Hey Kim,
You said “Put a piece of hot metal in water, it cools”. That’s true if the water is cool. If you put cool metal in hot water, the metal heats. Seems to me that the water on the roof would work only if you keep the water cooler than the temperature of the metal on the roof. You’d still get some cooling from evaporation of the water but I don’t think it’d be enough to be noticeable. I am interested in the cool roof technique because I was thinking of putting the water storage tanks (from a rain catchment system) underneath the house where it stays fairly cool in the summer and they’d be out of the way there as well.
Would the cool roof pictures and technical descriptions be on the Yahoo *Group* “HREG” home page? I couldn’t find the pictures, etc on the HREG Yahoo Group home page but maybe you have to be a member? I’m really interested in the cool roof since I already have a metal roof….I’m supposing I’ll need to install gutters and a tank to catch the run-off and then distribute it to the garden/flower beds/etc. but I’ve been wanting to build the rainwater catchment anyway… if I caught enough rainwater I wouldn’t need to use as much city water, which would be a good thing!
Your sprinklers run for 12 minutes/day total….how cool do you keep your house? And how dry is it? Do you notice that your towels and sheets stay damp? These aren’t challenging questions… they’re something I’d really like to know before I invest time & money in a system I don’t know if I can live with or not. I really can’t *stand* for my sheets to be damp. That’s the biggest problem I have with leaving the windows open at night in the spring when it’s cool….it’s usually also damp and it gets everything in the house damp. EEEEyyyech!!! J
Thanks!
Pat
From:
Sent: Sunday, September 02, 2007 11:37 AM
To:
Subject: Re: [papercreters] containers -was- Re: ugly eco home
Greetings,
I am only 125 miles from the Gulf coast, average humidity: 80% most of
the time that seems like a low number. The idea actually originated
with a charter member of the Houston Renewable Energy Group. The limit
he found was that it will destroy a shingle roof, metal or some other
durable roof is required. His original experiment that was using grid
power and city water, save the homeowner about 40% net on his electric
bill. By that I mean that after he paid the increase in his water bill,
he was still around 40% less money out of pocket for his electric.
As you have stated, insulation in the ceiling is the most important. We
have opted to use a cool roof instead. The sun can't heat the roof as
the water carries the heat away with it. The water is then collected
and used for the gardens, so at the end of the day, I have used almost
no extra water for my cooling.
Put a piece of hot metal in water, it cools. Put water on metal, it
cools. My sprinklers actually run for 12 minutes total most of the time
in a day, unless the temperature are hitting triple digits, then I do
opt to run them more so I use 30 minutes worth of sprinkling for the
day. This is not a high water usage.
Pictures and technical descriptions are on HREG@yahoo.com home page.
A couple of people are using solar pumps and recirculated water on their
buildings and are working on controls that run by temperature, not time.
All of this, down here on the
Bright Blessings,
Kim
slurryguy wrote:
> Why are you sorry? Disagree with me all you want. We all can learn
> from a friendly respectful debate. Especially me!
>
> I think you'll admit that your sprinkers are an unusual exception.
> I'm glad they work so well for you. Of course that sprinkler system
> works best in a low humidity climate. Higher humidity levels will
> inhibit the evaporative cooling that is taking place.
>
> One also needs to have a reasonably plentiful water supply. Many of
> the arid climates where evaporative cooling can work best also have
> very limited water supplies for the exact same reason. Many of our
> deep aquifers are reaching their limits. The once mighty
> River dries up before it reaches the ocean. The resivoirs are also
> low. Water supplies are getting more and more precious.
>
> In the right situation though, your solution is down right
> ingenious. I like it.
>
> Any pictures?
>
>
>
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