Solar now seems much less efficient

organum

With the recent sunny days I thought the solar system would work rather better, but found that especially the rear panels are now giving out less that 1kW when last year they gave out a lot more, enough to heat the hot water anyway.

I tried to contact the supplier TP solar but they seem to have gone out of business.
I then contacted their insurers IWA who said to fill in a claim form.

Is IWA a worthwhile route or is it better to just pay for someone to check the system?

Thank you
Richard

bengalknights

They tend to get less efficient beyond a certain temperature due to heat amount however best to get a check done then claim for anyhting

organum

bengalknights wrote: »

They tend to get less efficient beyond a certain temperature due to heat amount however best to get a check done then claim for anyhting

Thanks. Any suggestions for competent person/company near Leighton Buzzard, Bedfordshire?

Martyn1981

organum wrote: »

Is IWA a worthwhile route or is it better to just pay for someone to check the system?

Thank you
Richard

Hiya Richard. How is the system performing annually compared to expectations/projections when installed and to PVGIS?

If it's doing ok then maybe it's just down to the weather. These last 3 or 4 days I've had gen far higher and lower than my MKI eyeball has suggested. Yesterday never seemed particularly sunny, but it was very warm/hot, and gen turned out 50% more than daily target. ???

How did your May generation compare to PVGIS and to others near you? In Cardiff I got about 108%, were you above or below target?

Mart.

Rheumatoid

bengalknights wrote: »

They tend to get less efficient beyond a certain temperature due to heat amount however best to get a check done then claim for anyhting

Reading around it seems you can lose about 0.5% for every 1 degree C over 25 degrees so on a hot day when panels can reach 45 degrees you can lose about 10%. Maybe yesterday was a strange hazy day or its just getting hot and panels are struggling. Some comfort that I am not the only one who has noticed this recently and as this is my first summer with them maybe it is just something I need to get used to.

Rheumatoid

Martyn1981 wrote: »

Hiya Richard. How is the system performing annually compared to expectations/projections when installed and to PVGIS?

Does PVGIS take into account impact of temperature on generation? Is that the reason May is my biggest month and summer targets are lower?

Martyn1981

Rheumatoid wrote: »

Reading around it seems you can lose about 0.5% for every 1 degree C over 25 degrees so on a hot day when panels can reach 45 degrees you can lose about 10%. Maybe yesterday was a strange hazy day or its just getting hot and panels are struggling. Some comfort that I am not the only one who has noticed this recently and as this is my first summer with them maybe it is just something I need to get used to.

True, and whilst it might have just been a Cardiff 'thing' yesterday, there was very little wind compared to the last month*. The wind obviously moves the air around more and helps to cool panels 'sitting' in their own bubble of warmed air.

*Looking at Gridwatch, wind generation is now low, and was low yesterday too compared to Mon-Thur.

Mart.

Rheumatoid

Martyn1981 wrote: »

True, and whilst it might have just been a Cardiff 'thing' yesterday, there was very little wind compared to the last month*.

Mart.

Good point re air cooling. It is breezier today - there is a windmill generator next door that I can see and its spinning nicely.

Wasn't just a Cardiff thing - same here as you will see from my other posts.

generation also seems low today. Full sun at nearly 11am and only just tipped over 3kW. would expect it to be maxing out at around 11.30

Martyn1981

Rheumatoid wrote: »

Does PVGIS take into account impact of temperature on generation? Is that the reason May is my biggest month and summer targets are lower?

PVGIS climate takes account of local weather, but of course that's an average, based on past weather.

I may be wrong, but I think the figures seem to favour May more than previously, so there may have been revisions, or I'm completely misremembering. :think:

Panel pitch can also make some difference, but regardless, May seems to be doing rather better than I recall!

Mart.

Martyn1981

Rheumatoid wrote: »

generation also seems low today. Full sun at nearly 11am and only just tipped over 3kW. would expect it to be maxing out at around 11.30

Yep, same here, the ESE is on about 1.5kW, but doors wide open, and I'm wandering around the garden barefoot and in shorts and Tshirt, whereas recently gen has been 3kW+, but too cold to stand outside unless in direct sunlight, and doors had to be closed a lot of the time.

June a couple of years ago was very cold, I recall that everytime I (or a room) wasn't in direct sunlight it got cold fast, but gen was very, very nice 3/4MWh. :cool2:

Mart.

organum

I have been checking my previous year's logs and find that I am wrong and that the daily output is the same as last year!

Sorry to put folks to a wild goose chase.

However my concern is that the 4kW system is only giving out 2.1kW with both sets of E/W panels being fully illuminated by brilliant sunshine. This has clearly been the same as when the unit was installed and I cannot find the original estimates.

I understand that E/W systems are not as good as fully S but nevertheless?

Any pearls of wisdom on this chaps/chapesses ;-)

TVM