Tuesday, May 25, 2010

Temperature reducing the PV harvest: proof

24 May: EvoEnergy rang me today because some of their customers are confused by seeing their PV harvest not being as good as expected in this hot spell. They are grateful that they can direct customers to look at my Sunny Web box output, and see how temperature affects PV.
In this chart (from Sunny Portal) you can see 3 days of generation, plus the last month of generation, set against the red line for max daily Module temperature, that is, the surface of the panels.
   The best ever day was May 11th, but you can see that the temperature was particularly low, compared with the 2 weeks after that date - when it has been a lot sunnier, but also much hotter on the surface and in the air. The red line dips at the end, because I screen-captured it at 1 in the morning, so it is suddenly dipped.) In recent days of high sunshine, we have had surface temperatures touching 50ÂșC, on the East roof!
   I am not expecting it to get more than 24 kWh in a single day in June unless we get another strong north wind combined with clear skies. But if there are lots of 20-22 kWh days, I will be happy!

No comments:

Post a Comment

Comments will be moderated before showing. Please make them relevant to the subject of the posting. Comments which advertise commercial products will usually be deleted.

Popular Posts