I need to find the performance degradation of some mechanical equipment (boilers, cooling towers, Photovoltaics, Motors/VFD's, Cogen, and fuel cells) and I'm having trouble finding the info. Does anyone know of any sites that would have this? Any help would be great.

Thanks!  
 

Not that you will be very likely to find this kind of data for free off the internet, "performance degradation" could encompass a wider range of problems with very different degradation characteristics, even more so than the very wide range of equipment types you are interested in finding more about, making it very difficult search proposition.

For sure you will have to search many websites.  DOE Los Alamos Labs website had some degradation data on PV installations.  In fact you can take that as a straight line at anywhere from 5% to 20% over 20 years, ie. 0.25% degrade per year for the good ones to 1% per year degrade for the cheap ones.  The PV manufacturers typically show what output they will guarantee after 20 years in the data contained in their warranty.   

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