Noob - Air Con for Home Cinema and bedroom questions

[jon b]

Hi all

Am new to this forum but hope you can help. Been doing a little research re air con options including the "too hot" posts within general discussion.

I have a home cinema, pretty high spec with projector, two amps, eight speakers, pc and large screen. The cinema was a conversion of one of the 1st floor bedrooms. There is a huge loft above which has been very useful to accomodate wiring etc. The room is getting too hot which is not only an issue for me but for the performance of the projector and pc.

In addition to this I need to get air con into two of the upstairs bedrooms

I should have really built air con into the original spec but have now decided its a must

Taking into account the above, there are a number of criteria that need to be met plus considerations that i have thought about:

- Home Cinema air con unit needs to provide variable temp and variable fan speed.
- Home cinema air con MUST have low noise levels / db from fan to ensure it does not intrude into cinema sound levels
- Ideally I would be able to control temp between bedrooms and home cinema - but this is not critical.

Taking the above into account - the best option i can think of is to have an outside condenser unit (or whatever their called) feeding into a central control unit (positioned within the large loft) with ducting that feeds into each of the rooms. At the end of each ducting would be a venting cover with slits that can be opened or closed.

And here are my questions:

- Do you think the ducting proposal above is my best solution?
- Does a remote/ outdoor condenser need to be plumbed into the water system to remain topped up - or does it purely feed precharged liquid / coolant into the internal air con unit?
- Is there a good web site providing comprehensive information on a best install solution?
- what are my best options re equipment suppliers / web pages?
- Any other advice or assistance would be greatly appreciated

Thanks all

Hope someone who has relative experience can advise?

Cheers
Jon B

Here are my specific questions.

 

[oilman]

This is not really a diy exercise. There are units available which you just position and plug in, but I doubt they are satisfactory for your requirements. Fujitsu and Mitsubishi are major manufacturers, and there are lots of installers around. You need to be able to do pipework to a high standard to take the refrigerant gases (not soft solder) then you have to know about handling the gases. Find some people in your area and talk to them.

 

[JohnD]

If one of your problems is electronic equipment that is dumping hot air into the room, it would be a Good Idea to ventilate it to the outside.

If you can put in (e.g.) 100mm or 150mm ducting (as is used for extractor fans and cooker hoods - rigid or flexible) through the ceiling and venting (preferably through the roof with a tile vent) then you can put all your equipment into a cabinet (like a LAN cabinet or 20" equipment racks with doors) and let it vent upwards through the duct.

You will be amazed at how the natural convection of hot air creates a lot of movement without needing any kind of fan. (this method can also be used to extract steam - which also rises - from kitchens and bathrooms but it makes them cold in winter)

I suppose you could even put a dust filter at the air inlet at the bottom if you felt like it.

If the room has a (disused!) fireplace and chimney you could use that.

You could also vent through the wall but unless you can do this at high level you will need a fan. Centrifugals are quieter.

 

[boilerbeasty]

You could use ceiling-recessed extractor ducts, with the fans mounted remotely in the loft space. This would draw away quite a lot of heat if you mount it near the source. They are very quiet in this configuration.

You could also cool the room using a portable air con unit if this is a minor seaonable problem e.g. nasty in the hot weather this week but not a problem for 90% of the year. Not very slick for your home cinema set up though!

 

[Agile]

Most people with this problem get excited when the weather is hot but rapidly forget when its cool again a week later.

You have not said what sound level you hope to achieve. Whatever it is its probably not achievable without a very expensive system. A pre-requisite of quietness is slow air speed which means large cross section vents and certainly not 100 mm diameter.

You have not mentioned the heat insulation or wall construction or size of the property. Thats would be the starting point!

When I worked in the Gulf I managed using a single 14 kW of cooling in a single window unit that was quite old but very quiet compared with the other two new but noisy 11 kW Toshiba units which were about 60 dB at 1 m. The larger unit was left running 24/7 and we kept all in internal doors open. It was a larger two bed flat and the main function of the unit was to reduce the humidity to well below 50% when it was 100% outside.

When you learn that a proper very quiet system will be costing about £16,000 you will probably think again.

Tony Glazier

 

[Steve]

I agree with JohnD, venting heat from appliances is a very good and efficient idea. Many shops box in the top of dairy fridges and freezers, in order than the vast amount of heat they produce is contained within the wooden boxes and extracted outside. This then lowers the demand on the air conditioning system.

Portable air con units are noisy in my experience, not suitable for this environment. I would definitely go with a loft-mounted cooling box, with ducting going off to each room. The cooler will need a large air intake, though, probably from the hallway - you dont want to be taking hot, stale air from the loft.

Beware 3 phase systems. You dont want a 3 phase system unless you want to spend another thousand or so upgrading your electricity supply.

Some wall-mounted units are very quiet, we have a mitsubishi one at work, and on the minimum fan level it is very quiet, you cant hear it unless you put your ear up to it. But the condensate pump is loud and intrusive, so I would go with the loft box.

my 2c worth.

 

[jon b]

Hey guys - thank you very much for your time and experience.

Taking what has been said, I think I will take a one step at a time approach.

There are two main criteria - lowering the temp within the room yet achieving this through very low db

Provide cool air to Projector, PC and possibly the two amps i run.

Looking at the air con route - clearly this is going to be expensive even if i do it myself plus low db levels may be expensive to achieve. But some sort of ducting system may help reduce this. So i think this will be a stage 2 if required.

I will however look closely at ducting cool air from outside, via the loft. I have large wooden, horizontal panels that sit at the base of the roof , accessible from the loft (can't think of the correct name - is it eavs?). This area is shaded all day long and therefore should be provide relatively cool air.

I have done a similar process as an extraction system for the bathrooms i,e having a vent panel within the ceiling leading through flexible ducting to a fan, then leading through additional ducting to the horizontal wooden panel (eavs)- to expel air outside.

Here's my question

Hot air rises and i assume cool air drops, so ideally i would have cool air fed in at the lowest possible level through a ducting fan system and have an extraction system (as said above) within the ceiling. The problem is, I have walls that are concrete block walls with dry wall lining - a gap of maybe 20mm+ between the two surfaces. I assume there is just no way of ducting between this gap suitably given the small gap?

So i will probably only be able to feed cool air through the ceiling and also extract the warm air. So maybe two in and two out.

I have a 12v trigger switch that somehow operates the electric cinema screen to lower as soon as the projector is turned on and visa versa. I would like to connect to this cabling in order to turn on the cool air feed and extraction fans. Any experience of the best way to do this?

Thanks all

 

[JohnD]

if you rely in the narural convection of the air, you will want the hottest air to escape through the ceiling, and the coolest as low as you can get it - an air-brick or something.

 

[simond]

My bruv, a single chap, has a Mark Levinson (predominantly) system with 6 amps, Simm2 HD projector, subs, 6ft high speakers etc.....

Generates massive amount of heat, has it's own 30A supply. He's a complete anorak (he spent £1200 on a speaker cable), but I don't mind going round and watching/listening to it from time to time.

He had aircon professionally fitted, I think it was Daikin, to his lounge and master bedroom. The install was about £4.5K all up. The internal unit is very small and sited above the main equipment behind the speaker line; this way it is furthest from your ears and least likely to be heard.

Unless you listen to some very quiet classical passages you would not hear it.

Like the others, I would strongly recommend a professional installs it.

 

[Bambi]

Hi, I too have just finished a 3 year purpose built cinema project. 8 VIP Odeon cinema seats, fixed 8' screen, 9.1, electric curtains, exit sign, the whole shooting match at a cost of around £17k. I've simply used a potable air-con unit with the extractor pipe fixed to a purpose made whole where the fireplace once was. The db from the unit is high, but I cool the cinema for about an hour before sitting down with the popcorn and again after the movie has finished. The windows have been sealed up with MDF with safety catches for emergency exit so there is NO ventilation at all. The ceiling, floor and walls are insulated ( RW6 nearly 8" thick) for sound proofing thus causing a problem regarding a comfortable temperature. I have found the portable air con unit perfect for my needs and I'm sure you will find the same. Your amps should have built in cooling fans which should protect them but as a consequence give off more heat as does the projector (LCD or DLP).

With regard the 12v trigger switch for the screen, X10 is your answer. Marmitek produce an X10 multi-switch which can be wired to your projector which, I assume is CRT. I have used one for my electric screen curtains operated from X10 compatable software. I set the computer to commence the macro at say, 7pm and the air-con comes on at 7pm and at 8pm the air con stops, the lights dim, the amp comes on, the curtains open and film starts. It's great.

I considered having air-con installed and had quotes but decided that the money was better spent elsewhere. A company called G-Con based in Dover were the cheapest at £6,900 plus VAT and they recommended a Fujitsu (don't know if I've spelt it correctly) system. Don't know the spec but I would not advise a DIY job because of the gases etc.

On a different note, I'm glad to say, I haven't got 6' high speakers, mine are just about 4" square but they're made by Bose and I have 18 of them with an incredible 3600 watt (total gv) output.

Good luck with your project !

Regards,
Den.

 

[jon b]

Hi Den

Thanks for your help - i will think about the portable air con unit should my 1st solution not work

Does anyone know a good web site that does reviews on portable air con units?

That sounds like a lovely dedicated room - have you got any pictures?

I have an Optima H79 with Arcam dvd/ amp and Monitor Audio gold series speakers with a PV1 sub plus an Alienware PC

 

[Onetap]

Hot air rises and i assume cool air drops, so ideally i would have cool air fed in at the lowest possible level through a ducting fan system and have an extraction system (as said above) within the ceiling.

That's displacement ventilation, have a google; works at low velocities, supply air temperature is 2 or 3 degC below the room design temperature (not certain of the numbers, my design guides are in the loft).

Normal AC uses high-level & high velocity to project the cold air stream to very corner of the room. Supply air is colder.

You may be able to get a quiet split system (Toshiba, Fjitsu, LG type thing as seen in building societies). The compressor unit (noisiest bit) would be outside.

You might have a look at chilled water systems (ICS). Cooling is by local fan-coil units or by cooling coils in a central air-handling unit. It's more flexible and controllable, but condensation can be a problem if the pipe insulation isn't doen meticulously.

 

[jon b]

Hot air rises and i assume cool air drops, so ideally i would have cool air fed in at the lowest possible level through a ducting fan system and have an extraction system (as said above) within the ceiling.

That's displacement ventilation, have a google; works at low velocities, supply air temperature is 2 or 3 degC below the room design temperature (not certain of the numbers, my design guides are in the loft).

Normal AC uses high-level & high velocity to project the cold air stream to very corner of the room. Supply air is colder.

You may be able to get a quiet split system (Toshiba, Fjitsu, LG type thing as seen in building societies). The compressor unit (noisiest bit) would be outside.

You might have a look at chilled water systems (ICS). Cooling is by local fan-coil units or by cooling coils in a central air-handling unit. It's more flexible and controllable, but condensation can be a problem if the pipe insulation isn't doen meticulously.

Do you know of any web sites that explain/ diagram what you're describing?
cheers
Jon

 

[Onetap]

Do you know of any web sites that explain/ diagram what you're describing?
cheers
Jon

No, I regret not. A search for "displacement ventilation" produces about 35,000 hits. I found a good description in a BSRIA document (Displacement ventilation and static cooling devices". This seems to be a 'taster' to persuade you to buy the full document.

"Generally, there are two ways to ventilate a space. The traditional option is known as a mixing ventilation system which is based on the philosophy of continual dilution of stale warm air from a fresh supply. The
ventilation air may be provided by an air conditioning system in which the
air will typically be supplied at 12°C to 14°C. To encourage mixing, the
air is supplied at high velocity and with a high degree of turbulence. A
feature of this system is that conditions within the enclosure are
considered to be predominantly uniform.


The second method, namely displacement ventilation, intends to keep
new and stale air separated and involves introducing the air at low speed
directly into the occupied zone at a temperature usually slightly lower than the room temperature. A feature of this system is that the supply air
spreads across the floor forming a ‘reservoir’ of fresh cool air. This
reservoir of air is in contact with heat sources (particularly people) and
gets warmed so that it is lifted directly up and along the person and some
is breathed en route to the plume that develops over the head, rising to a
height of some 2 m to 2.7 m above the head. The warm stale air is
extracted at the highest point. As a result, a temperature and
contamination stratification of the air exists within the enclosure. The
restriction to the supply air temperature limits the cooling capacity of the
ventilation system and static cooling is often used to augment this."

The rest of the post is just derived from about 14 years involvement with AC as a site engineer. Split system installers tend to add up the rule-of-thumb heat gains, bung in the system which most closely matches this and tear off to the next job. If you want to get innovative and consider stuff like dehumidification, central AHUs, displacement ventilation, chilled water, etc., you need to be able to design the system yourself, or employ an engineer, from the components on the market.