Mark Series Coal Efficiency

Does anyone know the Harman's Mark Series test lab efficiency assuming the manufacturer's recommended damper is used and set to their recommended settings? My stove has this huge placard on the back that shows it went thru lab testing though I did'nt see any efficiency #. Some wood stoves now do note efficiencies, lots of variables though one general # is usually what they note. Thanks for any input.

I'd be currious how a number could be arrived at.. If the stove is just idling,, and the stove pipe is only warm to the touch,, then most of the heat from the burning coal is being absorbed by the stove body, and radiated into the room.. [ High efficiency]
But if you have the fire really 'cranking' then a much larger percentage of the heat from the coal would be going up the chimney... [poor efficiency]

So I'm not sure how you would rate a hand fired stove..

I know with the the 'Bureau of Mines Report' on the Axeman Anderson boiler,, they weighed the coal coming in, the ashes going out, the amount of water being heated, and how hot and how often,, and the heat going up the chimney.. pretty sophisticated,, especially for the date it was done [~1950].

Greg L

Greg said, "I know with the the 'Bureau of Mines Report' on the Axeman Anderson boiler,, they weighed the coal coming in, the ashes going out, the amount of water being heated, and how hot and how often,, and the heat going up the chimney.. pretty sophisticated,, especially for the date it was done [~1950]."

Well don't keep us in suspense . What number did they come up with?

rberq wrote:Greg said, "I know with the the 'Bureau of Mines Report' on the Axeman Anderson boiler,, they weighed the coal coming in, the ashes going out, the amount of water being heated, and how hot and how often,, and the heat going up the chimney.. pretty sophisticated,, especially for the date it was done [~1950]."

Well don't keep us in suspense . What number did they come up with?

Full report is here: http://nepacrossroads.com/post10763.htm ... nes#p10763

LsFarm wrote:I'd be currious how a number could be arrived at.. If the stove is just idling,, and the stove pipe is only warm to the touch,, then most of the heat from the burning coal is being absorbed by the stove body, and radiated into the room.. [ High efficiency]
But if you have the fire really 'cranking' then a much larger percentage of the heat from the coal would be going up the chimney... [poor efficiency]

So I'm not sure how you would rate a hand fired stove..

I know with the the 'Bureau of Mines Report' on the Axeman Anderson boiler,, they weighed the coal coming in, the ashes going out, the amount of water being heated, and how hot and how often,, and the heat going up the chimney.. pretty sophisticated,, especially for the date it was done [~1950].

Greg L

Remember you have two efficiencies, the combustion efficiency and the operating efficiency. The first measures how well you are burning the fuel (coal) by measuring the combustion gases for proper CO and O2. The second measures production of Btu's, a measure of heat exchanger performance. The Bureau of Mines Report did both. 84-86% operating efficiency. Boilers have be tested in this way since the late 1800's, only the instrumentation changes, much easier to do today. And more accurate.

Measuring the Btu's of a stove or furnace is much more difficult, but it's the same idea, measure the heat produced for a given fuel input.

Gentlemen, thanks for the conversation. Here's what was found on Google for what it's worth. As pointed out above, lots of variables. These #'s kind of correlate with what has been read read regarding being able to bring the stack temp down to the 150*-200's* with a baro while keeping up a pretty fair to good heat output.

Coal Heating Systems
Older Coal Furnace/Boiler - 50% to 65%
Modern Coal Stove - 60% to 80%
Stoker or Hopper-Fed Stove - 70% to 85%

Goal here is to kinda predict the # of tons that may be consumed vs past oil usage for heating alone.

BTW, may have just made another coal convert at the workplace.

Uglysquirrel wrote:Goal here is to kinda predict the # of tons that may be consumed vs past oil usage for heating alone.

Use the DoE energy calculator to compare the fuel costs. http://www.eia.doe.gov/neic/experts/heatcalc.xls You should be able to use your annual oil consumption and oil burner efficiency. For coal boiler efficiency use 84%, which would be about the highest you can get in a coal boiler. You will find coal to be much less expensive.