Modules

Modules are the key to capturing light and creating power but how important is it to spend hours trying to decide which one is best for me?

Well it depends.
 

It is basically a cost benefit decision.  Limited roof space would require a more efficient module in order to achieve higher power production at potentially a higher cost per watt.  On the other hand if you have a large roof space, you could use a less efficient module at potentially alower cost per watt to generate the same energy production as the higher cost modules.

You have to look at your potential power production and decide whether the additional cost for a more efficient module would net out at more dollars for you in the long term.

There is some nomenclature you would need to know when evaluating modules.  This is handy when comparing modules.   A common test situation needs to be defined so the data can be replicated anywhere in the world and provide common data points.  There are 2 standards that you will see when discussing modules.

STC

Means Standard Test Conditions. Module performance is generally rated under standard test conditions (STC): irradiance of 1,000 W/m², solar spectrum of AM 1.5 and module temperature at 25°C.

  Basically, this defines a standard test that manufactures and test labs perform to test a module.  The companies would have a indoor solar testing simulator that meets the standard and therefore you would have a common data standard in order to compare  modules.

You would find STC in this context: A Siliken solar module is 240 Watts (STC).  Therefore 10 Siliken modules would be 2,400 Watts (STC).

PTC

Stands for PVUSA Test Conditions.  This is much closer to real world conditions.  You will find this value being used in California.  They use this to obtain the rebate that is provided in this jurisdiction.  PTC are 1,000 Watts per square meter solar irradiance, 20 degrees C air temperature, and wind speed of 1 meter per second at 10 meters above ground level

Other things to consider is the warranty for power and manufacture defects and power production over the 20 year period.  But beware,  the company might have a great warranty but will they be in business in 15 years?  Modules will lose efficiency year to year and this is stated in the warranty. The warranty may state something like this:

25 year linear power warranty/assuring 97% performance level the 1st year, from the 2nd to the 20th year module degradation is guaranteed to be less than or equal to .7% per year (Siliken module  performance warranty).  Modules are made to last.  I’ve seen a module that has been in continuous production since 1987; it’s slightly discoloured but still functioning.  Your modules should have a productive lifetime much greater than the 20 years warranted.  They are also designed to stand up to hail stones of a certain size and velocity.

  2012 is the year of implosion for module production-lots of companies have gone out of business.  What also is important is the temperature cooeficient- lower is better.  The lower the number the more efficient the module is at a high temperature.. Why this is important is that the modules can get very hot in direct sunlight 40- 50 degrees celsius.  Higher module temperatures will reduce the voltage by 0.04 to 0.1 volts for every one Celsius degree rise in temperature (0.04V/°C to O.l V/°C). 

(http://photovoltaics.sandia.gov/docs/PDF/98TLREF13.pdf page 21)

Here is another explanation that I picked up while surfing the net:

Unfortunately, the 25ºC cell temperature used for testing is not a typical operating condition. In full sun, PV modules typically operate between 15°C and 30ºC (approximately 60°F to 90ºF) above the ambient temperature depending on how they are mounted (flush on a roof, on top of a pole, etc.). Thus, on a 25ºC (77ºF) day, cell temperature may be closer to 50ºC (122ºF). On a hot summer day, cell temperature can routinely approach or exceed 65ºC (149ºF). As cell temperature increases, voltage decreases. A decrease in voltage, at the same level of irradiance, means a proportional decrease in power. 

 Side by side, and all else being equal, a module with a 43ºC NOCT (nominal operating cell temperature)  should produce about 3% more power than a module with a 50ºC NOCT. 

The state of California does an review of modules and provides their own real word evaluation using PTC rather than STC

http://www.gosolarcalifornia.org/equipment/pv_modules.php

In Ontario, Canada you are restricted to modules manufactured or assembled in Ontario.  There are a few companies such as Silfab, Heliene and Canadian Solar to name a few that manufacturer in Ontario

Unfortunately there are many more manufacturers out there such as Sunpower  (who make excellent and efficient modules) which do not qualify as meeting the Ontario MicroFIT regulations.  For those of you going solar but not through MicroFIT, then you have a wider range of options.  From a price perspective take advantage of the cheap Chinese modules that are entering the market. Whether this is dumping or just that fact that the Chinese have decided to build capacity in this area, I don’t know but the prices are great.

You can search for current Ontario Solar Module Manufacturers by navigating to:

https://www.showreg.net/OSEI2009/default.asp?mode=2

Ontario Made Module Links

http://osmsolar.com/products.html

http://www.heliene.ca/

http://www.silfab.ca/

http://www.heshomeenergy.com/sharpsolarpanels.html (no website)

http://www.wsetech.com/solar%20panels%20csa.php

http://solgate.ca/about/

http://www.luminsolar.com/

http://www.eclipsall.com/

http://www.canadian-solar.ca/residential/

http://www.luminsolar.com/

http://www.magnum-solar.com/

http://ca.sanyo.com/News/-For-Reference-SANYO-Solar-Modules-used-for-Markham-s-first-municipally-owned-Solar-PV-Rooftop-project-to-power-under-the-Ontario-s-Feed-In-Tariff-program

http://www.schueco.com/web/ca/residential/solarheat_solarpower/products/photovoltaic_systems/pv_modules

http://www.solarizetech.com/

http://www.unconqueredsun.com/

http://www.soventix.ca/

Key points for Installation of modules on your roof

Orientation

For proper operation, the modules must be oriented as close as possible

toward the equator. In the Northern Hemisphere, this direction is south.

In most areas, this varies from the magnetic south given by a compass. A

simple correction must be made.

Height from roof

4-6” to allow proper ventilation and reduce heat although the modules can be mounted lower for visual appeal.

Angle of inclination

Permanently mounted modules should be tilted up from the horizontal .  The correct tilt angle varies with the times of year the system is used, and the latitude of the site.

The tilt angle is measured from the horizontal, not from a pitched roof or hillside.

The tilt should be within 10 degrees of the listed angle. For example, a system used throughout the year at a latitude of 35° can have a tilt angle of 25° to 45° without a noticeable decrease in annual performance.