Portable Air Conditioning Units

[Jay]

I am fed up sittingin a 40C home office and so is my PC!

Anyone using a portable air con unit and can give me some feedback?

Thanks

[Blitzen]

I am...i bought one from Scan last year (£140 i think it was).

Very nice, and keeps everywhere nice and cool.
Downside = No way could you sleep with it on, as it is too loud.

[Barakka]

How big is the room ?
How many people in the room ?
Any opening windows ?
What equipment running in the room (PC's / Monitors etc) ?

[jim]

Same situation here. I was looking around on the web recently, noticed that Scan don't seem to do them any more. All seemed really expensive with no particular praise for any of them :/

[Barakka]

The cooling capacity of an air con unit is measured in units called BTU.

Basically you work out how many BTU's are generated by the room (the floor space, location (N/S/E/W facing), the windows, the occupants, and the electrical equipment generating heat.

There are many complicated methods and calculations you can get into, but for a simple idea;

• Room: length (m) x width (m) x 337
• Occupants: no of occupants x 400
• Windows: height(m) x width(m) x 800 for south facing or 200 otherwise
• Equipment: total wattage of power supplies x 3.4
• Lighting: total wattage x 4.25

Add them all together and that's your BTU rating for the room, you need an air con unit with higher than that to successfully keep it cool.

Example for my room i'm in now,

• Room: 1.8 x 2.4 = 4.32 sq/m x 337 = 1456 BTU
• Occupants: 1 x 400 = 400 BTU
• Windows: 1.2 x 1.4 = 1.68 sq/m x 800 (south facing) = 1344 BTU
• Equipment: approx 600W x 3.4 = 2040 BTU
• Lighting: 3 x 35w = 105W x 4.25 = 446.25 BTU
• Total = 5686 BTU

So I would need a 6000 BTU unit - anything lower would be running constantly when it's hot - about a 7500BTU unit would cope very easily - a 10,000 BTU unit would be overkill.

Bear in mind running an under powered unit is futile, and running an overpowered unit is not efficient - 1W is 3.4 BTU so my 6000 BTU unit will be running at 1764 Watts and if I went upto the 7500 unit 2205 Watts.

You also need somewhere to vent the hot air out to, most portable units come with a vent hose, and sometimes a panel to fit in the window opening to help stop too much cold air out/warm air in. If you have false ceilings you can pump the air up there IIRC - but that might have changed.

HTH

[Jay]

my office is tiny, probably 4m by 5m

I do have a bit of gear in there,

1 x ProCurve 1810 24 port switch
1 x 4bay QNAP NAS
1 x Cisco 1841 router
1 x Draytek 2820 router
2 x UPS devices (not sure what they are, but I know not APC )
1 x Cisco WAP4410N AP
and 1 Gaming PC thats not on all the time.

Just me and maybe sometimes Gary my dog in the room.

The problem is it gets direct sunlight all day and starts to boil, the room also holds this heat all night so it just never cools. There is an almost floor to ceiling window but only a tiny top flap opens at the top of the window.

The Ceilings are high maybe 9ft

I am worried about popping the fuses in the house to be honest! The stupid room only has 2 plug sockets.

[Barakka]

Without specifics of equipment wattage and the size of the window i'd say you're looking for a 10,000 BTU unit, probably around the £250-350 mark. I've used an AMCOR 10,000 BTU unit to cool an office about that size (with south-facing windows) successfully in the past.

The best time to buy air-con is Winter - ready for the next summer.

[peterb]

Ah, thius comes up every year - perhaps I ought to stickify it in April and remove it in September!

However, this was last years thread on the subject...

http://forums.hexus.net/general-disc...ir-cooler.html

Some good stuff and one or two additional links.

[rox0r]

We bought one of the larger ones from B&Q a few years ago and although it only gets used for about 1 week in any given year and it's a honking great lump of ugly to store and it makes the leccy meter spin like a roulette wheel, it's a Godsend.

When the 'orrible British humidity gets ridiculous and the temps go mental we stick it in the bedroom at about 6pm and by the time we go to bed the bedroom is a lovely chilly 20 degrees. Means we get a good night's sleep, although sleeping with the AC actually on is a different matter. They're far too noisy, although I can just do it with earplugs in but the missus can't. The room stays cool enough overnight so long as we keep the windows shut so it's fine.

[Blitzen]

Just me and maybe sometimes Gary my dog in the room

I thought i was the only odd one with pet names.......my cat was called John!

[smargh]

FYI: if a 12000 BTU portable A/C unit is turned on in a small sealed office by cleaners on a Friday evening and left running all weekend with no venting & tupperware to collect the water, the room will reach at least 40C and the floor would be quite soggy.

[Zak33]

You also need somewhere to vent the hot air out to, most portable units come with a vent hose, and sometimes a panel to fit in the window opening to help stop too much cold air out/warm air in. If you have false ceilings you can pump the air up there IIRC - but that might have changed.

HTH

this sums up the essential part of it...

the Air Con unit works by pulling large volumes of air through a cooler system, and the resultant air comes out really warm... that NEEEDS venting into the outside atmos, and NOT into the room.

the other air going into the maching is the air that wil come out cool and that volume of air is a lot lower... ie it's the cooling draft and it needs to keep cooling the room air over and over.

so getting plenty of air INTO the machine and OUT of a window is the first thing to plan.

I have walked into so many offices with a massive white aircon unit in them, with one person benefiting from a weak ice cold draft, but the rest of the room getting worse ... and eventually even the bloke sat next to it is getting no benefit as the air coming through the machine is so warm it fails to assist in the cooling of the vaporised coolant.

[Biscuit]

Is there any method of using these with swinging door type windows rather than a slidey lift one (gotta love the technical terms )?

[scaryjim]

... this was last years thread on the subject...

http://forums.hexus.net/general-disc...ir-cooler.html

...

Thanks peterb, that saves me the hassle of remembering what I wrote last year and repeating it all