Pv solar install the inverter in loft or garage

Martyn1981

Got both in the downstairs toilet. Easy to read, and surprisingly quiet even last August when they were buzzing (quietly).

With two inverters, and 4 isolators, looks a little like a powerstation, still, something to look at whilst availing oneself of the facilities!

Mart.

thenudeone

lofts will get hot which affects teh efficiency. Mine's is in the utility room

larkim

How hot is hot? And by how much is efficiency impacted? And do solar panels on the roof (which is presumably where the hot loft gets it heat from) insulate the roof tiles from the heat sufficiently to stop the loft from getting as hot in the summer? (Certainly my panels cover the vast majority of my roof space)

Matt

Dave_Fowler

larkim wrote: »

How hot is hot? And by how much is efficiency impacted? And do solar panels on the roof (which is presumably where the hot loft gets it heat from) insulate the roof tiles from the heat sufficiently to stop the loft from getting as hot in the summer? (Certainly my panels cover the vast majority of my roof space)

Matt

My loft is much cooler now in the summer - and appears to be slightly warmer in the winter. Instead of the roof tiles being at 80 deg C in the summer, it is the panels. They shade the roof and the air gap between roof and panel provides good insulation.

I'm guessing they're at 80C They are certainly too hot to touch.

On a similar line, a SE facing roof is likely to generate more power than a SW roof because the air temperature in the morning is usually cooler than the afternoon and hence the panels are more efficient.

Dave F

larkim

80deg C roof tiles??!? Wow!! I've never been up to measure mine, but I wouldn't have guessed they got that hot!!

Matt

larkim

To answer my own Q about efficiency, my Fronius IG30 technical data sheet shows no drop off in efficiency until an ambient temperature of 40degC is reached. I've never measured the temp in the loft, perhaps I'll give that a go in the summer!

http://www.fronius.com/cps/rde/xbcr/SID-F977D829-0B58CB68/fronius_international/Daten_Fronius_IG_M_06_0009_EN_151825_snapshot.pdf

Matt

zeupater

Hi

Further information on temperature derating for those with SMA inverters ..... http://files.sma.de/dl/7418/TempDerating-UEN103910.pdf

Effectively the units reduce their output in order to reduce the heat which they produce as a by-product of operation in order to protect themselves and extend lifespan. At around 40C the maximum output is limited by software and as the temperature rises the limit decreases to an extent where at 60C the output is limited to ~60% of nominal ... above 60C the inverter will shut down.

The reasoning behind temperature derating is that in theory, for every 10C increase in operating temperature you half the expected lifespan of an electronic system ....

HTH
Z

larkim

Z

That's really useful, thanks - I've ranted in the past when I used to be interested in PC components that people blithely stated that a component was running "too hot" without measuring it, nor quantifying why, say, an 80degC operating temp was any worse than a 90degC operating temp. If there is a good rule of thumb about increases in component temp vs lifespan (presumably above certain temps), which you describe as +10decC/half expected lifespan then that makes some sense.

Though does the inverse apply? e.g. if I chilled my PC by 10degC, would the components last for double the lifespan?

Matt

Dave_Fowler

larkim wrote: »

Z

That's really useful, thanks - I've ranted in the past when I used to be interested in PC components that people blithely stated that a component was running "too hot" without measuring it, nor quantifying why, say, an 80degC operating temp was any worse than a 90degC operating temp. If there is a good rule of thumb about increases in component temp vs lifespan (presumably above certain temps), which you describe as +10decC/half expected lifespan then that makes some sense.

Though does the inverse apply? e.g. if I chilled my PC by 10degC, would the components last for double the lifespan?

Matt

Whilst the life expectancy of semiconductors is related to temperature in a reasonably linear fashion over a wide temperature range (-40C to +120C is not uncommon), things like electrolytic capacitors and batteries usually have a much narrower specified working range, perhaps 0 to 85C or less.

Dave F

Solar_Novice

Martyn1981 wrote: »

Got both in the downstairs toilet. Easy to read, and surprisingly quiet even last August when they were buzzing (quietly).

Excellent for keeping an eye on things!

I had the inverter put in a cupboard above the stairs – very cool place. And my father located his within a cupboard under the stairs next to the electric meter - again very cool. His installers wanted to mount in the dormer loft, but this is a very hot place in summer. I think they were more interested in the easy option not the longevity of the inverter.