Has anyone used the Woodmiser product for wood burning stoves?

zeupater

cairndog wrote: »

Thanks zeupater, we are doing things you suggest but not able to identify wood but it does seem very dense. Our log storage is good and eventually this lot will improve. In desperation I have sent for a moisture meter so will see whether it helps and we are splitting larger logs (very dense!) to try and make them easier to ignite. Have also tried briquettes but they collapse if touched so can't be mixed with anything else and burn out too quickly.

Hi

Smaller logs will have a higer surface area to mass ratio and will therefore dry quicker so that's really the best you can do at the moment .... if you are having trouble lighting the fire - how are you laying the fire and how are you selecting the logs to burn first ?

Z

Holdcroft

If you Google for CoalMiser, you'll come across a few links that make the claims seem genuine to me. I'm a new forum user, so I can't post links, but you can do your own Googling and choose the following links:

• From shellspringboard.org: Winning Idea - CoalMiser
• From nottingham.ac.uk: Coalmiser - University of Nottingham
• From theengineer.co.uk: Material sustains burning fires | News | The Engineer

whasup

Of course a log produces X amount of heat and no contraption will make it produce more. A problem with any heat producing appliance is getting the heat to exactly where you want it when you want it. Any heat not in the right place at the right time is wasted. In the analogy of the fireplace the heat is only useful for as long as it stays within the firplace opening. Once in the chimney that's it really - gone. So a roaring fire with licking flames is wasting heat up the chimney. A slower burn with no flame is much more efficient - if a little less satisfying. So it is possible that this device may well improve the efficiency of log burning just by holding the heat in the fireplace longer. I wonder how long these things last. If it's made from steel mesh I can't see it being that long.

whasup

Meant to say that it is a shame when these companies don't quite give you all the information. I would have thought it fairly easy to properly test and explain the process behind the thing. So it makes you wonder why they don't? And why didn't they have it tested by an accredited ukas type organisation? Not doing these things only raises suspicion.

wuthton

whasup wrote: »

Meant to say that it is a shame when these companies don't quite give you all the information. I would have thought it fairly easy to properly test and explain the process behind the thing. So it makes you wonder why they don't? And why didn't they have it tested by an accredited ukas type organisation? Not doing these things only raises suspicion.

The wonderful benefit of the Internet is that crappy products are soon flagged up for those that can be bothered to search.

zeupater

whasup wrote: »

Of course a log produces X amount of heat and no contraption will make it produce more. A problem with any heat producing appliance is getting the heat to exactly where you want it when you want it. Any heat not in the right place at the right time is wasted. In the analogy of the fireplace the heat is only useful for as long as it stays within the firplace opening. Once in the chimney that's it really - gone. So a roaring fire with licking flames is wasting heat up the chimney. A slower burn with no flame is much more efficient - if a little less satisfying. So it is possible that this device may well improve the efficiency of log burning just by holding the heat in the fireplace longer. I wonder how long these things last. If it's made from steel mesh I can't see it being that long.

Hi

I see this so many times ... a log burner controls the amount of air entering the burn, this controls the oxygen available for combustion. At high temperatures the log surfaces 'evaporate' away to become volatiles which, in the absence of oxygen and flame, simply exit the combustion chamber and go up the chimney, some condense on the cooler lining creating a tar-like substance, but most just get carried away. To achieve an efficient burn there must be enough oxygen available to allow the volatiles themselves to combust, else you're just wasting unburned fuel ..... a slow meandering dark red & blue flame is what you're really looking for, one which ignites well above the fuel source.

HTH
Z

grahamc2003

whasup wrote: »

So a roaring fire with licking flames is wasting heat up the chimney. A slower burn with no flame is much more efficient - if a little less satisfying. .

No, I'm sorry that's completely incorrect. If you are just smoulering wood by choking the air supply, you won't be getting anything like complete combustion, and likely producing little heat and lots of carbon monoxide which of course can be a danger as well as inefficient.

In any burning, what you ideally want stoichiometric combustion - that is the amount of oxygen being excatly the amount required, and no more, for complete combustion (when you produce co2, not co). The volatile gasses released from the heated fuel need to be above the flash point in order to produce the chemical reaction (of the hydrocarbon and oxygen being converted to water and co2 in an exothermic reaction. Too low a temperature and a lack of air to cause smouldering is exactly what you don't want, with smoke being emitted, being basically the fuel you've paid for (unburnt hydrocarbons) plus various amounts of co2, co and water. You have got to have hot gases escaping up the chimney otherwise there'd be no oxygen supply to the fire - the key to efficient burning is to get the flow correct so just the correct amount of air is flowing through the fire (which, incidentally, you can't do with an open fire).

celerity

When I pack my woodburner with wood, I open the airvent to max and the whole stove becomes a flaming inferno of yellow / orange fire. Is that not the best idea?
The only time I get zeupater's dark red / blue flames is when the logs burn down to glowing charcoals. But if I put more wood on top of that I will get yellow flames again.

/\dam

whasup

grahamc2003 wrote: »

No, I'm sorry that's completely incorrect. If you are just smoulering wood by choking the air supply, you won't be getting anything like complete combustion, and likely producing little heat and lots of carbon monoxide which of course can be a danger as well as inefficient.

In any burning, what you ideally want stoichiometric combustion - that is the amount of oxygen being excatly the amount required, and no more, for complete combustion (when you produce co2, not co). The volatile gasses released from the heated fuel need to be above the flash point in order to produce the chemical reaction (of the hydrocarbon and oxygen being converted to water and co2 in an exothermic reaction. Too low a temperature and a lack of air to cause smouldering is exactly what you don't want, with smoke being emitted, being basically the fuel you've paid for (unburnt hydrocarbons) plus various amounts of co2, co and water. You have got to have hot gases escaping up the chimney otherwise there'd be no oxygen supply to the fire - the key to efficient burning is to get the flow correct so just the correct amount of air is flowing through the fire (which, incidentally, you can't do with an open fire).

You carry on with your raging flame if that's what you want. I'll stick with my nice hot glow.

zeupater

celerity wrote: »

When I pack my woodburner with wood, I open the airvent to max and the whole stove becomes a flaming inferno of yellow / orange fire. Is that not the best idea?
The only time I get zeupater's dark red / blue flames is when the logs burn down to glowing charcoals. But if I put more wood on top of that I will get yellow flames again.

/\dam

Hi

Do you have a stove thermometer and do you burn with a deep ash bed ? .....

We start up the fire the same way, both airvents open (bottom & doorwash) and get the skin temperature to 500F, then close the 'through bed' vent and adjust the doorwash to a position to maintain the burn.

The fire was last partially refuelled about 1 hour ago and currently has a skin temperature of 450F with a combination of blue/dark orange/dark red flames at the top of the combustion chamber, probably about 4" to 6" above the fuel, the only bright flame is at the end of one log ... the flames are winding their way around the chamber as if in slow motion, seeming to almost dissappear then reappear again as the balance between combustible volatiles and available oxygen changes .... I've just checked and there is absolutely no sign of smoke from the chimney. The fire has a deep ash bed which supports a good hot burn and holds the heat in buried charcoal well overnight, allowing easy lighting the next day, paper, wood, open vents ... fire (usually no need for a match after 10hrs-12Hrs). We tend to add logs when the skin temperature has dropped to 350F-400F and there is just the glow of charcoal, or at the stage before this temperature drop when the main flames in the chamber have stopped and you have thin blue flames in amongst the red charcoal glow. Refuelling is simply add fuel, open the airwash completely and the through bed vent enough to heat up the ashbed and charcoal to a bright orange before closing it down again, and then adjust the airwash (in stages) back to it's normal (balanced) position when the new fuel is burning well and/or the skin temperature is 450F-500F again ....

HTH
Z