Asphalt Pavement for Power Generation

IMHO, photovoltaic cells are a little expensive and fragile to drive over. Still, it is being tried, but I still think it wouldn't fly on a level playing field without taxpayer subsidies.

http://insights.globalspec.com/article/3050/solar-road-surface-set-for-testing-in-the-uk

Some way to capture the heat might be more practical, but you have to look at the cost of installation and maintenance versus the expected value of energy captured.

Asphalt has high thermal mass.Why not install NH3 tubes under the asphalt,via trenching,and utilize the resulting vapor to power turbines?

The asphalt remains hot enough long after the sun sets to boil ammonia, and could

provide power even on overcast days.

Certainly the output would drop with temperature,but it would not be a sudden change.

It might work. Of course, to get work out of heat you need a cool place to dump the heat. Efficiency = (T_hot - T_cold) / T_hot, according to Carnot. (A nearby river might be nice.)

What happens when there's a leak?? The pavement shifts under load, you have frost heaving, there will be leaks everywhere....we don't have enough road crews to handle the basic repairs necessary now....and I might add traffic is bad enough without having even more interruptions...you want to pump toxic gas under the roads that will leak like a sieve and cause evacuations and traffic disruptions and lawsuits??? A paved highway costs anywhere from $2 to $6 million dollars a mile to build, nobody in his right mind would spend this much money and not have a guarantee that any installed system would last the life of the roadway....This would be a money pit without end.....imo

Commenting only on asphalt's thermal properties, I will leave the photo-optics aspect to people with more knowledge. Modern asphalt is basically bitumen and aggregate (stone or crushed glass) with a few additives to increase the bulk, counter UV degradation and raise the melting point. Bitumen has a very poor rate of heat transfer, that is why it stays hot long after the sun goes down. It is also why it takes a long time after sun rise to warm up. So anything you gain on the swings (after sun set) you lose on the roundabouts (after sun rise). If you wanted to phase shift the sun's heating effect it would work, but an equivalent mass of sand would work equally well at less than 1% of the cost. As a way of extracting heat from the sun and removing the heat to a place where it could usefully be used it is one of the worst materials you could choose.

I was proposing using existing asphalt,which is already covering millions of acres and

seems to me to be an untapped reservoir of solar energy.

I mentioned using NH3 as a heat transfer medium,but other refrigerants would work

just as well,and perhaps, even water.

Asphalt cracks and allows moisture to migrate from the subsoil. It also has to be sealed and repaired frequently. Then there are the conflicts with striping and being covered when cars are parked.

Why not use the light poles and fences for solar collectors instead?

I read about this idea in the local newspaper ( The Press Enterprise)

Southern California Edison proposal is to install ( as they put it ) photo voltage sensors under sections of roadways.

The idea was that the system could generate enough electricity to power up to 10,000 homes ( how they came up with that number could only be through mathematical calculations although reality is often different )

There was no mention in the story about who would pay for this experiment ( I bet you dollars to donuts that the utility customers would get a levy of sorts, kinda like the fees charged by the department of motor vehicles such as the fee for the mentally challenged. )

Of course there was no mention of a public referendum ( usually they do this kind of work out here on a newly paved section of the roadway and most people usually dismiss it as like they forgot to do something )

The idea entailed that vehicles traveling on the section road way would generate power simply by having their vehicles driving on the roadway ( sort of like the reverse of a slot car track )

So, it's a win, win idea for the electrical utility, first they do it without asking, then they charge you for it, while it's being constructed you pay extra for vehicle suspension damage, then when it's done the levy is never rescinded, then they make power off of your dime and they never send you a refund check.

Such as thermopile and piezoelectric generators, combined with photo voltaic cells?

Because two weeks later the sewer, water, gas, cable, telecom... companies will arrive to trench it all up!

Because not all the roof space has been used up yet.

http://www.solarroadways.com/Research/Research

http://newatlas.com/solar-roadways-parking-lot/31780/?utm_source=Gizmag+Subscribers&utm_campaign=94f89528bb-UA-2235360-4&utm_medium=email&utm_term=0_65b67362bd-94f89528bb-90486313

It being worked on. Not sure how much abuse that top temper glass panel would take on a roadway. Initial cost looks high.

Wait for the first person to love a trailer and cut up the road, now you have a energized trailer.

Maybe a car accident, that would be exciting.

I don't know why this cockamamie idea keeps resurfacing. It is one of those for which some decimal point is at least one place off, likely two, and maybe even three.

I read a story about capturing the heat from asphalt pavement and storing it in a thermal mass like a water tank. They claimed there was enough to heat nearby homes throughout the winter.

You really should be wary of whomever "they" are, "they" have been responsible for all manner of chicanery.

I would think that phonon cells might work better than other technologies to recover electricity from the heat in pavements, without changing the road surface. The problem would be incorporating suitably ruggedized phonon battery banks in the subsurface of the paving material. Then the trenching/repaving crew shows up and wipes out the whole entire project.

There are many uses for the low voltage phonon cells, about 1.5 V ouput, but of the combinations I experimented with only produced output resistances as low as a few Ohms. To have "real" power, the parallel-series arrays of these would have to be immense.