DIYbanter - View Single Post

wrote
Oscar wrote
wrote
James \"Cubby\" Culbertson wrote

I live in Albuquerque and the swamp cooler is OK but not great.
The last few years has seen higher than normal humidities
so at night it struggles.

You might try a different configuration with better controls, eg
turn on the swamp to cool recirculated house air when the indoor
temp rises to 80 F and turn on a small exhaust fan when the indoor
RH rises to 65%.

This works in Melbourne Australia...

Few use swamp coolers there.

I too had the impression that Melbourne (vs Perth)
was too humid for swamp cooling, but I was wrong

They dont work very well there, which is why few bother with them.

(have you ever been wrong? :-)

Nope, never ever.

Practically every new house built (and there are a lot
of these at the moment, most badly designed and over
priced) has a large swamp cooler mounted on the roof.

Not in Melbourne they dont.

Melbourne is rarely humid. I think the highest dewpoint recorded is
23C.

'think' again.

We tried out your split-cycle swamp cooler idea a couple of nights
ago using a jerry-rigged humidistat using a SHT11 and a computer
to control the exhaust fan, and the brains of a commercial
refrigerative split-cycle system for the swamp cooler. We closed
all the windows (against standard practice with swamp coolers)

Its a ****ed approach with a swamp cooler, nowhere for the
higher humidity that comes out of the cooler to get out of the house.

Reading more carefully, you might wonder what the exhaust fan does.

No point in closing all the windows, stupid.

and ran the swamp cooler to a fixed temp (22C) and the
humidistat to a fixed humidity (65% at your suggestion).
That night it was 28C and 35% outside.

Then again, 22C is cool, but comfy (PMV = 0.007), with vel = 0.1 m/s
and clo = 1 insulation. Raising vel to 0.5 and lowering clo to 0.5 makes
35 C at 65% comfy (slightly cool, with PMV = -0.54, on a scale from

Presumably thats a typo and you mean 25C

Too cool for me.

-3 = cold to +3 = hot), according to the BASIC program in the ASHRAE
55-2004 comfort standard, so he might have just used a ceiling fan on
that day... 28C at 35% with clo = 0.5 and vel = 0.5 is "slightly
warm" in the comfort zone, with PMV = 0.23.

A properly designed swamp cooler system can run with
just the fan and no water, no need for extra ceiling fans.

Most think that 28C at 35% is too warm.