Solar panels for conventional vehicle fuel saving
Solar panels for conventional vehicle fuel saving
(OP)
Wouldn't putting solar panels on top of the trailer portion of a truck save enough fuel to be economically viable by taking load off the alternator/generator? Even 1 or 2 mpg savings in a long haul truck that spend most of the time in the sun anyway should add up for a vehicle like that, no?





RE: Solar panels for conventional vehicle fuel saving
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Solar panels for conventional vehicle fuel saving
So you'd need storage.
Storage is heavy.
RE: Solar panels for conventional vehicle fuel saving
The problem I see is that the tractor and the trailer are usually owned by diffferent people, neither of which has a financial incentive to help the other.
RE: Solar panels for conventional vehicle fuel saving
RE: Solar panels for conventional vehicle fuel saving
Now you want to put several thousand dollars of fragile plates on top?
RE: Solar panels for conventional vehicle fuel saving
RE: Solar panels for conventional vehicle fuel saving
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RE: Solar panels for conventional vehicle fuel saving
Consider this in the context of what it might take to get 10% to 40% better mpg in a light truck or SUV. Or divide the expectation by at least 10.
Norm
RE: Solar panels for conventional vehicle fuel saving
Just to clarify, it depends on the engine. A tier I or earlier diesel only needs electricity to start and hold the fuel shut-off solenoid. Modern diesels on the other hand are a different story, with ECU's and such.
And I agree with Norm, 1-2 mpg is overly optimistic. They don't even get that with the super low resistance wheels.
ISZ
RE: Solar panels for conventional vehicle fuel saving
For an extreme upper limit, estimate 1000 W / m2 incident and 10 % efficiency. A long hauler towing triple trailers has (as an upper limit) 3 x 8.7m x 2.4m of space available, or a little less than 63 m2.
This sets the upper limit output at 630 W, which is 0.84 hp. Compare that to the aerodynamic drag power requirement for a for a standard (single) tractor trailer, which Google puts at >100hp.
So, the highly optimistic upper limit of savings is <1%. Reality would be only a fraction of that.
For a single trailer, I don't think 200+ W will even help much with refrigeration.
A turbine on the top could churn out some real hp while cruising down the interstate though.
RE: Solar panels for conventional vehicle fuel saving
Cheers
Greg Locock
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RE: Solar panels for conventional vehicle fuel saving
Any idea what the actual hp required is for a semi cruising at highway speed?
22% cells don't sound like the typical low cost production units, but then this isn't my field. If 22% were available and appropriate for mounting on autos, 20 m2 on a trailer top would kick out 2.5 kW (3.34 hp) per trailer using your figures. Not a trivial amount, probably sufficient for some cooling purposes.
There aren't any electric semis to get handy figures for... but another way to look at the concept is if you could squeeze 4 m2 of the same dandy cells on top of a car, you would get (500 W * 8 hr) 4 kW-hr in a sunny 8hr day at work. Thats enough for 1/4 a 16 kW-hr charge in a Chevy Volt, or maybe 10 miles based on the 25-50 mile advertised electric range... If you were rolling for the same 8 hours, you would have extented your range by the same 10 miles while travelling approximately (8 hr * 50 mph) 400 miles, which means a 2.5% range / efficiency increase.
RE: Solar panels for conventional vehicle fuel saving
15 lbs rolling resistance per ton times 40T would be 600 lbs, which at 88 ft/sec = 96 HP. Aero drag is roughly the same at that speed.
Norm