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> But under very hot or cold weather, you will lose AC and Heat At least the "hot weather" situation could be remedied by adding a solar roof and possibly hoo
by the_third_wave 3y ago
> But under very hot or cold weather, you will lose AC and Heat
At least the "hot weather" situation could be remedied by adding a solar roof and possibly hood to the vehicle. While it does not really add much in the way of range extension it does provide power to run AC when it is needed. An average car roof is big enough to provide 400W to 600W which goes a long way in offsetting the power consumed by the AC.
- mcculley 3y agoAs a Floridian who has always consumed a lot of energy trying to keep cool, I am surprised by: "An average car roof is big enough to provide 400W to 600W which goes a long way in offsetting the power consumed by the AC." These numbers don't seem correct to me. What are you using for average surface area for a roof, expected solar collected, and AC consumption?
- rektide 3y agoThe Aptera is a huge beast of a car designed specifically for solar, and I believe the current figure is that it can get 700W at a nice solar optimum. Big sweeping hood, roof, and trunk of solar. I doubt many cars can get 400W. I don't think most cars could maintain even 80 degrees on a 100+ day, but that's just a guess.
- the_third_wave 3y agohttps://en.wikipedia.org/wiki/Aptera_(solar_electric_vehicle) https://en.wikipedia.org/wiki/Aptera_(solar_electric_vehicle... The Aptera is not "a huge best of a car", it more resembles a seed pod on three wheels. The roof and hood area are quite limited due to this shape which leads to the relatively low solar yield.
- rektide 3y agoYeah not as bad as I thought. It is Model 3 sized. I'd heard people reviewing it say they were quite surprised just how big it was. And the width is almost 88 inches at the wheel pods which is indeed quite big. But overall really quite ok size. I almost signed up for a pre-order but their site was broken, the car was so wide, and I definitely dont need one (but man it'd be cool). The total % of solar seems quite impressive to me. The elongated teardrop looks of anything to do quite a good job exposing surface for solar. There is some loss of "fill factor" with cells having some space between them rather than being totally dense. I'd love to see a car that had more solar. I have a hard time imagining it.
- the_third_wave 3y agoThe available roof area of a Skoda Octavia Estate - a common car in Europe - measures 2m x 1m which, given common 21% efficiency PV cells provides 420W at 1000 W/m² irradiance. This is considered a "medium sized" car. Add the hood and 600W is easily reached.
- mcculley 3y agoI have read Tesla owners reporting the AC consuming 1-3 kW. I still don't see how a roof of solar panels "goes a long way in offsetting the power consumed by the AC".
- the_third_wave 3y ago400W to 600W is 40% to 60% of that 1kW you mentioned, that is "a long way" as far as I'm concerned. An AC with a COP of 4.5 - a common rating - will be able to remove 1.8kW to 2.7kW of heating power from the vehicle using just solar power. Put it another way, a 20% efficient PV panel covering most of the vehicle combined with an AC with a COP of 5 should theoretically enable you to negate the total solar irradiance. Since the car is exposed to other heat sources - indirect irradiance, hot roads, hot outside air, warm people inside it - this is not enough to remove all excess heat from the vehicle but it should at least be able to offset direct irradiance.
- mcculley 3y agoI agree that if one assumes the most optimal theoretical possibilities, it would be great.