PDA

View Full Version : Why Don't We Melt Snow?


ducati
02-04-2011, 10:05 AM
I grew up in Michigan and Indiana. We had some good snows every year.
Kids, of course, look forward to a foot or two of snow and getting out of school for a while. I know I did.

But, the fact is that a few inches to a few feet can be troublesome for some cities.
People miss work, emergency workers get stuck, and many more problems.

I was just reading that some cities are considering dumping snow into waterways to get it off the streets and sidewalks, even though it would contain enough salt, chemicals, and trash to give the EPA a stroke.

Plows and snowblowers put it over there instead of here. That can only work so long.

Why not melt it? 12 inches of snow is only an inch of rain. Certainly most areas can use the water in the aquifer. It's going there anyway; why not put it there today instead of March? Damn. Apparently I'm not the first (http://www.boingboing.net/2011/02/02/when-the-mayor-of-bo.html)to think of this...

"What about ice?" you reply? Sure, wet roads can freeze. That's why you dry them.
Here's the best part. No unemployment! The gov't hires every warm body they can find and gives them a case of Brawny or Bounty paper towels, and they follow the melting trucks around and dab up every last drop!

Or perhaps NASCAR, Og help us, already has the answer (http://www.nascar.com/2010/news/opinion/08/19/splash.go.michigan.jet.dryer/story_single.html).

So what's wrong with having a fleet of monkey-driven jet-powered funny cars blasting down Wacker or Lake Shore Drive?:D

Or, and don't anyone steal this idea, 'cuz I'm working on the patent, a truck that scoops up snow into a hopper, boils it into steam, and a jet truck following behind to dry things up? Maybe a single unit that does both. Zambonis do it!

And of course we're going green and powering the the whole system with steam!
(Well, propane or CNG, which are still green!)


Ok, mathletes. Tell me why this won't work because it'll take X amount of energy to melt and dry Y amount of snow. Perhaps the same amount of energy in a mid-size neutron star, or all the remaining fossil fuels on earth.

Otherwise I'm buying a septic tank truck (http://www.pooptruck.com/images/poop%20truck%20001-Optimized.jpg)and converting it...

MikeG
02-04-2011, 10:06 AM
The amount of energy required to turn tons of snow and ice into steam is not inconsequential.

Markxxx
02-04-2011, 10:14 AM
It'll freeze is one huge issue.

I actually tried this when I was a kid. In the backyard we couldn't use salt, 'cause of Mr Dog and I got tired of using kitty litter for traction on recently shoveled back yard walkways.

So I decided to melt the snow. It worked OK, but it always seemed to leave a small residue of water that froze up and was more trouble than it was worth.

Now I was just a teen ager so maybe people doing it correctly could work it. I worked on this and I could never melt the snow so that I didn't wind up with a residue which froze into ice.

And if the temp was above 32F (0C) I wouldn't need to melt it as it would melt naturally anyway.

Also remember even if you could do it corrrectly, a rush of water is often as problematic as the snow itself.

muldoonthief
02-04-2011, 10:17 AM
They do melt snow. The machines to do so are huge, and expensive, and use lots of fuel. Usually they're used in parking lots and the like, not roads, since you've got to park the machine and dump snow into it.

Here's a video (http://www.youtube.com/watch?v=BPzMCy533ps) of one in action.

Leaffan
02-04-2011, 10:25 AM
The amount of energy required to turn tons of snow and ice into steam is not inconsequential.

Exactly. As it is Ottawa budgets $69 million a year for snow removal.

Pleonast
02-04-2011, 10:33 AM
Also remember even if you could do it corrrectly, a rush of water is often as problematic as the snow itself.
Yes. One inch of rain over frozen ground is more disruptive than 12 inches of snow.

Ferret Herder
02-04-2011, 10:47 AM
They do melt snow. The machines to do so are huge, and expensive, and use lots of fuel. Usually they're used in parking lots and the like, not roads, since you've got to park the machine and dump snow into it.

Here's a video (http://www.youtube.com/watch?v=BPzMCy533ps) of one in action.

Yup, I think last night's local (Chicago) NBC station said that the airports here were using them as they were out of space to put snow. There was some footage of one being used, as well.

Omar Little
02-04-2011, 10:51 AM
It is melted. The sun does it once the temp get's above freezing. In the meantime, we deal with it.

kopek
02-04-2011, 11:00 AM
It'll freeze is one huge issue.

I actually tried this when I was a kid. In the backyard we couldn't use salt, 'cause of Mr Dog and I got tired of using kitty litter for traction on recently shoveled back yard walkways.

So I decided to melt the snow. It worked OK, but it always seemed to leave a small residue of water that froze up and was more trouble than it was worth.

Now I was just a teen ager so maybe people doing it correctly could work it. I worked on this and I could never melt the snow so that I didn't wind up with a residue which froze into ice.



There was a commercial version of a "snow flame-thrower" around when I was young (late 50s/early 60s) and it worked about as well as the version you made. It was marketed to the older folks and commercial businesses with lots of sidewalk to be responsible for. And since some communities then were really cracking down on folks pushing snow into the streets --------- It sounded like a good idea. So you took your inch of snow and turned it into .017 of an inch of sheet ice. Unless you went General Westmoreland on it and ran it until your side walk was dry -- in which case you went broke from the fuel (diesel I think or maybe propane) or you cracked you sidewalk from the heating/cooling/heating.


http://i36.tinypic.com/2hnnrlf.jpg

panache45
02-04-2011, 11:09 AM
Mother Nature already melts snow. It's called Spring.

Sunspace
02-04-2011, 11:24 AM
There was a commercial version of a "snow flame-thrower" around when I was young...

http://i36.tinypic.com/2hnnrlf.jpg"Clears stairs (except wood)" :)

Floater
02-04-2011, 11:28 AM
My sister-in-law's neighbour, who lived on a little hill, once, but only once, tried to melt the snow on his driveway by sprinkling it with water. A first it seemed he was successful but the next morning he found that his car had glided down the hill, across the road and into a garden on the other side.

He had just moved out into the countryside from Paris and was not really used to clearing snow.

Pasta
02-04-2011, 11:39 AM
Just to melt one foot of snow on one acre of parking lot (say) would take about 260 gallons of gasoline. If the ambient temperature is 10 deg C below freezing and you want to make the water end up at 10 deg C above freezing so you can put it where you want it without refreeze, then you're up to 330 gallons. The process won't be 100% efficient, so let's call it an even 400 gallons (which would be a not-too-terrible 83% efficiency.)

400 gallons is a lot of fuel for a piddly 1-acre lot (about 200 ft on a side). Way better just to push the snow aside and wait for Spring.

Musicat
02-04-2011, 11:43 AM
And once you have melted it, where is it going to go? Down the gutter? What if it freezes before getting underground? Then you have an ice dam and a worse problem that can only be solved by sucking up the water immediately after melting. Then you have to keep that above freezing until you can dispose of it...

Seems like an unrewarding use of resources if something else is available, like waiting for Spring.

Dewey Finn
02-04-2011, 11:53 AM
It is also possible to keep your driveway or sidewalk clear by warming to above freezing using buried heating pipes or electrical coils. It's also expensive but not as much as melting snow.

Bridget Burke
02-04-2011, 12:05 PM
Yes. One inch of rain over frozen ground is more disruptive than 12 inches of snow.

Off work today, watching TV. All the local TV stations are on 24 hour Weather Watch because the predicted snowfall turned into freezing rain. Hey, look at everybody play bumper cars! (Although most places of work & school are closed down.) Precipitation has stopped but a real thaw looks unlikely until tomorrow.

Of course, Houstonians don't know how to drive in icy conditions. And our many immigrants from chillier climes tend to forget. Just on TV: A dreadful, fatal truck crash; the deceased were from Honduras, where they know even less about cold than we do.

Where people get serious snow, if they melted it, it would just freeze again. Into that nasty ice, instead of pretty, fluffy snow. (Even if my faint memories of South Dakota remind me that it doesn't stay all that pretty for long.)

Duckster
02-04-2011, 12:11 PM
I was just reading that some cities are considering dumping snow into waterways to get it off the streets and sidewalks, even though it would contain enough salt, chemicals, and trash to give the EPA a stroke.

Seems to me that your concern for a government agency is a bit misplaced. The EPA does its best to ensure that the air you breathe, the water you drink, and the food you eat are sustainable for you to have a long and healthy life. Or is the inconvenience of right here, right now travel so paramount that it must be surmounted at the possible expense for you to have a long and healthy life? Your children's lives?

BobArrgh
02-04-2011, 12:32 PM
A few years ago, I worked on an independent WWII movie. We had to film over several weekends. The day before the last weekend, we ended up getting about 5-6 inches of snow, which we had to remove to provide continuity with the rest of the movie. We spent all day Saturday just clearing snow from a field about the size of a football field, the road, and a portion of the field on the other side of the road.

The director had the great idea of getting one of those big propane heater/blowers. It worked great, as long as we were trying to clear a 2-foot by 10-foot path. After about an hour of messing with it, we reverted back to snow shovels, trucks, and tarps.

Absolutely one of the worst days of my life.

CC
02-04-2011, 12:59 PM
Yep - as has been pointed out, Chicago did use melters in this recent snow, primarily at O'Hare. But in the past, they've also dumped lots of snow into the lake. I haven't seen any reference to this method during our recent storm, but with this much snow, it's a worthwhile solution, I think. You can't just shove 2-3 feet of snow off to the side. There IS no off to the side. Everything is covered. When it comes to concerns about what else gets dumped into the lake, it's a matter of balance. Sometimes, for the greater good - mainly, of course, safety, but also convenience, commerce, etc. - you make that choice.

shiftless
02-04-2011, 01:17 PM
Mother Nature already melts snow. It's called Spring.

Using passive solar energy too. Does seem like one of those whacky Southern California ideas though. Seems like a good idea but probably won't really work in practice.

tdn
02-04-2011, 01:30 PM
A few years ago, I worked on an independent WWII movie. We had to film over several weekends. The day before the last weekend, we ended up getting about 5-6 inches of snow, which we had to remove to provide continuity with the rest of the movie. We spent all day Saturday just clearing snow from a field about the size of a football field, the road, and a portion of the field on the other side of the road.

I understand that Peter Jackson faced a similar problem with TTT. Frodo, Sam, and Gollum walking by a stream on a warm spring day. And Gollum wriggling his way after a fish in the stream.

Andy Sirkis deserves an Oscar for even trying that.

bump
02-04-2011, 01:33 PM
There was a commercial version of a "snow flame-thrower" around when I was young (late 50s/early 60s) and it worked about as well as the version you made. It was marketed to the older folks and commercial businesses with lots of sidewalk to be responsible for. And since some communities then were really cracking down on folks pushing snow into the streets --------- It sounded like a good idea. So you took your inch of snow and turned it into .017 of an inch of sheet ice. Unless you went General Westmoreland on it and ran it until your side walk was dry -- in which case you went broke from the fuel (diesel I think or maybe propane) or you cracked you sidewalk from the heating/cooling/heating.


http://i36.tinypic.com/2hnnrlf.jpg

You can still get those:

http://www.harborfreight.com/propane-torch-with-push-button-igniter-91037.html

Granted, it's from Harbor Freight, so it just as likely may burn your face off as melt any ice.

ducati
02-04-2011, 01:52 PM
I don't think you kids are getting the whole idea.

Ducati's Clean & Clear Snow Removal Unit (patent pending) would drive down the street, pulling snow in like a snowblower. The snow is fed to a hopper that's already boiling or hot. Propane or CNG heats the water to steam, which is exhausted into the air. We're not putting water back on the street to freeze. Then the jet exhaust (or whatever 300 to 500 degree air we can make) is blown down to heat & evaporate any remaining ice & moisture left behind.

Or perhaps two jets...
One to blow the road dry and one pointed up; feed the snow into the exhaust stream and it will be evaporated immediately. No hopper needed. This is a work in progress...

Seems to me that your concern for a government agency is a bit misplaced. The EPA does its best to ensure that the air you breathe, the water you drink, and the food you eat are sustainable for you to have a long and healthy life. Or is the inconvenience of right here, right now travel so paramount that it must be surmounted at the possible expense for you to have a long and healthy life? Your children's lives?

It wasn't my idea to dump snow in the river. It's these (http://www.nj.com/news/index.ssf/2011/02/nj_dep_allow_6_municipalities.html)guys. My idea avoids that.
Try paying attention.

And right-now travel is pretty important. Look at the billions in revenue lost from employees not getting to work, the danger in doctors, nurses, etc. not making it to the hospital for days on end, firefighters & paramedics stranded. How about all the cancelled flights when they shut down ORD, JFK, LGA, BOS and more?

A big snowstorm like the NE has this week is costing each state billions of dollars.
I'm thinking a system that gets traffic flowing quicker has some value...

You kids want to get in on the ground floor here, I'll consider taking on some investors! :D

Telemark
02-04-2011, 02:01 PM
I don't think you kids are getting the whole idea.
I don't think you are getting the whole energy cost of what you are proposing, nor the scale of the problem. It's much cheaper for the people who need to travel to buy snow tires and 4WD, and for everyone else to stay home.

vertizontal
02-04-2011, 02:22 PM
... The snow is fed to a hopper that's already boiling or hot. Propane or CNG heats the water to steam, which is exhausted into the air. We're not putting water back on the street to freeze...

But you can't really avoid putting the water back onto the street to freeze.
After you exhaust the steam into the air, it's going to cool. Eventually it will cool down to the dew point, upon which it will then condense onto stuff (typically the ground or street). Now you've got ice. Maybe not right where you removed it from, but somewhere downwind of where you're exhausting it.

Musicat
02-04-2011, 02:49 PM
I don't think you kids are getting the whole idea.

Ducati's Clean & Clear Snow Removal Unit (patent pending) would drive down the street, pulling snow in like a snowblower. The snow is fed to a hopper that's already boiling or hot. Propane or CNG heats the water to steam, which is exhausted into the air. We're not putting water back on the street to freeze. Then the jet exhaust (or whatever 300 to 500 degree air we can make) is blown down to heat & evaporate any remaining ice & moisture left behind.HUGE energy input required. HUGE costs. WAY more expensive than the present day alternatives. Impossible? No. Too expensive? Yes.

Enderw24
02-04-2011, 03:01 PM
I don't think you are getting the whole energy cost of what you are proposing, nor the scale of the problem. It's much cheaper for the people who need to travel to buy snow tires and 4WD, and for everyone else to stay home.

Yeah. You know that whole equal and opposite reaction thing? It's kinda the same concept here. For every degree that the boiler system brings into the mix to elevate the snow to water to steam, you have an equal fight on the other side of snow trying to lower the temperature of the boiler system. With a constant influx of new snow into the system, you're going to require constant energy to keep that heat up to the level you want. Energy = gas = money.

Here's a small scale example of this.
Get a pot of water and put it on a burner. You see how much energy it takes to bring that pot of water to a boil? Now is it nice and boiling? OK, drop an ice cube in it and watch the whole system collapse below boiling while it takes care of the ice cube and tries to push back up to boiling again.

Or skip the water. Get that pot really good and hot. Now throw in an ice cube and watch it sputter and splatter as it instantly turns to water and then boils.
Now throw in an entire bucket of ice cubes. Probably half of them will melt instantly and start boiling but the other half, even inside a pot that was really hot a moment ago, will just sit there as ice until the pot's hot enough again to melt it.

kunilou
02-04-2011, 03:06 PM
Why don't we just dump the snow into volcanoes (http://boards.straightdope.com/sdmb/showthread.php?t=595862)?

Chronos
02-04-2011, 03:42 PM
Ducati's Clean & Clear Snow Removal Unit (patent pending) would drive down the street, pulling snow in like a snowblower. The snow is fed to a hopper that's already boiling or hot. Propane or CNG heats the water to steam, which is exhausted into the air.Oi, now you're suggesting we take it through another phase change? The energy costs just went through the roof, there. It already takes a pretty hefty amount of energy to get from solid below freezing temperature, to solid at freezing temperature, then significantly more than that to get from solid at freezing temperature to liquid at freezing temperature. But now you also want to add enough more energy to get it from freezing temperature to boiling temperature, and then you also want to go through the incredibly energy-hungry liquid-to-gas phase transition, too? You'd need more gasoline than the amount of snow you're clearing.

Oh, and from the OP:
I was just reading that some cities are considering dumping snow into waterways to get it off the streets and sidewalks, even though it would contain enough salt, chemicals, and trash to give the EPA a stroke.Considering, nothing. Every single northern city that has a major waterway already does this.

CPomeroy
02-04-2011, 03:50 PM
Even if you do not directly dump the snow in the water, the runoff when it melts will go there via storm trains in most cities with surface water. Here in Minneapolis, they have painted signs near some of the drains that indicate which body of water they are connected to, so people are discouraged from dumping paint and other waste down them.

elfkin477
02-04-2011, 03:59 PM
They do melt snow. The machines to do so are huge, and expensive, and use lots of fuel. Usually they're used in parking lots and the like, not roads, since you've got to park the machine and dump snow into it.

Here's a video (http://www.youtube.com/watch?v=BPzMCy533ps) of one in action. I don't understand these machines. Cities already load dump trucks up with snow to move it place to place, so why don't they just bring the loads of snow inside? Surely there are garages to store public works machinery. The building would be far cheaper to heat than to buy and run a snow melter, and once the ice melts, you have water 1/12th the volume of the snow to deal with. But as far as I know, no one melts snow in the way I suggest.

sweepkick
02-04-2011, 04:01 PM
The Russians don't mess around when it comes to snow and ice removal:

http://www.automotto.org/entry/in-russia-jet-engines-go-to-work-as-snow-blowers/

Musicat
02-04-2011, 04:12 PM
I don't understand these machines. Cities already load dump trucks up with snow to move it place to place, so why don't they just bring the loads of snow inside? Surely there are garages to store public works machinery. The building would be far cheaper to heat than to buy and run a snow melter, and once the ice melts, you have water 1/12th the volume of the snow to deal with. But as far as I know, no one melts snow in the way I suggest.Are you aware that it uses the same amount of heat to raise 1 unit of water 1 degree, whether it is "inside," "outside," or in a pot, aren't you?

Exceptions...caves (and volcanoes), where you aren't paying for fuel to provide heat.

kenobi 65
02-04-2011, 04:20 PM
Are you aware that it uses the same amount of heat to raise 1 unit of water 1 degree, whether it is "inside," "outside," or in a pot, aren't you?

In other words, you'd be paying to melt the snow via the fuel spent in heating the building, versus the fuel spent in running the snow melting machine. You can't cheat the laws of thermodynamics. If you ask, "but the building's already warm, how does it cost more?", the answer is that, in the process of melting the snow brought into the building, the interior of the building itself will cool down, and will need to be heated back up by the furnace (or whatever is being used to heat the building).

MikeS
02-04-2011, 04:23 PM
Hell, let's do the math. One mile of residential street, 25 feet wide, with an inch of snow on it, will have about 300 cubic meters of snow on it. If snow is about one-tenth as dense as water, then its density is about 100 kg per cubic metre. So you've got about 30 metric tons of frozen water on the street. Melting this amount of water requires about 10 billion joules; heating it to 100C requires 13 billion joules; and turning it to steam requires another 70 billion. The energy content of a U.S. gallon of gasoline is approximately 130 million joules, so we're talking a grand total of 80 gallons of gasoline to melt all that snow, 100 gallons to warm it to boiling, and and another 500 gallons (!) or so to turn it into steam.

So the grand total for your plan requires the energy equivalent of almost 700 gallons of gasoline — multiplied by the number of miles of streets you have and the number of inches of snow that have fallen. (Remember, the calculation above assumed one mile of road with one inch of snow on it.) If, as recently happened, Chicago got a foot of snow, you'd need nearly half a billion gallons of gasoline (or energy equivalent) to melt all the snow. At that rate, it'd probably be more energy-efficient to give everyone in the USA a four-wheel drive SUV and not bother plowing the streets at all.

aruvqan
02-04-2011, 04:32 PM
Actually the EPA has made it illegal to just plow snowbanks into a body of water ...

Which made it absolutely hysterical in the Portsmouth Naval Shipyard when mrAru was duty stationed there. They could not plow the roads off the edge into the river, but they could plow the snow into a drydock and open the gates to let the water in to melt the snow ... :confused::dubious::rolleyes::smack::D

Honestly, those morons decided that 'the snow would melt and dillute the brackish water' despite the snow would naturally melt and run off into the river if left alone piled up on the ground by the river, or plowed into the drydock and flushed ... so WTF.

MikeS
02-04-2011, 04:34 PM
On the plus side, though, this did give me a good problem to assign on the next homework in my thermodynamics class. So some good came out of it.

Telemark
02-04-2011, 04:35 PM
I don't understand these machines. Cities already load dump trucks up with snow to move it place to place, so why don't they just bring the loads of snow inside?
Because all you'd have is a building full of snow and dump trucks full of snow lined up outside with no place to put it. The energy cost and logistics are well beyond what you are thinking. The building would basically have to be a power plant doing nothing but melting snow, and it still probably couldn't keep up.

Telemark
02-04-2011, 04:36 PM
Oh, and from the OP:Considering, nothing. Every single northern city that has a major waterway already does this.

As mentioned below, not any more they don't.

Dewey Finn
02-04-2011, 04:45 PM
I don't understand these machines. Cities already load dump trucks up with snow to move it place to place, so why don't they just bring the loads of snow inside? Surely there are garages to store public works machinery. The building would be far cheaper to heat than to buy and run a snow melter, and once the ice melts, you have water 1/12th the volume of the snow to deal with. But as far as I know, no one melts snow in the way I suggest.
In addition to the amount of energy needed to melt the snow, the other problem is that there isn't enough room in the public works garages to store all of those dump trucks indoors.

scr4
02-04-2011, 04:59 PM
Many cities in Japan have sprinkler systems (http://www.google.com/images?q=%E6%B6%88%E9%9B%AA%E3%83%91%E3%82%A4%E3%83%97&um=1&ie=UTF-8&source=og&sa=N&hl=en&tab=wi&biw=1333&bih=925) on roads to melt snow. They usually use groundwater which is warm enough to melt the snow without additional heating.

mnemosyne
02-04-2011, 06:44 PM
I don't think you are getting the whole energy cost of what you are proposing, nor the scale of the problem. It's much cheaper for the people who need to travel to buy snow tires and 4WD, and for everyone else to stay home.

Because all you'd have is a building full of snow and dump trucks full of snow lined up outside with no place to put it. The energy cost and logistics are well beyond what you are thinking. The building would basically have to be a power plant doing nothing but melting snow, and it still probably couldn't keep up.

Although the cost isn't really something municipalities who rarely get snow can afford, if you're going to have lots of snow and don't want the city grinding to a halt every couple of weeks, you do what Montreal does; physically remove the snow from the streets and dump it at designated dump sites.

Montreal uses giant snow blowers to load up dump trucks, which drive to specific locations (I know one is an unused rail yard, another is part of the ports) and dump the snow. The entire city gets cleaned up within about a week, with major arteries being clear 48 hours after a storm. We had a good dumping of snow on Wednesday; half our street got done last night, the other half gets done tonight - they split it because of on-street parking. If you leave your car parked on the side that's going to get cleared, the city tows your car and leaves it on a side street somewhere, and fines you (I don't know how much).

Then, when spring rolls around, the snow melts. After a heavy winter, the last bit of now very filthy snow tends to disappear by August or so!

Montreal budgets (http://ville.montreal.qc.ca/portal/page?_pageid=5637,30739566&_dad=portal&_schema=PORTAL)about $145 million a year to clear all of its boroughs.

Video (http://www.youtube.com/watch?v=pE6N7CDV-9s)of the process, because it's so damn cool!

chrisk
02-04-2011, 06:53 PM
Back when I was going to school at York University, (which would be in the later 90s,) after one huge blizzard I remember people saying that somebody in charge had 'sent in the Army' to deal with the snow. What the Army apparently had, for some reason, was big machines that would do all this - it would melt the piles of snow left by the plows and run the water down the storm drains in the street.

I don't think I actually saw one of the melter machines, but I believe that I did see some of the snow piles suddenly vanish over the course of a day or so. And the explanation for why this wasn't done every time it snowed was, yes, the cost of running the machine. But there was so much snow all over the place, even days after the blizzard, that it was a major problem for getting back to business as usual. (I think I even remember something about people whose cars had been plowed under who couldn't dig them out because there was nowhere to dig out too.)

t-bonham@scc.net
02-04-2011, 07:31 PM
As mentioned below, not any more they don't.Well, they do, but not directly.

Most northern cities (like here in Minneapolis) have locations (empty lots, parkland, river flats, etc.) where they dump snow during the winter. Then when spring comes, it melts, and makes its way to the Mississippi River, eventually. But along the way it is filtered through the ground, creeks, lakes, wetlands, etc. so that it's much cleaner by the time it actually gets into the river (or an aquifer). Also has the advantage that this takes a while, so the risk of flooding is reduced.

outlierrn
02-04-2011, 07:57 PM
So what's wrong with having a fleet of monkey-driven jet-powered funny cars blasting down Wacker or Lake Shore Drive?:D


I'd have thought the price of sunglasses and cigarettes would be prohibitive right there.

Magiver
02-04-2011, 08:12 PM
The Russians don't mess around when it comes to snow and ice removal:

http://www.automotto.org/entry/in-russia-jet-engines-go-to-work-as-snow-blowers/OMG, that's the old Rolls Royce Nene engine the Soviets reverse engineered for the Mig-15. It's a 1940's design.

A simple idea would be to vacuum up the snow into a trash compacting style truck which would squeeze it into water. pull up to a sewer and dump as needed.

Sunspace
02-04-2011, 08:18 PM
Squeeze it into water? How? All you'd get is snowballs! I mean, unless you were using cosmic-style pressures or something, and you'd have to check the phase diagram of water to be sure.

Magiver
02-04-2011, 09:52 PM
Squeeze it into water? How? All you'd get is snowballs! I mean, unless you were using cosmic-style pressures or something, and you'd have to check the phase diagram of water to be sure. Squeeze it with a hydraulic ram. Pressure = heat. It's the reason turbochargers need intercoolers. You could also run the trucks exhaust through pipes around the chamber to ultilize scavenged heat.

So to summarize, you heat the snow in the process of sucking it up, compressing it, and heating it with engine heat.

kunilou
02-04-2011, 09:54 PM
Hell, let's do the math. One mile of residential street, 25 feet wide, with an inch of snow on it, will have about 300 cubic meters of snow on it. If snow is about one-tenth as dense as water, then its density is about 100 kg per cubic metre. So you've got about 30 metric tons of frozen water on the street. Melting this amount of water requires about 10 billion joules; heating it to 100C requires 13 billion joules; and turning it to steam requires another 70 billion. The energy content of a U.S. gallon of gasoline is approximately 130 million joules, so we're talking a grand total of 80 gallons of gasoline to melt all that snow, 100 gallons to warm it to boiling, and and another 500 gallons (!) or so to turn it into steam.

So the grand total for your plan requires the energy equivalent of almost 700 gallons of gasoline multiplied by the number of miles of streets you have and the number of inches of snow that have fallen. (Remember, the calculation above assumed one mile of road with one inch of snow on it.) If, as recently happened, Chicago got a foot of snow, you'd need nearly half a billion gallons of gasoline (or energy equivalent) to melt all the snow. At that rate, it'd probably be more energy-efficient to give everyone in the USA a four-wheel drive SUV and not bother plowing the streets at all.

Hell, let's do a little more math. My small suburban town has 27,000 residents and 221 miles of street. The city doesn't call out the plows until there's at least 2" of snow already on the ground.

So, to melt the two inches of snow on the 221 miles of street takes approximately 35,360 gallons of gasoline. Assuming the city gets a break on the price of gas, and can get it for $2.50 a gallon, that works out to $88,400 per snowfall, or $3.27 per resident for a rather piddling snowfall.

Now this area averages about 20 inches of snow per year. Let's say only half of that comes in snowfalls of more than 2 inches, leaving 10 inches per year that has to be plowed. Now we're talking 166,800 gallons of gas to melt the snow, with a total cost of $417,000, or $15.44 per resident, per year.

Damn good thing I don't live in Buffalo.

Nunzio Tavulari
02-05-2011, 12:12 AM
Suppose we used a 1920's Style Death Ray to vaporize the snow?

And it could be used to eliminate flies and ants during a Summer picnic as well. In the Fall to get rid of fallen leaves. In the Spring to disappear noisy children that wake me from my afternoon nap.

BigT
02-05-2011, 12:53 AM
Yes. One inch of rain over frozen ground is more disruptive than 12 inches of snow.

Am I the only one who initially read this as sarcasm? I was all set to explain how ice is often more dangerous than snow, but now I think I was just reading wrong.

BigT
02-05-2011, 01:03 AM
<double post>

Nunzio Tavulari
02-05-2011, 01:57 AM
Suppose we used a 1920's Style Death Ray to vaporize the snow?

And look, it's been perfected. I knew today's youth were more than a bunch of sexting slackers.
http://www.dailymail.co.uk/sciencetech/article-1351935/Eric-Jacqmain-invented-Death-ray-dish-intensity-5-000-suns.html

Dag Otto
02-05-2011, 03:07 PM
Suppose we used a 1920's Style Death Ray to vaporize the snow?



Why, when you could use the 1940's Style Melt Ray?


OMG, that's the old Rolls Royce Nene engine the Soviets reverse engineered for the Mig-15. It's a 1940's design.

Johninsana
02-28-2015, 03:55 PM
I know im late to this discussion this is my first post too

NYC has 10,000 km of roads. If their all 2 lanes thats about 6m wide and lets say they get 1m of snow per year. I looked up the amount of roads, and their probably larger than 2 lanes and this also doesnt include any municipal parking lots or sidewalks etc. So 1m of snow is probably on the high side but its a reasonable assumption. I looked up the density of snow and it ranges from 100-800 kg/m^3. 100 makes the easiest math. 10,000,000 m of roads x 6m wide x 1m of snow= 60,000,000 m^3 of snow/yr. thats at least 6,000,000,000 kg of snow per yr and when you melt it it would still be the same weight in water. Latent heat of fusion for water is 334kj/kg so you need 2,004,000,000,000 kj to melt the snow or 2x10^15 j. Thats on the scale of the largest nuclear weapons. 1kWh is 3.6x10^6 j and in NYC electricity is just under 20/kWh your looking at costs on the order of $200,000,000 with 100% efficency. And this is also if the snow is already at 0C if its colder it will use more energy to raise the temp of the snow before changing it to water. With another measure a barrel of oil has around 6x10^9 j so you have to burn around 1,000,000 barrells of oil once again at 100% efficency so near $50,000,000 at current prices. NYC has a snow removal budget of ~$60,000,000. It would seem that burning oil would be a good idea(1,000,000 barrels is on the very low end of estimated) but in reality it would probably be well below 50% because you cant capture all the heat and oil prices are pretty low at this point not to mention sll the pollution.

Freudian Slit
02-28-2015, 04:00 PM
It'll freeze is one huge issue.

I actually tried this when I was a kid. In the backyard we couldn't use salt, 'cause of Mr Dog and I got tired of using kitty litter for traction on recently shoveled back yard walkways.

So I decided to melt the snow. It worked OK, but it always seemed to leave a small residue of water that froze up and was more trouble than it was worth.

Interesting...how did you melt it?

Steophan
02-28-2015, 06:33 PM
If you burn enough oil, you'll reduce the need for clearing snow in the future, so it's a win-win situation.

Arrogance Ex Machina
02-28-2015, 10:43 PM
Interesting...how did you melt it?

Markxxx was banned like a year or two ago so I doubt he'll return to tell us the secret. Maybe this (http://what-if.xkcd.com/130/) will tell you everything you need to know about melting snow, though.

Guinastasia
02-28-2015, 11:28 PM
Wouldn't you also have to worry about floods?

md2000
02-28-2015, 11:46 PM
IIRC, the melter referenced in the video was supposed to dump the meltwater down the storm sewer. Even in the dead of winter, many of these will be open; pipes are deep enough to never freeze (imagine the damage if they did - pipes wouldn't unplug until May, and all April the city would flood from melt and rain).

The logic was that many snow dumps in the Toronto area were getting to be tens of miles out of town, in crappy stop-and-go traffic, so the cost of hauling a dumptruck load of snow too far was comparable to the cost of melting it. A place like Ottawa might be small enough the fuel calculation goes the other way, cheaper to haul to the outskirts.

The EPA rules are not as stupid as they sound. If you dump a huge load of road snow directly into a river, it breaks through any ice and there is a huge amount of road salt, car exhaust and leaking oil, and garbage, all dumped into the water at once. A giant snow dump that melts over 3 months in spring will trickle that pollution in slowly, diluted by rainwater and added to the river's water in small stages as it flows by. Garbage and sand likely remains behind at the site for cleanup after the melt.

For the same reason, the snow melters, if used as a major means of snow clearance, risk sending dollops of polluted water into the local river. Probably for that reason they are not recommended.

enipla
03-01-2015, 08:12 AM
Here in the central Colorado rockies, for the rural roads, they use 6 wheel drive articulated graders with a plow on the front, and a shoulder blade on the side. Quite an impressive machine. The articulation allows them to 'crab' a bit sideways, and also allows them to turn around at the end of the road (like mine). They can cut about a 20-25 foot wide path of snow with one pass.

Even while the plow on front moves most of the snow, the operators will also use the grading blade to clean up and cut into the hardpack. The operators are quite talented.

We only got a couple of inches of snow last night so I doubt they will bother with it, but one may come down the road today. donno.

Guinastasia
03-01-2015, 08:20 PM
Yep, flooding is a concern:
Melting may create a watery mess in the spring (http://www.bostonglobe.com/metro/2015/02/12/another-boston-snow-worry-all-going-melt/qUoAtE2eOjZkswZpwGNRIJ/story.html)

What Happens When It Melts? Floods 'More Than Likely' in N.Y. (http://www.nbcnews.com/news/weather/what-happens-when-it-melts-floods-more-likely-n-y-n252186)

TheUsual
09-16-2017, 05:14 PM
Revisiting an old thread because this general topic is on my mind. The problem I have with most of the responses is that they ignore the fuel that is already used to power the snow plows and the sand trucks. If you are replacing those vehicles, not adding to those vehicles, then the fuel costs should not be higher. But I think the move it to mimic those poop sucking devices used in Paris. Instead of melting the snow per the OP, or pushing it to the side (as currently happens with plows), build a truck that has a large tank the size of the salt holders or slightly larger. The truck would suck up the snow, melt it in the tank and then take the water to a location to dump it. The reason to do this is to reduce the snow mountains during heavy storms and cut down on the ice when the snow melts and freezes. Again, I'm not talking about adding an extra fuel cost; rather, the goal is to shift fuel costs into snow removal rather than simply pushing snow to curbs or surrounding cars.

PoppaSan
09-16-2017, 07:01 PM
Revisiting an old thread because this general topic is on my mind. The problem I have with most of the responses is that they ignore the fuel that is already used to power the snow plows and the sand trucks. If you are replacing those vehicles, not adding to those vehicles, then the fuel costs should not be higher. But I think the move it to mimic those poop sucking devices used in Paris. Instead of melting the snow per the OP, or pushing it to the side (as currently happens with plows), build a truck that has a large tank the size of the salt holders or slightly larger. The truck would suck up the snow, melt it in the tank and then take the water to a location to dump it. The reason to do this is to reduce the snow mountains during heavy storms and cut down on the ice when the snow melts and freezes. Again, I'm not talking about adding an extra fuel cost; rather, the goal is to shift fuel costs into snow removal rather than simply pushing snow to curbs or surrounding cars.

But the snow does not magically fall where the melt machine is so you still need to spend the fuel and man-hours that are currently plowing the snow to the side of the road to collect the snow for the melting system. Plus in my area (western shore of Lake Michigan), the plows are out for the early part at least of every major storm, keeping the roads passable until the late evening, They then pull off for the night and attack the fallen snow in the predawn hours. Sucks to be getting home from work at midnight.

aceplace57
09-16-2017, 07:13 PM
I'm considering heated snow mats.

Apparently they've been available for a long time. Proven technology.

Especially in my location. We typically get at most two brief ice/snow events a winter. There's always several days warning that it's coming. Plenty of time to roll out a mat. Plug it in just as the snow begins.

The danger of a broken hip or leg worries me more as my wife and I age. One fall could mean months off work and medical bills.

My deck is the biggest headache. It's over two feet off the ground. Ice/snow stays on it several days longer than it does on the ground. The cold air under the deck keeps refreezing the mess.

The advantage too a heated mat is the snow/ice never gets a chance to accumulate. Moisture can't freeze on a heated surface.

I'm still researching and trying to confirm these can be used on wooden decks.

I'm not interested in keeping my driveway clear. Our city doesn't have snow plows. Roads here are impassable right after snow & ice. A clear driveway is useless when the street in front is icy.

https://goo.gl/images/expcXw

friedo
09-16-2017, 07:18 PM
Your power company is going to love you.

aceplace57
09-16-2017, 07:38 PM
I'm thinking about trying a small mat. See how effective it is and how much my electric bill increases.

A 24x36 inch mat will keep a clear area in front of a door. Not a big cost to test whether these things work as advertised.

They won't clear a snow covered area. They need to be plugged in just before a winter storm hits. We typically get two a year.
https://www.amazon.com/HeatTrak-HCM24-3-Carpeted-Snow-Melting-Door/dp/B001E5CUHG

AncientHumanoid
09-16-2017, 08:57 PM
I'm thinking about trying a small mat.

WeatherTech?

aceplace57
09-16-2017, 09:09 PM
I didn't notice any particular brand. I linked the first hit on Amazon with a high rating.

I'd guess one company's mat with heating strips is as good as another.

They all have to pass safety tests and get the Underwriters Laboratories seal.

scr4
09-16-2017, 09:31 PM
The problem I have with most of the responses is that they ignore the fuel that is already used to power the snow plows and the sand trucks.

OK. Let's make a pessimistic assumption that a snowplow only gets 1 mpg fuel efficiency while plowing snow, and has an 8' wide plow. That means the plow can clear 1 mile of a road lane with 1 gallon of fuel.

What if we instead take that gas and use it to melt snow? 1 gallon of gasoline has 33.4 kWh = 1.20e8 Joule of energy. Water has heat of fusion of 334 J/g, so that amount of energy can melt 360,000 grams = 360 kg of snow. If the snow is 30% density of water, then that's only 1080 liters of snow, or 38 cubic ft. If there is 4 inches of snow on the road, 1 gallon of gasoline can only melt snow over 15 feet of the road lane.

Riemann
09-16-2017, 09:47 PM
So, that solution is obvious. Take the money that you would have spent on the huge amount of fuel to melt the snow, go and stay in a luxury resort in Mexico until spring.

Chronos
09-16-2017, 09:51 PM
It's scary how many people can't do the math. It's even scarier the number of people who don't even seem to realize that the math can be done.

Dewey Finn
09-16-2017, 10:14 PM
The problem I have with most of the responses is that they ignore the fuel that is already used to power the snow plows and the sand trucks.OK. Let's make a pessimistic assumption that a snowplow only gets 1 mpg fuel efficiency while plowing snow, and has an 8' wide plow. That means the plow can clear 1 mile of a road lane with 1 gallon of fuel.

What if we instead take that gas and use it to melt snow? 1 gallon of gasoline has 33.4 kWh = 1.20e8 Joule of energy. Water has heat of fusion of 334 J/g, so that amount of energy can melt 360,000 grams = 360 kg of snow. If the snow is 30% density of water, then that's only 1080 liters of snow, or 38 cubic ft. If there is 4 inches of snow on the road, 1 gallon of gasoline can only melt snow over 15 feet of the road lane.
Also, it's not as if you can take the fuel that the snowplow used and instead use it to melt snow. The snow-melting truck also has to move down the road.

aceplace57
09-17-2017, 12:13 AM
The snow plow's engine heats water that circulates through the radiator. There's also the heat from the exhaust pipe.

That's two heat sources generated automatically during any routine plowing operation. I'm sure a third source of heat would still be needed. Perhaps a propane burner heating a tank of water? The three sources combined is a lot of heat energy.

A bit of engineering could, perhaps melt some of that snow instead of just pushing it into a huge pile.

I'm not suggesting a specific design. But there are heat sources that could potentially be used. I'm sure a third source of heat would be needed and that would require fuel.

That doesn't address what to do with the water or how to dry the road to prevent icing.

I'm just suggesting possibilities in the spirit of the thread's original post.

2nd Law
09-17-2017, 03:11 AM
In my hometown, they do melt the snow on city streets and sidewalks with waste heat from the local power plant.

Holland, Michigan Snowmelt System (https://www.cityofholland.com/streets/snowmelt)

Robot Arm
09-17-2017, 04:46 AM
I'm considering heated snow mats.

Apparently they've been available for a long time. Proven technology.

Especially in my location. We typically get at most two brief ice/snow events a winter. There's always several days warning that it's coming. Plenty of time to roll out a mat. Plug it in just as the snow begins.My idea, should I ever build a house of my own, is to dig a two-foot-deep pit where the driveway will be, line the bottom with gravel for good drainage, put in some short posts, then build the driveway out of the same sort of metal grating that's used for the road surface of drawbridges. In the winter, the snow will fall through the grating. If it doesn't melt until spring, who cares? As long as I don't get more than two feet of buildup, I'm fine.

Chronos
09-17-2017, 07:25 AM
You think that metal gratings don't get snow piled up on them?

scr4
09-17-2017, 07:40 AM
My idea, should I ever build a house of my own, is to dig a two-foot-deep pit where the driveway will be, line the bottom with gravel for good drainage, put in some short posts, then build the driveway out of the same sort of metal grating that's used for the road surface of drawbridges. In the winter, the snow will fall through the grating. If it doesn't melt until spring, who cares? As long as I don't get more than two feet of buildup, I'm fine.

And how do you keep the pit clear of leaves and other debris? Cleaning out the pit sounds less fun than shoveling snow.

Personally, if I were going to such trouble to avoid shoveling snow, I would build a roof over the driveway. Maybe we should do that for all roads.

enipla
09-17-2017, 07:42 AM
You think that metal gratings don't get snow piled up on them?Metal gratings are quite common for stairs in the Colorado mountains. You'll also see a metal grate inserted in front of entry ways. Actually works well. Unless you drop your keys...

It's also IMHO a bit of a problem for dogs.

scr4
09-17-2017, 08:02 AM
I'm not suggesting a specific design. But there are heat sources that could potentially be used. I'm sure a third source of heat would be needed and that would require fuel.

Please read my post above again.

Waste heat still comes from the fuel. Even if you capture and use all the waste heat, and you are burning 1 gallon per mile, it will melt snow from less than 15 ft of road out of that mile. The "third heat source" needs to be enough to melt snow for the rest of the mile, i.e. 5265 ft. That's 351 gallons of gasoline per mile. Or 270 cubic ft of compressed natural gas at 2400 psi.

Darren Garrison
09-17-2017, 09:20 AM
Personally, if I were going to such trouble to avoid shoveling snow, I would build a roof over the driveway. Maybe we should do that for all roads.

Snow would drift in from the sides, so you would have to close those in, too. Essentially, you would need to build aboveground tunnels.

Dewey Finn
09-17-2017, 09:20 AM
My idea, should I ever build a house of my own, is to dig a two-foot-deep pit where the driveway will be, line the bottom with gravel for good drainage, put in some short posts, then build the driveway out of the same sort of metal grating that's used for the road surface of drawbridges. In the winter, the snow will fall through the grating. If it doesn't melt until spring, who cares? As long as I don't get more than two feet of buildup, I'm fine.
If you want a snow- and ice-free driveway, you can run radiant heat tubing (perhaps filled with antifreeze) under it. This is easier if you use the same sort of heating for the house.

md2000
09-17-2017, 10:19 AM
In Toronto where a most high rise apartments have a ramp to underground parking, the ramps are cleared of snow and ice with heaters embedded in the concrete... for drainage they have the telltale fish bone pattern of groves directing the water down the middle to a drain. Of course the cost is spread over a hundred or more apartments, and there needs to be some way to turn the heat on when snow is forecast. Melting as it falls is more useful and safer than waiting. Draining to the heated Center prevents building a dam of ice along the edges. Not sure the optimal configuration for a driveway but fortunately few are perfectly flat.

Qadgop the Mercotan
09-17-2017, 10:53 AM
It's scary how many people can't do the math. It's even scarier the number of people who don't even seem to realize that the math can be done.
Innumeracy is frankly as great a problem as illiteracy, but much more well hidden.

Riemann
09-17-2017, 11:19 AM
Innumeracy is frankly as great a problem as illiteracy, but much more well hidden.

We think there's a problem, but we haven't the faintest idea how to quantify it.

Riemann
09-17-2017, 11:20 AM
It's scary how many people can't do the math. It's even scarier the number of people who don't even seem to realize that the math can be done.

The snow plow's engine heats water that circulates through the radiator. There's also the heat from the exhaust pipe.

That's two heat sources generated automatically during any routine plowing operation. I'm sure a third source of heat would still be needed. Perhaps a propane burner heating a tank of water? The three sources combined is a lot of heat energy.

A bit of engineering could, perhaps melt some of that snow instead of just pushing it into a huge pile.

I'm not suggesting a specific design. But there are heat sources that could potentially be used. I'm sure a third source of heat would be needed and that would require fuel.

That doesn't address what to do with the water or how to dry the road to prevent icing.

I'm just suggesting possibilities in the spirit of the thread's original post.

Just two posts later?

Qadgop the Mercotan
09-17-2017, 12:20 PM
Just two posts later?
Yeah, and not an uncommon event either.

Depressing, isn't it? :(

Lightnin'
09-17-2017, 12:23 PM
Snow is a surprisingly good insulator. Heck, look at how warm it can get in an igloo.

Riemann
09-17-2017, 12:37 PM
Snow is a surprisingly good insulator. Heck, look at how warm it can get in an igloo.

That's the air trapped in the snow, though, so I don't know how significant a factor that is for deliberate melting? The fundamental issue is the large specific heat capacity and latent heat of fusion for water.

dtilque
09-17-2017, 01:18 PM
There's an obvious soliution. Go to your local nuclear power plant and get some spent fuel rods. They always have a bunch that they'd like to get rid of. Bury them under road. You could break them up and bury a piece ever few meters to extend them.

Voila! Two problems solved!

Muffin
09-17-2017, 01:24 PM
Revisiting an old thread because this general topic is on my mind. The problem I have with most of the responses is that they ignore the fuel that is already used to power the snow plows and the sand trucks. If you are replacing those vehicles, not adding to those vehicles, then the fuel costs should not be higher. But I think the move it to mimic those poop sucking devices used in Paris. Instead of melting the snow per the OP, or pushing it to the side (as currently happens with plows), build a truck that has a large tank the size of the salt holders or slightly larger. The truck would suck up the snow, melt it in the tank and then take the water to a location to dump it. The reason to do this is to reduce the snow mountains during heavy storms and cut down on the ice when the snow melts and freezes. Again, I'm not talking about adding an extra fuel cost; rather, the goal is to shift fuel costs into snow removal rather than simply pushing snow to curbs or surrounding cars.

What you have proposed is Toronto's MetroMelt, which has been used by Toronto and Montreal for over forty years. As moves down the street, snow dumped into it's tank is melted and drains down the storm sewers.

scr4
09-17-2017, 02:45 PM
What you have proposed is Toronto's MetroMelt, which has been used by Toronto and Montreal for over forty years. As moves down the street, snow dumped into it's tank is melted and drains down the storm sewers.

...by using an enormous amount of fuel.

Though these specs (http://trecansnowmelter.com/60pd.htm) indicate better than 100% efficiency; at a fuel consumption rate of 86 gallons diesel fuel per hour, it should only be able to melt 35 tons of snow per hour, but it claims 60. It does say its tank must be filled water first, so I can only assume that it produces slush rather than completely melted snow.

Muffin
09-17-2017, 07:06 PM
From 1960: Esso's vision of the future of snow removal. Count the number of fuel tankers attached to the snow-melter. (https://media.treehugger.com/assets/images/2014/02/19bftbv777c87jpg.jpg)

Riemann
09-17-2017, 07:09 PM
...Count the number of fuel tankers attached to the snow-melter.

To their credit, at least they could do math.

Muffin
09-17-2017, 07:14 PM
Diesel or gas are nowhere near as cost efficient at removing snow as solar as plowing and waiting for spring. It the cost of transporting to dumps that gets weighed against melting machines.

Enola Straight
09-18-2017, 08:26 PM
Back during the blizzards of '93 and '96 Philadelphia resorted to dumping snow off the bridges into the river.

http://www.phillymag.com/news/2017/03/13/philadelphia-blizzards-1993-1996/
https://cbsnews3.cbsistatic.com/hub/i/r/2003/02/20/cc54e662-a642-11e2-a3f0-029118418759/thumbnail/620x350/42ff5904d024bed6b94a324614b72c8b/image541322x.jpg

Dag Otto
09-18-2017, 10:16 PM
From 1960: Esso's vision of the future of snow removal. Count the number of fuel tankers attached to the snow-melter. (https://media.treehugger.com/assets/images/2014/02/19bftbv777c87jpg.jpg)

As I'm regrettably subscribed to this zombie, I'll just say:

Ah, a 1960's Style Melt Ray!







sorry