what absorbs more sunlight? steel metal or tin?

[Wheatmaster]

i'm designing a solar panel for my eng drawing class and i wanted to know if tin or steel metal was better as the layer under the glass for absorbing sunlight. should it be glass, below tin, and below steel? or glass, below steel, below tin?

 

[amnesiac]

Wouldn't either of them absorb more if you just painted it matte black? I don't think steel or tin has any more inherent capability to "absorb" more sunlight than the other. A matte black coat will be absorbing >95% of the light anyway. Now, if you're talking about heat conductivity, that's another thing. I wouldn't know.

 

[Wheatmaster]

Originally posted by: amnesiac
Wouldn't either of them absorb more if you just painted it matte black? I don't think steel or tin has any more inherent capability to "absorb" more sunlight than the other. A matte black coat will be absorbing >95% of the light anyway. Now, if you're talking about heat conductivity, that's another thing. I wouldn't know.

oh sorry, yea i am going to paint one or both (if i use both) black. so both are about the same absorbing power of sunlight? I think i need heat capacity also because this is for heating water and generating power for a pump.

 

[MegaloManiaK]

*Shine is produced by the light being reflected off the surface so paint it matte black.

Other than that i would say steel is better at storing the energy but tin would be more conductive.

Is the goal just to heat the plate up or are you moving it to some other storage medium?

Example: If you were to heat a cup of water with steel it would stay warm longer (as the heat is transfered more slowly) but it would not reach a high temp. If you do the same thing with tin it will cool faster because the energy reserve will depleat faster but you will reach higher temperatures.

Comments preceded by * are things i know for sure.
Comments not preceded by * are guessed and should be researched before you do something stuipid.

Edit: The less conductive material will hold energy longer, the more conductive material will pass it off quickly allowing you to use all the energy at once. I hope im making at least a little sense here.

 

[her209]

I think tin would absorb heat much faster compared to steel.

But because steel is a bad heat conductor, it stores the heat longer than the tin.

 

[Wheatmaster]

Originally posted by: MegaloManiaK
*Shine is produced by the light being reflected off the surface so paint it matte black.

Other than that i would say steel is better at storing the energy but tin would be more conductive.

Is the goal just to heat the plate up or are you moving it to some other storage medium?

Example: If you were to heat a cup of water with steel it would stay warm longer (as the heat is transfered more slowly) but it would not reach a high temp. If you do the same thing with tin it will cool faster because the energy reserve will depleat faster but you will reach higher temperatures.

Comments preceded by * are things i know for sure.
Comments not preceded by * are guessed and should be researched before you do something stuipid.

Edit: The less conductive material will hold energy longer, the more conductive material will pass it off quickly allowing you to use all the energy at once. I hope im making at least a little sense here.

hmm this is for heating water with a solar panel. Underneath whatever material i decide (steel or tin), are copper tubes that have the water which is being heated and then transferred into the house. The reason i might also need to generate electricticy is that i probably will need a water pump to pump water up into the solar panel to be heated.

 

[Wheatmaster]

Originally posted by: her209
I think tin would absorb heat much faster compared to steel.

But because steel is a bad heat conductor, it stores the heat longer than the tin.

hmm ic. i think i would not need a heat storer because the heat would transfer to the copper tubes which would heat the water

 

[MegaloManiaK]

I agree, its called "specific heat" you should look it up. Basicly a dense material has a higher specific heat resulting in it taking more energy to heat.

using tin sounds like a better idea. Also transfering the energy from the tin to the copper is tricky since air is a poor conductor, you would need either A. good surface area contact, or B. some other conductive material to fill in the gaps. Think thermal paste.

Good luck, sounds like a fun project.

 

[tnitsuj]

Is this an introduction to engineering design course?

 

[MegaloManiaK]

If you plan to generate electricity from this you should look here.

http://home.howstuffworks.com/solar-cell1.htm

Producing raw heat for say bathwater is easy. Producing electricty requires solid state electronics to convert sunlight into flowing electric current.

 

[Wheatmaster]

Originally posted by: tnitsuj
Is this an introduction to engineering design course?

i think it is. the course is called Engineering Drawing which is a 2nd course you can take after one year of technical drawing.

 

[Wheatmaster]

Originally posted by: MegaloManiaK
If you plan to generate electricity from this you should look here.

http://home.howstuffworks.com/solar-cell1.htm

Producing raw heat for say bathwater is easy. Producing electricty requires solid state electronics to convert sunlight into flowing electric current.

lol i printed that out earlier. producing the bathwater isn't as easy as it seems. You need to build the solar panel to withstand all elements of nature plus water will probably be pumped up which requires electricity from the panel itself, and etc etc etc gets complicated!

 

[Wheatmaster]

i guess i will be using black painted tin as the metal to absorb the sunlight and the steel sheet on the bottom.