Film-Tech Cinema Systems
Film-Tech Forum


Post New Topic  Post A Reply
my profile | my password | register | search | faq & rules | forum home
  next oldest topic   next newest topic
» Film-Tech Forum   » Operations   » Digital Cinema Forum   » Removing heat. (Page 1)

 
This topic comprises 2 pages: 1  2 
 
Author Topic: Removing heat.
Alan Gouger
Master Film Handler

Posts: 474
From: Bradenton, FL, USA
Registered: Jul 2000


 - posted 07-09-2017 12:46 PM      Profile for Alan Gouger   Author's Homepage   Email Alan Gouger   Send New Private Message       Edit/Delete Post 
For those running 6k lamps what are you using to remove the heat.
Looking at the typical consumer in line Centrifugal duct fans its hard finding anything beyond 600 CFM which does not cut it especially if there is 10 feet of duct between the projector and fan.

Thank you!

 |  IP: Logged

Leo Enticknap
Film God

Posts: 6906
From: Loma Linda, CA
Registered: Jul 2000


 - posted 07-09-2017 01:54 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
In the case of a screen I used to look after that ran a 7kW bulb in an NEC NC3240S for 3-D presentations, a Centri-Master PRN100 fan assembly with a Fasco UB91 motor (1/10 HP, 3.2 amps, 1550 RPM), mounted on the roof, with a 10" duct going straight up to it from the projector's lamphouse exhaust. This was a dedicated extract for that one projector (i.e. it didn't suck from multiple projectors through a manifold or plenum), and the other two in the booth had identical copies. I never had any overheating issues: every time I pulled the projector's log and looked at it, all the temperatures were comfortably within spec, even with the 7kW bulb running.

 |  IP: Logged

Chris Markiewicz
Expert Film Handler

Posts: 203
From: Oakland, CA
Registered: Aug 2002


 - posted 07-09-2017 02:32 PM      Profile for Chris Markiewicz   Email Chris Markiewicz   Send New Private Message       Edit/Delete Post 
In our drive-ins (West Wind) we use the 8" Fantech centrifugal duct fans (Grainger 4YM45) on our Barco 32Bs running 6500W lamps. 8" ducting to the roof. Fans are modified with a relay box to take commands from the Barco fan control socket. We have a spare fan ready in each booth in case of a failure. Maybe 6 failures in 5 years over 34 screens.

 |  IP: Logged

Richard Fowler
Film God

Posts: 2389
From: Ft. Lauderdale, FL, USA
Registered: Jun 2001


 - posted 07-09-2017 02:50 PM      Profile for Richard Fowler   Email Richard Fowler   Send New Private Message       Edit/Delete Post 
S&P - Powervent exhaust fan kit with reducer to 8 inch and rubber vibration collar can exhaust 654 CFM at 0 pressure. There are larger and smaller kits available.

 |  IP: Logged

Mark Gulbrandsen
Resident Trollmaster

Posts: 16116
From: Bountiful, Utah
Registered: Jun 99


 - posted 07-09-2017 06:01 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
I absolutely recommend the Fantech stuff. At least an FG12XL for more CFM. You want about 1000 CFM for a 6kw lamp.

Mark

 |  IP: Logged

Alan Gouger
Master Film Handler

Posts: 474
From: Bradenton, FL, USA
Registered: Jul 2000


 - posted 07-09-2017 10:56 PM      Profile for Alan Gouger   Author's Homepage   Email Alan Gouger   Send New Private Message       Edit/Delete Post 
Just what I was looking for, thank you!!!

 |  IP: Logged

Guy Burns
Film Handler

Posts: 15
From: Melbourne, Victoria, Australia
Registered: Jun 2017


 - posted 07-11-2017 02:57 AM      Profile for Guy Burns   Email Guy Burns   Send New Private Message       Edit/Delete Post 
I hope you don't mind a question from an outsider.

When I was shown around the projection room at the local cinema, in preparation for hiring it sometime, the operator said each of the four projectors used a 4KW bulb and the heat was exhausted to atmosphere.

A former electrical engineer, I immediately did some rough calculations: 16KW costs about $5 an hour. Say 10 hrs a day, seven days a week, that's about $20,000 of heat wasted every year. The theatres are heated most of the year, where I am. The response was: "Well, we don't worry about that."

Then you go the next step: multiplied by 10,000 theatres worldwide, that's $200 million, less some percentage for summer and hot climates.

Do any theatres use this heat to warm their cinemas?

 |  IP: Logged

Jack Ondracek
Film God

Posts: 2300
From: Port Orchard, WA, USA
Registered: Oct 2002


 - posted 07-11-2017 06:51 AM      Profile for Jack Ondracek   Author's Homepage   Email Jack Ondracek   Send New Private Message       Edit/Delete Post 
You probably could, though I don't know anyone who does this. Using exhausted heat from radio broadcast transmitters was common and worked very well, back when everything had tubes in them.

At my drive-in, dust is our biggest problem. When we converted, we set things up so we dump all the heat into the booth and remove it with refrigeration. It may be a bit of overkill, but the room stays at about 74°, I've only had to clean my filters twice in 5 years and all the computers in there are happy.

 |  IP: Logged

Guy Burns
Film Handler

Posts: 15
From: Melbourne, Victoria, Australia
Registered: Jun 2017


 - posted 07-11-2017 07:34 AM      Profile for Guy Burns   Email Guy Burns   Send New Private Message       Edit/Delete Post 
Just don't let Al Gore get wind of your double whammy to the environment!

My rough calculations were based on resistive heating. The benefit when heating via reverse-cycle (more efficient) would be less than half the figures I gave.

 |  IP: Logged

Marcel Birgelen
Film God

Posts: 2537
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012


 - posted 07-11-2017 07:37 AM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
In many cases, the heat produced by those projectors isn't entirely lost as at least some of it finds its way into the building, where it can do its part in heating up the areas that need to be heated.

Recouping energy from hot air exhausts is a pretty expensive business. You could do it using heat exchangers and use this heat to pre-heat the water which would be fed into a more traditional heating system. I know just one cinema who did this and I'm not entirely sure what the benefits were.

It could be more efficient, if you could use the hot air coming out of those projectors directly and mix it into the air of the HVAC system.

The problem here is the ozone which might be present in the exhaust air. Although modern projectors with Xenon lamps produce far less ozone than older models, there will still be some ozone generated. You really want to have this vented instead of being mixed with the air you're pumping into your auditorium.

 |  IP: Logged

Carsten Kurz
Film God

Posts: 3684
From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 07-11-2017 09:40 AM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
The larger, modern multiplexes in some (energy conscious) countries actually do use the hot air from projection (and other booth gear) to recoupe energy. But not in a dedicated way directly targeted at the projector hot air, but through heat exchangers that are part of the overall building ventilation and HVAC systems.

One must say, though, that many of those modern cinema buildings have so much gear operating, so many people coming in, so many shows per day (think of a large 10+ multiplex with 5 shows per screen/day), that even in winter time, heating is not their dominant energy use, but HVAC/cooling during summer or even modest temperature days.

For smaller operations, direct use of the air exhaust heat is probably forbidden most of the time because of ozon, and fire precautions (strictly limiting direct air flow from parts of the building into the auditoriums). You could overcome the latter point with heat exchangers again, but using them only for this purpose is probably not worth the money. These would be built-to-order systems and to cover all design/engineering/security/fire precaution aspects would be very expensive.

We thought about that idea years ago when we were operating our 35mm equipment with a 2kW Xenon arc lamp. The heat it produced was impressing. However, we then looked at the specs of our gas operated auditorium air heating system, and it said '100kW'. So, how much would the heat of a xenon lamp running at 2kW max for 3hrs a day help, if we are not even allowed to feed it directly into the auditorium, but would need expensive and lossy heat exchangers?

Since we are digital, we run the same screen size from two 450W UHP lamps. The whole booth now runs probably from around 1.5-1.8kW average. We installed LED lighting everywhere in the building, and programmed our heating to the most economical scheme. That's all we can do for our 400 seat building. We did see quite an improvement in energy consumption over the last years.

- Carsten

 |  IP: Logged

Frank Cox
Phenomenal Film Handler

Posts: 1945
From: Melville Saskatchewan Canada
Registered: Apr 2011


 - posted 07-11-2017 01:20 PM      Profile for Frank Cox   Author's Homepage   Email Frank Cox   Send New Private Message       Edit/Delete Post 
I actually tried this a few months ago.

A problem that I've always had here is that my projector exhaust goes up into the attic and from there out a vent in the roof. This caused an issue in the winter since blowing warm air from the projection room into the freezing cold attic caused condensation and every spring I had a bit of water dripping back down from the projection room ceiling near the projector. (I actually built a little "roof" over the projection equipment for that reason. I think an ice block forms in the attic over the winter.)

This year I decided that enough is enough and I'm going to fix that.

My initial idea was to leave the existing exhaust in place and set something up re-direct the projector exhaust into the auditorium during the winter, thinking that I could save a few dollars on the heat bill that way.

The issue is noise. After getting this re-director installed I could hear air blowing into in the auditorium when it was quiet, so it wasn't acceptable. I never actually tried it when playing a movie; I just decided that this isn't something that I wanted to do since I've gone to great lengths to make my auditorium as quiet as possible (Soundfold on the walls, hot water heat and insulated ductwork from the air conditioner.)

I considered getting an duct muffler and adding that to the setup but then thought, what if this doesn't work either and how much money am I going to spend on this just to conserve a little bit of heat.

So after giving up on that idea I had it ripped back out again and just had a new exhaust pipe run from the projector across the projection room ceiling and out one of the exterior walls of the building.

This might work for someone who's less picky or who has a larger auditorium than I do. But I'm not prepared to do anything that will degrade my customer's experience (whether they would actually notice it or not) so it's just not something that I'll do here.

On the other hand, now that I'm not blowing hot air into the attic any more I hope not to see any more "rain" in my projection room next spring.

 |  IP: Logged

Mark Gulbrandsen
Resident Trollmaster

Posts: 16116
From: Bountiful, Utah
Registered: Jun 99


 - posted 07-11-2017 03:44 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Fire codes usually don't allow an exhaust fan blowing into an attic. That can really cause a fire to spread quickly.

Mark

 |  IP: Logged

Frank Cox
Phenomenal Film Handler

Posts: 1945
From: Melville Saskatchewan Canada
Registered: Apr 2011


 - posted 07-11-2017 03:51 PM      Profile for Frank Cox   Author's Homepage   Email Frank Cox   Send New Private Message       Edit/Delete Post 
It didn't blow into the attic. It blew into an exhause pipe that travelled through the attic to the roof. Otherwise, there was no way for the pipe to get to the roof since the attic space was between the ceiling and the roof. However, I guess the fact that the warm air in the pipe would heat the pipe a bit on the way through the attic space was enough to cause condensation to form around it. Or so my theory goes -- there was condensation coming from somewhere and since it was right there I don't see what else it could be.

Now a similar exhaust pipe just runs across the ceiling in my projection room to the outside wall. Good thing I'm a short guy -- the projection room ceiling is very low to begin with and now that pipe brings it down even more. The service techs always hate me. [Smile] I'm about the only guy who can walk around up there without combing my hair with the stucco on the ceiling.

 |  IP: Logged

Marcel Birgelen
Film God

Posts: 2537
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012


 - posted 07-11-2017 04:24 PM      Profile for Marcel Birgelen   Email Marcel Birgelen   Send New Private Message       Edit/Delete Post 
quote: Carsten Kurz
One must say, though, that many of those modern cinema buildings have so much gear operating, so many people coming in, so many shows per day (think of a large 10+ multiplex with 5 shows per screen/day), that even in winter time, heating is not their dominant energy use, but HVAC/cooling during summer or even modest temperature days.
You should indeed also not forget the "human factor". A human produces about 100 W of heat, so a room of about 200 people will produce about 20 kW of heat.

Also, a 2 kW lightbulb will not produce 2 kW of heat via the exhaust. Obviously, some of the energy pumped in gets "lost" as light and the lighthouse will get hot, so some heat also dissipates via radiation. If you have a full multiplex of those heat sources, you might collect them to some central point, but in order to preserve energy, your air ducts would need to be isolated. Once you've recouped the energy in a somewhat useful form, usually warm water, you still need to find a purpose for it.

Modern multiplexes in moderate and hot climates indeed don't have a heating issue very often, more likely a cooling challenge.

So, even if you extract the heat from the exhausts, the use of it is, unfortunately, pretty limited. Even if there is, for example, a municipal heating system present. The energy left after the heat exchanger usually isn't sufficient to dump into the system, because the water you've warmed with it, just isn't sufficiently warm.

In the end, all you usually can do with it, is use it for your HVAC heating, which isn't running most of the time or to pre-heat your warm water.

quote: Frank Cox
My initial idea was to leave the existing exhaust in place and set something up re-direct the projector exhaust into the auditorium during the winter, thinking that I could save a few dollars on the heat bill that way.
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. The second one, because a fire inside the projector could lead possible toxic smoke directly into your auditorium.

 |  IP: Logged



All times are Central (GMT -6:00)
This topic comprises 2 pages: 1  2 
 
Post New Topic  Post A Reply Close Topic    Move Topic    Delete Topic    next oldest topic   next newest topic
 - Printer-friendly view of this topic
Hop To:



Powered by Infopop Corporation
UBB.classicTM 6.3.1.2

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.

© 1999-2018 Film-Tech Cinema Systems, LLC. All rights reserved.