Well.. I was smart.. or was I? I reframed my ceiling from vaulted to flat, built a small drop down that visibly divides one section of the room from the other (living from dining), and in that small drop down, I recessed the projector. Due to it being recessed in a little cavity, I knew that the exhaust from the projector would be pushing hot air into this small cavity, causing the hot air to re-circulate, and the projector to overheat.

Due to the above, I compensated by running a 6 inch air duct from that point, into the garage with an exhaust port that opens when air is pushed through it. Then, where the projector is, I put a fan to suck the air out of that little recess, and keep the projector cool. This worked fine for a while.. until...

Winter is here.. heater turns on.. 6 inch fan can displace the heat from the projector, but can't displace the heat from the central heater pumping heat out of an 8 inch vent only about 5 feet away... Since the heat rises, and that is the highest point of the room, guess where the heat accumilates...

Here is a picture of where the projector is recessed:



If you look to the right of the projector, in the recessed niche, you can see a black fan mounted to the side. That's the fan that exhausts the heat from the projector. The problem however is the big square 4 way air duct you can see that is only about 5 feet from the projector.

My plan was to cover all of the walls and ceilings with a blue suede paneling that I was making out of some 3/4 inch pieces of insulation panels (they're basically dense pieces of styrofoam that can actually take some beating). I figured I'd let the panels overhang the opening where the projector is, and so the only opening when everything is completed, would be the opening for the lens. This however would create more front suction from that lens hole, as all air that will be circulated in that little recess would be from that opening. That opening would also be directly in line with the heater vent.

My thoughts on a solution would be to close off that hole with a piece of plexi glass, and then make some holes in the lower rear part of the styrofoam. The holes would still be covered by the suede (actually microfiber), and hopefully will allow enough air to pass through to allow it to breath. I am not sure what else I can do, as if I open up a hole into the top of the niche, it would be exposing the projector to the heat of the attic in the summer time, and my problems would repeat, not to mention, I'd be cooling my attic when I ran my air conditioner...

Anyone else have some suggestions?

Only one... Can the idea of covering the holes with the wall covering... You need some considerable air flow to keep that cool. Warm air from the heating system will be fine as long as it is moving, and not just sitting...

Others will chime in with other suggestions. I don't have that many solutions, because we essentially refuse to do this ever.

Good luck

How about a 4" flex tube from the projector location down to floor level? Length will work against you if too long, but it would be a source of cooler air.

Ditto not blocking air flow into the projector area in any way. You could reduce the air flow substantially this way, and since fans are quite happy to run inefficiently if the air can't flow freely into them, you will not know how much the air flow has been reduced.

Tom reminds me of a system I once saw for factory use, that had a WAF of about zero, no matter how non-ugly I promised I would make it for home use. Tom's idea is to bring cold air from near the floor up to the projector, and that is a great idea, but it does involve plumbing at some level.

Anyway, he reminded me of a system consisting of a tube running from near the ceiling down to near the floor, with a fan at the top that blew air down the tube and a register near the floor that spilled the air out sideways. The point was to take hot air pooled near the ceiling and reintroduce it at the floor level. For the cost of running a fan, an area near the floor could receive hot air that was out of reach and therefore useless.

Your simplest solution is to run the heating system fan all the time. When the heating elements shut off, if the fan is in the AUTO position, the fan stops after the elements cool a bit. The air in the room moves by convection and hot air pools at the ceiling. Colder air pools at the floor, and when the air at the thermostat level gets cool enough, the heater turns back on.

If you switch the heating system fan to ON, the air will continually be moving, which is to say mixed. The ceiling air won't get quite so hot and the floor air won't get quite so cold. In fact, it is possible that this might cost less than leaving the fan off, because a setting of 72 degrees, with the air constantly moving, might feel as warm as a setting of 75 degrees where the air near the floor can stay cool.

LOL this reminds me of an installer i used to work with who came up with the bright idea of placing a qualia projector into a closed-in soffit and his cooling "system" was a duct that tapped off the whole house duct system. I said to him "that's great in the summer but what happens in the winter?" Just a big blank stare is all that I got in response.

If I am forced to do an install in this type of situation I will have the HVAC guys run a dedicated remote exhaust fan to the nearest ventable location with a thermostat. Air movement is the most important thing even if it's warm air.

Must have been a big ass soffit. Of all the PJs that I wouldn't want to hide in a soffit - that Qualia would be the worst. It blows some seriously hot air and is as big and heavy as a VW.

Make sure the vent flaps don't provide too much resistance for the fan's output to easily open... also in the winter.. could they freeze shut? (Depends on where you live of course)...
The micro fiber is too dense for air flow... Why not trim out the area below the projetor with a metal grill that would give you relatively free-flow of air? You could cruise the HVAC isles at Home Depot and find a wide variety of sizes and styles of heat register grilles and air intake grilles... Then grab some spray enamel to match the blue fabric as closely as you can...
A toasted projector lamp is $$$... so it might justify installing a thermal switching fan kit... Or better yet like Ernie suggested, just have the fan stay on when the projector is on... But my vote would be for a fairly large metal grille under the projector.

That's what I did.. I ran a dedicated exhaust fan with a duct to the garage and vented it out there. When the projector is on, the fan is on. It's on a relay rather than a heat sensor, so it's always on during projector use, regardless of the projector's temp.

Running a 4 inch duct to a low spot would be next to impossible. The walls are all framed with 2x4's leaving less than 4 inches gap in the walls, and all of the walls nearby are exterior walls, well equiped with insulation and fire blocks..

One idea I was thinking about was perhaps setting up a cooling device such as used in those portable electric coolers. Put it on a heat sync like some of the larger portable coolers use, and blow air across the grills of the heat sync, towards the intake of the projector. Anyone ever tried this idea?

You're going to spend a lot more on replacement bulbs and projectors then you are in a little drywall repair. But then again, most of the people offering solutions are professionals that do this stuff for a living.

i dont see the issue..... maybe i dont see the problem..... vent it and provide good air flow....its simple.... you should have thought of the heat issues before you put up the drywall. they make duct that is 3 1/2" x14' use that in the wall.....

my house i do what i gotta do to make the ventilation right..... then i fix my walls and ceiling and its all good

ed

I'm glad it ended up on a relay, because I forgot something obvious: you want to run the fan for some time after the projector is off.

I recently installed a Yamaha projector where the trigger voltage can be selected as either on and off with the projector power or with its fan. You would want your fan coordinated with the projector fan. I hope it can be.

If not, www.calrad.com has a digital delay timer that can be set for just about anything from a second to a couple of weeks. I used one of these to control a lift with a Sony VW10 a few years back, and set it to two minutes. I turned the relay on with a Xantech CC12, and had the timer set up to keep the power on for two minutes after the CC12 removed power. This was 12 volts, but heck, you have a relay!

As I said previously, I thought of the heat that the projector would be creating, and compensated just fine. I have no problems until the central heater kicks on. Then you're talking thousands of BTU's of heat being pumped out of a vent that's only 6 feet away. This is also an existing house that is being modified. The walls already had drywall up. All cableing and such has been retro'd. The modifications to the ceiling were changing it from a vaulted to a flat, which I did additional framing for. I ran a 4 or 6 inch (don't recall off of the top of my head) exhaust duct out into the garage, with a fan sucking the heat out, located right next to the exhaust port of the projector.

I do this stuff professionaly as well, but haven't done any recessed combined with closed enclosures in the ceiling before. Most of them are either fixed to the ceiling with nothing around them, or they are on a shelf that drops down electronically when it comes time to use it. This was a first time enclosing it like this, and this is things you will deal with when you work in the custom field. You try to account for everything, but sometimes you miss/overlook something. I accounted as much as I could for the heat, and didn't think about the fact that the heater vent was that close.. figured 6 feet away would be fine, but I obviously made a mistake..

3 recommendations, add a second fan at the air inlet for redundency, add an air filter at the inlet as well, use a piece of optical glass, not plexi.

I really don't like the flapper on the exhaust, if it ever sticks you're in trouble and it will get dust covered over time. Pulling fresh air from the floor is a good idea.

cant you put in a return vent at bottom and pull the cool ait from floor? return vents use the hole cavity without ductwork then vent it into soffit? then you can seal the fron of the soffit with glass and air cant get in and make it warm..... only air from return duct.