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What types of solar PV panels are there?

Posted by Paul Hutchens on 2 August 2010 at 9:58 am

Photovoltaic solar panels (PV) come in many different forms. Do you know your polycrystalline from your mono, or thin film from hybrid?

No - I thought not, and frankly I do not think I would if I were not in the industry!

There are a number of different types of solar photovoltaic systems available. Each do the same thing; convert solar radiation into electricity,  but have different characteristics and prices. I will try to explain each in turn.

 1. The cheapest (and least efficient) type of solar PV is known as "thin film" or amorphous silicon and is made by depositing a thin film of silicon onto a material such as glass. If you have a solar powered calculator or watch then it will use this technology. Although this type of solar is cheap, you need a large surface area. It is also suitable for high temperatures and is used in hotter countries to cover large areas. This type of system is not very prevalent in the UK yet.

2. Polycrystalline solar PV is made up of a number of smaller silicon crystals; usually cut to form a wafer. Although this is a less pure form of PV than, say, monocrystalline silicon (see later) it is still very effective and is generally cheaper than the mono version. It is generally dark blue in colour and widely available in the UK.

3. Monocrystalline solar is made up of a single silcon crystal and is considered purer than the previous 2 types. Generally it will be more efficient and more expensive than thin film or polycrystalline solar.

4. The premium type currently available is called hybrid or HIT (Heterojunction Incorporating Thin film) solar. This incorporates a monocrystalline material overlaid with a thin film layer. By placing one material into contact with the other, the power conversion efficiency can be greater than a single material. As a result a much higher efficiency can be achieved but this is the most expensive option.

So with all this variety which do I choose. Well, as always it depends on your requirements and budget. If roof space is not an issue and you want to maximise the the return on your investment then a budget priced polycrystalline system will meet your requirements.

If you want the best product available or the roof space in limited then maybe a hybrid, although more expensive, may be appropriate.

In this context the mono option could be seen as a mid-market, low risk product; reasonable effficiency for a reasonable price.

I would suggest that you get installers to quote you 2 or more options so you can compare prices and the expected solar output.

A word of warning though; even if low price is your goal, make sure that the installer and the product selected in MCS certified and make sure that the panels have a performance guarantee of at least 20 years at 80% efficiency.

More information about PV panels from YouGen

Solar PV panel information page

Solar PV tiles - the pros and cons explained

Comparing the performance of solar PV panels

Why don't solar PV panels work so well in the heat?

Find a solar PV installer

About the author: Paul Hutchens is founder and director of Eco2Solar, which installs solar systems around the UK.

If you have a question about anything in the above blog, please ask it in the comments section below.

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Comments

40 comments - read them below or add one

Cathy Debenham

Cathy DebenhamComment left on: 11 November 2014 at 2:07 pm

Hi Reena
This is what our expert has to say about your quotes:

The LG quote seems fairly standard.  I'm not a massive fan of power optimisers, preferring to see shade avoided rather than dealt with in this way, but if the client is keen on capacity, then the optimiser route is the right way to go.

The Hanergy quote seems a bit of a muddle in terms of messages, which is quite tricky to unpack.

As a thin film technology, they should give a small performance advantage over the LG over the course of a year, maybe 5% or so.

The reason for this advantage is that the Hanergy panels will be better at picking up bluer light in overcast conditions.

This is not the same as better performance in low light levels (we have low light levels early in morning and late in afternoon on sunny days as well, but this light is redder (red sky at night etc...).  Hanergy will not offer an advantage under these conditions.

So the better performance of Hanergy under some conditions is due to colour, not the overall light level.

So Hanergy will NOT help with performance when shaded (light is the same colour, but less of it)

As above I think you will see maybe a 5% advantage per kW for the Hanergy.  You will not see the kind of 35%+increase in performance increase claimed in the last statement.  Bit naughty this.

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Cathy Debenham

Cathy DebenhamComment left on: 10 November 2014 at 9:47 am

Hi reena I'm just seeking some expert advice on this question and will get back to you as soon as possible.

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reena

reenaComment left on: 8 November 2014 at 10:29 pm

Hi 

I am considering to quotes both similar in price. I live in merseyside and have a south east facing and south west facing hipped roof. There is a chimney on the southwest facing roof and so there are some shading issues.

The first quote is for LG monocrystalline panels, 250watts,  with 15.6% efficiency 16 panels in total to make up a 4kwatt system to be divided over the two aspects of the roof. They will also use solatech power optimisers . 

 

The second quote is from IKEA / Hanergy for their thin film  panels, 120watts each, 24 in total to make up a 2.88kwatt system, to be distributed over the two aspects of the roof and two converters. 

The Hanergy people claim that although these panels are only 12.8 % efficient they give better output in shaded and overcast conditions. Also will not degrade as quickly as the monocrystalline ones. They come with a guarantee for 80% output for 20years. They say that they are better at a lower wattage (120 watts) per panel as each panel reaches their maximum output quicker than a 250 watt monocrystalline one will. They say that even at a lower tottal wattage of 2.88kwatt their average output over the year will be more than the 4kwatt monocrystalline panels will produce and these are designed for overcast conditions. 

 

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Cathy Debenham

Cathy DebenhamComment left on: 18 June 2012 at 10:01 am

Hi AndyKP 

The best place to go to compare the performance of solar panels is the European Union's joint research centre.

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AndyKP

AndyKPComment left on: 8 June 2012 at 10:57 pm

Hi,Looking to put 16 panels of 4Kw on house roof facing S.E.  Does anyone know best pannels out of my quotas, all about same price :-

Suntech 250,Sunrise srm660250,Trina solar,Hyundai His-s250mg,Jetion250sb with a SMA3600TL or power one 3.6 outd fitted in the garage thank you for any help. 

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 21 March 2012 at 4:11 pm

I am about to have solar panels (4KW) 17 panels fitted but the company now say they want to install NSI panels (Nobel Solar Industries) with mini optimisers on each panel. They say these will be more efficient than the original offer they made me which was 17 panels LW235 P1650x 990 ( Lightway Australia) with a Platinum 3800S inverter.  I am now confused as to whether which system is the better of the two. Should I go for the first or second option? Have you any ideas as to which would be the better option?

Dear Trick 05

This is a difficult question to answer as I am unsure which optimiser they are recommending and I am unfamiliar with the LW235 panels. In general the mini optimisers optimise the voltage and ensure that the power flows smoothly. This will help generally but particuarly if any of the array may be subject to shading - as this will allow the energy that is generated to flow without interruption.

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TRICKO5

TRICKO5Comment left on: 20 March 2012 at 6:04 pm

I am about to have solar panels (4KW) 17 panels fitted but the company now say they want to install NSI panels (Nobel Solar Industries) with mini optimisers on each panel. They say these will be more efficient than the original offer they made me which was 17 panels LW235 P1650x 990 ( Lightway Australia) with a Platinum 3800S inverter.  I am now confused as to whether which system is the better of the two. Should I go for the first or second option? Have you any ideas as to which would be the better option?

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The Englishman

The EnglishmanComment left on: 29 October 2011 at 12:09 pm

Thanks Paul and that must be good advice! I am in the final process of obtaining quotes and hope that my final decision proves to be correct!

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 29 October 2011 at 10:54 am

Paul - I am very interested in the Sanyo HIT 250E10 and I believe you are in favour of them as well. I read on here that a west country installer has been running a test rig with several makes of panel and has found that the Spanish Silken has beaten them all substantially including the Sanyo HIT 240 unit!. Do you know anything about this panel and should I pursue it? I am in Herts. and intending to install a 4KW array on a south facing -5 roof of 40 degree pitch and 2.8% shading. I am also very interested in the box of tricks for heating my water tank and maybe a Sunny Backup Set s unit

Dear Englishman

I have no experience of the Siliken panel. We do know however that the Sanyo panels perform extermely well and are the best performing panel we have installed. The "box of tricks" for heating water is a great idea - albeit expensive and I believe that there are a number of back up units coming out including one from Sunnyboy.

Frankly, in light of the impending cuts it might be prudent to order the system asap and look at the ancillaries later. I believe that they can be retro-fitted.

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The Englishman

The EnglishmanComment left on: 28 October 2011 at 8:05 pm

Paul - I am very interested in the Sanyo HIT 250E10 and I believe you are in favour of them as well. I read on here that a west country installer has been running a test rig with several makes of panel and has found that the Spanish Silken has beaten them all substantially including the Sanyo HIT 240 unit!. Do you know anything about this panel and should I pursue it? I am in Herts. and intending to install a 4KW array on a south facing -5 roof of 40 degree pitch and 2.8% shading. I am also very interested in the box of tricks for heating my water tank and maybe a Sunny Backup Set s unit.

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 6 September 2011 at 8:03 am

I've a decent-sized south facing roof in Birmingham - but it has a Velux window right in the middle, making continuous solar panels rather difficult.  A number of slates need replacing and I'm wondering whether solar panels is the best bet, or to go for solar tiles at the same time as re-roofing.  Any thoughts - and how do solar tiles compare for price, weight etc?  Is this something most suppliers could do?

Hi John

The Velux window in the middle does not cause a problem and we have installed lots of systems around them - see http://www.eco2solar.co.uk/2111/harbury-stratford-on-avon-4/ as an example.

It is advisable to ensure that your roof is in good condition before installing solar PV so it would make sense to replace the slates at the same time.

Whilst solar tiles would appear to be the most elegant solution, the price of solar tiles is still very high; probably at least double the cost of installing conventional solar panels.

This obviously adversely affects the return that you get and the payback. Fixing the roof and then installing solar panels will probably be more cost effective.

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John Hopkin

John HopkinComment left on: 5 September 2011 at 7:41 pm

Hi Paul

I've a decent-sized south facing roof in Birmingham - but it has a Velux window right in the middle, making continuous solar panels rather difficult.  A number of slates need replacing and I'm wondering whether solar panels is the best bet, or to go for solar tiles at the same time as re-roofing.  Any thoughts - and how do solar tiles compare for price, weight etc?  Is this something most suppliers could do?

Best wishes

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Cathy Debenham

Cathy DebenhamComment left on: 30 August 2011 at 1:55 pm

Hi Paul. Have a look at this blog which should give you more of an idea of how you measure quality in a solar pv panel. Ideally you want it to perform as well as possible for as long as possible.

As Paul says in this blog, which type of panel that is best for you will depend on the space you have available and the amount of money you want to spend.

Also, watch out for that chimney. Hard shading can cause a problem for performance.

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Paul128

Paul128Comment left on: 26 August 2011 at 11:44 pm

Hi

What is the difference between panels manufactured in China eg Suntech and those manufactured in Germany/Japan.  I've been told the quality of the latter is better eg Sharp/Sanyo.  They have the same 'performance' guarantee. Is this correct and what do people mean by quality anyway. 

My roof is south facing on the sussex  coast no shading apart from my chimney of the SSW side of my roof. 

 Is it more a question of type of panels poly v mono v hybrid and which would be best?

thanks



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Eco2Solar

Eco2SolarComment left on: 13 June 2011 at 2:23 pm

Hi cautiousblue

I've been told panel performance loss over time is less with polycystalline panels than with mono panels.  Does anyone know if there is any truth in this?  I am thinking of going for the hybrid panels as we are short on roof space and they are supposed to be more performant. However the Sanyo panel did not even make it in a recent Photon report.  I'm not sure what to make of it all

This is a difficult one to get definitive information on but there is little to suggest that poly panels degrade less than mono ones. Mono will work better in low light conditions and give at least 5% more yield.

The hybrid panels work extremely well - especially the Sanyo's - adn we are seeing this now from real feedback/data from our customers that they are outperforming the estimates. I would treat these reports with a pinch of salt; Sharp effectively ignore them and pay for their own tests.

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 10 June 2011 at 8:59 am

Hi Ruth

With that price differential it is certainly worth considering the Sanyo option seriously.

What part of the country do you live?

I do think however that you may wish to get some competitive quotes. We would provide the Sharp solution for around £11,000 and the Sanyo for about £12,000 including VAT at 5%.

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Ruth

RuthComment left on: 9 June 2011 at 5:14 pm

I am wanting to install Solar panels on a roof with limited area ,at 30 degree elevation facing SSE. The best I can seem to get is either a Sharp monocrystalline producing 3.43Kw and costing £12,755 or  a Sanyo HIT  producing 3.50 KW and costing £13,789. Looking at a time period of 25 years which solution is the best option? Will the claims of Sanyo to out perform a monocrystalline system  in low light or higher temperatures be sufficient to pay back the extra £1000 investment? Can anyone  give further advice?

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cautiousblue

cautiousblueComment left on: 9 June 2011 at 10:02 am

I've been told panel performance loss over time is less with polycystalline panels than with mono panels.  Does anyone know if there is any truth in this?  I am thinking of going for the hybrid panels as we are short on roof space and they are supposed to be more performant. However the Sanyo panel did not even make it in a recent Photon report.  I'm not sure what to make of it all

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 6 May 2011 at 7:47 am

"Thank you Paul - so if roof space is not a problem go with the cheaper Sharps. I've had 2 quotes so far one said go for the Sunny boy 3300 another the 3800. The later as it would not be running at full capacity so last longer.....

Any thoughts ?"

The Sanyo array should give you around 10% more output across the year - based on our limited data from our customers. This is because they get more output when the temperatures are low or the light conditions are poor. The peak power should be the same.

The Sanyo system should cost around £1,000 to £1,500 more based on what we would charge; which would be around £13,000 + 5% VAT.

The Sanyo system could utilise the SB3300 or SB3800 according to a quick check using the Sunny Design tool (making certain assumptions such as south facing, unshaded 30 degree pitch roof and London weather data) but the Sharp may need an SB4000TL.

This will obviously need to be checked properly using all relevant data.


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IJKGENESIS

IJKGENESISComment left on: 5 May 2011 at 9:03 pm

Thank you Paul - so if roof space is not a problem go with the cheaper Sharps. I've had 2 quotes so far one said go for the Sunny boy 3300 another the 3800. The later as it would not be running at full capacity so last longer.....

Any thoughts ?

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 3 May 2011 at 7:34 pm

"I am looking at two PV installation of 3.92kw both with a Sunny Boy 3300 Inverter. Both have 16 panels but the Sharp panels are £1,700 less than the Sanyo panels. If they both generate 3.92 kw what am I missing ? is it that the Sanyo's are 19% efficient and the Sharp 15%. If so is the 4% difference worth the extra?"

Hi there

It would appear that you are considering Sharp and Sanyo 245wP panels. These have the same theoretical output but the Sharp's are much larger (1.642m2) and the array will be around 26m2 as opposed to 22m2 for the Sanyo. So the first significant difference is the area required.

If you have the space for them the Sharp's will perform in a similar way; there are some other advantages of the Sanyo in that they claim they work better in higher temperatures and lower light conditions.

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IJKGENESIS

IJKGENESISComment left on: 3 May 2011 at 7:02 pm

I am looking at two PV installation of 3.92kw both with a Sunny Boy 3300 Inverter. Both have 16 panels but the Sharp panels are £1,700 less than the Sanyo panels. If they both generate 3.92 kw what am I missing ? is it that the Sanyo's are 19% efficient and the Sharp 15%. If so is the 4% difference worth the extra ?

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 6 October 2010 at 1:23 pm

Hi Roke

Theft can be a problem particularly if you have installed on a flat roof without penetrating the roof.

You would need to ensure that the 'A' frames are securely fastened down and use bolts with tamper proof heads.

 Paul


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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 6 October 2010 at 1:20 pm

Hi Alan

Sanyo are the only readily available, MCS accredited hybrid PV modules in the UK market.As far as we are aware they are the most efficient panels available to us.

To quote Sanyo US website:

"SANYO HIT Power® solar modules are made of 72 hybrid HIT cells that combine two best-of-breed solar technologies -- high efficiency monocrystalline silicon with ultra-thin layers of amorphous silicon. The monocrystalline silicon is sandwiched between the amorphous-Si to offer superior conversion efficiency, excellent temperature characteristics and considerable output under diffuse and low light conditions"

I hope this helps.

Paul

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alan drever

alan dreverComment left on: 3 October 2010 at 9:47 pm

Hallo Paul

I am planning PV home roof installation on Isle of Skye, which has low end of UK sunlight levels (c740Kwp/yr).  I am planning big domestic array (initially c4kw) & if all's well, extending to 6-7Kw 12 months later.

I am wanting to maximise output to maximise PV contribution to reducing emissions, & am therefore prepared to to pay for more expensive panels to achieve this. Have 2 queries:

Have been unable to pin down what are most efficient MCS approved panels currently available (appreciate while key, not only factor to consider - but key one given my objectives). The best array effeciency I have found to date is Sanyo HIT 240 HDE4 @ 17.3%.  It does appear that there could well be a mono-crystalline panel that could beat that, but because of large range available, am struggling to pin this down (know that some Sunpower panels are more powerful, but yet not MCS accredited).

Secondly, am unclear as to whether hybrid panels perform any better in non-sunlight than MC.  If case - & significant, could well be better choice for Skye. Aware Hybrid have less drop off in hot weather (but little of that here!).

Look forward to hearing from you.

Thanks

Alan 

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RoKe

RoKeComment left on: 20 September 2010 at 9:18 am

Back to flat roofs! If we put panals onto our garage roof they would be easily accessible to everyone - how do we stop thiefs popping up a ladder and removing them? 

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 16 September 2010 at 7:46 am

Hi Kate

 Glad that was helpful and hope you are now able to move on to select an installer and start the project.

What area are you based by the way?

Paul

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KateW

KateWComment left on: 15 September 2010 at 9:26 pm

Hi Paul

Many thanks.  That has put my mind at rest re SWE and the Sanyo hybrids.

 http://www.posterus.s/?p=1247 was a very hard read not made any easier by the author's not being a native-born English speaker. Quite a bit of it was above my head but I was glad I had persevered as I think it provided a text for the attractive set of diagrams I had seen somewhere (and must find again) as well as explaining how the SWE of a-Si was mitigated by the construction of the HIT cells.

Thanks too for the Sanyo contact address but you have provided the information I wanted so I won't need to use it.

Regards

Kate W

 

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 15 September 2010 at 12:42 pm

Hi Kate

This is quite a technical area and there is a lot of information on-line. The SWE effect applies to thin film technology in the first 6 months or so and then stabilises for the rest of its life. This is taken into consideration in the performance figures quoted by reputable companies. 

It does not apply to hybrid systems in the same way. If you read all of the Wikipedia entry it says that one of the ways of reducing SWE is to combine layers e.g. hybrid systems.

 Also - see the following quote from http://www.posterus.s/?p=1247   "Advantages of HIT solar cells are numerous ... : good surface passivation, simple and low temperature process and high conversion efficiency. While the base material of the structure is crystalline silicon, the typical degradation (Staebler-Wronski effect) observed in amorphous silicon solar cells does not take place in HIT solar cells. This technology can be used to process very thin wafers (

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KateW

KateWComment left on: 15 September 2010 at 12:20 pm

Hi Paul

The knowledgeable chap might have quoted evidence but quite possibly my brain switched off and I do not remember.  However I have since read in Wikipaedia about the Staebler-Wronski effect (SWE).  Now I would like to what Sanyo has done to reduce the SWE but I can't find a way to contact them.  On their web site there is an attractive diagram that may explain it but without explanatory text; so I don't even know if it is relevant.

Can you possibly elucidate?  I would be very grateful if you could.

KateW

 

 

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 13 September 2010 at 8:18 am

Dear Kate W

I have never heard that there are any reliability issues with hybrid modules; or indeed any type of  module lasting longer than another! Sharp mono-crystalline modules have a 20 year guarantee too - but I do not think that this has anything to do with a shorter expected life span.

Did the knowledgable chap offer any evidence as to why this might be the case?

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KateW

KateWComment left on: 12 September 2010 at 2:15 am

I had decided to have hybrid panels installed and was in the final throes of deciding which installer to choose when today I visited an open Green Home and spoke to a knowledgeable chap who looked at the specs of the Sanyo HIT240 I had with me and said 'Ah yes, see here - only  a 20 year guarantee.  That's because it has amorphous silicon in it.  With monocrystaline alone, you'd get a 25 year guarantee.'  He went on to say that amorphous silicon can be unreliable, especially at first and it has a shorter life, hence the shorter guarantee. 

Is he talking sense?  I didn't think to ask him but where does one find out this kind of information?

 Please, can anyone tell me.

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 1 September 2010 at 8:00 am

Dear RoKe

Shading is generally a problem because even if part of the array is shaded it can cut off the flow of electricity for the whole system.  We would be particularly concerned about shading between 10am and 4pm.

If the shading is as you suggest then it is possible to have 2 arrays controlled by differerent inverters. One could provide power in the morning and the other in the afternoon for example; similar to an east-west configuration.

However it would depend on the level of shading and the relative times. When this is known we could look at the level of energy that could be generated and the financial return to see if it is viable.

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RoKe

RoKeComment left on: 31 August 2010 at 10:02 pm

Our flat garage roof and our house roof are both shaded by a tree at different times of the day. Would it be possible to have two panels functioning independently of each other and feeding into the same inverter? And does an export meter usually get fitted at the same time as the panels? 

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 27 August 2010 at 11:29 am

As you will see from the article above there are a number of types of panels. Monocrystalline modules are available from a number of manufacturers including Sharp and Kyocera.

The hybrid modules are a monocrystalline material overlaid with a thin film layer - to make it even more efficient. The only product widely available in the UK is the Sanyo HIT modules which have the highest efficiency.

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RoKe

RoKeComment left on: 27 August 2010 at 11:16 am

I have been reading of hybrid pv panels - monocrystalline + amorphous - can you tell me what is available and from whom? I have found one from Sharp and are there any sites that compare different types of panels, inverters and what ever other bits of kit are needed? 

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 20 August 2010 at 9:26 am

Hi Kate

Sanyo are the only readily available, MCS accredited hybrid PV modules in the UK market. They are extremely efficient (over 17% for the module and 20% for the cells) and there is no monocrystalline module that we know of that is more effective.

We have installed a number of these systems now & our clients are delighted with the results.

 Paul

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KateW

KateWComment left on: 19 August 2010 at 1:53 am

I have seen a table showing that hybrid modules are the most efficient. Please could the Solar Energy expert or anyone else who knows, tell me if any manufacturer other than Sanyo makes MCS acceptable hybrid modules. And where do I find them?

A prospective installer told me that his choice of Monocrystalline module was more efficient than my choice of a Hybrid module.  Is this likely?

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Paul Hutchens

Paul Hutchens from Eco2SolarComment left on: 17 August 2010 at 8:14 am

Hi Marsh

We have installed solar PV and thermal on flat roofs without any sort of roof penetration. There are 'A' frames that do not require roof penetration for PV modules and we can install solar thermal panels that lie completely flat without loss of efficiency due to the ability to rotate the collector fins during installation.

We would be happy to come and have a look if that would help.

 Paul (paul@eco2solar.co.uk)

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Marsh

MarshComment left on: 16 August 2010 at 9:47 pm

Am thinking of installing PV or solar thermal panels (or both) on my flat-roofed 3 story townhouse.  Does anyone have any experience of a flat roof installation?  Access to the rooftop for maintenance would be difficult (I've never seen it in 8 years!) and I'm concerned that an installation would have an adverse effect on the roof's waterproof-ness.

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