[RE-wrenches] Solar and pumped hydro

[jay peltz]

Hi Keith,

Sorry about #4, should have said " pumped storage just isn't practical  
for small systems.

So the long version is that to get away from batteries, you would need  
whats called an AC direct hydro.
This hydro would power the AC loads directly, no inverters, no  
batteries.
What gets tricky is that since the hydro has to power EVERYTHING  
including surge it needs to be pretty large for many of todays loads.
So 8 kw would be pretty small ( about a 4kw inverter system ) and 15kw 
+ not uncommon for an AC direct system.
Which means you need a lot of water/drop to get this kind of watts  
from your hydro.

In getting away from batteries, inverters etc its a very cost  
effective and reliable system, and really about the ultimate system.   
Typically these systems run for years, decades without problems, with  
a bit of maintenance of course.

Besides the turbine you need a controller system that will keep the  
voltage constant.  These use SS controls with diversion loads to keep  
the voltage constant under all loads ( within the parameters of the  
system) so you don't blow things up when the compressor turns off or  
on for that matter.
One benefit of these dump loads is that you can make hot water for  
domestic and space heating, air conditioning, leave lights on, you  
name it.

Hope this makes sense,

jay

peltz power


On Aug 25, 2009, at 1:10 AM, Keith Cronin wrote:

> Jay
>
> Ok....
>
> How about the long version?
>
> Can you also elucidate on # 4?
>
> Regards
>
> Keith
> From: jay peltz <jay at asis.com>
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Sent: Monday, August 24, 2009 3:11:41 PM
> Subject: Re: [RE-wrenches] Solar and pumped hydro
>
> Hi Keith,
>
> I get this question a lot.
>
>
> 1. Best efficiency for a hydro from potential energy in to actual  
> output watts( not including wire loss) is around 40-60% depending on  
> the exact application, turbine etc.
>
> 2. Efficiencies of pumps, is around the same at best.
>
> 3. This won't replace the battery for off grid usage.  Thats the  
> short version, the long answer if needed.
>
> 4. While hydro is magic if you've got it, pumped storage
>
> 5. So we've got some big loss's, 35% efficient at best and 15% at  
> worst. IE batteries are way more efficient than pumped storage.
>
> jay
>
> peltz  Power
>
>
>
>
> On Aug 24, 2009, at 11:43 AM, Keith Cronin wrote:
>
>> Hi
>>
>> Have any of you considered using PV to pump water to a holding area  
>> and releasing it and capturing the kinetic energy via a pelton  
>> wheel/hydro?
>>
>> If so, what do we think are the efficiencies and value of doing  
>> such a project are? Meaning, back of the napkin, PV is + - 77%  
>> efficient, minus "x" to pump the water to "x" elevation and the net  
>> result of the hydro = "____% efficient"
>>
>> It would be using the reservoir as the battery.
>>
>> There is approximately 300' of elevation from the PV system and  
>> water source to the reservoir area.
>>
>> I recall about 15 years ago, I visited a member on this lists  
>> Vermont home and he had a pond at the top of his property, but i  
>> don't recall how the source got to the reservoir? Might have been  
>> naturally fed?
>>
>> Anyway, the premise is, as grid access becomes more difficult to  
>> do, as the utility infrastructure gets saturated, what are our  
>> options for folks that want PV, but are limited in how much they  
>> are allowed to connect to the grid, without an interconnection  
>> study by a 3rd party to increase the comfort of the utility to have  
>> more non firm resources on their grid. We are seeing this happen  
>> here now and I was wondering if any of you have encountered this or  
>> are anticipating this in your areas?
>>
>> Any suggestions, calcs, recommendations, feedback would be  
>> appreciated.
>>
>> Keith
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