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jmthunderbirdturbo
jmthunderbirdturbo HalfDork
12/28/17 2:00 a.m.

let me ask this then:

 

I have a fairly large fire box. Its roughly 4ft wide, 3 feet deep, and 43 feet tall. It's a Fisher two door cast iron behemoth. 

 

Is there a good way to regulate wood fed into the fire? something I could weld up that would feed logs from one side of the box (well call it the cold side), to an area where the fire actually is (well call it the hot side). If I could set it up to get good and warm in the house, then load this 'widget' up with logs and go to bed, where they will feed the small fire over a 4 to 5  hour period, then I would still be above central heat setting at dawn. The issue I have now, is even if I load this pig to the brim with wood, I just get a big ass fire, it gets up to 85 degrees in the house, then after about 3 hours, its all coals. I need a way to slow the burn...

 

-J0N

Apexcarver
Apexcarver PowerDork
12/28/17 2:33 a.m.

Heres my cheaper solution...

 

Install pellet stove in basement

 

Replace thermostat with unit that allows you to regularly recirculate air in the house without kicking in its own heat source (mine does recirc intervals as well as just heat/cool)

 

When installing the pellet stove, to prevent the backbreak of lugging the pellets down, install a 5 inch PVC chute that leads to a bin in the basement near the stove installation. Make large funnel for 5 inch PVC inlet, and have a screw in cap when not filling. (and stash the funnel in the garage or whatever when not filling).  

 

wife and I have been thinking about an addition to the house in a few years and I am really really thinking about having a pellet stove installed when that happens to lower our winter heating bills.   Thing is, I have to see if it would even out as my homeowners insurance would go up if I have any kind of fireplace. 

DeadSkunk
DeadSkunk UberDork
12/28/17 7:37 a.m.

I had a wood stove in our last house. It wasn't an air tight design so it would burn down pretty quickly. The best I could do with it, to get through most of the night was throw in a couple of unsplit chunks of wood. They wouldn't burn as quickly. If you want a controlled rate of burn I think you'll need a pellet stove, or an air tight . Either case should utilize external combustion air, or you'll be just sending heated air up the chimney.

Ian F
Ian F MegaDork
12/28/17 7:40 a.m.

In reply to jmthunderbirdturbo :

Regulate the wood feed?  None that I know of.  That is one of the reasons pellet stoves came about - to be able to regulate fuel into the fire. Being a standard size, pellets are easier to feed than pieces of wood that can vary greatly in length and shape and thus easily jam any sort of feeding mechanism.

Typically, you regulate the rate of burn by limiting the amount of oxygen to the fire.  That is what we used to do at my ex's house and her fairly small/normal sized wood stove.  We would get a good fire going and then right before bed, pack it full of wood, then turn the damper down to the minimum.  By the time we woke up 6 to 7 hrs later, there would still be enough embers left to relight another load of wood.  When she worked closer to home, she would reload it during her lunch hour.  Sometimes to make more room we'd sift out ashes into a metal bucket, leaving the coal embers.  She did have a modern stove that she purchased new, so it sealed well and the damper was effective.

Streetwiseguy
Streetwiseguy UltimaDork
12/28/17 7:42 a.m.

I would explore routing hot air into the returns and using the fan.  Rerouting the returns to the stove would be easier than plumbing an entirely different water system.

A friend was telling me how much happier he has been since he dumped his wood heat with electric assist and went to propane. It costs less, and that was with "free" wood too.

SVreX
SVreX MegaDork
12/28/17 8:07 a.m.

You have individual returns NOW. Why can't that change?

Install a 2nd single large return in a central location near the wood stove with a dampener in line. 

During the winter, open the dampener to the big return and suck air from the wood stove room and circulate it through the house with the air handler. In the Summer, close the dampener and use the individual returns. 

It could be built with duct board for a couple hundred dollars. 

oldopelguy
oldopelguy UltraDork
12/28/17 10:05 a.m.

Step 1 is to turn the fan on for you central air and get the air in your house moving while the wood stove is running. That is free and should get the basement and bedrooms starting to get warm.

Step two is to replace something. Either swap the ac unit for a heat pump or swap the stove to a Fire King or similar or a pellet stove. My Fire King goes @36 hours on a good load of wood if it starts out hot and the coals will still be hot enough to light the next load of wood. Pretty much fill it before bed, toss in a couple logs morning and afternoon, and repeat. It works by using a thermostat to dampen the air intake to the stove so the fire smolders until it cools then the air opens and it's stoked until it gets too hot, then repeat. It also generates most of its heat from a catalyst bed on top of the box and not from the fire itself. There are several stoves like it.

Once you get the air in your house moving you could probably get much of the thermal battery effect you are looking for with bricks stacked up by the stove. They would get hot and concrete has a lot of specific heat capacity compared to pretty much everything else.

The0retical
The0retical SuperDork
12/28/17 10:20 a.m.
SVreX said:

You have individual returns NOW. Why can't that change?

Install a 2nd single large return in a central location near the wood stove with a dampener in line. 

During the winter, open the dampener to the big return and suck air from the wood stove room and circulate it through the house with the air handler. In the Summer, close the dampener and use the individual returns. 

It could be built with duct board for a couple hundred dollars. 

This is relevant to my own interests. Are there serious code implications here?

 

To OP: I've never seen a wood regulator. If you're getting wood cheap there are pellet mills that can be had for a reasonable sum if you wanted to roll your own with the saw dust.

Ian F
Ian F MegaDork
12/28/17 10:26 a.m.

In reply to The0retical :

There can be but it generally depends on where the stove is located. As long as it is located in one of the living spaces it should be fine.

SVreX
SVreX MegaDork
12/28/17 11:54 a.m.

In reply to The0retical :

What code issues are you thinking about?

If the wood stove is installed in a living space, I am working on the assumption the stove is already installed to code.    So, the only issue would be circulating heat which already exists in one area to another.

There is one other issue I see... If the HVAC fan is set to "On" instead of "Auto", it will always be running.  If there were ever a fire, the HVAC air handler would rapidly accelerate the fire by spreading it throughout the house.  This could be addressed by using a fire dampener, or perhaps with an automatic system shutoff tied to the smoke alarms (which probably IS illegal, but should solve the problem very well).  Note that this problem would exist if the HVAC fan was used at all, regardless of whether there was a new return added or not.

Residences always have this problem.  They rarely have fire dampeners.  The advantage they usually have is that the returns and thermostats are generally located in central locations, not in fire risk areas.   The difference in this situation is that the big return would be located very close to the highest fire risk in the house.

RossD
RossD MegaDork
12/28/17 1:06 p.m.

In reply to SVreX :

Fire dampers are to keep fire from spreading from differently occupied areas, not because ducted system are moving fire or smoke; it just happens the hole in the fire rated wall is within the ductwork. Code is that there is a smoke detector in the return duct and that shuts down the unit so if fire/smoke ever got in the ductwork it would shut down before being drawn through the unit and delivered elsewhere.

Having a bunch of different returns to use during different times of the year is fine. If you can get away with a larger wall return low near the stove, just put a manual balancing damper inline. Then when you switch from heating to cooling, open the bedrooms' returns and close the stove's return.

SVreX
SVreX MegaDork
12/28/17 2:14 p.m.

In reply to RossD :

I agree, but a mechanical air handler that does not shut off AND has no fire dampener (protecting the hole the ductwork creates) can accelerate a fire enormously. 

SVreX
SVreX MegaDork
12/28/17 2:19 p.m.

In reply to RossD :

BTW, the NFPA does not require smoke detectors in returns unless the system moves 2000 CFM or more. Older systems did not require this. 

Since we do not know either the age of the system or the CFMs, my suggestion was a recommendation to make sure such a system exists (especially considering the added risk with a wood burner).

The0retical
The0retical SuperDork
12/28/17 3:25 p.m.

In reply to SVreX :

That was mainly what I was wondering, big hole pulling air through it up into the structure of the house.

On the other hand I built a dutch door down to my basement so I can get heat up and keep the one year old from falling down a flight of stairs so it's not like there isn't a huge hole to the basement already there. I don't much feel like modifying the HVAC in the house so my own answer is probably going to involve a pellet furnace replacing the oil once I get the cash together as they seem carry a not inconsequential in cost.

imgon
imgon Reader
12/28/17 3:53 p.m.

Not sure why you can't get a new stove, a good one should give you 8 hours, will be wimpy towards the end but still providing heat. We had one in the basement of our old house (600 sq ft ranch) that kept the house so hot we left windows open to regulate the temp. I was able to get through the night and start the next day's fire with the embers. Maybe you just need to "tune up" the stove so it runs more efficiently. That and circulate the air around the house with the fan of your ac system.

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