Dumbest idea I've even heard in my life

[leroyjenkens]

Maybe they should have thought about the snow problem before they built a city in a place where it snows so much.

The idea is just so stupid. It's one of the most impractical ideas I've ever heard. How many roads would they cover? Just one, or all the roads in the city? Is snow really that bad that you need to change out all the roads in a city for it? Why not just make the cars better able to drive through it?

And I'd also love to see how good your traction is on wet glass.

 

[OmCheeto]

What cracks me up the hardest is that this fool thinks he found an ingenious place to put his solar cells, as if the Earth is running out of surface for them.

Also its funny how ignorant people are about solar cells, they think they exist therefore we can cover up an ocean with them, as if they're made of dirt. Even if the industry can crank out solar polymers faster than humans crank out feces, it wouldn't be enough to do jack.

bolding mine

Actually, they're made of sand.

I like the idea of heated roadways, and considered this a few years back. I work on a fairly steep hill and have witnessed 6 buses jack-knifed trying to go down the aforementioned hill. Melting the ice and snow from at least the steep sections would not be that expensive.

 

[Newai]

How about salt sprinklers in dangerous spots, like curves and hills?

 

[Curl]

How about salt sprinklers in dangerous spots, like curves and hills?

nah that's too simple.

we need a 4 million dollar, alien-tech bulletproof flexglass roadway with 17 layers of nano-tech UHMW synthetic polymer optical grids and computer chips to do the same job done by petroleum waste and salt.

 

[Proton Soup]

what we need is research to build carbon decatubes that we could drive inside of

 

[mugaliens]

Yes, but if you put wings on it, it'll work great!

You know, Russ, I really wanted to do that with my Acura Integra a few years back! Now I want to do it with my truck.

The problem is, light aircraft aren't designed for highway crash safety. Those extra pounds which keep us safe on the highway exact a huge toll on getting the dang vehicle into the air. Yes, it can be done, but my 1991 Acura Integra, with 120 HP would have been huffing and puffing through just about any flight, although it breezed it's way at 120 mph throughout the autobahns of Germany. Similarly, my truck sips less gas per mile at 90 mph than it does at 60, probably because of the tailgate. Still, I computed that if I turned into an aircraft, it would have to be a powered glider, at best. Yes, I could make California at about 100 mph, but using more gas than I'd have used if I'd driven, and at a total cost of 3 times what it takes me to drive to Denver, catch a commercial flight to Sacramento, rent a car to Merced, and back a week later.

Life is grand. Commercial air transportation is a freaking miracle.

 

[bassplayer142]

Wouldn't you get horrible traction driving on glass?

 

[Proton Soup]

Wouldn't you get horrible traction driving on glass?

you could have a rough surface, like sand or concrete. speaking of concrete highways, they do last a long time. but i think the traction and wear on tires is supposed to be worse.

 

[Newai]

Would full-spectrum solar cells be a difference in cloudy weather? Those are on the way.

 

[mugaliens]

Would full-spectrum solar cells be a difference in cloudy weather? Those are on the way.

Here's a thought: Incorporate carbon black in the asphalt roadway to absorb nearly all light.

http://en.wikipedia.org/wiki/Carbon_black" ...

Ok, then how about incorporating very finely shredded rubber tires in the concrete used for roads? Probably too much give. Perhaps incorporating carbon black in concrete might work, but it would take a lot of carbon black. Expensive.

Most asphalt roadways only contain about 5% asphalt, with the remainder being aggregate of stones, sand, and gravel. http://en.wikipedia.org/wiki/Asphalt#Rolled_asphalt_concrete" It's still black, however, absorbs most sunlight which reaches it, and around here (Colorado Springs) those roadways are the first to melt the snow.

This idea linked in the OP really is one of the dumbest ideas I've ever heard.

 

[Jimmy Snyder]

Here are some estimates. I don't intend to defend them so if you have different estimates, just post them. If there are mistakes in my math, please correct them.

1. 10 inches of snow is equivalent to 1 inch of rain.
2. It is not unusual for snow to fall at the rate of 1 inch per hour.
3. 1 inch of snow per hour on a square meter of road is 2.54 * 10^4 g/hr
4. Heat of fusion to turn ice to water is 334 joules/g
5. Heat to melt one hour's worth of snow falling on 1 m^2 is 334 * 2.54 * 10^4 joules = 8.48 * 10^6 joules
6. Heat of sunlight is 600 watts/m^2
7. 600 watts for 1 hour is 2.16 * 10^6 joules

Unless my assumptions and/or calculations are wrong, this idea won't work.

 

[lisab]

Whew...for the price of some of these ideas, it would be more cost effective to just put a roof over the road.

 

[NeoDevin]

Here are some estimates. I don't intend to defend them so if you have different estimates, just post them. If there are mistakes in my math, please correct them.

1. 10 inches of snow is equivalent to 1 inch of rain.
2. It is not unusual for snow to fall at the rate of 1 inch per hour.
3. 1 inch of snow per hour on a square meter of road is 2.54 * 10^4 g/hr
4. Heat of fusion to turn ice to water is 334 joules/g
5. Heat to melt one hour's worth of snow falling on 1 m^2 is 334 * 2.54 * 10^4 joules = 8.48 * 10^6 joules
6. Heat of sunlight is 600 watts/m^2
7. 600 watts for 1 hour is 2.16 * 10^6 joules

Unless my assumptions and/or calculations are wrong, this idea won't work.

You are assuming that snow falls at an average rate of 1 inch per hour, and/or that no energy can be stored during times of less snowfall.

While 1 inch per hour may not be uncommon, I sincerely doubt anywhere gets 1 inch per hour averaged over the entire winter (assuming winter lasts 3 months, that's ~185 feet of snow, imagine shoveling that!). If energy can be stored (as I believe was proposed in the article) when it's not snowing, and the road heated only while/after it snows, then you'll find that your energy calculation depends on the average rate of snow fall, rather than the maximum.

 

[FlexGunship]

For sure, the guy who has designed this contrapment must have ample evidence that it will work.

 

[FlexGunship]

Whew...for the price of some of these ideas, it would be more cost effective to just put a roof over the road.

That... is not a bad idea...

 

[NeoDevin]

Whew...for the price of some of these ideas, it would be more cost effective to just put a roof over the road.

And then we could put solar panels on the roof!

 

[FlexGunship]

And then we could put solar panels on the roof!

And then drive on the roof too!

 

[NeoDevin]

And then drive on the roof too!

And... we're back to square one...

 

[FlexGunship]

And... we're back to square one...

Grr... you're right. Maybe they could just put a roof on it.

 

[Kawakaze]

Wow Curl, your attitude stinks. I am not convinced of this idea myself either, I thinks its a lot of aggro to go through, when you can just use a plough. Who are you to call people retarded, with the dumbest idea ever, and so on? So many inventors in history have been considered retarded, crazy, or even heretics. What have you invented lately?

 

[Mech_Engineer]

Just to back up Jimmy's calcs, I made a similar calculation a little more than a year ago when someone posted asking about a heated road infrastructure to replace snowplows: https://www.physicsforums.com/showthread.php?t=351186&highlight=snow

Basically the power requirements to melt snow which is exactly 0*C and falling at a rate of 1 in/hr is about 190 W/m^2. Problem is, 1) there's no sunlight when it's snowing! and 2) solar irradiance would have to be on the order of a sunny day to keep up with melting the snow. So unless this magical road has magical energy storage, give it up. You're better off with a dark colored road, snowplows, and salt/deicer. Then when the sun does come out, the dark colored road absorbs the solar energy and melts the snow.

Well I've got a good reason why it can't completely replace snow plows: power requirements for a snow storm.

Say for example you have a 1-mile stretch of 2-lane road you want to keep snow free even during a fairly slow snowfall of 1 in/hr (heavier storms can be 6 in/hr). We will say the road is 7.5m (24.6 feet) wide, the snow falling has a density 8% that of water, and the snow falling is excatly 0 degrees C which means we only have to deal with water's enthalpy of fusion.

1 in/hr of snowfall correlates to 311 m^3/hr over a 1-mile stretch of road, or 25,000 kg/hr of snow. If we want all of this snow to melt right away and not accumulate, we need to put enough power through the heating coils to melt the snow as it falls. Given that water's enthalpy of fusion is 333.5 kJ/kg, that equates to a necessary power throughput of 2.3 MW for a single mile of 2-lane highway. Obviously the power requirements are substantial, at about 1.4 kW/m for 1 in/hr snowfall.

So say hypothetically tiny town X wants to completely get rid of their snow plow fleet and replace it with heated roads that are powered by wind turbines. They have a total of 5 miles of road, all 7.5m wide 2-lanes, that they want to be able to handle a maximum of 4 in/hr of snow. That would mean they would need a total power input of 46.1 MW to heat the entire road system during heavy storms (4 in/hr), and 11.5 MW during light storms (1 in/hr).

That sounds like a pretty significant wind farm/battery bank to me, especially for only 5 miles of road. It's obvious how this would scale up for larger areas, and shows why from a power standpoint a heated road infrastructure system just isn't practical.

 

[NeoDevin]

Just to back up Jimmy's calcs, I made a similar calculation a little more than a year ago when someone posted asking about a heated road infrastructure to replace snowplows: https://www.physicsforums.com/showthread.php?t=351186&highlight=snow

Basically the power requirements to melt snow which is exactly 0*C and falling at a rate of 1 in/hr is about 190 W/m^2. Problem is, 1) there's no sunlight when it's snowing! and 2) solar irradiance would have to be on the order of a sunny day to keep up with melting the snow. So unless this magical road has magical energy storage, give it up. You're better off with a dark colored road, snowplows, and salt/deicer. Then when the sun does come out, the dark colored road absorbs the solar energy and melts the snow.

You're making the same faulty assumptions that I pointed out about Jimmy's post.

 

[Kawakaze]

I can't vouch for the accuracy of these figures, there is a huge range of answers online. The figure of 1.4kW/m^3 crops up more than once for the amount of solar energy hitting Earth's surface, I have no idea how much of that is usuable by a solar cell, whether it is the average over a day, or peak during a sunny day. Assuming you stored it in batterys when conditions were good, and some hyper efficient solar cells.

If the numbers are good, ss this not at least possible without using external cells, ie only the ones under the road? I agree with the consensus this certainly isn't the best idea ever, but for a feat of "because we can" engineering, is it not at least feasable? Respect to the guys who actually crunched the numbers by the way.

Edit, one more thought, one the snow had melted, it would need to stay melted. If the panels gave up the ghost, all that would be acheived is to have made a huge ice-rink.

 

[Proton Soup]

speaking of dumb, how about a truck with a big magnifying glass held out front to concentrate the sun's rays and evaporate the snow?

 

[NeoDevin]

Edit, one more thought, one the snow had melted, it would need to stay melted. If the panels gave up the ghost, all that would be acheived is to have made a huge ice-rink.

Any sort of drainage (holes, slope, etc.) would solve this problem.

 

[JaredJames]

Any sort of drainage (holes, slope, etc.) would solve this problem.

Then the drains would need heating.

Whenever we get heavy rain, the first things to get overwhelmed are the drains. Long before the rivers and streams around us hit capacity. We get light flooding because the drains can't cope.

I also noted over the last few weeks of cold weather, that one of the first things to freeze over are the drains. Some rather interesting ice formations on the grids.

 

[Mech_Engineer]

You're making the same faulty assumptions that I pointed out about Jimmy's post.

I'll answer them.

You are assuming that snow falls at an average rate of 1 inch per hour, and/or that no energy can be stored during times of less snowfall.

The calculations make no assumptions about where the energy comes from, I specifically pointed out the "road" would need energy storage in my post (remember? I called it magical). Problem is, periods between snowfall would need to be sunny for a "solar road" to store energy in the first place.

While 1 inch per hour may not be uncommon, I sincerely doubt anywhere gets 1 inch per hour averaged over the entire winter (assuming winter lasts 3 months, that's ~185 feet of snow, imagine shoveling that!).

The average over the winter isn't important, it's the total output during the storm that matters, and how long the output has to kept up. For a 6 hour storm at 1 in/hr, you would need to store 8.4 kWh per meter of road length (EDIT- this also assumes all stored energy is going into melting snow, not conducting into the ground as well). The amount of energy storage you're proposing is truly fantastic (basically 7 large deep-cycle car batteries every meter of road length). Keep in mind the storage also has to maintain capacity in sub-freezing conditions, not an easy task...

It's yet another thing that makes this proposal ridiculous compared to snow plows, or even putting a roof over the entire road!

 

[Kawakaze]

Any sort of drainage (holes, slope, etc.) would solve this problem.

In theory yeah, but I can tell you, my driveway is about 10 degrees inclined, i spread normal salt (stupidly not rock salt) over it to get the ice off in winter, the water did drain, but it hit -10 at night and the thin layer of ice that formed was enough to put me flat on my arse when I stepped onto it! :D

 

[Mech_Engineer]

The figure of 1.4kW/m^3 crops up more than once for the amount of solar energy hitting Earth's surface, I have no idea how much of that is usuable by a solar cell, whether it is the average over a day, or peak during a sunny day.

For what it's worth, that is probably peak solar irradiance on a sunny day in summer at sea level. Average over the course of a year (day and night) is something like 100-150 W/m^2.

 

[Mech_Engineer]

In theory yeah, but I can tell you, my driveway is about 10 degrees inclined, i spread normal salt (stupidly not rock salt) over it to get the ice off in winter, the water did drain, but it hit -10 at night and the thin layer of ice that formed was enough to put me flat on my arse when I stepped onto it! :D

I think salt is only effective to about 0*F, the freezing point of heavily salted water...