Film-Tech Forum ARCHIVE: Need Heat/CFM specs for Booth AC

This is topic Need Heat/CFM specs for Booth AC in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Martin McCaffery (Member # 37) on 06-19-2007, 11:17 AM:

We're specing an AC for the projection room. This will include the exhaust and an AC system for the booth. Single Screen, two projector, Strong X-60D, 2000 watt.
Contractor needs Lamphouse Btu and Lamp CFM.

Posted by Steve Guttag (Member # 268) on 06-19-2007, 12:35 PM:

Good luck with that...there are rules of thumb and hard and fast facts on the Btu/hr based on wattage...however, once you add exhaust into the equation...how much heat load is still presented to the room is less clear.

For instance...a 2KW lamp will produce 6824 Btu/hr...however you have an exhaust stack right above that drawing some of the heat out and not presenting the full amount to the room. You will also need to add in for the rectifier and even the projector if you are to be completely accurate...as Mark G will tell you, the switcher type rectifiers are more efficient and will present less heat load to the room.

Posted by Louis Bornwasser (Member # 3063) on 06-19-2007, 02:10 PM:

Remember, too, the "cost" of replacement air. Louis

Posted by Steve Guttag (Member # 268) on 06-19-2007, 03:51 PM:

Nah Louis...you skip that and then save yet again on door closers for the booth...they will be "automatic" [Wink]

On a serious note, that replacement air can be specified as conditioned (temperature/humidity controlled) or unconditioned (fresh air). Take a guess which one you want.

Steve

Posted by Martin McCaffery (Member # 37) on 06-19-2007, 09:11 PM:

Thanks.
Louis, any idea how much heat the sound rack puts out? The rectifiers?

Re the replacement air. we were discussing ways of being able to switch between conditioned and non, because we actually go months without the heat or ac running in the auditorium.

the AC guy wanted to know if it was possible to vent straight into the front of the lamphouse. Didn't sound like a great idea to me, but thought I'd ask.

Posted by Kenneth Wuepper (Member # 1174) on 06-20-2007, 06:30 AM:

Martin,

I believe that your AC guy wants to make the projector lamp house a "closed circuit" air system. That is, he wants the booth air not to be involved in the venting of the lamp. The replacement air would come from a source outside of the booth as well as the vented air being discharged outside.

This system might have some advantages by eliminating the make up air coming into the projection room but it will also cause a lot more "plumbing" around your machines. That system would not assist with the heat radiated into the room out of the lamp house.

KEN