EEVblog #1269 - Solar Roadways SR4 DATA Hilarity!

[floobydust]

For steep concrete driveways we use heaters to prevent them from icing during winter. Typically 50W/sq. ft on a thermostat. Here that would be 220W per hex module or 6.6kW for the system. Assuming 50% duty cycle, 3.3kW the heaters are roughly using 79kWh per day say $0.10/kWh for $7.90/day or $237/month in grid electricity cost plus the display blinky LED drain.

The system is really putting out nothing for energy, 110W peak power at 12/08/2019 partly cloudy and under 0.3kWh for the past week!
Basically costing $8/per day heating costs for this installation over winter, entirely contributing to global warming.

Compare the cost to hiring someone to shovel the snow off the panels. Let's pay them $25/hr and assume 10 minutes work to clear a snowfall, and it snows 12 times per month, for $50/month snow clearing labour cost.
Basically costing $1.67/per day for snow removal over winter or 1/5 the cost of heaters.

In reality, the modules seem to have a 1206 or two running hot for a heater and you have to include possible gains over the summer to see net payoff.
Engineers do math for a reason, and solar systems aren't that hard to figure out if they are a fantasy.

[Red Squirrel]

The SR setup is hopeless at dealing with snow.  On a road you would still need snow plows... imagine the damage a snow plow would make to those!

Regular roads from asphalt aren't that sturdy either. The snow plows they use over here have a piece of rubber / plastic at the bottom in order not to damage the road.

Yeah I have to laugh when they come in spring and do "cold patching" on pot holes.  The next year the snow plow just rips those patches right out. 

[EEVblog]

Yeah I have to laugh when they come in spring and do "cold patching" on pot holes.  The next year the snow plow just rips those patches right out.

How do you integrate the inductive light sensors at every intersection?

[Red Squirrel]

Yeah I have to laugh when they come in spring and do "cold patching" on pot holes.  The next year the snow plow just rips those patches right out.

How do you integrate the inductive light sensors at every intersection?

Like for traffic lights?  I've seen some on some streets (can see where they cut to install it) but most  of our intersections don't have it and it's just a timer.   I imagine the wires are deep enough like about a foot or so.    I guess they can't be too deep though or they won't be as effective.

[floobydust]

Inductive road sensors (as an add-on) are small groove wet-saw cut as a square loop in the asphalt, with some caulk on that.

A bigger problem is ice jacking if water gets in and freezes. That will make things move or crack. Freeze-thaw cycles cause terrible potholes every year.
So another reason heating and melting snow might be a bad idea if the water gets underneath the SR4 module's drain (which is likely frozen too), I would expect the modules to get trashed.

[Red Squirrel]

Actually now that you mention it I think it may just be that, a groove, then a rubber sealant on top.  They go in with a tiger torch to melt it in so it blends decently with the road and makes a fairly solid fix.  At least that's how they fix cracks sometimes. not sure what the product is if it's rubber or something else, but it holds up decently.  May even be roof tar.

[rrinker]

 When you have money, you can do interesting things. Race car driver Mario Andretti has an Italian Villa style home with a block driveway - can't really run a plow on that as it would rip up the blocks. There are water pipes under the block - in Summer, the heat is used to heat the water in his pool. In winter, warm water is circulated through the pipes, and in a light snow, it's enough to keep the block warm enough that the snow never sticks. But get a heavy snowfall, and it's game over, it can't keep up, the snow eventually cools the block enough to be able to accumulate, and it gets all covered like any other road. Not sure what they do then - keep circulating the water until it melts, or end up hand shoveling it all, or use a snowblower or plow with a generous clearance setting at the bottom (since the warm water can probably easily melt an inch of snow off, set the blade high to avoid scraping any brick, and let the heated block take care of the rest).
 It's partially solar - he has solar panels that heat the water - but there's no way to get enough heat just from that. I've driven past during light snow - other driveways and sidewalks are covered, the main road is not due to traffic, and neither is his driveway.

 I do like the idea of putting a standard solar panel installation on the roof there and compare the output to the Solar Freakin Roadways blocks. Heck, just a single panel could probably outgenerate those silly things.