Solar Panels

[f0ster]

The good thing with generating your own electric us that it can be used for any purpose. Where hot water for a parlour is required we install biomass for heating the parlour water and then also feed t farm house which qualifies for the commercial tariff. We have also used the biomass to provide hot air for the parlour for winter. Just enough to stop freezing but it also depends on the design of the parlour. It is very difficult to use 100% of power generated. With carefull planning you can get close. The present technology of solar is up to 20% efficiency the world over. Better ones will be coming but not at the moment.

 

[Aceface]

I am a little confused by this thread, if your maximum grid connection can be met by your area of solar panels (existing roof space or an agricultural unusable area for a ground mount system), does it matter one jot that they are only 15% efficient as the feed stock is free?,....... if you had to buy sunshine then that would be a different matter.

 

[f0ster]

it does not matter on efficiency if you have the roof space, the most efficient presently available panel is sun power followed by the panasonic (which used to be sanyo) it is where roof space is limited that the better panels are better but you pay a hefty price for them, the sun power were .90p a watt last time I checked as opposed to about .45p for others. also with the extra cost you do not get the extra power to match the extra cost, they are vastly over priced for the kw you get.

 

[renewablejohn]

I am a little confused by this thread, if your maximum grid connection can be met by your area of solar panels (existing roof space or an agricultural unusable area for a ground mount system), does it matter one jot that they are only 15% efficient as the feed stock is free?,....... if you had to buy sunshine then that would be a different matter.

What your missing is the reason why the 39% efficient PV is more efficient than the 20%. Sunlight is obviously made up of multiple band widths the more band widths your PV collects the more energy your PV produces. Not a problem in the middle of summer but in winter being able to double your output is very useful. You could have a similar argument for tracking but again its just a cost benefit analysis.

 

[f0ster]

the sunpower is not 39% efficient it is only just over 20%

 

[renewablejohn]

the sunpower is not 39% efficient it is only just over 20%

Was not talking about Sunpower solar panels.

http://suncoreus.com/wp-content/uploads/2015/02/Z10_Brochure_2pg.pdf

 

[f0ster]

panel efficiency is usually worked out from volts, amps, panel surface area, I don't know what the suncorus people use but you often get manufacturers showing how much more efficient their panel is but it usually turns out they have worked it out another way instead of the standard method like what most other manufacturers do. I have a program with all panel manufacturers in it for doing pv calcs, (pv sol) the spec of the suncorus is not that much different from lots of others that are in the database. the current (imp) is slightly higher but the voltage (vmp) is a lot lower. it appears to be a panel made to suit the circumstances so it is difficult to compare like with like. you have cell efficiency and panel efficiency, the one to look for is panel efficiency. cells used to be smaller and there were 72 of them in a panel with a higher terminal voltage, now there are 60 of them and are larger with a slightly lower terminal voltage but slightly higher current. they appear to have made a one off design so it is not easy to compare. many panel manufacturers buy in ready made cells so if there was a super efficient one available they would all be using them. it would be very interesting to be able to see the output in lower light conditions, such as the weather we get.

 

[Exfarmer]

Was not talking about Sunpower solar panels.

http://suncoreus.com/wp-content/uploads/2015/02/Z10_Brochure_2pg.pdf

Looking at the figures they quote, they do not add up.
Generally 1 sq metres is reckoned to give 150 watts so 10 sq m. Should equal 1.5 kw. This is for standard 20% efficiency.
These panels claim a 12 sq metres of aperture focused on the panels give 1.5 KW and claim 39% efficiency ???
I am not doubting they have some very good performance, but it. Must relate to their tracking and water heating ability

 

[f0ster]

with my program I can tell it the panels are on a tracker and if I do the output shoots up by 40% if they are on a dual axis tracker.

 

[renewablejohn]

panel efficiency is usually worked out from volts, amps, panel surface area, I don't know what the suncorus people use but you often get manufacturers showing how much more efficient their panel is but it usually turns out they have worked it out another way instead of the standard method like what most other manufacturers do. I have a program with all panel manufacturers in it for doing pv calcs, (pv sol) the spec of the suncorus is not that much different from lots of others that are in the database. the current (imp) is slightly higher but the voltage (vmp) is a lot lower. it appears to be a panel made to suit the circumstances so it is difficult to compare like with like. you have cell efficiency and panel efficiency, the one to look for is panel efficiency. cells used to be smaller and there were 72 of them in a panel with a higher terminal voltage, now there are 60 of them and are larger with a slightly lower terminal voltage but slightly higher current. they appear to have made a one off design so it is not easy to compare. many panel manufacturers buy in ready made cells so if there was a super efficient one available they would all be using them. it would be very interesting to be able to see the output in lower light conditions, such as the weather we get.

Really.

These panels where originally manufactured for the European Space Agency. There concentrated multi layer panels converting 3 specific band widths about as far removed from normal panels as you can get.

 

[renewablejohn]

Looking at the figures they quote, they do not add up.
Generally 1 sq metres is reckoned to give 150 watts so 10 sq m. Should equal 1.5 kw. This is for standard 20% efficiency.
These panels claim a 12 sq metres of aperture focused on the panels give 1.5 KW and claim 39% efficiency ???
I am not doubting they have some very good performance, but it. Must relate to their tracking and water heating ability

Of course the figures dont add up just look at the assumptions made at arriving at those figures in particular a temperature of 40C and only half the insolation there designed for. Would like to see other panels cooking at 40C and see what there output is.

 

[f0ster]

they are not solar panels, they are mirrors

 

[renewablejohn]

they are not solar panels, they are mirrors

The solar panel at the focal point is only 10cm x 10cm therefore uses far less material then conventional pv. Because it is focused it allows thermal to be captured as well.

 

[renewablejohn]

This is the other sort of CPV panel again with very high efficiency but designed for areas of high direct sunlight.

http://global-sei.com/products/cpv/

 

[f0ster]

not sure but I thought the focal point might be a batch of those transistor type devices that produce electricity from heat,

 

[Exfarmer]

This is the other sort of CPV panel again with very high efficiency but designed for areas of high direct sunlight.

http://global-sei.com/products/cpv/

I believe these are a long way from production , the pictures are of conventional silicon panel tracking units , which are indeed much more efficient in capturing sun energy but the install costs normally far out weigh returns

 

[renewablejohn]

not sure but I thought the focal point might be a batch of those transistor type devices that produce electricity from heat,

Actually three different pv materials each collecting a unique band width which is why the efficiency is higher. Heat is a problem which is why the pv panel is cooled by water.

 

[renewablejohn]

I believe these are a long way from production , the pictures are of conventional silicon panel tracking units , which are indeed much more efficient in capturing sun energy but the install costs normally far out weigh returns

1MW already installed in Morocco with more going into Australia. Pictures are the other sort of CPV using concentrator lenses rather than mirrors.

 

[f0ster]

"Unfortunately the systems rely on Direct Normal Irradiation (DNI) since we are using mirrors to concentrate the light on a receiver. The UK is not a very favorable area for decent DNI and as such the payback will not be good."
I emailed them and this was their response.

 

[renewablejohn]

"Unfortunately the systems rely on Direct Normal Irradiation (DNI) since we are using mirrors to concentrate the light on a receiver. The UK is not a very favorable area for decent DNI and as such the payback will not be good."
I emailed them and this was their response.

As I said right at the very start see reply 10