One question,
How do portable units expel the heat?
Most units I have used in the past either have a heat exchanger (and fan)
mounted outside, or require a vent pipe for warm air to be blown out, so how
does a portable unit which says keep doors and windows closed expel the
heat?

"Al" wrote in message
m...
I can't take the heat any more!

Looking at a mobile/cheap air con unit.

B&Q do a couple (although out of stock at the moment) around £180.

Product
http://www.diy.com/bq/product/produc...5&CATID=190440

Anyone used this before or another similar unit? Any good for cooling
down a 12x12 ft room?

Thanks,

Al

"Martin" wrote in message
...

One question,
How do portable units expel the heat?
Most units I have used in the past either have a heat exchanger (and fan)
mounted outside, or require a vent pipe for warm air to be blown out, so
how
does a portable unit which says keep doors and windows closed expel the
heat?


Latent heat of evaporation of water. Room gets cooler, air gets damper.

You get the same effect if you drape wet socks over a fan.

Dave

On Sun, 10 Aug 2003 18:33:08 +0000 (UTC), "Martin"
wrote:

How do portable units expel the heat?
Most units I have used in the past either have a heat exchanger (and fan)
mounted outside, or require a vent pipe for warm air to be blown out, so how
does a portable unit which says keep doors and windows closed expel the
heat?

I've got one roughly the same size as the one linked by the OP.

If you recirculate the air, forget it - it'll add to the heat in the
room. Opening a window and dropping the exhaust pipe out can help, but
it doesn't really help much because more warm air comes in the window.

The only solution is a firking great 4in hole thru the outer skin of
the house, thru which you poke the exhaust pipe.

But a 12x12 room? No chance. I've got 2 PCs in my study, combined they
chuck out about 500w of heat. The mobile aircon just about keeps up,
but only just. If I go sit in the study to admire the slightly lower
temperature it's over the top. And my study is something like 6x9.

Basically these mobile units are a pile of pooh. Don't bother is my
suggestion. I understand from comments made by others that you really
need a dual unit, where the fan is inside and the heat exchanger is
outside (I hope I remembered that right). Expect to pay a grand or
more for something like that.

Andrew

Do you need a handyman service? Check out our
web site at http://www.handymac.co.uk

"Al" wrote in message
m...
I can't take the heat any more!

Looking at a mobile/cheap air con unit.

B&Q do a couple (although out of stock at the moment) around £180.

Product
http://www.diy.com/bq/product/produc...5&CATID=190440

Anyone used this before or another similar unit? Any good for cooling
down a 12x12 ft room?

As others have said the water filled ones aren't much cop (although some can
be filled with ice) and the portable proper ones don't have much power. A
friend of mine has one and it's about 500W or less of cooling. If you think
about how much energy it takes to heat a room up then it needs the same sort
of power to cool it down. And he has problems sealing around the exhaust
pipe (uses towel stuffed around the window).

--
Malc

Dave Gibson wrote:

does a portable unit which says keep doors and windows closed expel the
heat?



Latent heat of evaporation of water. Room gets cooler, air gets damper.

You get the same effect if you drape wet socks over a fan.

Errr No ;-)

The portable units have a large flexible vent pipe like a tumble dryer -
you poke this out a window or through a vent as Andrew says below. If
you use a window then you want to open it only enough to accommodate the
end of the vent pipe and then preferably "fill in" the rest of the gap
(use a towel or wrap the curtains round the gap etc - some units even
come with foam batts designed for the purpose)

They will condense lots of water out of the air as well - most have an
internal reservoir that needs emptying from time to time. Some you can
connect a hose to if you can find a way to have the water run down hill
to a suitable exit.


--
Cheers,

John.

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On Sun, 10 Aug 2003 21:23:15 +0100, Dave Gibson wrote:

Latent heat of evaporation of water. Room gets cooler, air gets
damper.

Some cheap "air con" units do use this effect and yes they do produce
a stream of cool air but as you say the humidity rises. After a few
hours your in cool sauna... and your own perspiration can't evaporate
either so it becomes really uncomfortable.

Anyway AFAICT the OP is referring to a proper aircon unit as the
features specifically mentions dehumidfication of the air, some thing
that only happens with a proper chiller unit.

Still need to dump the waste heat somewhere though. Depending on the
window design a board with a suitably sized hole would do, but really
only works on a sliding type window rather than an opening vent.

--
Cheers
Dave. pam is missing e-mail

In article ,
Andrew McKay writes:
On Sun, 10 Aug 2003 18:33:08 +0000 (UTC), "Martin"
wrote:

How do portable units expel the heat?
Most units I have used in the past either have a heat exchanger (and fan)
mounted outside, or require a vent pipe for warm air to be blown out, so how
does a portable unit which says keep doors and windows closed expel the
heat?

I've got one roughly the same size as the one linked by the OP.

If you recirculate the air, forget it - it'll add to the heat in the
room. Opening a window and dropping the exhaust pipe out can help, but
it doesn't really help much because more warm air comes in the window.

The only solution is a firking great 4in hole thru the outer skin of
the house, thru which you poke the exhaust pipe.

That doesn't help -- the air still has to come back in from outside.
That's why such units are not as good as two part or fitted units.
Someone gave me one, claiming it not to work, which was for exactly
this reason. I doctored it to add a second hose which draws air in
which is passed across the condensor and expelled again -- this one
fortunately had quite separate air intakes for the condensor from
that for the evaporator which enabled me to keep the inside and
outside air paths isolated. That fixed the problem, but I've never
seen one which comes with two hoses for this purpose.

But a 12x12 room? No chance. I've got 2 PCs in my study, combined they
chuck out about 500w of heat. The mobile aircon just about keeps up,
but only just. If I go sit in the study to admire the slightly lower
temperature it's over the top. And my study is something like 6x9.

Mine's in a 10' x 12' room with computer and TV, but they probably
only total about 200W, and having hacked it, it works quite well.

Basically these mobile units are a pile of pooh. Don't bother is my
suggestion. I understand from comments made by others that you really
need a dual unit, where the fan is inside and the heat exchanger is
outside (I hope I remembered that right). Expect to pay a grand or
more for something like that.

Indeed.

--
Andrew Gabriel

Andrew McKay wrote:

But a 12x12 room? No chance. I've got 2 PCs in my study, combined they
chuck out about 500w of heat. The mobile aircon just about keeps up,
but only just. If I go sit in the study to admire the slightly lower
temperature it's over the top. And my study is something like 6x9.

It seems the performance must vary a fair bit depending on the unit....
I have seen powers ranging from 4000 btu/hour to over 14000 for
monoblock units.

I use a 8000 btu/h in my office (approx 12'x10'x7'6"). With only 2 PCs
on, and me in it, the temp is currently 25.6c. The room next door is
currently 32c. It much less humid in here as well.

Basically these mobile units are a pile of pooh. Don't bother is my
suggestion. I understand from comments made by others that you really
need a dual unit, where the fan is inside and the heat exchanger is
outside (I hope I remembered that right). Expect to pay a grand or
more for something like that.

I would go along with the recommendation for a split unit, although I
would not be quiet as disparaging about the monoblocks if you get one
with enough power and can put up with the noise (i.e. probably not ideal
for the bed room!) Expect to pay 350 quid or more for a decent one though.


--
Cheers,

John.

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\================================================= ================/

I can't take the heat any more!

Looking at a mobile/cheap air con unit.


Get a split unit, where the compressor sits outside. Don't waste your money
on cheap portables.

I installed one of these a couple of months ago.
http://tinylink.com/?fgrEyo9D6N

Even with todays extream heat, I had to turn the thing down as it was
getting too cold indoors.

Stuart.

Anyone used this before or another similar unit? Any good for cooling
down a 12x12 ft room?


From experience, 8000btu/hr units are not equal. Some will do the job,
others wont.
I'd have a look on Ebay for a better quality unit.

Oscar

On 10 Aug 2003 23:16:47 GMT, EWS (Alex H) wrote:

The best deal on proper split air-con units, I've found is at TLC Direct
http://makeashorterlink.com/?U1AF32C85

I love the starting paragraph:

"No installation required.....".

This is a split aircon, right?

Andrew

Do you need a handyman service? Check out our
web site at http://www.handymac.co.uk

It seems the portable units aren't gaining favourable reviews. I'm not
keen on having a large floor standing unit on taking up space.

Having spent 5 years in the Middle East, I'm used to full house ACs -
a luxury I know!.

I'm keen on the split ACs. The wall units are not as obtrsusive and I
have a good place to put the condeser in.

A question about the external condensors - are they supposed to be
screwed into the floor/roof? I'm planning on placing it on a flat roof
so I can't screw it down.

Thanks,

Al.

A question about the external condensors - are they supposed to be
screwed into the floor/roof? I'm planning on placing it on a flat roof
so I can't screw it down.


Mine just sits on the patio. I haven't bothered to bolt it down. It's very
heavy; you may need a small crane or something to get it up to a roof. Also
consider the noise they produce, as it may upset the neighbours.

S.

I've been looking at these as well, thanks for the extra info... However in
the true DIY spirit I was also thinking about somehow using the existing
plumbing and radiators to do the job. If you pumped very cold water around
the house would this actually generate any coolness from the radiators? Any
other ideas for cooling the whole house (split ac's are good but only
designed for one room?)

Mat

"Al" wrote in message
m...
I can't take the heat any more!

Looking at a mobile/cheap air con unit.

B&Q do a couple (although out of stock at the moment) around £180.

Product
http://www.diy.com/bq/product/produc...5&CATID=190440

Anyone used this before or another similar unit? Any good for cooling
down a 12x12 ft room?

Thanks,

Al

I've been looking at these as well, thanks for the extra info... However
in
the true DIY spirit I was also thinking about somehow using the existing
plumbing and radiators to do the job. If you pumped very cold water around
the house would this actually generate any coolness from the radiators?

The water would have to be so cold to start off with, it would be ice!
Think of all that condensation, dripping onto your carpets too!

S.

In article , Andrew
McKay wrote:
I love the starting paragraph:

"No installation required.....".

This is a split aircon, right?

From what I can see looking at the pic the two bits look
permanently coupled so I presume you hang the compressor outside
a window?

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser
http://www.sda.co.uk/qsedbuk.htm

In article ,
(Al) writes:
It seems the portable units aren't gaining favourable reviews. I'm not
keen on having a large floor standing unit on taking up space.

Having spent 5 years in the Middle East, I'm used to full house ACs -
a luxury I know!.

I'm keen on the split ACs. The wall units are not as obtrsusive and I
have a good place to put the condeser in.

A question about the external condensors - are they supposed to be
screwed into the floor/roof? I'm planning on placing it on a flat roof
so I can't screw it down.

They're heavy, but I've seen them blown over on roofs.
If it is significantly taller than its width or depth,
you want to at least fix it to something with a larger
footprint, which also spreads the weight and might help
prevent damage to the roof covering. It's best to fix
them down if you can. Also think of the vibration
coming through the roof -- wouldn't be a good idea if
there's a bedroom underneath for example.

--
Andrew Gabriel

In article ,
"Matthew Augier \(dps\)" writes:
I've been looking at these as well, thanks for the extra info... However in
the true DIY spirit I was also thinking about somehow using the existing
plumbing and radiators to do the job. If you pumped very cold water around
the house would this actually generate any coolness from the radiators? Any
other ideas for cooling the whole house (split ac's are good but only
designed for one room?)

You would need fanned radiators, and you would need something to
collect the condensate. Then you just invented a fancoil unit.
Also, you need to insulate all the pipework very much better than
you ever do with central heating, otherwise you will have
condensate dripping off every tiny gap or crack in the insulation,
looking rather like it's all leaking.

--
Andrew Gabriel

Andrew McKay wrote in message . ..
On Sun, 10 Aug 2003 18:33:08 +0000 (UTC), "Martin"
wrote:

How do portable units expel the heat?
Most units I have used in the past either have a heat exchanger (and fan)
mounted outside, or require a vent pipe for warm air to be blown out, so how
does a portable unit which says keep doors and windows closed expel the
heat?

I've got one roughly the same size as the one linked by the OP.

If you recirculate the air, forget it - it'll add to the heat in the
room. Opening a window and dropping the exhaust pipe out can help, but
it doesn't really help much because more warm air comes in the window.

The only solution is a firking great 4in hole thru the outer skin of
the house, thru which you poke the exhaust pipe.

But a 12x12 room? No chance. I've got 2 PCs in my study, combined they
chuck out about 500w of heat. The mobile aircon just about keeps up,
but only just. If I go sit in the study to admire the slightly lower
temperature it's over the top. And my study is something like 6x9.

Basically these mobile units are a pile of pooh. Don't bother is my
suggestion. I understand from comments made by others that you really
need a dual unit, where the fan is inside and the heat exchanger is
outside (I hope I remembered that right). Expect to pay a grand or
more for something like that.

Andrew

Do you need a handyman service? Check out our
web site at http://www.handymac.co.uk

I have one of these from comet - i got it last summer, its a 8000 BTU
unit and it drops the temp of my bedroom (4M x 4M) by about 10
degrees. I agree about the vent pipe - you can either use the foam
rubber sheet they supply you with but with hinged windows (as against
sliding windows) you still end up with huge gaps to let in the hot air
and as you the alterntive is a 4" hold through the wall........BUT in
a true diy fashion i built myself a window wedge from scrap wood that
fits in the opening of the window when its about 1/3 open with a hole
for the vent pipe and sealed round the edges with pipe insulation. So
not i just need to open the window to it fullest extend, then shut it
on the wedge and insert the vent pipe - it makes a good seal all round
including top and bottom.......it works great....only problem is it is
a bit on the large size but still it works

gin

"Stuart" wrote in message ...
I've been looking at these as well, thanks for the extra info... However
in
the true DIY spirit I was also thinking about somehow using the existing
plumbing and radiators to do the job. If you pumped very cold water around
the house would this actually generate any coolness from the radiators?

The water would have to be so cold to start off with, it would be ice!
Think of all that condensation, dripping onto your carpets too!

S.

take a look at http://www.globalcooling.org.uk/index.html lots of
split units and very helpful on the phone - i will be buying from them
later this year

gin

Matthew Augier (dps) wrote:
split ac's are good but only
designed for one room

They certainly aren't only designed for one room.


Sorry I meant to say, I thought for only one room. I was also going to ask

You can have one external condensor feeding several internal air
handlers if required. The modern ones give you full independent control
of each of the air handlers as well.

The only thing you can't do use is mix the cooling and heat pump modes
(i.e. you can have all cooling or all heating but not a mixture of
cooling and heating)

ISTR one of the messages earlier in this thread had a link to a site
that showed a whole house system with several air handlers running from
a single external unit.

how they work, and if they can be installed by an average DIYer?

DIY - probably not. You would need access to the specialised equipment
that is used to charge the system with refrigerent once all of the
pipework is installed.

There are some portable split units that you can DIY - these have self
sealing connectors in the hose that allow you to separate the internal
and external units without losing all the refrigerant.

(I watched carefully when I had the aircon on SWMBOs car recharged the
other day. He used a dedicated aircon compressor to first purge any
residual coolant from the system, then he pumped in a small amount of
oil, followed by the refrigerent. The refrigerent came in a canister not
unlike a calor gas bottle. He stood this on special set of electronic
scales. The scales monitor the weight of refrigerent added to the
system. Supprisingly it took 45 mins or so just to refill it. Finally he
added a small amount of flourescent dye to help spot any leaks (although
I presume this stage might be ommited from a domestic setup!))


--
Cheers,

John.

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(Andrew Gabriel) wrote in message
They're heavy, but I've seen them blown over on roofs.
If it is significantly taller than its width or depth,
you want to at least fix it to something with a larger
footprint, which also spreads the weight and might help
prevent damage to the roof covering. It's best to fix
them down if you can. Also think of the vibration
coming through the roof -- wouldn't be a good idea if
there's a bedroom underneath for example.

There is a dining room under the flat roof - which isn't used a huge
amount. Wonder if the vibration would cause any cracking on the
internal ceiling/walls?

In terms of noise - I'm figuring there aren't any noise control laws
that would stop me using these? We are in a terraced house and the
neighbours bedroom window would be about 10ft away (approx. same
level) from where I plan to place the condensor unit.

My main worry (and the reason I asked about fixing the unit) is
someone nicking the condensor. The unit would be easily visible from
the street - our house is second one in from the street. Do these
things get stolen?!

One of the replies in this thread mentioed globalcooling.org.uk. Would
be interested in hearing on your experience once the AC has been
installed at your place.

Cheers all.

Al.

In article ,
(Al) writes:
There is a dining room under the flat roof - which isn't used a huge
amount. Wonder if the vibration would cause any cracking on the
internal ceiling/walls?

No, just a hum. Imagine your fridge with a compressor some 10
times the power.

In terms of noise - I'm figuring there aren't any noise control laws
that would stop me using these? We are in a terraced house and the
neighbours bedroom window would be about 10ft away (approx. same
level) from where I plan to place the condensor unit.

I would say that's far too close, given their window is likely
to be wide open and possibly trying to sleep in there when your
AC is running. Also, they might pick up a large amount of the
hot air on occasion.

My main worry (and the reason I asked about fixing the unit) is
someone nicking the condensor. The unit would be easily visible from
the street - our house is second one in from the street. Do these
things get stolen?!

Not often -- they aren't really any use by themselves.
We did have one taken from someplace I worked a long time ago,
but we were told that was rather unusual.

--
Andrew Gabriel

On 13 Aug 2003 10:07:45 GMT, Huge wrote:

How do I spec how much cooling I need?

I my very rough an ready experience of aircon 1kW of heat input to a
space needs at least 1kW of air con to keep that space cool.

The room is 24 by 12 and the 9,000 BTU/h Haier cannot cope.

Something bigger than 9,000BTU or around 3kW. B-) Might have to
start thing about a separate spur to provide it's power...

--
Cheers
Dave. pam is missing e-mail

Huge wrote:

- How do I spec how much cooling I need? The room is 24 by 12 and the
9,000 BTU/h Haier cannot cope.

I have seen one formula suggested that was volume of room (cubic feet) X
5 = btu/hour required.

You are then supposed to add something for the number of people and also
for heat generating kit. (where 1 watt is approx 3.4 btu/h IIRC)

So assuming your room is 8' high then you would be looking at 12,000
btu/h minimum - possibly more if you are dealing with solar radiation
through a window for example.

- Can anyone recommend a split unit? One of the ones I've seen says
that the umbilical is "disconnectable" (*), which would be excellent,
because then I could run it through the hole I made in the wall for the
monobloc's exhaust.

This link somone posted the other day on one of the threads seems to
have quite alot of info on self installable kit.

http://www.globalcooling.org.uk

- What's a good price? All the ones I've seen so far are from ?700 to
?1000 and more. And a good way of benchmarking it - per kilowatt of cooling?

On the link above they listed for example:-

Haier 12,000 btu 3.3 kw Cooling Only at 565 inc VAT + about 130 quid for
the self install kit.

- Can anyone recommend a good supplier? Then I can call them and not bother
you lot.

Don't worry, most of us like talking about this sort of stuff - and
winding up those that don't can be fun as well ;-)


--
Cheers,

John.

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Dave Liquorice wrote:

Something bigger than 9,000BTU or around 3kW. B-) Might have to
start thing about a separate spur to provide it's power...

Common misconception I think - IIUC the power rating of the aircon
relates to how much heat it can *move*, not how much electrical power it
consumes.

Since these things simply move heat from one place to another, they can
appear to be more than 100% efficent. i.e. you will often find a 2kW air
con will consume say 800W of electrical power.

(this is why the heat pump versions can be quite economical when used
for heating in the winter - they are reclaiming more "free" heat from
outside than they consume doing it).


--
Cheers,

John.

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