Solar Roadways - Another farce

[charby]

Actually,that's a really bad idea, liability wise.  Glass has a very low co-effiecent or friction, and even worse when wet.  Lots of slip and fall injuries, you'd be paying many, many, many times more just in lawyer fees then any possible energy savings.

Probably no worse than glazed ceramic tiles.

[charby]

Ah, so "it pays for itself" ...when everyone else pays a little for your system.
Got it. :/

So are college educations at state schools.

[onions!]

Actually,that's a really bad idea, liability wise.  Glass has a very low co-effiecent or friction, and even worse when wet.  Lots of slip and fall injuries, you'd be paying many, many, many times more just in lawyer fees then any possible energy savings.

I don't know,panels made to be trod upon might be manufactured with a rough texture more like a few thousand five sided pyramids per square foot.These little bumps would provide traction and would also focus el Sols rays onto a very specific spot.Then there's the fact that a massive surface area with an(admittedly)less than optimal conversion rate would still yield benefits.
  Cost is still the stumbling block. 

[KD5NRH]

My buddy just spent $6800 on a system that generates 4000 watts of power when the sun shines.

$1.70/watt?  Where did he find this setup?

As for the solar roadway, ever notice those gouges in the roadway from somebody having a bad blowout?  Imagine those costing $3-400 per linear foot to fix instead of a couple bucks worth of hot patch.

[charby]

$1.70/watt?  Where did he find this setup?

As for the solar roadway, ever notice those gouges in the roadway from somebody having a bad blowout?  Imagine those costing $3-400 per linear foot to fix instead of a couple bucks worth of hot patch.

His FIL sells them, probably got it at cost.

I've been to his FIL's deer camp in the north, completely run by solar, except for the range and water heater, which are propane. Nearest power line is close to 15 miles away.

Flushing toilets, running water, electric lights, refrigerator, pretty sweet for an outpost deer camp. Too bad the soils and growing season isn't productive for agriculture, be a great place to wait out the zombie apocalypse.

[KD5NRH]

I've been to his FIL's deer camp in the north, completely run by solar, except for the range and water heater, which are propane. Nearest power line is close to 15 miles away.

Solar preheat on the water would save him a fair bit of propane.  I can't see doing PV->heater, but if he's getting the PV cheap enough, it might be a decent option.  Tank type solar water heaters can be had fairly reasonably though; I'd just want some way to protect it the rest of the year with such an intermittent use as a deer camp.  It would suck to have something that gets used 1-2 months a year damaged by hail or animals in the off season.

[Scout26]

Probably no worse than glazed ceramic tiles.

And you notice they aren't used much for walking areas (Un glazed tiles are different), and unless you cver it with ground glass, it will still suck as a walking surface once it's wet.

Plus imagine a slip and fall where your customer ends up in broken glass,  Not good.

[charby]

Solar preheat on the water would save him a fair bit of propane.  I can't see doing PV->heater, but if he's getting the PV cheap enough, it might be a decent option.  Tank type solar water heaters can be had fairly reasonably though; I'd just want some way to protect it the rest of the year with such an intermittent use as a deer camp.  It would suck to have something that gets used 1-2 months a year damaged by hail or animals in the off season.

My do that now, been a while since I have been to the camp, his FIL is pretty all about going as much solar as possible.

[charby]

And you notice they aren't used much for walking areas (Un glazed tiles are different), and unless you cver it with ground glass, it will still suck as a walking surface once it's wet.

Plus imagine a slip and fall where your customer ends up in broken glass,  Not good.

Pools, gym showers, lots of wet areas use glazed tile.

Hell even trowel finished cement is slick as snot when wet.

If the glass surface was roughed up some, slickness could be reduced.

[birdman]

Pools, gym showers, lots of wet areas use glazed tile.

Hell even trowel finished cement is slick as snot when wet.

If the glass surface was roughed up some, slickness could be reduced.

And the scattering would increase dramatically, with a huge reduction in power.

[Ben]

And the scattering would increase dramatically, with a huge reduction in power.

That there is probably one of the most glaring (ha!) problems. The safer you make the surface for vehicles, the very much less efficient you make it for energy intake, and vice versa. Maybe we need to hold off on these roadways until we have hover cars. :)

[Brad Johnson]

That there is probably one of the most glaring (ha!) problems. The safer you make the surface for vehicles, the very much less efficient you make it for energy intake, and vice versa. Maybe we need to hold off on these roadways until we have hover cars. :)

I dunno... the rougher the texture, the greater the surface area. I could see the texture being designed with a lensing or directional effect in mind.

Brad

[charby]

I dunno... the rougher the texture, the greater the surface area. I could see the texture being designed with a lensing or directional effect in mind.

Brad

Potential there.

[birdman]

I dunno... the rougher the texture, the greater the surface area. I could see the texture being designed with a lensing or directional effect in mind.

Brad

Only the surface area normal (perpendicular) to the direct of the sun matters.  And the problem with directional effects is they change where the light goes as the sun moves--the light is brought to a different spot depending where it came from.

[tokugawa]

This is a classic case of trying to combine two incompatible functions-transportation and energy gain. They probably have over looked the much simpler scheme of generating power by pumping water up a hill and using the down flow to run a turbine and generate power for the pump.......

 And no, I don't mean using the water as an energy storage impound.

[KD5NRH]

This is a classic case of trying to combine two incompatible functions-transportation and energy gain.

Not entirely incompatible, just not compatible in socially acceptable ways.  What is the BTU content of the typical idiot going 10 under in the fast lane when no adverse weather or road conditions exist?

[Firethorn]

Big debate on another forum for this.

My conclusions: Solar car shades would be better in parking lots -use the panels as a roof.  Protects cars from sun & snow.  Proper design up north would have heaters and dump the snow where its easy to deal with.  Pavement would also last longer with the shelter.

The led markings are unlikely to be visible enough in full sun, and the panels too expensive, but might be able to justify themselves in areas light on vehicles but heavy in pedestrian traffic.  Amusement parks, perhaps.

[Brad Johnson]

Only the surface area normal (perpendicular) to the direct of the sun matters..

Correct. Given the additional surface area of a textured surface, it shouldn't be too hard to design the texture to not only keep the exposed area constant throughout the day, but also mimic the amount of area exposed on a non-textured surface of similar dimensions placed directly perpendicular to the sun's rays.

Brad

[birdman]

Correct. Given the additional surface area of a textured surface, it shouldn't be too hard to design the texture to not only keep the exposed area constant throughout the day, but also mimic the amount of area exposed on a non-textured surface of similar dimensions placed directly perpendicular to the sun's rays.

Brad

Sorry it doesn't really work that way (trig), so "shouldn't be that hard" is actually really hard. 
The area of the surface not perpendicular will never be similar to the equivalent perpendicular area.
The more the texture tries to compensate for that, the more shadowing and worse the area ratio becomes.
If there were a way to efficiently use a texture to effectively provide tracking, it would be on every pane line distance,

[KD5NRH]

Sorry it doesn't really work that way (trig), so "shouldn't be that hard" is actually really hard.

https://www.q-cells.com/uploads/tx_abdownloads/files/43_The_influence_of_textured_surfaces_02.pdf

FWIW, pretty much all the large panels (>150W) use a LOP texture on the glass.

My conclusions: Solar car shades would be better in parking lots -use the panels as a roof.

Been there, designed dozens of those.  They work extremely well if the parking is aligned close enough to the right direction.  (rows E-W, cars pointing N-S) though there are some interesting solutions for long N-S rows out there.)

[Brad Johnson]

Sorry it doesn't really work that way (trig), so "shouldn't be that hard" is actually really hard. 

Basic plane geometry and optics science.  No different than designing, say, a Fresnel lens. 

Brad

[birdman]

https://www.q-cells.com/uploads/tx_abdownloads/files/43_The_influence_of_textured_surfaces_02.pdf

FWIW, pretty much all the large panels (>150W) use a LOP texture on the glass.

Been there, designed dozens of those.  They work extremely well if the parking is aligned close enough to the right direction.  (rows E-W, cars pointing N-S) though there are some interesting solutions for long N-S rows out there.)

Basic plane geometry and optics science.  No different than designing, say, a Fresnel lens.  

Brad

Projected area is projected area.  It simply changes it from a sin^2 to a sin curve.

The effective area of a flat plate at an angle to the sun CAN NEVER EXCEED the original area * sin(angle)

My point wasn't that textured coatings can reduce the snell-reflection loss, my point was that since roads are flat, the effective area relative to solar intensity can never "be similar to" the area of the cells...unless the road is in the tropics, and during a few hours on either side of noon.

ALSO,

Basic plane geometry and optics science.  No different than designing, say, a Fresnel lens. 

Brad

Relies on pretty precise geometry...as in, something easy to damage.

While texture to prevent snell loss is easy, what your original comment suggested was texture to avoid angle of incidence loss.  Which IS hard...actually impossible.

[Brad Johnson]

The effective area of a flat plate at an angle to the sun CAN NEVER EXCEED the original area * sin(angle)

Which is precisely the point.  Using geometric texturing, the presented surface area can remain constant throughout the sun's arc while the cell remains stationary. This gives a stable output without necessitating costly, complex, and fallible drive systems.

My comment was a "what if", not a "could fix this specific situation".  A thought experiment and nothing more.

Brad

[Sergeant Bob]

I have not seen the glaringly obvious addressed.

 Assume all other objections are solved.

What is going to be the power output when it gets dirty?

This right here. Roads are DIRTY.

[Firethorn]

This right here. Roads are DIRTY.

Per the site testing shows that dirt tends to knock of about 11% of power generation.  Improper angling due to it being a road and not sloped is another 10% or so.

I've said it before - solar panels aren't so far over the affordability line that you can just give up 20%.  It'd only make sense if they developed some method that made the panels also do solar for essentially free.