a good guesstimate for heat loss of a home is this
1/R x delta = heat loss per square foot x area = heat loss in btu per hour
so lets say your home is 1800 square feet with 8 foot ceiling the walls around this house would be 60 x2 x 8 feet high = 960 + 30 x2 x 8 =480 480+960=1440 square feet of wall
lets say wall is r 20 (good insulation) 1/r x delta(60) 1/r x 60/1 = 60/20 = 3= 3 btu per square foot of heat loss = 4320 btu loss per hour x 12 hours = 51,849 btu lost through the walls in the 12 hour time period
ceiling is 1800 square feet and we will say well insulated at r30 = 1/30 x 60/1 = 60/30 = 2 btu per square foot of heat loss = 3600 per hour x 12 hour period = 43200
add the two together is 95,049 btu lost in the 12 hour time frame
1 pound of "dry" wood has about 8000 btu in it "dry" wood is 20 percent moisture, to boil out this moisture to get the wood to burn takes about 2000 btu leaving us 6000 "usable" btu...now we also know that a non gasser OWB is about 50 to 60 percent efficent so we will say 50 percent so our btu getting to the hosue is 3000 "usable btu per pound of wood ...so, 95,049 btu devided by 3000 = (about) 31 pounds of wood for a 12 hour period. i am not here to doubt anyone, and i get these formulas from the net (accuracy is not confirmed) but if these figures are correct, that is one long 3 inch round.
on another note i read is a post that the writer claimed when no heat was being used in the house the delta was 0 and the water was just ciculating from the boiler to the home and back...there is always a delta! your lines are five feet below the ground at about 55 degrees and your water in the lines is 180 so you have a delta of 125.. also from logstors information (one of the leading underground piping specialests) thier 1 inch double pex lines lose (at 5 gpm) about 1 degree in 100 feet. you say you are about 100 feet from your OWB to your home and i think i read a while back you think you are moving 12 gpm. you will be losing the exact same amount of btu to the earth as you would at 5 gpm but by moving it faster you will see a much smaller loss due to the weight of water you are moving. it is likley so small you can't measure it. 5 gpm is about 40 pounds so Logstor says you lose 1 degree (according to specs) that is 40 btu or 1 btu per pound..at 12 gpm you are moving almost 100 pounds of water per min. that would be about .3333 degrees per pound (still 40 btu), likely non measurable by any thermometer you have.
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Topic: wood consumtion questions???? (Read 8878 times)