XPost: alt.tv.hometime, alt.building.construction, alt.tv.home-imprvment 
 XPost: alt.home.automation 
 From: philscott@philscott.net 
  
 "Some Guy"  wrote in message 
 news:42BF3E57.659FD057@Guy.com... 
 > 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 
  
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