A SERIOUS OVEN FOR RENEWABLE FUEL

[Vernon Smith]

Seasons greetings everybody.
As some of you old forum hands might know, I am a renewable energy consultant (one of many hats I wear) in the Solomon Islands. Anyway, I am also known to breed and raise seriously large pigs and cure seriously large hams of up to 12 kg each. The question is, how do you roast seriously large pieces of pork ar ham with a low carbon footprint?

My answer is to make a large oven that is heated by fire wood. I confess this would not be much use in a bed-sitter but for those out door activities in warmer climes or even our famous English summers it works suberbly.

I found a disused 45 kg LPG cylinder and took it to a local sheet metal works to have the oven welded up from 2mm steel plate (one 8 ft X 4 ft sheet did the job) and off cuts of 1.1/2 inch pipe. Steel plate is expensive here in the Solomons but the whole job still only cost me a little over �60.00 and it will last for years.

The drawing appears below. If anyone would like the original as a Visio file or in pdf format let me know and I will email it. It will take a whole pig carcass up to 30 kg dressed weight but don't use it solely for pork and other meats, it works equally well for tandoori food, pitta, pizza and any other form of bread and cakes. It roasts 24 chickens at a time and no doubt many other uses I haven't tried or thought of yet .

I would welcome any feed back or innovative thought from members that give it a try. I have the drawing for a draught control damper that sits at the front of the firebox if anyone wants that too.

[Lee]

Here's some feedback, can I come visit?!?

[Vernon Smith]

Of course Lee, come and visit any time. It will be an excuse to off another porker and have a huge roast.
Cheers,
Vernon

[Coote]

What a great post!!! Very interesting.

I guess there is no shortage of fuel on the Solomons. So there is probably no immediate need to be looking into 'frugal' woodburners like the rocket stove and solar cooking. I quite often cook using rather primitive methods and the whole subject 'flicks my switch'. Here is a link if anybody is interested:

http://www.bioenergylists.org/

Your steel oven is simple and effective....and should be fairly bullet-proof for a few years at least. Great idea.

[porker]

Any pics of it in use? Thanks

Cheers

[Wal Footrot]

Vernon - this question might help you answer your own.

This question was asked by a student at our school of their science teacher who was in the process of teaching all the kids about 'climate change'.

"If carbon dioxide is heavier than air then how does it get up into the upper atmosphere to cause global warming?" She couldn't give a satisfactory answer.

I've yet to talk to a single 'greenie' who can answer that question. In other words, forget about the carbon footprint issue - it's mostly a specious load of codswallop!

[Oddley]

Hi Wal

Wow I found the question asked very provoking. as I'm not a scientist and had never thought of it that way.

The atmosphere is made up of approx 99%, Nitrogen 78%, Oxygen 21%, I'm not really interested in getting in controversy of decimal points.

I've had a look at the periodic table and this is what it reveals.

http://www.corrosionsource.com/handbook/periodic/

Nitrogen

Atomic Weight: 14.00674

Nitrogen makes up 78% of the air, by volume. The atmosphere of Mars, by comparison, is 2.6% nitrogen. From an inexhaustible source in our atmosphere, it can be obtained by liquifaction and fractional distillation.

Nitrogen molecules give the orange-red, blue-green, blue-violet, and deep violet shades to the aurora.

Oxygen

Atomic Weight: 15.9994

A gaseous element, oxygen forms 21% of the atmosphere by volume and is obtained by liquefaction and fractional distillation. The atmosphere of Mars contains about 0.15% oxygen. The element and its compounds make up 49.2%, by weight, of the earth's crust. About two thirds of the human body and nine tenths of water is oxygen.

So going on the intimations of your questioner, There would be layers of gases according the molecular weight of the gas. On Earth therefore there would be approx 2 Km of pure Oxygen the approx 4 * that height of Nitrogen, then other lighter gases.

I think the sea would be a good analogy. The sea is a composition of water salt and even heavy metals ie: Gold, Lead mercury, etc, and yet we only see very dilute layers of these materials why? because of the natural forces of earth wave motion churning these ingredient together and the natural ability of water to hold very small particles in suspension.

I think the same could be said of the atmosphere with the churning effect of the weather. So don't be too hard on the science teacher. I think I would have struggled to answer, without a few minutes to reflect.

[Ianinfrance]

Sorry Wal, but the answer is a matter of O level physics.,

"If carbon dioxide is heavier than air then how does it get up into the upper atmosphere to cause global warming?" She couldn't give a satisfactory answer

Then the teacher shouldn't have been teaching the subject.

and the answer is twofold "Brownian motion" and "atmospheric turbulence. Gases aren't immiscible, they consist of molecules hurtling around at very high speed and therefore mixing up. So although the ratio of different gases does vary slightly, depending upon the height in the atmosphere, it is largely homogenous. Think of fluoro-chloro-carbons, these are FAR denser than the oxygen/nitrogen mix that makes up most of the atmosphere, yet the evidence - in the depletion of the ozone layer, is that these gases get right up to the high stratosphere, (about 20 kms up). If these gases get up there, then there's no earthly reason for CO2 not to. However, that's not the point. Increasing levels in CO2 in the atmosphere tend to reflect more heat back (greenhouse effect) at no matter what height it is to be found. And don't forget that much of the problem over the "carbon footprint" is due to the release of CO2 in the high atmosphere by hairyplanes.

Deary me.

[Lee]

Sorry Wal, but the answer is a matter of O level physics.,

"If carbon dioxide is heavier than air then how does it get up into the upper atmosphere to cause global warming?" She couldn't give a satisfactory answer

Then the teacher shouldn't have been teaching the subject.

and the answer is twofold "Brownian motion" and "atmospheric turbulence. Gases aren't immiscible, they consist of molecules hurtling around at very high speed and therefore mixing up. So although the ratio of different gases does vary slightly, depending upon the height in the atmosphere, it is largely homogenous. Think of fluoro-chloro-carbons, these are FAR denser than the oxygen/nitrogen mix that makes up most of the atmosphere, yet the evidence - in the depletion of the ozone layer, is that these gases get right up to the high stratosphere, (about 20 kms up). If these gases get up there, then there's no earthly reason for CO2 not to. However, that's not the point. Increasing levels in CO2 in the atmosphere tend to reflect more heat back (greenhouse effect) at no matter what height it is to be found. And don't forget that much of the problem over the "carbon footprint" is due to the release of CO2 in the high atmosphere by hairyplanes.

Deary me.

I was going to give the rather flippent answear of 'Wind', but thats better explanation

[Wal Footrot]

Sorry Wal, but the answer is a matter of O level physics.,

"If carbon dioxide is heavier than air then how does it get up into the upper atmosphere to cause global warming?" She couldn't give a satisfactory answer

Then the teacher shouldn't have been teaching the subject.

and the answer is twofold "Brownian motion" and "atmospheric turbulence. Gases aren't immiscible, they consist of molecules hurtling around at very high speed and therefore mixing up. So although the ratio of different gases does vary slightly, depending upon the height in the atmosphere, it is largely homogenous. Think of fluoro-chloro-carbons, these are FAR denser than the oxygen/nitrogen mix that makes up most of the atmosphere, yet the evidence - in the depletion of the ozone layer, is that these gases get right up to the high stratosphere, (about 20 kms up). If these gases get up there, then there's no earthly reason for CO2 not to. However, that's not the point. Increasing levels in CO2 in the atmosphere tend to reflect more heat back (greenhouse effect) at no matter what height it is to be found. And don't forget that much of the problem over the "carbon footprint" is due to the release of CO2 in the high atmosphere by hairyplanes.

Deary me.

I was going to give the rather flippent answear of 'Wind', but thats better explanation

No, that's methane