You may not quite realize for how long roads are impassible to all traffic in northern states. Where I live, a couple hundred miles south of Grand Rapids, the snow and ice still make roads entirely impassible for a total of a week or so every winter; it takes the coordinated effort of hundreds of salt trucks and plows to get it cleaned out enough to drive, bus, walk, or bike on. Then that same effort has to be expended again a couple of weeks later.
Piping existing waste heat underground into a system like this, when the road is uncovered for repair anyway, would make a lot of sense for high-traffic areas so that plows can focus on other locations instead; it would also reduce the salt budget and plow fuel budget, and reduce the maintenance budget for cleanup and repair due to salt damage.
Going even a little bit further north, this would likely be even more effective. In some Michigan cities, roofed streets make economic sense; this seems even more cost-effective and less likely to require heavy repair.
Bike lanes, public transportation, roadway maintenance, and snow & ice clearing are all expensive. None of them have to turn a profit.
The downsides, the same weather that makes the snow and frost also causes shifts in the ground during freeze thaw cycles, causing damage to the road and heating pipes. The warm melt water also enters waterways and cause shifts in seasonal temperatures, messing with fish and insect hatching times causing them to potentially hatch too early for the spring food they rely on.
Since damage to the pipes and to the road tends to be concurrent, they can repair one when they repair the other.
As for the meltwater, this is going to be a fairly small amount of hot water in a regional sense. Snow is fluffy, but it’s about 10x less dense than in its liquid state; meaning that ten inches of snowmelt is the equivalent of only about an inch of rain. That’s about 27,000 gallons per mile of roadway (a mile is about an acre) going into the storm sewers, which is more or less the same amount of water that a large building goes through in a day. But this snowmelt isn’t a daily occurrence, it’s only going to happen a few times a year.
I recognize that I just did a lot of handwaving, but the point is that, to within an order of magnitude, it’s hundreds of times less impact than building another large office building (which cities do frequently).
Building water will often go to sanitary sewers, which has a lot more treatment involved than going to storm sewers, so comparing road melt to a buildings water use isn’t a perfect comparison.
As for repairs, a pothole can easily be patched on the surface relatively quickly by a road crew. A damaged pipe may need additional work such as cutting around the damage, depressurizing the entire system, and replacing the compromised section of pipe followed by a larger patch than needed for a pothole.
a pothole can easily be patched on the surface relatively quickly by a road crew. A damaged pipe may need additional work
Based on the image posted here, it looks like the pipes are flexible and laid several inches below the final grade of the road (look at where the manhole covers are for an estimate of the grade). That will keep the pipes from experiencing much more mechanical action than they can handle, and they’ll be far below the level of a pothole.
They’re also installed in parallel (note the line of fittings crossing the road about halfway up the photo). Any breakage or blockage in one of the loops will be passively compensated for in other lines.
comparing road melt to a buildings water use isn’t a perfect comparison.
I’m not going for a perfect comparison, I’m just going for an order of magnitude. I know that sanitary sewers and storm sewers are different (in fact my city is currently in the middle of a big, multi-decade project to separate the two).
But let’s do the math anyway. So, we’re not talking about the water from a sanitary sewer being super cold here. Water leaving a treatment plant is usually around 68-95°F because that’s the temperature required for the biological reactors that break down the gross stuff. Either end of that range is substantially higher than the melting point of water, so the snowmelt flowing from the storm sewer due to this under-road heating is going to be a great deal colder at release than the treated sewage flowing from the office building.
You may not quite realize for how long roads are impassible to all traffic in northern states. Where I live, a couple hundred miles south of Grand Rapids, the snow and ice still make roads entirely impassible for a total of a week or so every winter; it takes the coordinated effort of hundreds of salt trucks and plows to get it cleaned out enough to drive, bus, walk, or bike on. Then that same effort has to be expended again a couple of weeks later.
Piping existing waste heat underground into a system like this, when the road is uncovered for repair anyway, would make a lot of sense for high-traffic areas so that plows can focus on other locations instead; it would also reduce the salt budget and plow fuel budget, and reduce the maintenance budget for cleanup and repair due to salt damage.
Going even a little bit further north, this would likely be even more effective. In some Michigan cities, roofed streets make economic sense; this seems even more cost-effective and less likely to require heavy repair.
Bike lanes, public transportation, roadway maintenance, and snow & ice clearing are all expensive. None of them have to turn a profit.
Yeah; trains that can be their own ploughs would be communist.
They’re already doing this in Holland, Michigan.
https://www.cityofholland.com/879/Snowmelt-System
The waste heat comes from their power generation.
Nice. Holland seems like a pretty great place.
it is!
The downsides, the same weather that makes the snow and frost also causes shifts in the ground during freeze thaw cycles, causing damage to the road and heating pipes. The warm melt water also enters waterways and cause shifts in seasonal temperatures, messing with fish and insect hatching times causing them to potentially hatch too early for the spring food they rely on.
Since damage to the pipes and to the road tends to be concurrent, they can repair one when they repair the other.
As for the meltwater, this is going to be a fairly small amount of hot water in a regional sense. Snow is fluffy, but it’s about 10x less dense than in its liquid state; meaning that ten inches of snowmelt is the equivalent of only about an inch of rain. That’s about 27,000 gallons per mile of roadway (a mile is about an acre) going into the storm sewers, which is more or less the same amount of water that a large building goes through in a day. But this snowmelt isn’t a daily occurrence, it’s only going to happen a few times a year.
I recognize that I just did a lot of handwaving, but the point is that, to within an order of magnitude, it’s hundreds of times less impact than building another large office building (which cities do frequently).
Building water will often go to sanitary sewers, which has a lot more treatment involved than going to storm sewers, so comparing road melt to a buildings water use isn’t a perfect comparison.
As for repairs, a pothole can easily be patched on the surface relatively quickly by a road crew. A damaged pipe may need additional work such as cutting around the damage, depressurizing the entire system, and replacing the compromised section of pipe followed by a larger patch than needed for a pothole.
Oh, I forgot to answer this part:
Based on the image posted here, it looks like the pipes are flexible and laid several inches below the final grade of the road (look at where the manhole covers are for an estimate of the grade). That will keep the pipes from experiencing much more mechanical action than they can handle, and they’ll be far below the level of a pothole.
They’re also installed in parallel (note the line of fittings crossing the road about halfway up the photo). Any breakage or blockage in one of the loops will be passively compensated for in other lines.
I’m not going for a perfect comparison, I’m just going for an order of magnitude. I know that sanitary sewers and storm sewers are different (in fact my city is currently in the middle of a big, multi-decade project to separate the two).
But let’s do the math anyway. So, we’re not talking about the water from a sanitary sewer being super cold here. Water leaving a treatment plant is usually around 68-95°F because that’s the temperature required for the biological reactors that break down the gross stuff. Either end of that range is substantially higher than the melting point of water, so the snowmelt flowing from the storm sewer due to this under-road heating is going to be a great deal colder at release than the treated sewage flowing from the office building.