Question:
These two units have very different functions but in terms of human
comfort there's a conundrum. My understanding is that lowering the air
temperature will increase the humidity but reducing the humidity will
increase the effectiveness of the body's natural cooling mechanisms.
Does any one have any experience of using dehumidifiers like this (ie
does it actually work) or got any usefull thoughts on the subject.
Answer:
If you cool air, the absolute humidity will stay the same until the air
becomes saturated, when water will start to condense out. The relative
humidity will, however, rise until saturation point and that does affect
comfort levels.
A proper air conditioner, as opposed to an air cooler, cools the air to
saturation point and condense out some of the excess moisture. Then it
reheats the air to the desired temperature, possibly injecting water or,
preferably, steam to control the relative humidity
If you simply dehumidify the air you reduce both relative and absolute
humidity. Although that might make your sweat marginally more effective
at cooling you, once you get down to around 30%RH you will find it gets
uncomfortable. At very low humidity levels you get burning eyes and
itchy skin.
There was a period when one of our air conditioning units was burning
out steam generators at the rate of about one a week. It was the staff
complaining of those symptoms that alerted us to the problem. Possibly
acclimatisation could account for your lack of symptoms. My staff had
50%-60%RH outside the clean room and 20%RH or less inside it.
