house, then above the barrel (1 meter or so) have a drying rack suspended from your ceiling. You should be getting cooler temperatures (80 to 100 Celsius) with natural convection off of the barrel.

I need a stand alone outdoor unit.

Small stuff I can already dry in my oven - 3 racks in a commercial sized oven.

What if instead of putting the dehydrator after the stove, we put the stove after the dehydrator? Maybe the rockety-ness of the stove the air could provide enough airflow for some good dehydration? Just an idea...

Joe Braxton wrote:This might give you some ideas...


http://www.aprovecho.org/public/Publications/Still-The.Winiarski.Wood.Fired.Agricultural.Food.Dryer.pdf

Browsing this topic 5 years later, , I found the new link to the PDF:
http://aprovecho.org/?paybox_id=141

Hi Martijn,

Welcome to Permies and the world of rocket science!

If you want to design something to meet these parameters and want it be standalone, first you would need a very small rocket engine for it like say 3".  Then you need to run it into a mass that is in the base of the dryer.  I would suggest not even putting the bell into the dryer itself.  Use that for a small oven for baking bread or some other small heating application, perhaps to heat the shed that the dryer resides within.   By making the heater quite small and trying to capture that heat into a thermal mass in the dryer.  You would not be dealing with something that was getting excessively hot nor requiring an excessively long burn time to reach operating temperatures.  This is at the opposite end of the design scale from the rocket oven I am currently building (actually currently on hold) which I am hoping to achieve in excess of 1000 deg F (>500 deg C).

By not including the bell in the mechanism of the dryer you permit the burn temp to get to rocket temps (producing clean burn) without causing huge temp swings in the dryer itself.  With a minimal amount of experimentation you could figure out how often you would have to burn to maintain the range of temps you need for proper dehydration.  An alternative would be to employ a brick bell rather than metal as it would hold the heat without having the temp swings caused by a metal bell.

My steel drum cools down to quick ?

Wayne lawrence wrote:My steel drum cools down to quick ?

I am not sure if your comment was directed at what I had posted, but I realize that it may have.  My ref to metal or brick bells was not in regards to it cooling down, rather how quick it hers up and how much heat is radiated.  A brick bell does not dump so much heat out to the space where it is located as a metal bell does, but instead it stores most off the heat and slowly releases it.

Sincerely,

Ralph