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Author Topic: Lamphouse exhaust booster recommendations Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 03-17-2004 01:56 PM                        I'm still trying to figure out how one would create a positive airflow in the booth with lamp exhaust that pulls the air out. Does it require an HVAC system with HEPA filter to blow air into the booth (at a greater rate than it is being exhausted by the lamp blowers)? Sounds expensive; presumably this would be more easily achievable in smaller booths than larger ones. I gather that this is mostly a design/architectural issue and not one which can be easily addressed in existing buildings.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-17-2004 02:30 PM                        That's pretty much it Scott. Although it is possible to do with existing buildings it can be difficult since some older buildings leak pretty badly. As for the cost of heating or cooling all that air, we've got some plastic factory clean rooms with high volume heat exchangers that handle upwards of 15,000 cfm while maintaining positive air pressure. So it is possible, but it isn't cheap. I've found most booths in a typical multiplex can keep at least neutral air pressure if they use about the same size HVAC system for the booth as one of their large auditoriums.  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 03-17-2004 03:24 PM                     In a proper HVAC system, every room should have a return fan and a supply fan. Negative or positive pressure is just a matter of balancing them. --jhawk  |  IP: Logged William Hooper Phenomenal Film Handler Posts: 1879 From: Mobile, AL USA Registered: Jun 99 posted 03-18-2004 01:46 AM                        quote: I'm still trying to figure out how one would create a positive airflow in the booth with lamp exhaust that pulls the air out. Is there any sort of construction code which prevents the cooling air for the lamphouses to be ducted from the outside? Lamphouse design probably precludes most cases, & it's probably a legacy from the carbon arc days of huge theatres with hot booths & little financial reason for divorcing the lamphouse cooling air from the huge auditorium. It seems like it would be no big deal to pull it all into a distribution manifold at multiplexes. quote: Change the ducting from the roof to the projector (or even just a section) to the largest size you can. Another huge detriment to airflow in a duct or windline is turbulence. Use smoothest interior duct (that's tin!), the fewest bends possible, & then the easiest. Curves work beter than elbows, 2 45 degree bends are better than a 90 or steeper, which contribute enormously to turbulence.  |  IP: Logged John Walsh Film God Posts: 2490 From: Connecticut, USA, Earth, Milky Way Registered: Oct 1999 posted 03-18-2004 07:49 AM                     -Is there any sort of construction code which prevents the cooling air for the lamphouses to be ducted from the outside?- Been thought of before... but if it's raining outside, a lot of moisture will be brought in, rusting the inside of the lamp... or if you live in a sunny area, the air coming in may be so hot the lamp is not kept cool. It's a good idea, but might not be workable everywhere.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 03-18-2004 09:32 AM                        So, William... You're using recycled pipe-organ air to pressurize your booth?  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 03-18-2004 02:28 PM                     What are the opinions here regarding bringing air from above the ceiling grid to the air intake of the lamphouse?  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-18-2004 02:42 PM                        I'm against it. It's a good way to suck dirt and humidity into your lamphouses.  |  IP: Logged Joshua Lott Expert Film Handler Posts: 246 From: Fairbanks, AK, USA Registered: Nov 1999 posted 03-18-2004 03:00 PM                        A question that I have in regards to the lamphouse exhaust is for a portable set up. It will have to be run directly into the room that the projector is in. Strong Lamphouse Page The lamphouse at the bottom of the page is what I am looking at. (ultra 80) If I was running a 2k or 3k bulb would adding a second unit like the one that is already there work? Or do I need to consider something different? How much air would I need to run out of the lamphouse for a 3k bulb? Josh  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 03-18-2004 03:14 PM                        Interesting question. What's the maximum size lamphouse that can be vented into the booth? I suspect that this is a no-no with carbon, but I've run a couple of booths with two 16mm xenon machines with 1kw bulbs in each. The booth gets warm, but not excessively so. Otherwise, I don't think there's any issue with 1kw (at least not with modern "ozone-free" lamps).  |  IP: Logged Christopher Seo Jedi Master Film Handler Posts: 530 From: Los Angeles, CA Registered: Jun 99 posted 03-18-2004 05:32 PM                     I think it just depends on how warm you want the booth to get. When I visited Strong International a couple of years ago, I saw them testing repaired switching power supplies by hooking them up to a 7 kW lamp. The lamphouse was simply vented into the room. Although they switched power supplies often, I suspect the bulb was on a good part of the day. Of course, this was early January, and they said it gets pretty toasty in the summertime.... In the real world, I have seen 1600 W lamps (I think... they were in the range of 1000-2000 W anyway) vented into the booth.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 03-18-2004 05:40 PM                        If you smell ANY ozone, the lamphouse should be vented to protect your health.  |  IP: Logged John Walsh Film God Posts: 2490 From: Connecticut, USA, Earth, Milky Way Registered: Oct 1999 posted 03-18-2004 06:02 PM                     Regarding bringing air from above the ceiling grid... it depends on what's up there. If it's closed (required in Connecticut) then you can't, since the lamps would be sucking for air. If it's a part of a return air plenum (sometimes shared with other auditoriums, sometimes not) it would work, but might mess up the air balancing for the auditoriums if the additional load of many projectors was not calculated for. The Strong lamphouse manual states the exhaust should be 700cfm. If the second fan unit matches that rate, it should work. I guess venting the lamp exhaust into the booth is OK (disregarding local codes and using ozone-free bulbs) but if the temperture in the booth gets to 90'F or so, I might be concerned that the supply might be too warm to cool the bulb.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-18-2004 06:31 PM                     "The Strong lamphouse manual states the exhaust should be 700cfm." Good Lord John, I hope you don't totally rely on all the manuals that everyone puts out. Thats a bare minimum spec for decent cooling of a 2kw lamp! Mark @ CLACO  |  IP: Logged John Walsh Film God Posts: 2490 From: Connecticut, USA, Earth, Milky Way Registered: Oct 1999 posted 03-18-2004 07:02 PM                     700cfm for a little 2K lamp? I would think that to be fairly excessive... But this is an example of how different equipment can be... I'm at a theater right now (I don't rate a 'real' office, so I have a storage room ) and have a 3K console doing 680cfm, and it's cool as a cucumber. Bulbs last 3-4k hours; I change them just because I get scared, not because they darken or flicker. I also just happen to have received my brandy-new Fluke 61 IR thermometer... The hottest place I can measure is 135'F at the snood, which seems reasonable. Although, not trusting everything stated in a manual, is well taken!  |  IP: Logged

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