The Epoch of the Axeman

Lightning wrote: ↑

Wed. Feb. 26, 2020 8:49 am

No it didnt.., you guys are both correct. The extra coal is definitely validated between the out building and DHW. The hand fed only preheated water and the electric tank finished heating it. The Axe is doing all the work heating DHW currently for a family of 5, of which a few are oblivious to hot water conservation

As a first guess I would place your daily coal usage for DHW at somewhere around 5-6 lbs. How does that impact your Lbs./HDD?

And better: Lbs./HDD/Sq-Ft

I think the hot water cost is probably more than 6 pounds per day.. I need to get that water meter installed to know for sure. I'll do some more math later on and see what I come up with..

If I've done my math right in the past, one normal 10 minute shower should cost 1 pound of coal.

So according to statistics, a normal shower uses 17.2 gallons of water at 105 degrees for a duration of 8.2 minutes. This works out to ~9300 BTUs of energy. A pound of coal nets about 10,000 after factoring efficiency. Maybe one likes it a little warmer for a little longer.. To keep it simple we can call it a pound of coal per shower. I'll vote that my wife, granddaughter (bath), and myself use about that much. The 2 teens however use much more. I'd say their showers are 20-25 minutes or until I'm pounding on the bathroom door threatening to go in the basement and shut the water off. But before ya'll think I'm a big meany, I've only resorted to doing that once, shut the water off that is So their showers are worth 2-3 pounds of coal each.. We'll take an average of 2.5 pounds. So there alone is 8 pounds of coal worth in showers and we haven't done any dishes yet, laundry, washed hands or whatever.. I would say 10 pounds of coal per day total in hot water is a good figure.

So, we can take 10 pounds off the 77 per day for 67 pounds worth of heating space.

Oh boy this is getting real exciting now!
After doing the math I'm finding that the hand fed ran at about .625 pounds of coal per 1000 sq ft per HDD
The Axe is running at around .667 pounds of coal per 1000 sq ft per HDD

I included the new building space in the Axe's figure. I'm sure there is a lot of wiggle room for variables (line loss, ect..), none of this is precise. This comparison was done with cherry picked weeks, not averages so you have that too. With all that said, it still ended up within .042 pounds of each other so something fits somewhere My brain hurts now but I think the 8-9 tons per year will be about right

What a steaming pile this post turned out to be...

I'm not quite as generous with the BTU output of coal in these boilers as you are. Where you presume 10,000 BTUH yield per pound, I presume more like 9,000.

I would also presume that you are losing about 4 lbs. per day to the underground run, presuming that water circulates 24/7 through it.

The energy guide on my old electric HWT claimed that a family of 4 could expect it to consume 450 KWH per average month.

450 x 5/4 = 563
563 x 3,412 = 1,921,000 BTU's per month
1,921,000/30.44 = 63,100 BTU's per day
63,100/9,000 = 7 Lbs. of anthracite per day

7 lbs. for DHW + 4 lbs. for the underground run = 11 lbs. per day

Cost of 7 pounds of coal then would equate to how much electricity to do that whole HW job???

McGiever wrote: ↑

Wed. Feb. 26, 2020 2:55 pm

Cost of 7 pounds of coal then would equate to how much electricity to do that whole HW job???

Ballpark $0.90 for 7 lbs. of anthracite (in Ohio). Or about $27.40 per month for coal.

Ballpark $0.143 per delivered KWH here, x 563 KWH = $80.50 per month for electricity.

Does that sound about right?

No work tomorrow, breadman snow day, went for a few drinks with a fellow route driver for his birthday. Came home then check on the Axe, man I love this machine... it just keeps on kickin ass and keeps on takin names.... and to think its 60 years old... I hope I'm in this good of shape at 60

So far, during an average of 27-31 degrees OAT I seem to get 2 full ash tubs in 6 days. At that point I weigh the ash tubs and run the numbers...

What really blows my mind are the averages. Pounds per HDD are within 1% of the last 6 day period and Ash vs Coal percentage is within half a percent. Even thru all the variables of hot water usage and turning the thermostat up and down in the salon. That's crazy... I stuffed a couple holes in my foundation to slow down cold air infiltration, maybe that's how I gained the .02 pounds per HDD, or was it in the ash
I put the previous 6 day averages in ()'s

At any rate, this will be awesome data to compare against next year after making some improvements this summer.

02/25 5:00pm bin level/empty tubs
Date....#'s added.......average OAT(F)
02/26 +73...................37.3
02/27 +82...................20.8
02/28 +70...................17.6
02/29 +122.................16.8
03/01 +81...................25.7
03/02 +71...................43.6

Coal Total 499#'s
Ash 58.4#'s
Coal vs Ash 11.7% (12.1% previously)
Days 5.875.... 85#'s per day
Average Temp 27 degrees
2.24 (2.26 previously) pounds/HDD

Axe is running stock parameters.
Between 1-2 clicks ashing.
Anthrastat setting 142 degrees.

Heating 2400 sq ft home and domestic hot water for a family of 5 along with a 500 sq ft out building used as a salon/music studio..

Many thought me to be crazy when I've stated that coal stoker boilers really do adhere rather closely to a fixed number of Lbs. burned per HDD (the value for which being unique to each home and boiler). You are confirming what I've been saying all along. Reasons I've heard as to why HDD's can't work include:

Cloudy vs. sunny
Windy vs. not windy
Snow blanket of insulation vs. no snow blanket

Good points Larry. I didn't even think about those variables. They must all work out in the wash over periods of time, meaning they become consistent variables. Hows that for a brain twister "consistent variables"

I've been thinking again lol... I should be subtracting something for DHW and line loss of the underground pex run. Otherwise my pounds per HDD will become skewed at other average OATs..

Another 6 days and another 2 ash tubs full.. My ash vs coal percentage reads a little higher. I think it's due to fine separation, I've been shoveling off the floor lately and have noticed a lot more fines and small peices. I also recalced my HDD pounds with an allowance of 12 pounds for DHW and the underground pex run..

Still running like a Swiss watch since the sleeve repair..



02/19 9:00pm bin level/empty tubs
Date....#'s added.......average OAT(F)
02/20 +109...................16.6
02/21 +99.....................20.3
02/22 +75.....................29.1
02/23 +69.....................37
02/24 +64.....................43
02/25 +35.....................39

Coal total 451#'s
Ash 55#'s
Coal vs Ash 12.1%
Days 5.83..... 77.4#'s per day
Minus 12#'s for loop and DHW
65.4#'s for heating 2900 sq ft
Average temp 31 degrees
1.923 pounds/HDD (base 65)

----------------------------------------------------

02/25 5:00pm bin level/empty tubs
Date....#'s added.......average OAT(F)
02/26 +73...................37.3
02/27 +82...................20.8
02/28 +70...................17.6
02/29 +122.................16.8
03/01 +81...................25.7
03/02 +71...................43.6

Coal Total 499#'s
Ash 58.4#'s
Coal vs Ash 11.7%
Days 5.875.... 85#'s per day
Minus 12#'s for loop and DHW
73#'s for heating 2900 sq ft
Average Temp 27 degrees
1.921 pounds/HDD (base 65)

----------------------------------------------------

03/02 2:00pm bin level/empty tubs
Date....#'s added.......average OAT(F)
03/03 +75.................42.0
03/04 +78.................33.4
03/05 +81.................32.0
03/06 +84.................31.8
03/07 +80.................29.0
03/08 +46.................34.4


Coal Total 444#'s
Ash 58.4#'s
Coal vs Ash 13.1%
Days 6.0.... 74#'s per day
Minus 12#'s for loop and DHW
62#'s for heating 2900 sq ft
Average Temp 33.8 degrees
1.987 pounds/HDD (base 65)


Axe is running stock parameters.
Between 1-2 clicks ashing.
Anthrastat setting 142 degrees.

Heating 2400 sq ft home and domestic hot water for a family of 5 along with a 500 sq ft out building used as a salon/music studio..

We had a few warm days thru this 6 day period. You'll notice the spike in my coal/ash comparison. 20% which is up from 12%. Its reflected in the HDDs per pound somewhat also. I've noticed a lot of "black sand" in the ash bucket. To the point that material is piling up higher on the separation cone side of the ash tub.. I've been digging coal from the floor directly under the coal chute door which is the densest with fines in the bin.. Not a big deal, it's just interesting lol

03/08 2:00pm bin level/empty tubs
Date....#'s added.......average OAT(F)
03/09 +81.................53.6
03/10 +41.................43.7
03/11 +82.................33.9
03/12 +41.................44.2
03/13 +44.................44.9
03/14 +62.................33.2

Coal Total 351#'s
Ash 71#'s
Coal vs Ash 20%
6 Days ... 58.5#'s per day
Minus 12#'s for loop and DHW
46.5#'s for heating 2900 sq ft
Average Temp 42.25 degrees
2.043 pounds/HDD (base 65)