My Projector + Cooling Design, Help&Feedback wanted

This is my design for a 7" lilliput projector using parts from an OHP to be later upgraded to a 400W discharge system

It isn't to scale - but i'm after a check as to whether its layed out correctly and if my cooling system is sufficient ( and how bad will light leakage be) - The projector will be mounted directly to a ceiling so I will have no vents on top




2004-07-25 10:06 pm
I am not aeronautcs engineneer but i don´t think it is the best way of using fans.

There are two ways making a forced air cooling sistem; evaquating air from a box (as a vacum) and making air enter a box (as if it was coming from a compresor and you push it into the box. Both will cause the air movement and both will cool the device, but there is one way better than the other.

All cooling devices i have seen on different machines are always vacum type (there is a fan extracting air from the box so there needs to be some admision holes in the box, this way we can also make the air go trhoug the desired path).

Your design is based on pushing fans. Just wonder if it is the best way...

Let me tell you an anecdotical event; when the wright brothers did the wind tunnel for testing the wing shapes so they could found the best aerodinamical shape, they did a big mistake; the air was pushed from the tunnel intake, and they test the wings on the tunnel before it get out. Know we know it is the wrong way, it is better to do it vacum type (on wind tunnel, the rason is that there are some turbulences doing it as wright brothers did).


2004-09-27 11:26 am
Maybe add 3 fans for a push pull config?
Seems a good way, and you should be able to lower the speeds and still have a good cooling system with little noise.

Or another solution, put a cold mirror after the light box then that might open some diffrent cooling methods. But a general push pull config will work best IMO

theres simply no need for 3 fans if you use a IR filter infront of the lamp, the LCD will not heat up at all (doesnt for me) and you can easily get away with 1 fan!

And a pull design is deffinatly more efficent from my findings, you can control where the air enters from, and it all doesnt have to be at one point.. so you can efficently cool multiple devices with the single fan.

If you use a IR filter and condensor, you focus should then be on those two items... as the LCD will stay cool as.


2004-12-08 12:41 pm
Commenting on the original plan: I'd lose the fan at the front of the box, blowing onto the front fresnel won't be necessary with the others positioned over it. It shouldn't get too hot anyway, its the rear fresnel you want to be more worried about :hot:

As for the push/pull arguement I'm not qualified to lecture :D I would however say from experience that I've always found a push/pull arrangement more efficient in forced convection through radiators (watercooling) - I realise were not talking highly dense fins and huge air resistance here but.... I think with the appropriate ducting and fan speed control you can get just as good airflow with less noise?