new here with questions about Osburn 3300 vs 3500 and Chinook 30.2

[ABMax24]

You forget.thay the interaction time.of air and stove top decreases linearly with increased flow speed.

Here's the math should you want to do it, the heat transfer coefficient increases with airflow. It's the exact same reason that car radiators have fans in them, because increasing air flow increases heat removal.

I'm fine agreeing to disagree on this, but you're going to have to re-write engineering textbooks to prove yourself right.

Convective Heat Transfer

Heat transfer between a solid and a moving fluid is called convection. This is a short tutorial about convective heat transfer.

www.engineeringtoolbox.com

 

[bholler]

Suggesting that (with the princess, because Tstat) the stove simply burns thru the wood faster,.but not necessarily that more energy per pound burned is transferred into the room.

So where do you propose those BTUs are going if the stack temps don't change noticably?

 

[stoveliker]

I'm sorry, but The dT there is between air and stove top. And that one goes down when the fan is on.

(I also wonder whether the speed is even in the range of validity of this empirical relation.)

Finally, going from zero to 2 m/s, you can't say anything from this curve about what's happening. It's extrapolating an empirical curve beyond its validity.

I'll leave it at this as I disagree. But this won't be resolved here before I get my college books on this out again. And that's not going to happen anytime soon.

 

[stoveliker]

So where do you propose those BTUs are going if the stack temps don't change noticably?

In the room. Simply because the Tstat opens more as evidenced by the shorter run time.

The blower only makes the stove work faster thru the load (because Tstat) but does not extract significantly more heat, just extracts the same in a shorter time.

Regardless, have a good evening.

 

[bholler]

In the room. Simply because the Tstat opens more as evidenced by the shorter run time.

The blower only makes the stove work faster thru the load (because Tstat) but does not extract significantly more heat, just extracts the same in a shorter time.

Regardless, have a good evening.

So you are saying that simply by turning the fan on more heat is extracted from the stove causing the thermostat to open further to maintain stove temp. But the fan doesn't increase heat output??? I am not following that train of thought.

 

[stoveliker]

Not more heat output per pound of fuel is what I said.

Per hour, yes. But a shorter run time.

 

[bholler]

Not more heat output per pound of fuel is what I said.

Per hour, yes. But a shorter run time.

No one ever said fans made more heat per pound of wood. Just that fans help extract more heat from the stove. Which you just agreed with.

 

[stoveliker]

Fundamental difference.per pound it per hour.
And, so does inching up the Tstat... (the per hour, certainly not the per pound).

 

[stoveliker]

Because fans are a rather expensive solution to take the place of opening the air supply. And if one is running full throttle and can't open upthe air more, then it's best to buy a higher BTU output stove. That is why I remarked that earlier to the OP, and gave the example of me not needing to run full throttle in my home (so she can compare).

 

[ABMax24]

No one ever said fans made more heat per pound of wood.

I'll venture out and say that. If burn rate is being held constant, fans/blowers increase the amount of heat extracted per pound of wood. Which effectively increases the efficiency of the stove.

 

[bholler]

Fundamental difference.per pound it per hour.
And, so does inching up the Tstat... (the per hour, certainly not the per pound).

But without the thermostat the fans on the regency dropped flue temps. The fan is extracting more heat from the stove. On a thermostatically controlled stove the thermostat will open up maintaining the same stove temp. That will shorten burn times. On non thermostatic stoves it won't shorten burn times.

The debate isn't about efficiency or burn times or anything other than the fan and whether it extracts more heat off the stove or not

 

[bholler]

I'll venture out and say that. If burn rate is being held constant, fans/blowers increase the amount of heat extracted per pound of wood. Which effectively increases the efficiency of the stove.

Very possibly yes. On the regency I would say it did. By lowering flue temps at the same burn time efficency has to have increased.

 

[bholler]

Because fans are a rather expensive solution to take the place of opening the air supply. And if one is running full throttle and can't open upthe air more, then it's best to buy a higher BTU output stove. That is why I remarked that earlier to the OP, and gave the example of me not needing to run full throttle in my home (so she can compare).

And a bigger stove isn't a rather expensive solution as well?

 

[stoveliker]

And a bigger stove isn't a rather expensive solution as well?

Oh, come on. There are many stoves out there that have a higher output than the Chinook, but cost less.

I sure hope you are not advising a stove to someone if it would only satisfy the heating output needs when a fan is used to boost the speed with which the stove chews through the fuel.

A fan is useful to spread heat thru a room or more. But arguably that can be done with other fans that cost less than special ones that fit on a particular stove. I believe we didn't really get the layout of the private quarters of this building to make the call that this would be needed.

 

[bholler]

Oh, come on. There are many stoves out there that have a higher output than the Chinook, but cost less.

I sure hope you are not advising a stove to someone if it would only satisfy the heating output needs when a fan is used to boost the speed with which the stove chews through the fuel.

A fan is useful to spread heat thru a room or more. But arguably that can be done with other fans that cost less than special ones that fit on a particular stove. I believe we didn't really get the layout of the private quarters of this building to make the call that this would be needed.

But you clearly stated that a fan does infact pull more heat off of a stove correct? And no I wouldn't recommend a stove that needs a fan all the time. But I will recommend a fan for those times when someone needs a little more heat.

And as I said before a fan only decreases burn times on thermostatically controlled stoves. Considering I don't sell any of those my recommendation of a blower won't make the stove burn through wood any faster at all.

 

[moresnow]

@stoveliker Just out of curiosity. How much time/data have you personally accumulated using a BK with the factory blowers installed?

The factory fan setup makes a huge difference in overall heat distribution in the BK equipped homes I am around. I have operated a BK with and without factory fans in my home. I would not have or recommend these stoves without the blowers. My RWE for what it's worth.

 

[SpaceBus]

This last page and a half of arguing about fans is probably not helpful for the thread. @begreen can you make it a separate thread? I find the data and debate interesting, so I don't want it to disappear.

 

[BKVP]

To the OP, next time I'll just send you a PM.

 

[bholler]

This last page and a half of arguing about fans is probably not helpful for the thread. @begreen can you make it a separate thread? I find the data and debate interesting, so I don't want it to disappear.

I will do it later if he doesn't get around to it by then

 

[EbS-P]

actually.... funny you should mention that. I have a VaporFire 100 sitting unused in my basement for the past 5 years. The story of why is long and frustrating. At the time I bought it, I was still running retreats and having regular gatherings here and needed a way to more easily heat the first floor bar, kitchen, and owners quarters in a less back breaking, economical, and eco-friendly manner (I have two LP gas heaters for the kitchen and bar) . Plus, I didn't live here full time so I would drain the house for weeks at time in winter ... and then quickly fire it all up again for family weekends or large gatherings. I wated a non-liquid heating system to replace the gas heaters, and since I was already running one woodstove, the VF seemed the best solution. However, a retrofit installation ended up being quite complicated and expensive and basically made the basement unusable. My partner at the time was overseeing it all, but finishing projects and making decisions was not his strong suit, so the VF sat there for years waiting for the perfect solution. Now that I live here full time, geothermal seems like a much better way to go and will give me freedom to go away for a few days or a few weeks worry free. I am also EXTREMELY sensitive to low frequency fan hum. I love the silence of the woodstoves. Furnaces and fan noise in general usually drive me nuts. The dry blown heat of a furnace plus fan noise plus expensive and complicated duct work means that I now have the unused VaporFire sitting in my basement. Can I interest anyone in a VF100 furnace?

Guests and wood stoves present a challenge I have been trying to think about. I just installed a Drolet insert. It’s made by the same company as Osborn but it’s a bit cheaper. I’m impressed by the quality. My thoughts are these. If my guests are going to use it it needs to be simple. I agree no cat. Radiant over convective but that’s just a preference. And an Auber AT200 temp alarm to have their and your back when they/you are not paying attention. I’d stick with 6 inch new stoves just because it gives lots of options. Firebrick interior over refractory for the cheaper replacement cost. Secondary tubes and vermiculite baffle over all stainless for the same reason. Over fire a tube stove once or twice a tubes may warp easy cheap fix. Stainless Baffle is 10x the cost. Bigger is better to a point. Bigger will consume more wood. I keep think 10 cords Monogrammed suuggies for your guests Anything to make that physical work more manageable helps. 100$ discount for every cord they split and stack.

Evan

 

[bholler]

Guests and wood stoves present a challenge I have been trying to think about. I just installed a Drolet insert. It’s made by the same company as Osborn but it’s a bit cheaper. I’m impressed by the quality. My thoughts are these. If my guests are going to use it it needs to be simple. I agree no cat. Radiant over convective but that’s just a preference. And an Auber AT200 temp alarm to have their and your back when they/you are not paying attention. I’d stick with 6 inch new stoves just because it gives lots of options. Firebrick interior over refractory for the cheaper replacement cost. Secondary tubes and vermiculite baffle over all stainless for the same reason. Over fire a tube stove once or twice a tubes may warp easy cheap fix. Stainless Baffle is 10x the cost. Bigger is better to a point. Bigger will consume more wood. I keep think 10 cords Monogrammed suuggies for your guests Anything to make that physical work more manageable helps. 100$ discount for every cord they split and stack.

Evan

Well said. The only thing is it takes way more than one or 2 overfires to warp tubes or stainless baffle

 

[BKVP]

Several years ago a consumer sent me (which I have since misplaced) a single 1/2 page operating instruction sheet for visitors to their cabins. He actual had it laser cut into a piece of stainless and then a black painted background sheet of 18 gauge. He made it out of metal so with abend at the bottom it stood up on top of the stove.

He had, as I recall, 6 cabins and had six signs made. Very cool looking. The top of the page" said, "THIS SIGN IS HOT". You could not avoid seeing it and because it was hot, it didn't get moved. He said it helped tremendously.

 

[begreen]

Stainless Baffle is 10x the cost. Bigger is better to a point.

What is this in reference to? Can you provide some specifics? Stainless tubes do not commonly go unless the stove is being pushed very hard over a long period of time. Same for stainless baffles except in some of the oldest Drolets, but their baffles were not replaceable. With normal use a PE stainless baffle may last the life of the stove. Pricewise a replacement tube can be $60-100, while a PE baffle kit was about $350 last time I checked, but that would be the equivalent of replacing all 3-4 tubes or $180-400.

 

[EbS-P]

If you had to buy new tubes and vermiculite vs a whole stainless baffle assembly.. 10x is probably an over estimate but I bet is greater than 5x . Thinking of prices for my F400 or new f500 assembly vs baffle and tubes for my Drolet . Again just thinking worst case.

I agree it’s going to take a lot of abuse to get to this point but.

 

[begreen]

A lot of abuse is going to eventually get expensive for any stove. A warped bypass assembly can be very expensive to fix on some stoves.

A set of Drolet tubes will be $180. The F400's stainless baffle is about $350 or 2x.