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Topic: Removing heat.

Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 07-11-2017 06:42 PM

Might be lot of heat coming out of the stack, but not enough of it to use it effectively. Need 100 units burning a 6k bulb to make it worth while, but the expense would be totally idiotic.

Now, when you got a 300 seat house full of people, and each person put off close to 4000 BTU, and you have no air circulation in that house, it doesn't take much to raise the temp of that house in one hour, plus the 100 percent humidity each person emits with each breath exhaust...you got a sticky mess.

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Frank Cox
Film God

Posts: 2234
From: Melville Saskatchewan Canada
Registered: Apr 2011

posted 07-11-2017 06:58 PM

quote: Marcel Birgelen
You might also violate local health and fire codes this way. The first one, because of the ozone which might be present in the exhaust.

I don't see this as a problem since my projector (Christie 2210) can be run with or without external venting. The vent kit is actually a separate optional accessory for that projector. Without it, the exhaust just vents into the projection room directly. Unless it's a conspiracy to kill the projectionist? [Smile]

quote: Marcel Birgelen
The second one, because a fire inside the projector could lead possible toxic smoke directly into your auditorium.

I suppose that's a possibility, but there's really no particular fire separation between the projection room and the auditorium now and there never has been. I've got a big port window that's made of glass, for one thing, plus the air conditioner ducting comes down into the projection room and then goes out through the wall into the auditorium. Not to mention the wires for the sound system and so forth and so on.

It's all academic now anyway; I've routed the exhaust out through the wall and hopefully that will solve the condensation problem.

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012

posted 07-12-2017 07:01 AM

quote: Frank Cox
I don't see this as a problem since my projector (Christie 2210) can be run with or without external venting. The vent kit is actually a separate optional accessory for that projector. Without it, the exhaust just vents into the projection room directly. Unless it's a conspiracy to kill the projectionist?

You know DCI is just a heinous plot to kill all projectionists? Those who survived the initial killings now will face extinction via slow ozone poisoning. [Wink]

It probably depends on your local regulation. For example, around here the maximum concentration permissible in public spaces is 0.1 ppm, which is pretty low, still, it seems to be too high for some very sensitive people. A modern digital projector usually doesn't produce much ozone, if everything is in perfect working order.

But, since you're working with high voltages and high amperages, if there's some arcing which is exposed to the outside airflow, you might see ozone production sky-rocket.

Nowadays, projection booths are usually far less occupied than they used to be, so better lamphouse and lamp designs combined with shorter periods of possible exposure reduce possible health dangers. I would still try to vent the hot air exhaust of any DCI projector with light sources considerable into the air, just to avoid prolonged exposure to ozone.

I know a few locations were they have their projectors vent into the booth and in turn vent this air directly into the lobby. I personally do think, those kind of constructions are pretty bad and you're potentially exposing the people working inside the lobby to ozone in the long term.

quote: Frank Cox
I suppose that's a possibility, but there's really no particular fire separation between the projection room and the auditorium now and there never has been. I've got a big port window that's made of glass, for one thing, plus the air conditioner ducting comes down into the projection room and then goes out through the wall into the auditorium. Not to mention the wires for the sound system and so forth and so on.

Even if there's no real fire separation, most people don't die from fire, but from smoke inhalation. Before there is fire, there is almost always a lot of smoke. The most likely place for a fire to start, in a cinema, is the booth. The projector is by far the hottest thing in the room and most heat is concentrated in and around the lamphouse.

Although the separation between your booth and auditorium might not be entirely airtight, it might be sufficient to stop most smoke from entering into that room. What's important in the situation of an uncontrolled fire is that people have sufficient amount of time to escape. So, most efforts in modern fire proofing are put in 1. not allowing a fire to happen and 2. make sure people are alerted in time and 3. make sure the smoke is contained sufficient to allow people to escape.

quote: Frank Cox
It's all academic now anyway; I've routed the exhaust out through the wall and hopefully that will solve the condensation problem.

You might still see some condensation inside the airduct, so it's best to have some kind of bend in it, to avoid this condensate reaching the exhaust of your projector. Also, you should regularly inspect it, to avoid nasty mold build-ups.

If condensation is a real problem, there are also condensate collectors which you can put into your air ducting.

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Frank Cox
Film God

Posts: 2234
From: Melville Saskatchewan Canada
Registered: Apr 2011

posted 07-12-2017 12:34 PM

I actually have the pipe angled (very) slightly down toward the outside wall.

I don't think I'll see any condensation in or on it now since the pipe is now in a heated area right to the point that it gets to the wall so there's very little area exposed to a low temperature now.

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Jim Cassedy
Phenomenal Film Handler

Posts: 1661
From: San Francisco, CA
Registered: Dec 2006

posted 07-12-2017 05:20 PM

quote: Guy Burns
Do any theatres use this heat to warm their cinemas?

I had someone ask me about this several winters ago, when the
heating system at a 70 seat screening room broke down and it
was going to take a couple of days to get the part.

What was suggested was to get some flexible ducting and
exhaust the heat from the Xenon lamphouse into the back
of the auditorium.

I said that the screening room xenon was only 2K, and that the
auditorium would probably be losing heat at a rate faster than
we could pump what little hot air we had, into it.

Also, I pointed out that the lamphouse blower was anything but
'silent' & that its' noise would be easily heard in the small auditorium.

The idea of using the 'wasted' heat is bascialy a good one. Perhaps
there are some limited applications where it could be used to heat a
stock room or manager's office located next to the projection room.

I've read about, and seen pictures of, old radio stations where in the
winter they would use the excess heat from the transmitter to heat
their studios or office space. This was back in the days when most
radio stations had their studios & transmitter space co-located.

But from what I've read, it wasn't all that uncommon to do back then.

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Arnold Chase
Film Handler

Posts: 41
From: West Hartford, CT United States
Registered: Nov 2013

posted 07-12-2017 11:22 PM

For a number of years I have successfully used a setup that utilized an extraction fan, two motorized dampers, and a little bit of ducting. Rather than just dumping the waste heat from my 6 KW lamp into an auditorium, I use the motorized dampers to alternately select either outside air dump (in the Summertime), or feeding the heated air into the return duct system of the HVAC unit that feeds the auditorium in the Wintertime. That way, the waste heat gets supplied and circulated properly. The small amount of Ozone created (relative to the volume of air the system supplies) isn't such a bad thing and serves to slightly deodorize the auditorium as well!

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Tom Bert
Expert Film Handler

Posts: 134
From: Belgium
Registered: Apr 2010

posted 07-25-2017 03:00 AM

Don't know if it was already covered, but it is important to match the external exhaust (-CFM) to the projector CFM. We have seen cases where a tight connection was literally sucking -too much- air through the projector, making it de facto the booth vacuum cleaning system. Not good for dust management in the unit you can imagine.

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Mattias Mattsson
Film Handler

Posts: 90
From: Göteborg, Sweden
Registered: May 2007

posted 07-25-2017 07:19 PM

quote: Tom Bert
it is important to match the external exhaust (-CFM) to the projector CFM. We have seen cases where a tight connection was literally sucking -too much- air through the projector, making it de facto the booth vacuum cleaning system. Not good for dust management in the unit you can imagine.

Do you have a recommendation for an instrument (make/model) to measure that the airflow is up to spec?

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Tom Bert
Expert Film Handler

Posts: 134
From: Belgium
Registered: Apr 2010

posted 07-26-2017 01:27 AM

Afraid not (at least not field-usable)

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 07-26-2017 09:04 AM

There are many air flow meters (Anemometer) out there and the prices on them range a bit. I use one that has a vane type sensor and it has been accurate enough.

Tom, you mention having too much air flow causing problems. To the best of my knowledge, Barco (like everyone else) only mentions minimum air flow requirements (by projector model). Does Barco have any maximum values? If this is as important as you say (and I agree with you, by the way), why not publish the range/preferred amount rather than just the minimum. I realize that the preferred amount would be lamp size dependent but that could also be part of the spec.

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Tom Bert
Expert Film Handler

Posts: 134
From: Belgium
Registered: Apr 2010

posted 07-26-2017 12:05 PM

The maximum only applies if there is an "airtight" fit between projector exhaust and HVAC. Otherwise, the extra air will just be sucked out of the booth. I'll inquire if we have an advise on max value.

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