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

["Chas Hurst" <hurst1@xxxxxxxxxxx>]

Don't cooling towers use evaporative cooling?

"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
>
>