Radiation between 2 surfaces

[Thomas-Lc]

Hey guys !

I have an LCD Display behind a plexiglass window in an enclosure. The enclosure is installed outdoor (for advertising).
There is 5 cm between the plexiglass and LCD display. I have some issues with the surface temperature of the screens. I wonder, it is not better to put directly the plexiglass on the LCD display? So there is no gap between LCD display and plexiglass, so it can prevent “greenhouse” effect ?
If not, How can I determine the airflow to cool the screen (between this gap) ? Because it’s hard to determine the heat flux of the screen.
You can find attached a schematic.

You are surely better informed than me about physical phenomena.

Thank's in advance !

 

[MintJulep]

Use an IR blocking plastic.

 

[Thomas-Lc]

It will not impact the transparency of the plastic?

 

[racookpe1978]

Two fans on top and two (screened !!!) vents, one fan and one screened vent on the bottom?

What is your intended air circulation pattern? That will be more important than "radiation" inside the steel box. Or more important from the two LED panels to the air inside the box and the walla of the box.

 

[Thomas-Lc]

No, at the bottom there are 2 fans and at the top 4 exhaust fans

 

[IRstuff]

I would consider putting the LCDs directly against the plexiglass JUST for the fact that you got fans and openings in the box. Don't care how good you think your filters and seals are, if there's a gap, there'll spider webs and dirt getting collected.

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[Thomas-Lc]

But in terms of surface temperature of the screen,on direct sunlight, what is better : 5 cm gap between lcd and plexiglas or no gap ?

 

[chicopee]

If the sun radiation create a glare problem, provide a sun shield that way people will be able to see the LCD screen better and radiation heating is minimized. I would think that four screens on the bottom and two on the top would be more logical.