Re: Cooling attic (and home) by spraying water on roof (shingles)- good/bad?

["Phil Scott" <philscott@xxxxxxxxxxxxx>]

"Chas Hurst" <hurst1@xxxxxxxxxxx> wrote in message
news:0uednRz508PCbCLfRVn-1w@xxxxxxxxxxxxxx
> Don't cooling towers use evaporative cooling?


Yes they do... but they discharge 100% relative humidity
air...but its outside so its fine...the water in the process
is cooled and that cool water is used to cool most often the
condensers on large tonnage refrigerated AC systems.  that
water typically runs 65 to 80 degrees F... sufficiently cool
to cool condensers but not cool enough to be used directly for
conditioning air  (below 40F is required)

Phil Scott
>
> "Phil Scott" <philscott@xxxxxxxxxxxxx> wrote in message
> news:d9ocdq$2hf$1@xxxxxxxxxxxxxxx
> >
> > "Some Guy" <Some@xxxxxxx> wrote in message
> > news:42BF3E57.659FD057@xxxxxxxxxx
> > > Phil Scott wrote:
> > >
> > > > > Doesn't a mister waste water by atomizing it and
then
> > the
> > > > > wind will blow it away?
> > > >
> > > >      The latent heat of evaporation for water ...
> > >
> > > I still don't see an effective way to arrange a
residential
> > cooling
> > > system based on the evaporation of water.
> > >
> > > I don't think you can concentrate and deliver a
substantial
> > amount of
> > > heat to a surface you can cool via evaporation.
Evaporative
> > cooling
> > > would be effective if the heat inside a house could be
> > brought to an
> > > out-door device who's surface temperature is well above
> > boiling and
> > > the application of water would result in evaporative
> > cooling.
> > >
> > > > Evaporative cooling would be limitlessly popular if it
> > > > did not add an equal amount of humidity in the form of
> > > > 'steam' to the air it was cooling to *sensibly lower
> > > > termperatures.
> > >
> > > So what you're saying is to mistify the air circulating
in a
> > house in
> > > order to cool it.  I don't think that would work once
you've
> > saturated
> > > the air (ie humidity > 75%) not to mention the effects
of
> > saturated
> > > air on items in the house, the wood, the machinery, etc.
> >
> > I am a mechancal engineer doing these sorts of
calculations
> > and systems for over 40 years.. and you are entirely
correct
> > if the humidity is say 50% and the outside air is 90F...
you
> > can cool the air to 75 or so but the humidity is then up
into
> > the 80% range and all the problems you mention manifest.
> > Thats why evaportive cooling is not used in many cases.
> >
> > However in areas where the relative humidity is in the 20
to
> > 30% range, and the outside air is over 90F... then the
supply
> > air can be cooled to 70F and 50% relative humidity..that
works
> > very well/
> >
> >
> > >
> > > I think only the roof makes a workable item to cool with
a
> > water
> > > cooling.  It's designed to get wet, to collect runoff,
and
> > gets very
> > > hot in the summer, and cooling it can lead to reduction
in
> > cooling
> > > requirements of the house.
> >
> >      Its workable...but there are problems ..its seldom
used
> > because of those problems.   You get to do whatever you
wish
> > though its yer house.  Have fun.
> >
> >
> > >
> > > The only thing that makes more sense is a temporary tarp
or
> > canopy to
> > > cover the roof during the summer (to be taken down
during
> > nasty
> > > weather, storms, etc).
> >
> >   Oh please.
> >
> >
> > Phil Scott
> >
> >
>
>