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Solar Panels that Cernunnos Homes work with
How we select the right panels for you…
Defining Solar panels…
There are thousands of different solar PV panels on the market – you can see this if you go to the MCS website and search for the certified products under Solar PV. Not each panel is the same, but in the same manner as you have different types of cars, they all do very much the same thing!
There are two main types of make of PV cells on the market:
Mono: called as such as the panels are made from Monocrystalline Silicon. These are the most efficient types of cells but are more expensive.
Poly: called as such as they are made from Polycrystalline Silicon. Cheaper to produce but are also less efficient.
There are also PV cells made from Amorphous Silicon, but these make thin-film cells which are not used for solar PV installations on properties.
The cells are added together to make up each panel. A typical Solar cell will be no bigger than an A5 sheet of paper. Putting a few cells together creates a PV panel (putting panels together creates a PV Array – but more on this later).
Panel Power…
When we talk of cell efficiencies, we mean how much energy they actually capture from the sun. The way this is measured is by testing every cell under what are called “Peak Test Conditions”. These conditions are 25 degrees temperature of pure sunlight. The amount of energy captured from 1 square meter of sunlight (i.e. light put onto 1 square meter of cells) is then measured for each square meter of cells. Once this is known you get the Wp (Watt Peak) of a square meter of a cells. This is the number of Watts produced under Peak conditions.
Panel Sizes…
However, panels not only differ in make (i.e. Mono and Poly) but they also differ in size. Below are the typical panel sizes available on the market:
993mm * 1685mm * 42mm
1001mm * 1495mm * 42mm
994mm * 1318mm * 46mm
Thus, the number of cells and their Wp in each panel will differ, as the area/size of each panel differs (note none of the above panels are one meter squared!). To overcome this the manufacturers give each panel a W (Watt) rating – i.e. the number of Watts the PANEL will produce under peak test conditions. Typical panels come in the following W sizes:
170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250
As you can see, the “weakest” panels are 175 with the most powerful being 250W.
Different manufacturers make different types of panel. Some manufacturers include:
- Sanyo
- Mage
- REC
- Canadian Solar
- Mitsubishi
- Romag
- Suntech
- Schott
- Schuco
- Sharp
- Yingli
Thus you may hear people talk about the Sanyo 245’s or Mitsubishi 210’s. All this means is that the Panel is made by Sanyo or Mitsubishi and is 245W or 210W.
Selecting the right panel for you…
To create a system – or something we call an “array” – you simply decide how many panels you want / can afford / can fit on the roof. The weaker panels (170) are much cheaper than the strongest (250W). Some panels are smaller in size, so you can use more of them if you are limited to the amount of space you have. Choosing the right panel depends largely on three factors:
- How much roof space is there?
- How much are you willing to spend?
- How much energy you need/want to produce?
Some clients will be more limited by the amount of roof space, and thus will be focused on the highest power panel that will fit in a certain area. Others will be more concerned about cost and will therefore look towards the cheaper, less powerful panels. Those with unlimited space will be more concerned with using the most powerful panel on a cost efficiency basis. Cernunnos considers all these factors when selecting the right panel for a client. We work with over 100 panels and select the best on a cost/performance ratio. We work out the cost per panel per Watt per meter squared – giving us the best efficiency panels on the market.
Panel Efficiencies…
Here is a table from www.solardesigntool.com that shows different panel efficiencies when comparing the data on the manufacturers datasheet:
These tend to be the 5 most popular panels we work with for various reasons:
- The Sanyo HIT 250 Hybrids are claimed to be the best panels on the market, and subsequently the most expensive. They offer a new technology that works better in areas that suffer from shading and on cloudy days, claiming to offer increased efficiency levels of 20%. We have not taken account of this claim in the estimated returns, so although the payback looks less it would be about the same if the panels outperform by 20% on energy production. For more information please see Sanyo (now Panasonic)
- The Mage Solar panels come from a German company that specialises in engineering (they built the roof of the Millennium Stadium!) and renewable energy. They come with a very good 30 year efficiency warranty and a 10 year parts warranty (most other panels only have a 25 year efficiency and a 5 year parts warranty). Additionally, they are one of the most cost effective on a cost/performance basis (as measured by cost per watt per meter squared) with one of the best warranties. The company has been in engineering for over 80 years and producing Solar PV panels since 1994. For more information please see: Mage Solar
- The Canadian Solar panels are made by one of the largest Solar PV manufacturers in the world. The company is listed on the Nasdaq Stock Exchange and is one of the most well respected Solar PV companies in the market. They focus solely on Solar PV products (unlike most other energy companies) and produce one of the most cost effective panels on the market. Like the Mages, the Canadian Solar panels also come with a 10 year parts warranty, but only have a 25 year efficiency warranty. For more information please see Canadian Solar
- The REC panels are made by a Norwegian company, the “Renewable Energy Corporation”. They claim to have the lowest carbon footprint of any panels on the market and thus are one of the best for those looking to minimise the carbon emissions from their panel choice. The company was formed in 1999 and has experienced huge growth in its 13 years existence. For more information please see REC Solar
- The Suntech panels are a very good panel on a cost/benefit basis made by a Chinese company (founded in 2001) which is the largest PV manufacturer in the world – they account for nearly one in every 10 panels produced globally! For more information please see Suntec Power
Further Information:
A complete list of panels and their accompanying datasheets can be found here.
To view some of the systems we retail please visit our Online shop.
To view Testimonials or Case Studies please click here.
