1. burn profile. 80,000 btus is nice, but sounds like a peak output that couldn’t be sustained for long. I’d be more interested in Woodstock's version of what Blaze King calls its real-world results: the “average†range of btus we can expect to see over a full burn-cycle, over a decent (10-12 hour) burn time.
Sorry but I do not have that information yet. Naturally one expects the peak temperature to hold for a short time and then very slowly decrease as the fuel is burned. We've found in the Fireview that we can hold well over 600 for quite some time and, of course, this depends upon the fuel.
2. specific expectable burn time. 16 hours sounds good. And other Woodstock owners suggest that their figures can be believed. But can they be more specific? How long could we expect the stove to go, damped down and with a full load of decent hardwood, maintaining a surface temperature of 300 or greater?
We will probably not know until feedback is received from the first buyers. My wife and I will plan on keeping some good records and providing feedback to Woodstock. For sure we would expect greater than 300 degrees though and would look more at 400 or above.
3. does the introduction of the secondary burn element increase the risk of run-away fires? That seems to be one disadvantage of non-cat stoves: it can be tricky to get the air mixture right when burning high enough to engage secondary combustion.
No.
4. what is the current thinking about thermostat options? Todd posted from an email he received from Woodstock:
"One of our suppliers now makes a damper operator that runs on a couple of thermocouples and looks interesting. It could close a damper to prevent over-firing, or it could open a damper to prevent oxygen starvation. It looks interesting. Separately, we developed an algorithm that controlled a damper and a fan to pressurize the secondary air and was driven primarily by an O2 sensor. We have applied to EPA for an SBIR grant for a related project. One of these last two is more likely the direction we will go in."
These all sound great--any idea when one or the other might be available? And what difference in stove operation would they expect it to make?
Indeed this is something that is presently being worked on and will soon be available (hopefully in the next couple of months). Of course the difference would be a more controlled fire with less input from the operator. Only time will tell if it will mean longer burn times but I would expect that to be the case.
5. control of burn at low air settings. One of the trademark advantages of cat stoves. Todd's email also included the information that
"the new stove has a “butterfly†damper: the butterfly has very good control of the burn rate at low firing rates."
This degree of "control" sounds great. Could they elaborate on how exactly it works? Is there similar control at higher burn rates?
I will be posting a video showing what happens. Tom and I had been discussing this and some folks walked up behind us (we were sitting in front of the Progress). I heard them talking and nudged Tom to go adjust the draft control. He did and the stove went from looking like the Pits of Hell to the flames lifting off the wood and holding at the top of the stove. Unfortunately I did not take the time to test this and watch if there was a change in stove top temperatures but you should have heard those people with the "Oh's" and "Ah's" behind us. Everyone loved it. For sure I would think this would have to give longer burns as the fire was completely off the wood and not burning so strongly. It may raise the stove top temperature though but probably decrease the total btu output.
6. related question about over-heating. Blaze King and Fireview owners often report being able to control the heat output so that, even with a full load, the stove can be kept from blasting you out of the room. From the Blaze King manual:
Many new woodstove users hesitate to load enough wood to sustain a fire, fearing that a full woodstove automatically means a hot fire. The combustion air control, set at the lowest air control setting, permits a low fire even with the firebox full. . . . The stove can be FULLY loaded without increasing the heat output. The fire will simply burn longer.
This again sounds like an extremely desirable level of control: to be able to load all the way up and not necessarily get burned out of the room. Can the Progress do this?
Yes.
7. how the two burn technologies work together. Here's what the post in the blog says:
"at a medium burn rate, the secondary flames and catalytic combustor alternate depending on the conditions in the firebox."
Do they really "alternate"--i.e. switch back and forth? Or do they cooperate, so that both are functioning at the same time, and it's possible that some smoke might be captured by the secondary air and some, at more or less the same time, by the combustor?
The cat will burn what the secondary will not so I would call this cooperation rather than alternate, although it can be controlled somewhat by the draft.
8. trade-offs. What, if any, compromises the two systems have to make in order to work well together. The blog says:
"the Progress will automatically deliver unused secondary air to the combustor at lower burn rates, or allow the air to combine with gases in the firebox at higher burn rates for a spectacular secondary burn."
Is delivering unused secondary air to the combustor going to reduce the efficiency of the combustor at low settings? Or is it just what you want to help the combustor deal with all the smoke that's being generated during a smoulder?
Lots and lots of pics from all angles! Did I mention pics :ahhh:
Most of the immediate energy will be directed to the Progress but hopefully the new things will slowly be released. If I hear more it will be posted.
