"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