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