Hybrid stoves are exactly what you described secondary air and a cat. And no it doesn't make cats last longer infact if done wrong it can seriously reduce cat life
It can work quite well if done correctly or as I said above they can eat cats in a hurry if done wrong
When I was looking at new stoves to replace my old Osburn, I looked at one manufacturer's hybrid cat. The cat was located just below the stove pipe collar. The combustion heat generated by the cat is sent right up the stove pipe. That was a no-go for me.
Anyone think we may start seeing more automated stoves, adjusting incoming air, flue temps?
For the record it wasn't blazekings idea. But yes I am surprised more cat stoves don't use thermostatic controls
I think my reasoning stands; If jacketing keeps the box hotter, more heat is going up the flue, unless that heat is moved into the room by a blower. I just mentioned it as an aside to begreen's post about his cast iron jacket evening out the temp swing vs. a radiant stove. I wasn't saying that jacketing was somehow bad, only that it can impact the delivery of heat to the room vs. up the flue, unless a blower is used to counter that. I figured I would throw that out there since this has turned into just another cat vs. non-cat thread.
Yep, my BIL's basement stove, a '79 VC Resolute III, has a thermostat.
So why do jacketed modern stoves easily run well with such lower flue temps? Do you think maybe the stove designers and engineers are purposely keeping firebox temps up in certain areas directing it exactly where they want it. Making for more complete combustion and lower clearances. And they then extract heat in other areas so you aren't wasting heat up the chimney.I think my reasoning stands; If jacketing keeps the box hotter, more heat is going up the flue, unless that heat is moved into the room by a blower. I just mentioned it as an aside to begreen's post about his cast iron jacket evening out the temp swing vs. a radiant stove. I wasn't saying that jacketing was somehow bad, only that it can impact the delivery of heat to the room vs. up the flue, unless a blower is used to counter that. I figured I would throw that out there since this has turned into just another cat vs. non-cat thread.
You saw an extreme example of the effect of jacketing with the Princess, where they also have jackets inside the box, and the stove on high can't match the heat delivered to the room by your Regency.
I actually have a bit of jacketing on my stove, a rear heat shield I added to keep radiation from being absorbed by my exterior masonry fireplace and chimney. There's no blower though, so I think some amount of the heat kept in the box is going up the flue.
How much heat is actually lost up the stack due to jacketing with no blower, I don't know. But as I said, I can swing open the trivets on the T5 and see the stove top temp drop 50 degrees. And the trivets aren't even solid, they are more of a grill, but still hold that much heat in the box. I will get the blower for my SIL's T5 soon..
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Yep, my BIL's basement stove, a '79 VC Resolute III, has a thermostat.
The main advantage I can see is that when the stove is in the coaling stage, the thermo will open and fire up the coals to keep the output up a bit, if no one is home to manually do that when needed. On my stove, I don't see a huge difference when opening the air on the coals, but it is appreciable. It will keep the stove top up around 300 for several hours, as opposed to the stove top drifting down to 250, then 200, over a longer period of hours.
When firing up the coal bed in my stove, the stove top holds at 300, and the sides also warm up more from the radiation directly hitting them. In a BK with internal shielding, maybe the warming of the side walls wouldn't be as pronounced, I don't know.
In average weather, even with my leaky house and suspect insulation, I don't often open the air on the coals since room temp remains within a couple degrees regardless.
Bottom line, grated ash-handling and other features were way higher on my list of priorities than having a thermostat was. It strikes me as just another red herring, like the chimney-clogging, no-heat-output low burn.
That's trying to apply soapstone logic to a steel stove. The heat radiates quite intensely off the steel body of the stove and the fact that the cast iron jacket an inch away absorbs that radiant heat does not slow down it at all. The firebox is tightly insulated to keep the fire as hot as possible. Once our stove is up to temp the stove top temp and digital probe temp are close to equal.
Couple of comments here. Thermal radiation heat transfer occurs between surfaces. The temperature difference between the surfaces is one factor that determines the amount of thermal radiation absorbed by the surface. The larger the temperature difference, the more thermal radiation is absorbed. The cast iron or steel jacket will be much hotter than the walls in the house, thereby decreasing thermal radiation to the jacket.
Yes, they concentrate heat in the top of the firebox, so that the tubes or baffle can burn the smoke better. They do that with firebricks in the box. I don't think that they are trying to concentrate heat in the stove with the shields. If they were, why would they put blowers on stoves? The shields are to direct blower air along the sides and top of the stove to extract heat from the box and distribute it into the room, not concentrate heat in the box.
I thought you said that when you ran both stoves on high, the Regency was able to raise room temp more quickly than the Princess? Both fireboxes had to be plenty hot, with flame burning in both. Granted, with the tubes burning the Regency box was probably quite a bit hotter, as was the top of the stove where secondary flame exits, as opposed to the top of the Princess box which is hot near the cat but not as hot as you get away from where the cat is.
I don't even understand soapstone logic..coefficients of heat transfer and all that jazz.
That's what I'm saying, the cast iron jacket isn't absorbing all of the radiation, some is reflected back to the stove. And you also point out that radiation transfer is less once the jacket is heated up, which makes sense..the jacket is radiating as well, back at the stove.
So which is it? Does the jacket raise temps in the firebox or not? I am confused what your theory is now.
I would say yes, the jackets reflect radiation back to the stove, increasing firebox temperature unless the blower is on, stripping that heat off the box.
On the Regency, I assume? And with both stoves cranked up, trying to recover room temp?
That doesn't explain why the unjacketed Drolet Austral has similar probe temps to jacketed stoves.
I think bholler may be on to something when he said that the jacket increases convective heat transfer.
Pointing out the Austral probe temps gave me an idea. I looked at the Drolet specs for the Myriad II and the Legend II. Both have identical firebox sizes and appear to be the same stove except the Legend has steel side jackets. Both come with a blower, but the forced air path does not include the side shield air gaps on the Legend. Both stoves are rated the same at 90K BTU output.
So we made the very first "hybrid" wood stove in 1983. It had secondary air delivered to the firebox separately from the air supplied to the combustor. Our experience was the stove did not burn any cleaner, but did increase production costs. (Read more expensive retail pricing as well)
