flywheels and ultracapacitors [RE-wrenches]

[daryl_solar at yahoo.com]

HI
When I investagated flywheels a few years ago for a client the following
1) I could not actually buy one, (if I could afford).
2) the cost was astronomical
3) it had a significnet "self discharge rate, most solar batteries have a range of .001 to .1 percent discharge/day , flywheels are 1 to 10% per day
4) The volume storage seemed about the same as lead acid batteries
5) the electrical interface was not ready for solar apps.  
Advantages they can cycle very many times without loss of performance.

I have used ultra capacitors, they have the following concerns:
1) high cost/kwh HIGH COST
2) terrible voltage/energy curve (most solar equipment can not utilize the voltage power curve and utilize much energy from the capacitor.  an MPPT type controller is required to use up to 75% of the power from and into a capacitor.  (In every energy tranaction a certian amount is lost period)   
3) High standby losses, high self discharge rate, IIR about 10 to 15% per day.  (means larger array cost)
Advantages
high cycle life
Temperature stability wrks hot or cold.  

All above comments based on faulty memory of old man.
/darryl
PS BoB Gudgel knows how to work the MPPT to function with capacitors

--- On Sat, 6/28/08, Kirpal Khalsa <solarworks at gmail.com> wrote:

> From: Kirpal Khalsa <solarworks at gmail.com>
> Subject: flywheels and ultracapacitors [RE-wrenches]
> To: RE-wrenches at topica.com
> Date: Saturday, June 28, 2008, 1:01 AM
> Hi folks.......has anyone tried using any of the Beacon
> flywheels or
> the Maxwell Technologies ultra-capacitors in back up PV
> systems?  I am
> curious if they have are able to slow down the release of
> power to
> make them effective in residential or small commercial
> grade back up
> power systems?  Both products sound viable, and
> interesting..........any experiences? Thanks.
> 
> -- 
> Sunny Regards,
> Kirpal Khalsa
> NABCEP Certified Solar PV Installer TM
> Renewable Energy Systems


      


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