Lbs. Anthracite Burned Per Day & Avg BTU's Per Hour Output

The linear chart as seen below isn't pretty, but if you want to know how many BTU's you are outputting to your home per average hour in your nominally 80% efficient stove, boiler, or furnace that is burning strictly anthracite coal, I've put the figures here.

KEY:
Lbs. = pounds of anthracite burned over 24 hours
BTU's = average output of heat as BTU's per hour

Lbs. = BTU's
----- --------
10 = 4,050
15 = 6,075
20 = 8,100
25 = 10,125
30 = 12,150
35 = 14,175
40 = 16,200
45 = 18,225
50 = 20,250
55 = 22,275
60 = 24,300
65 = 26,325
70 = 28,350
75 = 30,375
80 = 32,400
85 = 34,425
90 = 36,450
95 = 38,475
100 = 40,500
105 = 42,525
110 = 44,550
115 = 46,575
120 = 48,600
125 = 50,625
130 = 52.650
135 = 54,675
140 = 56,700
145 = 58,725
150 = 60,750
155 = 62,775
160 = 64,800
165 = 66,825
170 = 68,850
175 = 70,875
180 = 72,900
185 = 74,925
190 = 76,950
195 = 78,975
200 = 81,000
205 = 83,025
210 = 85,050
215 = 87,075
220 = 89,100
225 = 91,125
230 = 93,150
235 = 95,175
240 = 97,200
245 = 99,225
250 = 101,250

What potential value did you assign to a pound of coal? 12,000 BTU?

Lightning wrote:What potential value did you assign to a pound of coal? 12,000 BTU?

I assumed "as received" (A. R.) anthracite at a nominal 6% moisture content, and averaging 12,150 BTU's per lb.

This correlates well with data as seen on the Jeddo website for their anthracite.

http://www.jeddocoal.com/specifications.html

Using 10,000 BTU net output per pound comes pretty close to your figures.

Firing at the sweet spot of the stove might increase the output while firing above or below will lessen output.

Of course if you have more than one stove you must sum total the coal used between all of them to get the cumulative total BTU output, though this does not change anything for the chart.

Example: If you have two stoves and one burns 40 lbs. on a day when the other burns 60 lbs, your combined average hourly BTU output is 40,500.

Ok, using this chart my question is for Matt or Dave:

What is the max pounds per day that the WL110 can push off the grate?

kstills wrote:Ok, using this chart my question is for Matt or Dave:

What is the max pounds per day that the WL110 can push off the grate?

I am not Matt or Dave, however using Isayre's numbers your equation would be X = ((110,000 BTU x 1 lb.) / 12,150 Btu)......so X = 9.053 lbs

So roughly 9 lbs of coal on the input for the boiler...based on Isayre's numbers

Neal

ntp71 wrote:

kstills wrote:Ok, using this chart my question is for Matt or Dave:

What is the max pounds per day that the WL110 can push off the grate?

I am not Matt or Dave, however using Isayre's numbers your equation would be X = ((110,000 BTU x 1 lb.) / 12,150 Btu)......so X = 9.053 lbs

So roughly 9 lbs of coal on the input for the boiler...based on Isayre's numbers

Neal

Max 9 lbs./day??? Or is that /hr.???

McGiever wrote:Max 9 lbs./day??? Or is that /hr.???

That would be per hour.

Very cool chart thanks for putting it up!

My coal is just a bit hotter than this, but running the chart numbers I have a very nice reserve capacity that will more than get me through the colder than normal winters we see once in a while.

I have thought for a while that oversizing the stove and then controlling the air to throttle it back is one of the nice advantages with coal.

SD

kstills wrote:Ok, using this chart my question is for Matt or Dave:

What is the max pounds per day that the WL110 can push off the grate?

Oh sorry...9 lbs per hr x 24hr = 216 lbs. per day

SheepDog68 wrote:My coal is just a bit hotter than this, but running the chart numbers I have a very nice reserve capacity that will more than get me through the colder than normal winters we see once in a while.
SD

If your supplier is telling you (as most will) that they have lab tested their anthracite at 13,000+ BTU's/lb., ask them if they are lab drying their coal first. "As Received" coal (even if it appears bone dry to you) typically has about 4 to 8 percent water by weight. The water that the labs fully drive out in order to squeeze out the most optimistic BTU figures they can report must be considered, since you will not be driving it out until you toss the coal into your stove.

Looking more closely at the very honest Jeddo 'A.R.' figures, I should probably have chosen about 12,300 BTU's per pound rather than 12,150, but that hardly changes my chart.

neat, this would support my estimates that my stove was pushing around 32,000 BTU for the extended period we were -20F last season.

the rest of the time about 22,000 btu. both examples leave a decent margin of untapped potential.

too bad the season was so LONG on both ends.

this yr. I expect to do very well, of course if it's real nasty I do have 6 tons to run thru and a lock on more.

steve

I'm amazed at how cold Indiana can get in the winter.

lsayre wrote:

SheepDog68 wrote:My coal is just a bit hotter than this, but running the chart numbers I have a very nice reserve capacity that will more than get me through the colder than normal winters we see once in a while.
SD

If your supplier is telling you (as most will) that they have lab tested their anthracite at 13,000+ BTU's/lb., ask them if they are lab drying their coal first. "As Received" coal (even if it appears bone dry to you) typically has about 4 to 8 percent water by weight. The water that the labs fully drive out in order to squeeze out the most optimistic BTU figures they can report must be considered, since you will not be driving it out until you toss the coal into your stove.

Looking more closely at the very honest Jeddo 'A.R.' figures, I should probably have chosen about 12,300 BTU's per pound rather than 12,150, but that hardly changes my chart.

Since I'm running my stove at 25-50% I expect that a small tweek in the number will not hurt me that much!

I should add that running my stove at the temps I usually do make it very kid friendly. My son can play right next to it and even if/when he does touch it he is not burned like a wood stove would have done.

That part of burning coal was not intuitive and was a happy surprise when I discovered it.

SD