[rahulrahul155]

hi frends
can anybody tell me hw to calculate solar radiation load on car

[Ahmed]

taking the sun surface temperature to be 5200 K, this will give a solar flux of about 1800 W/m2

[Charles Rundle]

Hello,

If I may I would suggest reading a good book on solar radiation. Presuming your car in on earth's surface the radiation flux that it experiences will be different from the black body radiation flux from the sun. The atmosphere will reduce the flux and angle of the sun may also have significant impact on your results.

If you are only referring to the solar radiation entering the car through the windows then the type of glass may have an effect as well. I'm more familiar with transparent building facades so I don't know for sure how directly my experience translates to car windows.

With regards to a book, I have used the following book in the past with good results.

Wieder, S. (1982). An Introduction to Solar Energy for Scientists and Engineers. John Wiley & Sons: New York.

For the record I am not affiliated with the author or publisher in anyway. I'm also sure there are a wide range of other published works, which would be suitable, but I have found this one to be useful.

I hope I have been helpful. Have a good day.

CAR

[rahulrahul155]

thanks Ahmed & charles rundle for your valuable help.
i m intrested in calculating heat transfer from outside to car cabin, due t o solar radiation (both conduction & radiation)
in this solar position is changing also vehicle direction is changing with time
so i not understand which solar position should i take & how to calculate solar load on car

[Charles Rundle]

Hello,

If I may ask how accurate do your desire your simulation to be and which parts of the car are included in the mesh? Also are you using a radiation model?

It would be much easier to answer your question if I understood what your goal was. For instance the approach I would recommend if you were trying to prove that the AC in the car was sufficient would be significantly different then if you were trying to match experimental data to validate code.

In the mean time, I’ve included an image showing the effect that the angle of the sun can have. Theta is the sun zenith angle, as you can see the projected area and therefore the amount of solar radiation received by the objected changes with the angle of solar radiation.

I should also note the image assumes the sun is far enough away that the solar radiation can be treated as parallel. Also in your case you would have to be concerned with the horizontal distance (W) as well make A=Lsin(theta)+Wcos(theta).

I should also add that while I believe everything I’ve shown and stated to be correct I do not guarantee it as such and accept no liability arising from its use. It is entirely use it at your own risk.

I hope I have helped. Have a good day.

CAR

[Charles Rundle]

Hello,

My apologies I have just found your other thread. Since you are using Fluent I have a revised suggestion. I believe that FLUENT offers a solar radiation model. I'm not a FLUENT user, so I am unsure of the input it requires or how accurate it is. If you check FLUENT’s documentation or in the FLUENT section of the forum you may find your answer much quicker.

I hope this helps. Have a good day.

CAR

[rahulrahul155]

Thank you charles rundle for your help ,
my project is related to fluent & i hv to do transient analysis of cabin AC so it require boundray condition calculation, in that solar load calculation part i not understand.
so anybody know hw to calculate plez help