Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Sunday, January 01, 2006

Evaporative Cooling

Judy and I weakened, and escaped from the heat of Robertson to even hotter Canberra (Max: 39.9*C and 12% humidity). But Judy's house has evaporative cooling! 36 degrees outside, 24 inside. No CFCs being used to achieve this, just a bloody big "Coolgardie Safe" contraption on the roof. It works like a charm (but only in a dry atmosphere - no problems today.) It probably would not work in Robertson in February, I feal sure, but then again, there is less need at that time of year than in this relentless dry heat we have been suffering from.
It is a simple evaporative device, dribbling small amounts of water across absorbent panels, and as the water evaporates, the air around it is cooled (Latent heat of vapourisation, I seem to recall from Physics classes, from 40 years ago) then sucking the cooled air down inside the house, and pumping it around. You need to have an open door or window to allow the moist air to escape. So, it has a large fan, the evaporative panel, a (small) water supply, and lots of dedicated air ducting. Pretty damned good, and requires none of the nasty chemicals empoyed in Air Conditioning.

Appropriate technology rules, OK?


ah said...

Hi Denis,
Below twenty and foggy in Robbo today!
My keyboard is working again. It just stopped somewhere around +37. (Actually, it didn't get at all as hot as that indoors. But it was pretty bad.)
Anyway, your peonies should be enjoying themselves today. There was some rain overnight, not much but with the fog today everything looks much better.

Denis Wilson said...

Thanks Anni.
Canberra was cooler today than yesterday, but still clear and dry. A 2 minute squally shower was all they got last evening; not enough to cool the air, even.

This morning, I was watching the Weather Bureau automatic reporting for Moss Vale, and thought it must have been faulty. Anyway, we came back this afternoon, to a lovely misty evening.