Posted by Ron Rosenfeld on February 9, 2009, 10:03 pm
On Sun, 08 Feb 2009 20:19:08 -0600, david.williams@bayman.org (David
Williams) wrote:
>-> How much is 'plenty' again? Lets say one 'pond' 100m across and 1m
>-> deep.... about 300 m^3, and you have it up on a hill 10m high.
>-> potential energy is mgh00,000 kg x 9.8 x 10 or about 3 million
>-> joules. If your micro hydro generator gives you 100watts, you have
>-> enough energy for 30000 seconds... 500 min.... 8 hrs. Use it wisely.
>
>Ummm... Radius = 50 m. Volume = pi x 50^2 x 1 = 7850 m^3. Call it 8e3
>tons or 8e6 kg. Times 10 for g and another 10 for the height: 8e8
>joules. Enough to run a 100 watt lamp for 8e6 seconds or about 2000
>hours.
>
>But that's a huge pond. And we're assuming 100 percent efficiency.
>
> dow
Well, the little bit of research I've done suggests that micro-hydro will
be maybe 53% efficient.
If you also have to supply electricity to fill the upper pond, you'll lose
some more in that transition.
--ron
Posted by wmbjkREMOVE on February 10, 2009, 1:39 pm
On Mon, 09 Feb 2009 17:03:50 -0500, Ron Rosenfeld
>Well, the little bit of research I've done suggests that micro-hydro will
>be maybe 53% efficient.
>If you also have to supply electricity to fill the upper pond, you'll lose
>some more in that transition.
>--ron
And don't forget to account for evaporation. Recently I estimated the
energy needs of filling a pond from a 400' well. Based on the owner's
observations of evaporation rates, I found that he needed to supply an
average of 50,000 gallons per day just to keep up. He'd hoped that a
solar pump could do that part of the job. Turned out he'd need 20 of
them!
Wayne
Posted by Ron Rosenfeld on February 10, 2009, 6:41 pm
On Tue, 10 Feb 2009 06:39:46 -0700, wmbjkREMOVE@citlink.net wrote:
>And don't forget to account for evaporation. Recently I estimated the
>energy needs of filling a pond from a 400' well. Based on the owner's
>observations of evaporation rates, I found that he needed to supply an
>average of 50,000 gallons per day just to keep up. He'd hoped that a
>solar pump could do that part of the job. Turned out he'd need 20 of
>them!
>Wayne
Good point. I guess that rate varies with temperature and wind speed. How
big a pond were you dealing with?
--ron
Posted by wmbjkREMOVE on February 11, 2009, 11:18 pm
On Tue, 10 Feb 2009 13:41:02 -0500, Ron Rosenfeld
>On Tue, 10 Feb 2009 06:39:46 -0700, wmbjkREMOVE@citlink.net wrote:
>>And don't forget to account for evaporation. Recently I estimated the
>>energy needs of filling a pond from a 400' well. Based on the owner's
>>observations of evaporation rates, I found that he needed to supply an
>>average of 50,000 gallons per day just to keep up. He'd hoped that a
>>solar pump could do that part of the job. Turned out he'd need 20 of
>>them!
>>
>>Wayne
>Good point. I guess that rate varies with temperature and wind speed. How
>big a pond were you dealing with?
>--ron
1 acre existing pond with a proposed tripling of size. General
evaporation rates here
http://www.grow.arizona.edu/Grow--GrowResources.php?ResourceId 8 and
here
http://www.ocs.orst.edu/page_links/comparative_climate/arizona/arizona.html ,
but owner's tests and observations proved a higher rate than expected
due to wind. His place is in the valley off the right side of this pic
http://www.citlink.net/~wmbjk/images/snowman.JPG . :-)
Wayne
Posted by Ron Rosenfeld on February 12, 2009, 2:08 am
On Wed, 11 Feb 2009 16:18:18 -0700, wmbjkREMOVE@citlink.net wrote:
>On Tue, 10 Feb 2009 13:41:02 -0500, Ron Rosenfeld
>>On Tue, 10 Feb 2009 06:39:46 -0700, wmbjkREMOVE@citlink.net wrote:
>>
>>>And don't forget to account for evaporation. Recently I estimated the
>>>energy needs of filling a pond from a 400' well. Based on the owner's
>>>observations of evaporation rates, I found that he needed to supply an
>>>average of 50,000 gallons per day just to keep up. He'd hoped that a
>>>solar pump could do that part of the job. Turned out he'd need 20 of
>>>them!
>>>
>>>Wayne
>>
>>Good point. I guess that rate varies with temperature and wind speed. How
>>big a pond were you dealing with?
>>--ron
>1 acre existing pond with a proposed tripling of size. General
>evaporation rates here
>http://www.grow.arizona.edu/Grow--GrowResources.php?ResourceId 8 and
>here
>http://www.ocs.orst.edu/page_links/comparative_climate/arizona/arizona.html ,
>but owner's tests and observations proved a higher rate than expected
>due to wind. His place is in the valley off the right side of this pic
>http://www.citlink.net/~wmbjk/images/snowman.JPG . :-)
>Wayne
Ah, very large. Thanks for the links.
--ron
XML site map
>-> deep.... about 300 m^3, and you have it up on a hill 10m high.
>-> potential energy is mgh00,000 kg x 9.8 x 10 or about 3 million
>-> joules. If your micro hydro generator gives you 100watts, you have
>-> enough energy for 30000 seconds... 500 min.... 8 hrs. Use it wisely.
>
>Ummm... Radius = 50 m. Volume = pi x 50^2 x 1 = 7850 m^3. Call it 8e3
>tons or 8e6 kg. Times 10 for g and another 10 for the height: 8e8
>joules. Enough to run a 100 watt lamp for 8e6 seconds or about 2000
>hours.
>
>But that's a huge pond. And we're assuming 100 percent efficiency.
>
> dow