Comparing Collectors Using SRCC Rating Data

The document below is a good example showing how to use SRCC performance testing data along with prices to evaluate several collectors to see which one gives the best price for performance for a specific application.  You can easily perform an analysis similar to the one Alan uses for your solar heating application.


The only caution I would offer on this excellent example: Because some of the collectors that Alan was considering have not as yet been rated by the SRCC, he was forced to use performance data for similar collectors that have been rated.  While this is certainly a reasonable think to do, it does carry some risk, as collectors rating (particularly for evacuated tubes) do vary over a fairly wide range.



Download Alan's Collector Comparison Example (pdf 20K)



See also these pages:

        Where to get the SRCC ratings data


         interpreting SRCC collector test data.


And, here is an email  comment on Alan's chart from Drew Gillett:


Thank you Alan.    The data is interesting and helpful.  I have drawn the same conclusion for years but carry it even further.
After considerable research I have concluded that the SRCC test presentation method vastly underrates collectors with steep slopes on their efficiency curves.  This is most notable with but is true of all the flat plates.  This is because the performance on the partly cloudy and cloudy days assumes the radiation is equally distributed over the day when in fact that radiation comes in spurts as the clouds roll by.   An unglazed or low slope collector might not reach the minimum delivery temp under the average insolation (and so is scored zero production) , but certainly does produce significant output  under the real life variable insolation.  This is compounded by the fact that the test method is limited to small (less than 10x10) collectors and can not account for the advantages of large format site built systems ( such as dawn's and Steve Baer's and Francis Dewinter's) .  Further the weather data does not take into account that the collector's losses modify the local environment at the collector . this is most important for wind and temp effects.  
Al Rich has some inexpensive lightweight collectors that are SRCC rated. he will be on extreme home makeover soon.  has some cheaper systems 
Also, has some inexpensive larger evacs and has a tracking vac tube system
Recent data from Robb Aldrich publicized by CARB   (please read this) lends some credence to that.  below is my email commenting on their newsletter and the reference.  perhaps you and others  would like to provide the SRCC numbers and costs for dawn and the others above  to  Al Rush for inclusion in his chart.

Drew Gillett, P.E. 








Gary 5/25/07