Compare the Squares
I think a vertical cylinder stove with round horizontal baffles (using Efficient Solid Fuel Burning Appliance design technology), would be a superior design. The following is the basis for my hypothesis.
It can be seen with the baffles in Dakota Stove being horizontal and only having a very narrow gap between the baffle and fire box, the bottom baffle absorbs heat (radiant and convection) then reflecting the heat back to the fire, it will slow down the rate of convection. Then slow the rate that combustion gases are exiting the combustion area, possibly making a more efficient burn rate.
The baffle in Dakota Stove is horizontal. That slows down (slowing down would imply some increase in compression) the rate combustion air is allowed into the stove and the speed of combustion. With the small gaps total surface area equal to the whole inside circumference of a cylinder, plus the whole outside circumference of the baffle plus the vertical height of the area that maximizes convection , that surface area is quite large. With each baffle you increase the vertical height area that convection is maximized.
Most fluids, especially liquids, are transported in circular pipes and for most internal combustion engines cylinders are, circular cylinders. Cylinders can with stand large pressure differences between inside and outside without undergoing any distortion BUT that does not even take into consideration preventing distortion and warping from high amounts of heat. Dealing with extreme temperatures is/should be the same as dealing with extreme pressures.
When looking at already available data for shapes and formulas for plane walls, cylinders, and spheres the math (some is above my skills) you can apply Nusselt Numbers of fully developed laminar flow in circular tubes and rectangular channels, natural convection heat transfer coefficients, Nusselt number for natural convection over surfaces, transient temperature charts known as Heisler charts, and view factor relations, and some I missed.
The magnitude of radiation heat transfer, in general, is comparable to the magnitude of natural convection heat transfer. And the rate of heat transfer increases relative to the vertical orientation. Some stoves have a baffle at an angle. A box shaped stove with a baffle at an angle, equals fast convection.
To me, the math does not add up for a box or horizontal cylinder heating appliance.
Additionally, a poor firebox design does not burn fuel correctly. Softwoods have more energy than hard woods but some stoves burn softwoods very fast. I can only think of one way to slow combustion down to maximize the energy content and extraction of heat before it is in the atmosphere.
This is an excerpt from:
Wood As An Energy Resource,
David A. Tillman,
1978 Academic Press
Page 69, last complete paragraph
” Table II presents the ultimate analysis of numerous wood fuels on a dry weight basis. The Btu/lb values presented are higher heating values. These data demonstrate generally that wood is a highly oxygenated fuel with about two-thirds the energy content of coal. SOFTWOODS GENERALLY CONTAIN MORE ENERGY THAN HARDWOODS on a dry weight basis due to higher lignin (hence carbon) content plus the presence of more resins in the extractions .”
I have reason to believe the more water in a tree when alive, the more hydrogen in the tree when dried and seasoned. But, you have to control the rate of combustion air and the rate of combustion to release the energy over an extended time period.
I obtained information from “Heat Transfer: A Practical Approach” 2nd Edition, Yunus A. Cengel, 2003 McGraw-Hill
Efficient Solid Fuel Burning Appliance design technology – Patent Pending
The Best Wood Stove
Before I say my choice, I will say the best stove and cleanest burning really is a stove that has completely dry/seasoned wood in it. The best stove in the world is almost junk with 50% water content in the fuel. Testing with an EPA/UL certified equivalent company does not make a customer burn with more knowledge. I have learned just as much about the fuel that goes into a stove as I have about the importance of the shape of a stove.
People need more education about the fuel they are burning.
I have yet to see any stove with the shape or baffle system as Dakota Stove. Dakota Stove is only one example of the application of the patent pending technology.
Dakota Stove or a stove with Efficient Solid Fuel Burning Appliance technology could build a catalytic style stove and match (maybe beat in efficiency/EPA) other stoves with a catalytic design. A catalytic stove would cost more and have more maintenance than a non-catalytic stove, I believe.
I am not trying to offend any one but I am trying to promote my heating appliance advancements. I think it is substantial. Why not have a heating appliance that uses less fuel, gives off more heat, and should/could require less material to build compared to a similar BTU rated stove. With the baffle advancements – flue temperatures are lower and the chance of a chimney fire is much lower and predict, they could be eventually eliminated completely.
Round For A Reason LLC