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re: heating oil vs. electric
16 sep 2000
bill bonde wrote:
>ruby tuesday wrote:
>> i have a 2 bedroom old house (new windows) that i am renting...
>> i was already considering small ceramic heaters for the bedrooms,
>> however, with the price of heating oil as it is, i am wondering
>> if it might be cheaper overall to heat with those this winter.
>i can't believe that electricity attempting to heat the entire home
>is better than any other method including oil...
electricity might be more frugal with local heating, in a 40 f room.
who sells electric socks (used by hunters) and how much do they cost?
do they make jackets or thin gloves as well? it's hard to type or turn
pages of books in a room below 50 f. some hunters wear latex next to
the skin to reduce evaporation loss and avoid condensation in insulated
clothing. my $10 surplus pair of arctic army pants has 2" of padding,
but no vapor barrier or heaters.
the aluminized suits with heaters inside used by astronomers are pricy.
bloody viking enjoys winding his body up with 24 ga stranded speaker
wire in chicago, but the winding and unwinding could become tedious in
non-urban areas. maybe something like a small electric heating pad or
a hot water bottle worn on the stomach under a jacket with an immersion
heater. a body with good circulation can distribute the heat regardless
of where it's applied.
an average 68" 154 pound ashrae huming with about 20 ft^2 of skin
generates about 100 watts (340 btu/h) at rest. with a deep internal
temp of 98.6 in a 70 f room and ordinary clothes, the huming-to-air
thermal resistance is about (98.6-70)/340 = 0.084 f-h/btu, with a us
r-value of 20x0.084 = 1.7, like 1/2" of fuzzy fiberglass insulation.
with the same clothing, the heat loss might be about (98.6-40)/0.084
= 700 btu/h in a 40 f room. we might provide equivalent comfort in a
40 f room by raising the r-value to 20(98.6-40)/340 = 3.4 with another
1/2" of insulation (not much) or adding 700-340 = 360 btu/h (about 100
watts) of heat next to the skin, or some combination of these.
one renewable energy combination might involve gaining weight in the
winter (which increases internal heat generation by m^0.75 while raising
the fat layer thickness, ie the internal r-value, but only increases
the heat-losing dubois skin surface to 0.0108m^0.425l^0.725 ft^2, where
m is the mass in pounds and l is the height in inches.) bears do it.
we might wear sweaters and hats and thermal underwear indoors, too.
and increasing activity helps: simply standing up raises heat generation
20%. one might scrub floors, use an exercise bike, or walk all the way
to the tv to change channels, which doubles the rate of heat generation,
vs "quietly sitting." dancing triples it, basketball doubles that, and
an ashrae-standard 154-pound competitive wrestler can make 1 kw of heat.
nick
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