Hi Wyomiles,
Thanks for the links. I've been reading and watching a lot more about it tonight.
I would need more information to be able to make a small testing model.
I'm looking for detailed like the length of the exhaust pipe, the measure of the burning chamber or of the space between it and the top of the barrel.
But as I want to adapt it for hot water heating, I think that I need more general info than a building plan for one specific model.
The "fire science" post of Erika Wisner is very instructive.
The "fire science" dvd of "wood burning stoves 2.0" should probably be very complete (they talking about math
) but it's only coming out later this year.
As I understand, the burning chamber should be left a the higher temperature possible (in order to burn all the gas left).
The water exchanger should be out of the exhaust gas, to prevent corrosion.
Here a splendid drawing of a first idea. In blue the water exchanger. Red the mass in the combustion chamber. Yellow insulation.
What I would need are :
- General infos about the measure of a RMH
Do you know if I could find this in the book (rocket mass heater) sold on Erika & Ernie site, or in one of their building plan, or any where else ?
- Infos about the differents temperatures along a RMH system. From combustion chamber to exhaust pipe.
I suppose I've to take a lot of the heat but not to much to prevent disturbing the draft.
A first thing I could share about the problem of boiling water. I use two things :
- one good "pressure valve" which would open at 2.5 bars. It would prevent any explosion of the system but not boiling water (which could damage the RMH just by movement and high dilatation of the exchanger pipes)
- one double (for security) "temperature valve", this one open when the temperature of the exchanger goes up to 95°C (water boil at a bit more than 105°C at 1.5 bars pressure)
at the entrance of the exchanger is a "pressure valve" which let cold water flow through if the pressure goes under 1.00 bars.
So, if you have a problem with the system (electrical failure of the pomp, to much heat in the RMH when your buffer tank is already very hot) the "temperature valve open" and release hot water (outside) : the pressure drop.
When under 1.00, the second pressure valve let cold water come in the exchanger and cold it.
I've been experienced this home once and at my clients (6 times) and it works perfectly. Even if it is quite impressive.... imagine a 250kg boiler starting to boil...just a bit.
Finally, do you know if any one as already make measure of the quality of the air at the exit of the exhaust pipe ( temperature, CO measure, CO2 measure, O2 measure, NOX measure) ?
Damien
