Novice Really Needs AC Help & Advice - Plasma Cooling Question!

[Bazzy]

Hi All!

I recently had a Fujitsu (ARY14ELA/AOY14EM) 14K BTU ducted AC system installed in the loft above my room (W4m x H2.4m x L2.9m). The AC has a wall mounted control panel, is cooling only & cools down to 18 degrees centigrade. The installer fitted 3 circular ceiling vents of 200mm - two for supply & one for return.

I will soon have some wall to wall, floor to ceiling integrated cabinets/wardrobes made with side sections for my clothes & a central section dedicated for audio visual equipment & a 50" Plasma TV. The Plasma TV JUST fits into its section (so it all looks seamless) but this will mean very little ambient air will be able to get to the back of it although there will be an near empty space in the same height & width of the Plasma (1233mm x 763mm) but at about 500mm deep. I will also have some slots cut into the shelves beneath & above the Plasma.

As you already most probably know, Plasma's get pretty hot at the best of times and they way I will be enclosing it so tightly within the cabinets, it will mean even heat up even more so as there will not be much circulation or the normally large area to dissipate the heat. I am concerned that it may get so hot that it auto shuts off all the time or even worse, may damage the Plasma. There will be a gap around 2.5cm - 3cm around the plasma between it & the cabinet walls.

I would like to therefore ask if the following will work: Run some smaller diameter ducting (like that from a vacuum cleaner) either directly from the AC blower in the loft (blue) or from an existing supply ducting in place at a convenient location (purple) and run it directly behind the TV so cold air blows in its enclosure, cools it down & forces the hot air into the room. To aid the process even further, I plan to fix two reasonably sized & decent fans within the cabinets as well.

Now, I know nothing about AC or airflow dynamics & just came up with this as a novice idea & would like to ask you all if my idea will work, is viable, will be very effective or just mildly effective? Is there another better or easier way that I can achieve what I am trying to do? I really would welcome any help, advice or ideas as a little knowledge is a dangerous thing and I know, being a average Joe, have no idea about these things! I have enclosed some images out what I propose, hopefully they will show pictorially exactly what I have in mind and portray things better!

Many Thanks To All,

Bazzy!

[Toosh]

Hi All!

I recently had a Fujitsu (ARY14ELA/AOY14EM) 14K BTU ducted AC system installed in the loft above my room (W4m x H2.4m x L2.9m). The AC has a wall mounted control panel, is cooling only & cools down to 18 degrees centigrade. The installer fitted 3 circular ceiling vents of 200mm - two for supply & one for return.

I will soon have some wall to wall, floor to ceiling integrated cabinets/wardrobes made with side sections for my clothes & a central section dedicated for audio visual equipment & a 50" Plasma TV. The Plasma TV JUST fits into its section (so it all looks seamless) but this will mean very little ambient air will be able to get to the back of it although there will be an near empty space in the same height & width of the Plasma (1233mm x 763mm) but at about 500mm deep. I will also have some slots cut into the shelves beneath & above the Plasma.

As you already most probably know, Plasma's get pretty hot at the best of times and they way I will be enclosing it so tightly within the cabinets, it will mean even heat up even more so as there will not be much circulation or the normally large area to dissipate the heat. I am concerned that it may get so hot that it auto shuts off all the time or even worse, may damage the Plasma. There will be a gap around 2.5cm - 3cm around the plasma between it & the cabinet walls.

I would like to therefore ask if the following will work: Run some smaller diameter ducting (like that from a vacuum cleaner) either directly from the AC blower in the loft (blue) or from an existing supply ducting in place at a convenient location (purple) and run it directly behind the TV so cold air blows in its enclosure, cools it down & forces the hot air into the room. To aid the process even further, I plan to fix two reasonably sized & decent fans within the cabinets as well.

Now, I know nothing about AC or airflow dynamics & just came up with this as a novice idea & would like to ask you all if my idea will work, is viable, will be very effective or just mildly effective? Is there another better or easier way that I can achieve what I am trying to do? I really would welcome any help, advice or ideas as a little knowledge is a dangerous thing and I know, being a average Joe, have no idea about these things! I have enclosed some images out what I propose, hopefully they will show pictorially exactly what I have in mind and portray things better!

Many Thanks To All,

Bazzy!

Hi Bazzy, personally I don`t think blowing cold air on it will solve your problem, the manufacturer must have given instructions for the amount of space you need to dissapate the heat generated, your problem is that there is nowhere for the heat to go. Is there anyway you can a small exhaust fan then your air conditioning will remove the heat.
Norm

[Brian_UK]

I would forget the two fans as all they will do is circulate the hot air around behind the TV and add the heat of two motors to the problem.

Personally I think the best option is to improve the airflow path behind the TV by having some fans to draw the hot air from the space.

Ensure that the incoming air, from below, has to pass across the back of the TV.

The fans could be switched via a thermostat but you would need to investigate getting really quiet ones. Quiet normally means large slowly rotating blades.

[Bazzy]

Hi Again!

"Hi Bazzy, personally I don`t think blowing cold air on it will solve your problem, the manufacturer must have given instructions for the amount of space you need to dissapate the heat generated, your problem is that there is nowhere for the heat to go. Is there anyway you can a small exhaust fan then your air conditioning will remove the heat. - Norm."

Norm, do you mean install an "extractor fan" (like those used in bathrooms?) somewhere to suck all the heated air up and direct it elsewhere? If so, can you kindly elaborate on how best I might achieve this?


"I would forget the two fans as all they will do is circulate the hot air around behind the TV and add the heat of two motors to the problem.

Personally I think the best option is to improve the airflow path behind the TV by having some fans to draw the hot air from the space.

Ensure that the incoming air, from below, has to pass across the back of the TV.

The fans could be switched via a thermostat but you would need to investigate getting really quiet ones. Quiet normally means large slowly rotating blades. -Brian"

Brain, forgive my ignorance but can you expand on this a further? You say get rid of the two fans that blow air & then install some fans that will "suck out air" instead? Again, how would I do this, where would I install these (how many) given my set up?

I just assumed a constant stream of ac cooled air hitting the back of the TV would be best (as AC is generally best cooling ever!) & that the heated air will be not only cooled down but be forced into the main room area where the main AC can absorb any remaining heat! Shows how much I know!!

If anyone has any other ideas & thoughts, Please kindly provide your input - I am in the company of experts after all!

Regards,

Bazzy!

[Brian_UK]

Bazzy, meant to say, nice diagrams, always helps to sell a story.

My plan is based on a box. If we assume that your box comprises back wall, two sides, top and bottom plus, of course, the front wall which is your plasma tv.

Now open the bottom and top sides with some ventilation holes/slots and the hot air from the plasma will start leaving the top of the box by convection. Cooler air will be drawn in via the bottom slots.

If you added a fan at the top of the box then the convection air flow will be changed to forced ventilation. Placing the fan on the outlet means that the cooler air will be drawn into the box through whatever holes there may be. These could be your slots in the bottom or any gap/vent holes in and around the plasma itself.

Perhaps the better choice of fan would be an , sorry forgot the proper term here - I'll dig up a picture and come back.

[edit] http://www.lionballmotor.com/upload/upFiles/index/ca685cdb3af4a7bc4cbb9caa1229c369.jpg
From here.. http://www.lionballmotor.com/

[Bazzy]

Hi Brian,

Thanks for the help so far - just so I make sure I get it right with the "TV Section" is this kind of what you have in mind?

Thanks,

Bazzy!

[Brian_UK]

That's the sort of thing yes.

Now assume that you have a fan extracting air from the top slot(s).

I wouldn't have any vents in the sides of the box as this will allow incoming air to bypass the back of the plasma.

Also have the slot in the base towards the front of the box, near the plasma so that the cooler incoming air goes directly to the plasma.

You could, I suppose, almost halve the depth of the box and achieve the required effect.

[Bazzy]

That's the sort of thing yes.

Now assume that you have a fan extracting air from the top slot(s).

I wouldn't have any vents in the sides of the box as this will allow incoming air to bypass the back of the plasma.

Also have the slot in the base towards the front of the box, near the plasma so that the cooler incoming air goes directly to the plasma.

You could, I suppose, almost halve the depth of the box and achieve the required effect.

Hi Brian,

OK, I will modify the vent placements and get back to you for approval! Regarding the "incoming air" you mentioned & which I have highlighted, are you referring to just general air or that coming from the AC duct? Just making sure as I believe you felt the ac option may not work well?

Finally, seeing as you are in Sunny Dorset, do you have any friends or colleagues who maybe able to fit the extractor thingy for me? I am in NW London? You of course, are more than welcome!

Bazzy!

[Brian_UK]

I would try it with just room air at first, if you have your AC running then we assume that it will be around 21/22°C anyway.