Why Not Heated Streets?

[smiling_bandit]

[quote=“Aspenglow, post:18, topic:711788”]

These are being tested in Sandpoint, Idaho: [URL=“http://www.solarroadways.com/intro.shtml”]Solar Freakin’ Roadways![/URL

[quOTE]

Just a random question, but: Solar panels generally aren’t mean to radiate heat, so how does this work at all? And wouldn’t the snow kinda block the solar panel itself?

[tomndebb]

I don’t think that this is really going to be a debate. It has a pretty factual set of answers.

Off to General; Questions.

[Skald_the_Rhymer]

@Anaamika

I would vastly prefer moving sidewalks, if we are going to spend that kind of money. Just imagine how much faster we could get everywhere!

You want to make America even fatter?

[jz78817]

@Little_Nemo

I won’t pretend I’ve done the figures. But my intuitive thought would be that this idea would take a huge amount of energy.

it would. water’s incredibly high specific heat capacity means it takes a tremendous amount of energy just to change its temperature. Never mind getting it to change phase.

this would be an (IMO) criminal waste of energy.

The other problem is that when you melt snow, it doesn’t disappear. It turns into water. And that water is just going to flow to someplace where you haven’t heated the ground and turn into ice, which is generally a worse problem than snow is.

yep. like under that heated roadway, thus heaving it up and leaving it a potholed mess come spring.

[zombywoof]

I believe there are some heated sidewalks in both Aspen and Vail, CO (luxury resort sorts of places, of course.)

[DSeid]

And Oak Park IL.

[Honey]

@Bone

Heated driveways

I’ve seen them. They are neat.

Yup. There a lot of people around here with heated driveways.

[Aspenglow]

@The_Joker_and_the_Thief

No.

I’m not here to defend it or advocate for this caper, I was simply pointing out it was being pursued as an idea. It apparently has enough merit for the Federal Highway Administration to fund it experimentally. Twice.

[davidm]

@Aspenglow

I’m not here to defend it or advocate for this caper, I was simply pointing out it was being pursued as an idea. It apparently has enough merit for the Federal Highway Administration to fund it experimentally. Twice.

I think that may speak more to the competence of the people who decided to fund it than to the merits of the idea.

[EdwinAmi]

Entire resort towns/developments have heated streets in the more ritzy skiing towns of Colorado (Aspen, Vail). Seriously, like the WHOLE downtown attraction area. It’s crazy.
I think one of the reasons it makes sense financially is because of the crazy liability we have

[Aspenglow]

@davidm

I think that may speak more to the competence of the people who decided to fund it than to the merits of the idea.

Of course you do.

[GreasyJack]

Heated roads or driveways also make the most sense in places that get huge amounts of snow but don’t get too cold, which describes most “destination” ski regions but not a whole lot of other places.

[davidm]

@Aspenglow

Of course you do.

Correct.

[bob_2]

I lived in Cardiff as a teenager in the 50s where I learned to drive. There was a hill which was notorious for accidents when it froze and the City council experimented with heating it. I did drive up it once after a light fall of snow and it was clear. What happened to the experiment I have no idea.

Can’t find a cite either:(

[california_jobcase]

In 1969, the Eisenhower bridge was completed across White River in Anderson, Indiana. It has quite a hump in it so it could go over the railroad tracks. Therefore, it had an electric heating system for the winter. Unfortunately, road crews still salted it. The salt permeated the heat strips, corroding them. They never worked again.

[FluffyBob]

The idea of solar roads to melt snow is so silly, ignorant and foolish I have trouble believing it is not a media prank. Just… wow. Besides Joker’s short list of faults, if there is enough energy falling on the road to melt the snow…

Entertaining outlandish ideas long enough to evaluate if they are feasible can lead to impressive achievements. Seems to be Elon Musk’s modus operandi. Some things shouldn’t make it past the stoned musing stage though.

[iamthewalrus_3]

@Jim_B

It wouldn’t take too much energy, I would think. Just like your rear window defrosters, it only has to raise the temperature above freezing. And surely it would easier–and more cost-effective–than all the money we spend on snow plows and rock salt.

:eek:

It would take absurd amounts of energy. It would be vastly more expensive than current methods.

A single lane of freeway is 12 feet wide. A cubic foot of fresh dry snow is about 10lbs of snow. Melting ice requires 334J of energy per gram. So, melting 1 foot of snow on a single lane of a road one mile long takes:

334 J / g * 454 g / lb * 12 feet * 1 foot * 5280 feet * 10 lbs / ft[sup]3[/sup] = about 100 billion Joules of energy. There are ~ 125000 J in a gallon of gas, so that would take 800+ gallons of gas. For a single lane of road, one mile long.

How much do you think the snowplows are using?

And, even if possible, it would be incredibly dangerous, since you’d end up with a thin layer of water underneath the ice and snow on top, which would give any people or vehicles trying to move around on top of it no traction whatsoever.

[iamthewalrus_3]

That was supposed to be 125 million Joules per gallon of gas. The result is correct, I just typoed the input.

[Habeed]

It almost sounds like it would be cheaper and more efficient to just have in sheds along the roadway permanently installed robot snowplows. These machines would sit there year round until there’s snow, then leave their storage sheds and plow the section of road they are dedicated to.

[GreasyJack]

@iamthewalrus_3

A single lane of freeway is 12 feet wide. A cubic foot of fresh dry snow is about 10lbs of snow. Melting ice requires 334J of energy per gram. So, melting 1 foot of snow on a single lane of a road one mile long takes:

334 J / g * 454 g / lb * 12 feet * 1 foot * 5280 feet * 10 lbs / ft[sup]3[/sup] = about 100 billion Joules of energy. There are ~ 125000 J in a gallon of gas, so that would take 800+ gallons of gas. For a single lane of road, one mile long.

Slight nitpick: your calculation seems to assume that one foot of snow = one foot of solid ice. Snow is usually about 90-95% air, so it would take significantly less (though still a huge amount) of energy to melt it.