OK explain this one!?

[IceBoy]

Hi All,

I have been having condensation problems inside Mrs Ice's car for a while. I finally tracked it down to blocked drainage holes around the bottom of the windscreen which has not all been sorted!!! Big thanks to everyone.

Now I have a new problem....well not really a problem but this is a strange one.

Mrs Ice's car also gets lot and lots of condensation on the outside of the car as well, when others around it don't?!

So I just took a photo. Mrs Ice has the dark grey C-class and mine is the silver E-class estate.

I hope the picture is clear enough but my car has just the roof covered in a tiny amount of dew/condensation. My wifes car is absolutely dripping everywhere. Every square inch of her car is covered in HEAVY dew.

I just don't get it?!

IceBoy

[johnnyBv8]

At a guess.... darker colour absorbs more warmth from the sun during the day than silver does. As the temp drops, moisture in the air condenses on it more than the cooler (ony temp-wise) silver. Hence more dew.

[IceBoy]

Jeeezz Johnny, that is a great theory!

That never even occurred to me.

IceBoy

[Mave]

Why would it condense more on a warmer surface? I'd suspect a difference in cleanliness / waxing between the cars, dirtier car tending to initiate condensation more easily than clean.

[mybrainhurts]

Could just be position. I sometimes get one car misted or frozen and the other one clear.

[northwest monkey]

Voodoo.

[mybrainhurts]

Yes, I do...

[IceBoy]

I'm not sure position has anything to it. They are both parked on my driveway but facing different directions.

It is really weird.

IceBoy

PS. The grey car is totally covered.....everywhere!

[mybrainhurts]

IceBoy said:

I'm not sure position has anything to it. They are both parked on my driveway but facing different directions.

Yes, so are mine. Or on the drive and on the road.

[Swordman]

You wouldn't get more condensation on a warmer surface, it would be the opposite. The thing is, as dark colours absorb more infrared radiation, they also emit more, so during the evening, the temperature would drop lower. Then the water vapour in the air would touch the surface, lose energy and condense to liquid water.

[Momentofmadness]

Mave said:

Why would it condense more on a warmer surface? I'd suspect a difference in cleanliness / waxing between the cars, dirtier car tending to initiate condensation more easily than clean.

+1

[Jimmy No Hands]

That's the optional 'Self-cleaning' part of Mercedes Convenience Pack. Your pauper spec obviously doesn't have this feature. Happy to help.

[shost]

Swordman said:

You wouldn't get more condensation on a warmer surface, it would be the opposite. The thing is, as dark colours absorb more infrared radiation, they also emit more, so during the evening, the temperature would drop lower. Then the water vapour in the air would touch the surface, lose energy and condense to liquid water.

Yes you are referring to the Stephan Boltzman law, and I completely agree with your explanation.

[Mr GrimNasty]

Dew/Condensation/black body radiation/temperature deep space/how do car ports stop frost/what colour is the best emitter/blah blah/Google. Have fun.

[Mave]

I really don't believe that radiation is the dominant heat transfer in this situation...

[baccalad]

You bought the wrong car.

[johnfm]

Black body radiation I expect.

While a black body certainly gets hotter when in direct sunlight, that wouldn't promote condensation.

Condensation occurs when moisture laden air comes into contact with a surface below the temp at which the moisture will condense.

Black bodies cool quicker than non-black bodies. I would suspect the black car gets cooler than the silver one.

[Eighteeteewhy]

northwest monkey said:

Voodoo.

Who do, what you won't, they'll do people.

[craig_m67]

Worst, my wifes dark, dirty and always dripping wet when I reverse park with her on a cold evening thread ever.

Edited by craig_m67 on Sunday 30th November 14:33

[baccalad]

craig_m67 said:

Worst, my wifes dark and dirty causing her to be dripping wet when I reverse park with her on a cold evening thread ever.

Say what? Your wife? Dark and dirty? Dripping wet?