Nehmo Sergheyev wrote:
- Edwin Pawlowski -
I wonder how long it would take to get the surface from say, 5
degrees to 33 degrees.

- Nehmo -
You only need to get the surface of the pavement above freezing while
there is freezing precipation. You would have a control system. The
heat wouldn't simply be left on at max for the night of a snowfall -
unless that were required.

From a practical point of view, you need to turn on the heat enough
ahead of the time you want the drive cleared, to allow time to heat the
concrete and melt any snow or ice. That can be a long time indeed. Since
many people want to be able to get out of their drive in the morning, they
have the choice of saying up all night or guessing.

Frankly if it were cheap and easy to melt snow this way and if the
hardware had a long life (if often does not) then you would see it used a
lot more than it is. Even in high density commercial areas, you don't see a
lot of it being used. Heck if it were cheap, the airports would use it,
they can afford it more than most home owners.

The fact is it is just not a practical tool for removing snow most
places.

The exceptions may be sloped drives where someone must be able to inter
or exit and they are not physically able to remove the snow using
conventionally and can afford both the original expense and operational
expense.

Failing to warn someone who is considering this choice, is I believe a
disservice to them and if done by the salesman it is a dishonest act.


Snowfree electrically conductive asphalt
http://217.172.161.215/ktml2/images/...ATALKFINAL.pdf
"The up heat time required to reach operating temperature is
approximately 2.5 hours based on a power input of 45 watts/f^2 and a
starting temperature of 25°F."

- Edwin Pawlowski -
If the numbers work:
Take a driveway that is 10' x 50'. That is 500 square feet times 50
watts per sq.ft. = 25,000 watts.
25,000 watts = 25 kW * .12 per kW hour comes to $3 per hour. In a
modest snowfall, it would run about 12 hours or $36. In a larger
storm it could easily run 24 to 36 hours here. I'd also have to
add at least a 200A service to handle it.

- Nehmo -
We pay .081 US$/KWH here in Kansas City. 9 feet can accomodate any
car. And your using unlikely on times. But your estimated operating
cost would be acceptable to many - particularly if the road were
critical.

--
Joseph Meehan

26 + 6 = 1 It's Irish Math