Though sometimes called "air conditioning", it is nothing like the usual air conditioning most of us are used to.
You may have noticed, if you've been here, these boxes on the roofs of houses here, like this one:
The pump carries the water up to the top of the box, where it is then allowed to drip over the four sides.
These four sides have tiny louvres, which allow the water to evaporate, in the hot air drawn in by the fan and then the cooled air is ducted into the rooms of the house. Excess water falls back into the bowl and subsequently re-circulated.
Two words from my General Science days in secondary school summarise this process: latent heat.
Is it effective in cooling the house?
This recent shot shows the external and internal temperatures in our house recently (ignore the date and time, as I did not set them).
This method of "air-conditioning" ceases being effective when humidity starts to exceed 80%, in my experience.
However, for the whole hot season, we'd get maybe 3 - 5 such days, if that many. I much prefer the 40°+ dry days to humid weather.
For humid days, we use the bedroom "real" air-conditioning to sleep in (given to us by Son No 1, when he upgraded his). This season, we've used it once.
We've used this "air-conditioning" from the early 80s, and about 4 years ago had to replace the whole system, as the side panels had rotted, the insulation round the ducting had also disintegrated and it was generally no longer efficient.
I don't mind the hot dry weather in Perth but it's the bush flies that I can't stand.
ReplyDeleteI agree with you Luke, the flies are a damn nuisance.
DeleteUsed to be much worse, however, till they introduced the dung beetle, which eats the larvae of the flies. Nowadays its better. I used to see people's backs black with flies. Nowadays no more, though there are still annoying ones flying around, trying to get at the moisture in your eyes and lips. haha.
A famous mathematician Kurt Mahler at ANU used to have this solution to the flies problem in summer. He would wear a hat whose front rim is attached with a net that prevents the flies from getting to his face. It's quite a sight to see him walking around like that in summer.
DeleteI think that hat isn't too uncommon. I've see it worn a few times. An old joke hat is the one with corks dangling off the brim, which the wearer can swish around to drive the flies away.
DeleteDon't swap the flies, a dead fly will attract more flies.
DeleteI've swallowed many a fly whilst cycling. Must learn to grimace with my mouth shut.
DeleteI meant "swat" and not "swap" of course. No one wants to swap flies for anything, including Arthur's open mouth!
DeleteTalking about open mouths, life must be hazardous for senior folks since they often sleep with mouths open. Maybe they are a hardy lot, swallowed flies notwithstanding.
DeleteFlies don't get out at night?
DeleteSenior folks, especially retired ones, sleep anytime of the day, :)
DeleteThis is interesting! So it does not work here? We have a kind of fan where one would have to put in water...or something frozen in the freezer...and the air that comes out would be cooler, not as cold as an air conditioner but cooler than a normal fan.
ReplyDeleteIn humid climates, evaporation cannot take place and therefore the cooling effect is not there. Won't work in a place like Singapore, and I'd imagine Sibu's pretty humid.
DeleteWhen we were in Longreach in mid summer when it was high 40s and the humidity was less than 10%, a similar unit sent the room temperature down to about 37C and the humidity to 80+ %. You are right, it became like Singapore on a bad day.
ReplyDeleteIn the high 40s, it's probably overreached the limit of its usefulness, as it can only bring temp down by 10-12° max. But I wonder if the humidity is caused by not having enough windows (or doors) open. Unlike "real" air-conditioners, if there are insufficient such openings, humidity will build up.
DeleteAnother trick I've found is to turn it on in the mornings while the house is still cool. That way, it's more likely to keep the house cool throughout the day, rather than turning it on after the house has already heated up. Without a compressor, I've found that it can't lower the temp of a hot house by very much.
What about the good old electric fans? They should be as effective in blowing away the hot air and cooling the rooms. When it gets windy here in SG, the heat is less unbearable. The rains too help in cooling the place. The heat wave usually comes with the dry spells. Does it get windy in Perth? What about the rains?
DeleteWe get strong easterlies blowing in summer, and the wind is hot too. Doesn't rain much in Summer, just the odd storm. Most of the rain is in winter. Fans are effective to a certain extent, but the air in the house can get very hot.
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