On 7/9/2018 10:32 AM, trader_4 wrote:
On Monday, July 9, 2018 at 12:36:21 PM UTC-4, Ed Pawlowski wrote:
On 7/9/2018 12:04 PM, trader_4 wrote:
On Monday, July 9, 2018 at 11:51:30 AM UTC-4, Ed Pawlowski wrote:
On 7/9/2018 10:47 AM, trader_4 wrote:


I'm not even sure I understand how they work in an area with dry climate
when they are inside. I would think it would work fine for a few hours
until the humidity got to a reasonable level. Once the humidity passes
about 60%, then what? Do you open windows to let hot, dry air in? Or
do you just use them to cool one or two rooms and the rest of the house
is hot and dry enough that there's enough dry air?


I imagine you can feel cooler for a while sitting right in front of it
but the heat does not disappear, it is just moved to the other parts of
the room. To truly cool, you still have to move the heat out, not just
disperse it. Since the motor is running, it is actually creating more
heat.

Putting a bag of ice on your head would be more beneficial.

It's not just feel, it really does cool the room, ie the temp will drop,
the heat is moved into the water by evaporating it. The part I question
is what happens after the temp drops a bit, but the humidity has increased
to 60%, 70%+? Then what?

The water will release its heat back into the room.

It won't release it heat into the air unless it changes phase again,
back to liquid. Let's assume it's a perfectly insulated chamber with
air at 90F and humidity at 10%. By evaporating water, the temp will
drop and the humidity will increase. Say it gets to 80F and 50%.
It will stay there. The problem is a house is nowhere near perfectly
insulated, so before long it will be back to 90F, but now with 50%
humidity, instead of 10%. So, what do they do then?



You can't make cold, you can only remove heat. Temporarily you can move
the heat to water, but there is no drain for the water so the cycle
continues.

I agree that to continue it, you'd have to get rid of the water, you're
right, that's where the heat is, which
is why I was questioning how these swamp coolers are really used? If
it's outside on a patio to blow cool air on you, I can see it. But
I don't see how they can be used effectively to cool a whole house,
even in a dry climate. You could continually bring in 95F dry outside
air and run it through the cooler, getting a lower temp and maybe that;s
what they do? If so, I wonder what temp delta you can achieve in a
typical dry environment between outside air and inside air?


These things were seen often when I was a kid traveling through dry
western country. Air conditioning was not so prevalent then. Maybe they
worked well then because buildings were not sealed like they tend to be
now, so the air was being constantly refreshed. In a modern "sealed"
house, they probably wouldn't be as effective over time.

You also frequently saw vehicles with canvas water bags hanging in front
of the bumper. Evaporation would keep the water cool to drink, even in
the desert sun.