CA May Ban Black Cars

You're kidding right?

 

I think all cars should be white. No other colors allowed. I'm going to send an email to Governor Arnold right now. :madgrin:

 

Nope, I'm not.

White reflects light. Dark colors absorb light, then radiate the solar energy as heat. In the interior of a car, here's the results: A lot of light is reflected off the lighter interior colors back out of the windows. The dark interior absorbs that light and warms the stagnant air via conduction. Thus making the darker interior color a hotter car.

The exterior color does not effect interior temperature of the car due to construction. The only effect is from the sun entering the windows. The sunlight passes through the windows and is absorbed by the interior colors. If the interior is a lighter color some of it will be reflected back out but not all of it. That is why the Heat-block for windshield or Tinted-Windows works. Most are light/silver in color to reflect the light and the light does not get shine into the interior of the car, regardless of exterior color.

 

I smell a conspiracy here! You are demanding only white cars. The 2010 Prius does come in white - but at a premium price of $ 220.00 more than of the 6 other colors offered........

Keith

 

That is because white is better.

 

The drying of the paint requires net absorption of energy in order to vaporize the solvent. You want the fastest absorbing/radiating color if drying time is the concern. So the answer is "yes."

 

I was in agreement with details of your analysis up until this point. The construction of the vehicle is going to be perhaps R-2 or R-3 as an insulator as best I can tell. In a hot sunny climate you can fry an egg on a dark surface with direct overhead sunlight. With little insulation the exterior color will definitely have an impact. As to which predominates? They would appear to be roughly the same order of magnitude as driving forces, so I wouldn't place a bet on either one.

This is true as best I can tell. When I tinted my vehicles down in Texas it made a huge difference when entering the vehicle mid-day. Sun shades helped too.

And as to the suggestions from some that just rolling down the windows dissipates the heat...my response is: "only if you are moving." What tends to happen after work when your car is hottest? You get stuck at low speeds for the first 5 minutes or more, getting out of the parking lot, out of the plant, waiting for lights to get onto the main arteries. In a hot climate (particularly a humid one), most of us will run the AC during that time.

Not that I'm in favor of banning black cars.

 

The exterior color is part of the contribution to the interior temperature, the rest is greenhouse effect, the darker the interior the hotter it gets.
Black cars usually have black matching color interior, so it makes the worst of all colors.

 

then first get rid of ur challenger, arnold. why try so hard to be green, cali???

 

White may be better (for many reasons), but it shouldn't cost more...

Keith

 

That may be for sure. So, what the state would gain is the cooling energy for that delta 20 degrees I would certainly have the AC on whether it was 100 degrees inside or 120.

Have you measure when it is not so hot? What was the outside and inside temps?

 

If the interior was hotter than the outside, it has to cool down to equilibrium with the outside air no matter what. Moving just does it faster. If you leave your windows open all day, the inside should be about the same temperature as the outside, right?

 

They should ban cars with UNTINTED windows then. Ultra-reflective tinting keeps the interior cooler. They could require white cars with shiny mirror like tint!

 

But white cars should not be allowed on the street when there's snow on the ground... it's a visibility issue.... and mirror cars never for the same reason.

 

Marketing. :madgrin:

 

Wrong for several reasons. First, the Sun is usually still shining in on the hot summer days when this is occurring , so the "equilibrium" would still be hotter than the ambient air temperature (which itself is likely to be 100+ in various locations I used to live.)

Second, eventually reaching equilibrium is little help if that is going to take half an hour or more with the windows down and barely moving/stopped for lights, etc. I ran at lunch in 100+ F weather, but it was still too hot for me to sit in traffic in the heat without some climate control. Now if one could make an immediate run up to highway speed it wouldn't matter much, but I doubt more than a few percent have that luxury. It's ironic that the time when you most need the rapid air transfer for cool down is also when it is hardest to get it.

Leaving your windows down all day is likely to result in critters in your car as well as drenched seats from popcorn storms. This assumes you live in a place where you aren't also concerned about theft. It was common practice for many of us to crack our windows at the plant, which led to a rush for the parking lot when a brief afternoon rain appeared. Still, this (without the rain) made the cars more comfortable, but not as cool as the ambient air.

 

You are right!

Generic White Paint + $ 220 Marketing BS = Blizzard Pearl.

Keith

 

CA isn't going to ban black autos.

/bank on it

 

It's not totally inconceivable that some pigments would cost more than others.

 

I believe your statement to be correct that some pigments are indeed more costly than others. Until about 30 years ago, the base pigment of most paints was lead oxide because it was: 1) cheap, 2) very white, and 3) chemically stable. Unfortunately lead is very very bad for humans and other living creatures.

Fortunately there was a viable solution - titanium dioxide. It is: 1) very abundant, 2) cheap, 3) not harmful to humans, 4) chemically stable, and 5) very very white. Today it is still the base pigment of most paints.

Now when it comes to "Blizzard Pearl" I still believe that it is mainly $ 219 in marketing BS and $ 1 in titanium dioxide. Being the cheap guy that I am, I wish Toyota Marketing would let me keep my $ 219 and call it "Titanium Dioxide White".

Keith