Rationing wood

[chuck172]

I need some kind of woodburning schedule, or pattern. I'm wasting too much wood. Everyone says you burn more wood the first year, then learn the right way to do it, or the way that works best for yourself.
It's been a cold November. Or should I say normally cold. I've gone through over a cord of wood already. I'd like to stay at about 6 cords max.
Would it be reasonable to limit myself to 1 heaping wheelbarrow of wood per day? Is that about par with what most veterans burn?
The next step would be to figure out how many cu. ft. of wood in a heaping full wheelbarrow, then I could gauge how much wood I'll need.

 

[Birdman]

I have a Tarm 40 Solo Plus. New this year. Burning for 4 weeks. Temps here are everywhere. 15 one night. then next week.. 40s in day and high 20s at night. I am using very little wood. Even with colder temps... I am thinking may use about 4-5 cord from Dec 1 to mid march. 70 in house and alot of hot water. Tell me how your pressurized storage is working out? I am thinking of doing it next year

 

[chuck172]

I expected better results. I guess 500 gallons isn't enough. The water goes from 180* to 130* allot quicker than I thought.

 

[Birdman]

Describe to me your process of heating your storage? What is a typical day? How many hours are you getting 180 water to use? Can you heat up alot of water to 180? like all 500 gallons? How long does it take to heat up half of your storage to 180?

 

[Jerry_NJ]

chuck172

How big and insulated is your home? Your wood burning seems high to me. I live in northcentral NJ, so mus have similar temps. I don't burn when the temp at night doesn't go below 32 degrees, and don't burn during the day if the temp is 40 degrees, or higher. So, my Insert has been sitting cold most of the time. Still my usage is so far below yours I wonder. I'd estimate I've used no more that 1/4 cord so far, and as for per day I'd say when I burn all day and most of the night/morning I use only about a "level" wheel barrow of wood....said another way I'd estimate about 20 to 25 splits. My splits are small, less than 18" long, perhaps 4-6 pounds. These are rough estimates, but too my burning may be so different from yours that my data isn't useful. I watch your post and see what else develops.

Even if you wood lot produces all the wood you use, cutting, splitting, stacking, seasoning 6+ cords a year is a LOT OF WORK.

 

[chuck172]

Jerry,I'm not using a wood stove. I'm using a Tarm boiler. With that I'm heating all my domestic hot water, and heating through all my hydronic zones evenly. I'm using many more btu's than I would with just a stove.

 

[chuck172]

Birdman, I'm heating the 500 gallons of storage to the high 170's. Temps at the bottom of the tank are 160*+
What I'm working on now is one wheelbarrow of wood daily. That would bring the wood total to about 7 cords, +-
Seems like the storage drops from 175 to 140* too quick. I guess the btu's can be figured.

 

[Bad Wolf]

Chuck is your tank insulated? How about your pipes? Lots of heat loss there.

On mild days I burn once in the evening. I start when I get home with a good load which alternates between taking care of zone demands and heating the tank back up. At 10:00 all my thermostats kick down and its 100% going to the tank. I usally fill it up at this point and go to bed, tank reaches 168 to 172 at its peak. In the morning I decide if I'm going to build a second fire. If the tank is still in the low 160 to high 150 and its above 40 outside I won't even build a fire. If its cold or going to get cold I'll fire it with a moderate size load before going to work.

Try keeping a log of starting/stopping temps and outside temp and how long it takes to heat your tank up. You should be able to work out a ratio of so many pound/cu ft/ armloads of wood you need to raise your tank by "X" degrees.

 

[chuck172]

The tank is insulated but the pipes aren't. I have the insulation coming in a few weeks. I'm banking on pipe insulation making my system more efficient. The
1 1/4" mains are 40' long, bare copper. I know I'm loosing heat there.

 

[smokinj]

I am right now with the temps where they are 10 cu ft every 24 hrs. witch is a cord evey 13 days!

 

[overshot]

For round numbers
175-140=35 deg drop in tank
500 gal x 8.33 lbs = 4,165 lbs H2O
4,165 x 35 deg = 145,775 BTU's out of tank
145,775 BTU's/time in hours for temp change in tank = BTU's/hour your house used at a given outside temperature

Lets say it took two hours for your tank to drop temperature and the outside temp was 20 deg. and the inside temp was 70 deg.
That is a 50 deg. difference from outside to inside.

145,755/2 = 72,887 BTU's/hour to maintain 70 deg inside temperature to an outside temperature of 20 deg.
72,887BTU's/50 deg. = 1,457btu's/hour/deg.

So if your outside temp = 0 and you want it 70 deg. in the house
70 x 1,457 = 101,990 BTU's/hour
145,775 BTU's stored in tank/101,990 = 1.42 hours untill your tank reaches 140 deg.

If the outside temp = 50 and you want it 70 deg. in the house
20 x 1,457 = 29,140BTU's/hour
145,775 BTU's stored in tank/29,140 = 5 hours untill your tank reaches 140 deg.


This is all approximation and I hope I didnt confuse you.

 

[Birdman]

Chuck172.

What is the upper limit for the storage? Can you heat it to 190 if you want? I am hoping to not use above 5 cord from now until md march. I am guessing storage should increase your efficiency? How many sq ft are you heating and at waht temp do you try to keep it?

 

[Nofossil]

I'd agree that you're burning way more wood than I'd expect. Could be one of four things that I can think of:

1) Technique
2) Wood quality
3) Boiler adjustments
4) Heat load

Technique: This is easy to fix and perhaps easy to rule out. Are you getting a nice clean burn with steady secondary combustion?

Wood quality: Wood needs to be pretty well seasoned. What kind of wood do you have and how was it stored and seasoned?

Boiler adjustments: I'm not a Tarm expert, but there may be something there.

Heat load: Your heat load seems really high, and the rapid drop of your storage seems to reinforce that theory. How big a house? How well insulated?
If you have a previous year's history of oil consumption, that would be a good way to do a quick check.

 

[chuck172]

Thanks OverShot.
I'll paste and save your figures.

Wow, 0* temp outside, I'll get down to 140 from 175* in just 1.42 hrs.
That's pretty quick.

 

[Valhalla]

[quote author="chuck172" date="1228165894"]I need some kind of woodburning schedule, or pattern. I'm wasting too much wood. Everyone says you burn more wood the first year, then learn the right way to do it, or the way that works best for yourself.
It's been a cold November. Or should I say normally cold. I've gone through over a cord of wood already. I'd like to stay at about 6 cords max.
Would it be reasonable to limit myself to 1 heaping wheelbarrow of wood per day? Is that about par with what most veterans burn?
The next step would be to figure out how many cu. ft. of wood in a heaping full wheelbarrow, then I could gauge how much wood I'll need.[/quote]


Chuck,

Just dump your next wheel barrow load and stack it into a close, tight rectangle. You have to do this anyway.

Then measure the rectangle and you have it.

H X W X L = the cubic dimension of your average wheel barrow load.

For example: 2ft X 3ft X 2 ft = 12 cubic feet

Your load may vary as you fill it. Also, if you measure in inches, then just convert to cubic feet afterward.

 

[Nofossil]

Here's another sanity check. Here in Vermont, we've had just under 1400 degree days since October 1. That's about 18% of what we'd expect in a full heating season (ending April 30). You'd expect to have burned about 1/5 of your wood by now.

In my case, I'm at about 3/4 of a cord at this point, which puts me right on track for 4 cords.

It's worth remembering that DHW takes about 60,000 BTU/day regardless of the outside temperature. For me, that's a sizable percentage of my heat load this time of the year - perhaps 25% of the total heat load.

 

[chuck172]

I think I'm getting a good burn, I'm burning seasoned wood, moisture reading `15-20% birch, red maple hickery.
Wood is in the wood shed, well seasoned.
house is about 1700 sq. ft. I have a high DHW demand, three showers two whirlpool baths daily.
2'X6" insulated walls, the house is fairly tight.
I can't go by last years oil consumption, I've always burnt wood in a wood burner. Probably go through about 4-5 cords a year.

I wonder if the un-insulated lines in the basement could be the culprit? I know the heat I'm loosing, I'm not really loosing, but I'd have better burn times and control.

 

[Nofossil]

I think I'm getting a good burn, I'm burning seasoned wood, moisture reading `15-20% birch, red maple hickery.
Wood is in the wood shed, well seasoned.
house is about 1700 sq. ft. I have a high DHW demand, three showers two whirlpool baths daily.
2'X6" insulated walls, the house is fairly tight.
I can't go by last years oil consumption, I've always burnt wood in a wood burner. Probably go through about 4-5 cords a year.

I wonder if the un-insulated lines in the basement could be the culprit? I know the heat I'm loosing, I'm not really loosing, but I'd have better burn times and control.

That all sounds right - perhaps the DHW demand is high enough to be a factor. Did your previous wood installation also heat the DHW? No way the uninsulated lines are making a big difference in wood consumption.

 

[chuck172]

No, I burnt oil for the hot water.

 

[Medman]

Along the same lines - NoFossil, how did your wood consumption and/or performance change from the first year with no storage vs. having storage? I am seeing about a 5.5 hour burn time with a full load of dry wood into an already hot system. Since I usually like to sleep a little longer than that, I am really motivated to add storage to extend my time between firings. Additionally, I was wondering about the net "savings" in wood. Any noticable reduction in amount?

 

[Nofossil]

Along the same lines - NoFossil, how did your wood consumption and/or performance change from the first year with no storage vs. having storage? I am seeing about a 5.5 hour burn time with a full load of dry wood into an already hot system. Since I usually like to sleep a little longer than that, I am really motivated to add storage to extend my time between firings. Additionally, I was wondering about the net "savings" in wood. Any noticable reduction in amount?

I really can't say that storage reduced my wood consumption at all. However, I was doing short frequent full throttle burns when I didn't have storage. I expect that I did pick up some efficiency, but that was offset by the fact that I ended up keeping the house at a higher average temperature (less fluctuations).

Storage really allows me to make fires when I want, and allows me to skip days in the shoulder seasons.

 

[overshot]

Thanks OverShot.
I’ll paste and save your figures.

Wow, 0* temp outside, I’ll get down to 140 from 175* in just 1.42 hrs.
That’s pretty quick.

Those numbers are just numbers I plucked out of my head. What you need to do is record the outside temperature and the inside temperature of you house and the length of time it takes to draw down your tank. This gives you the approximate heating demand for your house. Then plug in your numbers to get the actuals.

Remember if your storage tank high low is 175/140 - you are only storing 145,775 BTU's.

 

[MaineMike100]

I think I'm getting a good burn, I'm burning seasoned wood, moisture reading `15-20% birch, red maple hickery.
Wood is in the wood shed, well seasoned.
house is about 1700 sq. ft. I have a high DHW demand, three showers two whirlpool baths daily.
2'X6" insulated walls, the house is fairly tight.
I can't go by last years oil consumption, I've always burnt wood in a wood burner. Probably go through about 4-5 cords a year.

I wonder if the un-insulated lines in the basement could be the culprit? I know the heat I'm loosing, I'm not really loosing, but I'd have better burn times and control.

If the previous wood consumption was 5 cords, you have now added the DHW load as well as the likely increased heating load by keeping the entire house warmer than it was with a single woodstove. Given this I think the goal of 6 cords/year is probably a little unlikely.

How much oil did you consume in previous years for the DHW and other heating in addition to your old 4-5 cord wood usage? We can use that number to estimate the increased wood that will be needed with the new system.

 

[jebatty]

I think the down and dirty determination of boiler adjustment in the Tarm is probe stack temp + secondary air adjustment setting. If the probe temp (mine is about 15" above the boiler flue collar) is 400-500F, and the air adjustment (your set it and forget it setting based on your wood) provides relatively constant and solid gasification, as viewed through the site glass), then I would say boiler adjustment is pretty good.

If same but probe temp is staying in the 500-600F range, I still would say pretty good, but I would suggest some experimenting (mainly fan draft damper setting, close the damper some to reduce air input) to see if you can get it down below 500, except for the early part of a new load burn when volatiles are at their maximum.

If you're pretty constantly above 600, you're wasting lots of heat up the chimney. Draft fan damper adjustment definitely is in order; probably also consider tubulators (search the forum and you will find plenty of info). A pattern of high temps suggests very dry wood and/or very small splits (lots of surface area) and/or pine type wood with lots of pitch and/or excessive draft.

As to secondary air adjustment setting, I suggest striving for a set it and forget it position, unless you really want to spend lots of time in front of your boiler fiddling. It may need to be altered if you have a material change in wood quality, dryness, etc., but again strive for a set it and forget it setting. I followed the suggestion in the Tarm manual to set it in the middle and forget it. My wood is well seasoned (2 summers minimum) and splits now pretty consistently in the 4-5" range.

 

[chuck172]

I really can't estimate how much oil I used just for Hot Water. We have a 40 gallon superstor. We do use the whirlpool tub allot.
Can't compare the heat. It's 34* out now, I have the wood stove going. My wife is complaining that the house is cold. I have next years wood under a tarp. I might have to steal some.
With the Tarm the whole house is nice and warm, the floor is warm, the basement is warm. With the woodstove, we bake in the living room and freeze everywhere else. Also with the woodstove, heat has a tough time making it to my daughters room, she uses an electric blanket and an electric wall panel heater.