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The snowblower is one of the best pieces of equiment for clearing snow. The only potential problem is that you have a place to blow the snow to. For some people, that just means blowing it onto their lawn. But for parkinglots and other areas, that isn't a solution. Meet the Steamblower. It's a ride on
machine with a small diesel engine. The front plow works just like a snowblowers except that instead of blowing the snow out the other end, it blows it into a large tank. Since diesel engines reach pretty high temperatures,the exhaust is routed through the tank so that it melts the snow into water. [edit: melted and boiled into steam] Once the snow has melted into water, it is pumped through a filter and injected into the engine, instantly turning into steam. [edit: never mind the filter and injection process]
Snow Removal
http://what-if.xkcd.com/130/
Randall Munroe does the math, but without boiling everything [lurch, Feb 24 2015]
[link]
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And how long would it take this machine to clear a parking lot? Wouldn't the exhausted steam re-freeze and fall back to the ground? |
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It would probably take no longer than a lawnmower takes to mow a lawn. Yes the steam would eventually fall to the ground again but it would have to first evaporate and even then might just make the air more humid. |
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Dunno about "small" diesel engine, but using snow for cooling? [+] |
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I am pretty sure that for parking lots and other areas a snow plow works plenty good. I think you have made the process a bit slower and more complicated without any positive results. |
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One, in your description, you are using waste heat from the engine to melt the snow into water, then using that same heat "in the engine" to turn the water into steam. Looks to me like you are using the same heat twice. |
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Two, in your annotation you say "the steam would eventually fall to the ground again but it would have to first evaporate" Steam is already in gaseous form so does not need to evaporate. But dumping steam into a cold atmosphere is going to cause some pretty severe icing of cold surfaces. Probably starting with street lamps and parked vehicles. |
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//Looks to me like you are using the same heat twice.// In a way yes, but no ICE is in any shortage of heat. Diesel engines are up to 40% efficient, which means for every gallon of diesel that is burned at least 60% is turned into heat. |
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Surely ploughing and salt gritting is more effective? |
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Yes, but why are you heating the same substance from the same source twice? |
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Why not just let the waste exhaust heat boil the water directly out of the large tank the snow is deposited into? Same water, same heat, why process it twice? |
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//Why not just let the waste exhaust heat boil the water directly out of the large tank the snow is deposited into? Same water, same heat, why process it twice?// True. I think i'll edit that. //Surely ploughing and salt gritting is more effective?// Well first off you have to have a place to plow to and second salt would melt it to water, which would freeze into ice... Meaning that you would be worse off than with snow. |
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It just plain doesn't matter what order you take the heat - you don't have enough. No way, period. |
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Let's assume that you're plowing your parking lot when there's 2 inches (let me metricate - 5 cm) of snow on the pavement. Your machine is a ride-on - I'm going to assume about a meter wide. And you said that it would take about as long as lawn mowing, so I will assume a riding lawn mower goes about the pace of a brisk walk = 4 km/hr. OK, 5 cm high * 100 cm wide * the 4000 meters you go in an hour * 100 cm to make those meters cm for consistency = 200,000,000 cc of snow. |
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Density of new fallen very light snow: as little as 7%. Ask any boarder, they'll let you know that the fluffiest, lightest powder is not what you find on your walk. The range goes all the way to 100% (glacier ice), but I won't assume you've procrastinated that long; hey, there's only a couple inches, right? So we'll do a compromise at 15% - windblown, but only a little. That leaves you with 30,000,000 cc of water (a touch less than ten thousand gallons) (Remember, this is per hour, so total will depend how roomy your sidewalk / driveway / parking lot / estate is; horsepower, however, is a rate - so we don't care. Put the reindeer back and quit showing off.) |
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Now, we have got to melt / heat / evaporate all that water - and water has a very good storage capacity for heat. For one cc (which equals one gram) of water, it takes 334 Joules of heat just to melt it. Then 418 more to raise the water temp to 100 deg C, then a whapping 2260 J to get it evaporated. So, total of 3012 J / g, times 30,000,000 grams, is 90.36*10^9 J. |
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A horsepower is a little less than 2.7 * 10^6 J / hr., so you can produce all that with an engine outputting only: |
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(That's 33,466 to heat the snow and 34 to pull it around. No efficiency required.) |
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brilliant [lurch] I saw this idea the other day and was going to run the numbers the same way you have done above, but got to drinking some rum instead. |
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It would be more efficieint to load and haul the snow away. Or just melt and pump it away. |
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Jeez man you're exagerating... I mean it's not like it would take 34 whole horsepower to move the thing. |
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It will once you get 30 tonnes of water on board. |
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[acurafan07] - I'm hoping you won't delete this idea. I mean, it is a rather surprising outcome - the vast majority of people would not guess it would require anywhere near so much power. Thus, this particular idea keeps getting posted, then deleted. I've done this math demo twice before. If you would be willing to keep this in place, we could link to it next time. |
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If you are satisfied just to melt the snow, you can divide the hp needed by 9. You could melt it and pump it into a tanker truck. [lurch]'s numbers are based on 1 hour. The slower you go the less hp you need. By dividing things I figure that one could easily do this job in 8 hours using the hp put out by a Dodge Viper. I am not sure the Viper could tow the tanker truck, but it might be able to handle a long hose. |
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I think if you drive a Dodge Viper it pretty much indicates that you have a short hose. |
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