Which color of tank will heat water faster from the sun? Black tank or silver tank?

[magentawave]

Which tank filled with water will warm the water faster when placed in the sun - a silver stainless steel tank or a black plastic tank? I'm thinking the black plastic tank will heat faster but can anyone direct me to some data that proves this or tell me your experience with this please?

Thank you very much.

Steve

[inetdog]

Which tank filled with water will warm the water faster when placed in the sun - a silver stainless steel tank or a black plastic tank? I'm thinking the black plastic tank will heat faster but can anyone direct me to some data that proves this or tell me your experience with this please?

Thank you very much.

Steve

The black plastic tank will absorb more of the incoming sunlight. Common oil paints will have a similar absorption in the infrared regardless of paint color; painting the tank will not show as big a difference between black and white as you would expect.
s
A mirror finished stainless tank will reflect both visible and infrared light and so absorb a lot less heat.

If you try the experiment of putting a piece of plastic and a piece of steel in the sun, your estimate of the temperature of the steel by touch will be misleadingly high because it will conduct heat to your skin a lot faster. To see the real difference you need to use a thermometer.

[green]

The solution would be to paint the steel tank black. Steel will transfer the heat energy faster than the plastic, but shiny stainless steel will reflect more of the energy. I have a few experiments going on with solar thermal hot air, and I'm surprised at some of the results. I have a heater made of a shiny, black, thick plastic. It seems to put out warmer air than the other black steel collectors. I think it's beacuse the plastic transfers the energy slower, allowing the collector to maintain a higher temp. I guess my point is to be carefull interpreting your data when experimenting. In my case these are two totally different designs with different air flow patterns internaly. Consider what it is you want to accomplish, heat water to a higher temp, or heat more water faster, lots of factors to consider.

Sorry... I shouldn't drink coffee at night.

[magentawave]

Here is what I'm doing...

I want to use a pump garden sprayer like this black plastic one http://www.walmart.com/ip/RL-Flo-Mas...rayer/13376326 or this stainless steel one http://www.rlflomaster.com/sprayers/112.htm as a simple portable camp shower. I was thinking of getting the stainless steel tank so I can heat it on my camp stove when there isn't any sun. Instead of painting the stainless steel tank black, how well do you think it would absorb the suns energy if I sleeved it in a black canvas material? Maybe put a velcro seam on the sleeve so I can remove it when I have to put it on the stove?

[russ]

Instead of painting the stainless steel tank black, how well do you think it would absorb the suns energy if I sleeved it in a black canvas material? Maybe put a velcro seam on the sleeve so I can remove it when I have to put it on the stove?

I thought you wanted to hot the metal but instead you are insulating it.

[green]

Russ is right. The canvas won't tranfer heat very well and that makes it an insulator, preventing heat from getting into your tank. A word of caution, don't heat your tank with the lid on. Those tanks are meant to be pressurized but not to extreme pressures like you would get if you heat them to boiling. They might explode if the pressure gets high enough. Plus there are plastic and rubber seals used in them that will melt and fail. Even if you were to just heat the water in a pot on the campfire and pour it into a tank like these, the rubber seals and plastic control valve would melt and fail.

Maybe what you should do is just use a black 5 gallon bucket with a spigot and hose at the bottom. Just let it sit in the Sun and warm up, then hoist it into a tree with a rope and let gravity do its thing. Plus you could use the bucket to put things in for the hike.

[magentawave]

Yes you are right about the canvas cover insulating the tank. Any ideas for a super thin removable black material that wouldn't insulate? Of course there is always black paint meant for high heat.

[Rockfig]

Black paint works a treat

Yes you are right about the canvas cover insulating the tank. Any ideas for a super thin removable black material that wouldn't insulate? Of course there is always black paint meant for high heat.

I have used black high heat paint with great results

[cssolar]

I have used black high heat paint with great results

I Think black would be better , as it is less reflective isnt it ?

Tony

[inetdog]

I Think black would be better , as it is less reflective isnt it ?
Tony

That depends on the frequency of light that you are talking about. Some black paints reflect more of the infrared light than some white paints.
So not all black paints are equal.

[Naptown]

A selective coating would be best.

[cssolar]

solar dog

A selective coating would be best.

My dog is Black and , think she has got a selective coat , as she gets really warm when laying in the sun .

Would a white dog get as hot ?

Any way time to get another beer !

Tony

[inetdog]

My dog is Black and , think she has got a selective coat , as she gets really warm when laying in the sun .

Would a white dog get as hot ?

Any way time to get another beer !

Tony

And a polar bear is white, but the hairs act as light pipes to bring all of the non-reflected light down to the skin to be used to produce vitamin D.
An early use of fiber optics for a medium-scale mobile chemical plant.
Oh, you said BEER not BEAR.

[cssolar]

And a polar bear is white, but the hairs act as light pipes to bring all of the non-reflected light down to the skin to be used to produce vitamin D.
An early use of fiber optics for a medium-scale mobile chemical plant.
Oh, you said BEER not BEAR.

Good point, you dont see many black polar beers I mean bears

Mind you a black bear in all that snow would stand out a bit !

So would my dog be better off if she were white ( got some bleach under the kitchen sink )

Cheers Tony

[russ]

Good point, you dont see many black polar beers I mean bears

Mind you a black bear in all that snow would stand out a bit !

So would my dog be better off if she were white ( got some bleach under the kitchen sink )

Cheers Tony

Better look around and see if you can still find the dog Tony - I think it is hiding!