Solar Roof Vs 5 PM Sun

I am not sure on your location but living in Dallas, TX. 5 pm is where the hottest temps are recorded for the day, so I can see it making a big difference around here even if the sun is at a lower position than the middle of the day...

 

I am also in AZ, and I find the technology amazing. The other huge benefit is that you can start your air before you get in the car by pressing the button on the key, it starts blowing cool immediately when you get in if the solar fan has been on.

The car is sweet!

 

And you have to find a parking spot far away from office building ... so much for hauling around those dead weight. I think an aluminum window shield will do just fine.

 

That's a bummer. The 5pm-6pm window is the vast majority of when I'd really want it to keep the car cool. I'm in no hurry to buy, though, so I'll continue to keep an eye on people's experiences with it-- particularly those of you in Arizona.

I suppose you could always park the car on a huge, tilting platform to keep it lined up...

 

Best solution is to find a west facing hill to park on.

Or bring ramps.

 

Always try to park facing east so the angle of the solar panel is toward the west and that bloody big windscreen is facing away from the sun. Isn't it great that the Prius has tiny back windows. (Not according to me but other PCers who complain of bad rear vision.) Ceramic or metallic window tint will help too.

 

Remember that the solar vent is working to counteract solar heating, not high ambient temperature. Low sun means less solar heating, so less need for venting.

As for high temperatures in the late afternoon, it's not going to do any good to pull hot air into the car for cooling. The solar vent is just a vent, not a cooling device. It only works when the external temperature is lower than the internal temperature, which is what happens in the sun.

Tom

 

Low sun shines straight in vertical window surfaces but (apparently, from initial reports) does not sufficiently illuminate the horizontal solar panel to run the cooling fans. HTMLSpinnr's observation that his fans stop around 5 are particularly interesting to me-- he's in Arizona as well, and 5pm is not a time of day where the sun has stopped making things brutally hot. It is, however, late enough that a horizontal solar panel might not work well enough to drive the fans. That's why solar panels on buildings are angled up and faced toward the south rather than laid flat.

There's probably no easy answer for this, either-- it would require a battery for the fans in the evening, more panels on the sides of the car, or a tracking panel.

 

Just open all the windows when you get into your car to evacuate all the super hot air in the car, I keep them open until the car start moving for a few minutes, the a/c won't be cooling at 100% anyway. Just help the a/c do its job.

 

Just a correction - solar panels are angled south to maximum production due to the tilt of the Earth's axis.

Depending on your latitude, but assuming you're in the USA, somewhere around 20 degrees angled south will maximize yearly production, but if you are trying to maximize production for summer, the angle will be less (sun is closer to directly over head) or maximum production for winter, the angle will be more (sun is closer to the horizon.

To maximize production for 5pm summer heat, the panel needs to be tilted towards the sun, which sets in the west.

Ideally, the panel would raise when the car is parked and track the sun. Now that'd be a neat trick!