Ra
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« on: January 23, 2007, 02:46:49 PM » |
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Spotted this PV system on the outskirts of Quedgeley, Gloucestershire.  Must have cost quite a bit. Good to see that non blew away in the storms. |
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Ivan
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« Reply #1 on: January 23, 2007, 04:13:39 PM » |
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Notice the chimney shadow? If the panels are arranged in two strings of 12panels (it looks that way), then the chimney shadow is going to reduce the output of one string to virtually nothing, and possibly both, depending on the wiring. This is one of the problems of Solar PV. Hopefully it is an early morning picture, and the shadow spends most of its time OFF the panels!
Ivan
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Ra
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« Reply #2 on: January 23, 2007, 04:50:51 PM » |
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Notice the chimney shadow? If the panels are arranged in two strings of 12panels (it looks that way), then the chimney shadow is going to reduce the output of one string to virtually nothing, and possibly both, depending on the wiring. This is one of the problems of Solar PV. Hopefully it is an early morning picture, and the shadow spends most of its time OFF the panels!
Ivan
It was taken at about 8:30 this morning so the sun was fairly low. |
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Ivan
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« Reply #3 on: January 23, 2007, 04:58:57 PM » |
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I have a great site on my garage roof - I could site just over 2kW of PV south-facing, but I have a wind turbine tower in front - so it would cast a long thin shadow across the array for most of the day =no power  |
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insolare
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« Reply #4 on: January 23, 2007, 08:59:05 PM » |
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So if the shadow shields just 1 cell within a panel you get no output rather than a reduced output then Ivan?
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Mike N.
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« Reply #5 on: January 23, 2007, 10:59:40 PM » |
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Notice the chimney shadow? If the panels are arranged in two strings of 12panels (it looks that way), then the chimney shadow is going to reduce the output of one string to virtually nothing, and possibly both, depending on the wiring. This is one of the problems of Solar PV. Hopefully it is an early morning picture, and the shadow spends most of its time OFF the panels!
Ivan
Didn't another thread suggest a way of eliminating chimney shadows by attaching wind turbines to them in high winds?  Mike |
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Joules
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« Reply #6 on: January 24, 2007, 01:58:29 PM » |
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I'd actually question if the chimney is legal... As it's well below the apex of the roof, it certainly couldn't be used for solid fuel.  Joules |
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Ivan
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« Reply #7 on: January 24, 2007, 03:08:04 PM » |
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Yes with solar PV, even if once cell is shaded, the whole string goes down. It's like having a power supply made up of hundreds of tiny batteries (each PV cell produces 0.45v) - if one battery develops a high resistance (eg PV cell gets shaded), the whole lot goes down. Imagine a single bird poo on the panels!!
Ivan
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insolare
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« Reply #8 on: January 24, 2007, 07:07:02 PM » |
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I'd actually question if the chimney is legal... As it's well below the apex of the roof, it certainly couldn't be used for solid fuel. Joules I noticed the chimney. Classic case of backdrafts I reckon. Hence the cowl. I remember my dad telling me when I was young and just never forgot it. "Never buy a house with a chimney below the ridge." |
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ecogeorge
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« Reply #9 on: January 25, 2007, 11:09:03 PM » |
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used to live in Quedgeley! smokless zone !! bet a lot of money its a gas cowl. No houses around us had real fires.
rgds George.
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Paulh_Boats
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« Reply #10 on: January 26, 2007, 12:20:36 PM » |
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Yes with solar PV, even if once cell is shaded, the whole string goes down. It's like having a power supply made up of hundreds of tiny batteries (each PV cell produces 0.45v) - if one battery develops a high resistance (eg PV cell gets shaded), the whole lot goes down. Imagine a single bird poo on the panels!!
Ivan
Ivan, I never knew PV panels had that limitation - I learn something each day from this great forum. A data logger might be able to identify which panels get shaded by monitoring voltages all over the array. -Paul |
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Antman
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« Reply #11 on: January 26, 2007, 01:48:13 PM » |
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It's the angle of what looks like the TV aerial at the back that would worry me!
Strange polarisation angle....
Ant
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20 x 47mm, 172 litre cylinder, Heat Dump, 15 x Sanyo HIT-H250E, SB4000TL DIY Solar System Support at: http://homepage.ntlworld.com/anthony.cooper267/index.htmlAll support is wholly voluntary and free of charge. I'm not employed by Navitron and have a full-time job so responses may not be same-day |
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Paulh_Boats
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« Reply #12 on: January 26, 2007, 02:06:11 PM » |
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It's the angle of what looks like the TV aerial at the back that would worry me!
Strange polarisation angle....
Ant
Its beginning to look like a James Bond set, complete with solar powered Death Ray to zap all communication satellites.  -Paul |
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Ivan
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« Reply #13 on: January 26, 2007, 07:17:15 PM » |
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It's actually a roof-mount wind turbine half-way through installation
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