Quote:
Originally Posted by diesel_john
Energy Feasibility
Cost of 1 million Btu's from different energy sources in my area.
elect. 293kw @ $0.10= $29.30
" " " $0.06=$17.58
natural gas 90%eff. 11.1 therms @ $1.378Ccf=$15.69
LPG 90% 12.1 Gals. @ $2.25=$33.97
#2 oil 80% 8.929 Gals. @ $4.00=$35.71
air to air heat pump COP of 1.7, 172.4kw @ $.10=$17.23
geothermal heat pump COP of 4, 73.25kw @ $.10=$7.32
3413 BTU/kw
NG 100,000 BTU/Therm
LPG 91,800 BTU/Gal
#2 140,000 BTU/Gal
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You forgot wood.
White Oak 28.2 Million BTU per cord, $200/cord cut and split
Mixed hardwood 22 Million BTU per cord, $80/cord in logs
Assuming a 66% efficiency woodstove gives a cost of;
$10.75 per million BTU for white oak
$5.50 per million BTU for mixed hardwoods requiring your labour.
I am impressed that the geothermal heat pump beats processed firewood, someday when I get tired of, or unable to do firewood we will have to look into it.
I have never dropped a thermometer down the ice fishing hole but its my understanding that the whole lake is basically at the same temperature, if any water is significantly warmer it rises to the surface, gets cooled and drops again. But your system assumes this and still get the 4 to 1 return which is fantastic. I suspect a woodstove is a little bit cheaper to install but they are definitley not for everyone or all houses.
The way I figure is that I have 100 acres of natural solar collectors so I might as well use the free energy and its fun playing lumberjack once in a while too.
Ian