Use of Asphalt Paved Surfaces For Solar Heat

vg30e writes "It seems that a company in the Netherlands has found a way to use asphalt paved surfaces as solar heat collectors. Flexible tubes under the surface of the road collect heat from asphalt pavement using water as the working liquid. The heated water is stored underground for later use in defrosting the road, or heating buildings. With all the miles of highway in the continental US, this might be a viable way of collecting massive amounts of thermal energy."

Comments

Re:Old idea from Universty of Chicago

[madsenj37]

The idea is one thing, the implementation another. He may have been a visionary, but the buck stops there.

This is called a heat pump

[Colin Smith]

And they've been around for decades. You can buy a system today, in all civilised countries. They work in exactly the same way as your refrigerator.

Re:This could help safety also...

[Anonymous Coward]

The problem we have isn't an availability of energy. We have more energy than we know what to do with. The problem is an economical way of converting it to the desired form, and moving it to the places where it is needed. Oh, and do that without ruining our planet, hopefully.
That said, this is another solution in search of a problem; I can't imagine that it would be even remotely economical to embed tubes in asphalt during construction. Then, remember how roads get cracks in them? That's gonna tear your tubes apart, or at least leave them exposed enough that something else (a passing semi or snowplow) will do the job. Then you've got leaks. Now that's not too bad; you're using water, so it's not a big deal if you leak some. But over time you're going to have to repair the tubes, probably before the roads need to be repaved. And those leaks could, in some cases, lead to destruction of the roads; if you've leaked water into all the tiny little crevices inside the blacktop, and then the temperature drops below freezing, PRESTO! you have a road with tons of little cracks in it. And next time it freezes, there will be tons of larger cracks.
I have a feeling that the numerous drawbacks to this approach will negate the benefits one might get. Bonus points for trying to attack the problem from a relatively unexplored perspective, but there are at least a hundred other alternatives that are probably better than this. I'd be willing to bet that a system designed specifically for focusing the sun's energy and capturing it in water will be both cheaper and more efficient than this chimera.

Re:May as well bring back steam trains

[FroBugg]

Except that your analogy is ridiculous. The proposed heat pump is a closed system. Stick the water in once and you're done. Using a pump to circulate it requires very little power compared to what can be saved in heating by using the heated water.

Yes, the construction costs will be high, but that's what a lifecycle cost analysis is for.

Freezing?

[Dan East]

If any of that water were to freeze it would turn the roadway into a cratered, cracked and potholed disaster.

Dan East

Re:Freezing?

[hjf]

you would have to be really stupid to use tap water on a system like that. add some antifreeze and that's it.

Re:Old idea from Universty of Chicago

[lpangelrob]

It's an interesting idea. There are a lot of factors to weigh in, and the primary one is cost - odds are pretty good that doubling the initial cost of construction of a freeway this way won't result in nearly that much savings on maintenance (even accounting for less resurfacing, potholes, and salt spraying) down the line.

Then there's the fact that having a pump fail anytime during the cold season would almost certainly result in the destruction of the surface, unless there's some sort of way to engineer around this sort of failure.

Anyways, it's mentioned in the article that this isn't a new idea, and in fact warming a surface from below is commercialized on a smaller scale, only using electric power, and with surfaces about the size of driveways. ([1])

On highways and byways, this particular idea would work well on a larger scale only if there were enough other users to offset the initial costs of building the system, and if that engineering problem could be fixed.

Re:Broken pipe

[AmericanInKiev]

Yup, it's the operating costs stupid.
4 minutes MTBF.

KGO morning Traffic report: "We've got quite a back up on 101 northbound, they've been chasing a leak in lane 3 for 2 weeks; hopefully they'll find it, and we can get back to using the road as a - um - road thingy."

Operating costs are often the unthunk Achilles heel. -almost as bad as opportunity cost, and cost of risk.

AIK

Re:I thought of this before you...

[YrWrstNtmr]

I use this same technique to heat my pool. When filling it up in the summer...

Why do you empty it in the fall? Treat it well when you're done for the season, and you don't have to blow 15-20-30,000 new gallons in the spring.

Can't you just admit you're wrong?

[spun]

You failed badly in your analysis. Someone called you on it, and instead of admitting that you're wrong, you dig yourself in deeper. Do you want everyone to think you're stupid?

First, you have no idea what the capital cost of construction will be.

Second, the GP already said "that's what a lifecycle cost analysis is for." Duh.

Third, you have no idea how much water will be used. It will almost certainly be more than millions of gallons. Four hundred people use a million gallons of water in a day, for personal use, energy production, and industry. Per capita water use in the US is about 2,500 gallons a day. Your estimations are so far off base as to be laughable.

Fourth, that's not the point. We can easily use runoff from the roads, which is already contaminated and unfit for other uses. We can continue to use this source to replace any losses, and again, you have no idea of the magnitude.

You just spout words without understanding or any attempt at honest communication, just to try to sway people to your beliefs. It's disgusting to watch, like a retarded chimp flinging poo at passers by.

Re:Can't you just admit you're wrong?

[tjstork]

Fourth, that's not the point. We can easily use runoff from the roads, which is already contaminated and unfit for other uses. We can continue to use this source to replace any losses, and again, you have no idea of the magnitude.

You just spout words without understanding or any attempt at honest communication, just to try to sway people to your beliefs. It's disgusting to watch, like a retarded chimp flinging poo at passers by.

The arguments you've made are unconvincing. I'm sorry. I'd rather have a million people call me stupid than be just another fanboi. In the end, I am completely right.

The GP would have us believe that we can take a solution that works for the tiny country of Norway and do it to the entire United States. That's absurd. Really, where are you going to get the water in the west? Hint - its a desert.

But even in the Northeast US, I don't think this one has been thought through. First we go from getting a lot of water from existing sources, and now, we're talking about collecting rainwater. That's all fine, but I thought we needed that rainwater to go back into the ground and replenish acquifers. Oh, and by the way, the original article has them pumping water into the ground to manage its temperature. They put water into the ground in Ohio already and they've found that there's environmental consequences of doing that as well - it's one of the reasons why you don't see geothermal everywhere.

But think about it, again, from a common sense level. All we're really doing is talking about exchanging the exploitation of one resource, for another, and I just don't think the implications have been thought through at all.

I'm certainly no environmentalist, and in fact, I think most of it is crap, but I'd certainly be proud to stand with them and block any proposal to turn every American highway into a water exchange heat pump until the proposals for doing so have actually been thoroughly studied, piloted in different geographic areas, and really, really understood. What you people are advocating is the kind of "let's just get 'er done" madness that screwed the world up to begin with. Call me stupid as much as you want, but I'm not hopping on board that train.

Using bouncing energy usually backwards

[arete]

As a rule, this idea is usually backwards. In order to gather significant power from this, you're basically increasing the amount of energy the vehicles expend - because for this to work, you have to keep the pavement bouncy enough to generate the power. (Put another way, the vehicle is most efficient if the pavement is very flat and very rigid)

So you're usually sucking energy FROM poorly maintained oil driven vehicles and putting it TO a grid that at least hypothetically could be powered by nuclear or wind at much lower cost and environmental impact.

The major kinds of places this sort of technique is useful: a) because the main problem is that you NEED to be far away and disconnected from the grid... b) where the bounce energy you're trying to capture is orders of magnitude smaller than the actual bouncing action c) where the initial energy is biomechanical, which is both pretty efficient and otherwise hard to optimize further.

Using this to power small road sensors that didn't need to be wired up would be fine. Using it to power an efficient laptop would be fine - if you're actively looking for a way to easily get more exercise. Using it to power a watch is pretty much ideal, which is why this has been around a long time.