WHAT YOU NEED TO KNOW BEFORE BUYING SOLAR PANELS


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Categories: Solar Power

Up until recently thin film panels were produced using a-Si solar cells. These cells have the annoying trait to age quickly when directly exposed to sunlight. Despite the production process being cheaper in comparison to crystalline cells this makes them less interesting for use on a roof. The remaining two, CdTe and CIGS, are relatively new. Especially CIGS-technology seems very promising. The use of Gallium slows down the aging of the solar cell and ensures a more efficient energy management. Pure Gallium does not occur in nature but is amply present all over the world. In small quantities it is present in bauxite, aluminum, coal and even in the human body. This makes Gallium quite precious and expensive.

Currently there are crystalline panels being offered that are Gallium panels. The manufacturer adds a hint of Gallium to the conductors and claims that the efficiency is increased. Independent test results that could verify these claims are not yet available. Because of the precious Gallium these panels are more expensive.

Tinted solar panels

Sometimes the color of solar panels is a reason for people not to buy them. On many roofs the blue color stands out and some find that ugly, others do not mind. In other instances the building code simply does not allow such a color on a roof. In America the rules and regulations are often quite stringent and such an exclusion is often found. 

Transparent solar cells

If you have visited the new railway station in Rotterdam then you have probably seen them: transparent solar panels. I can vividly remember the first time I saw the immense roof of the platform hall made up of transparent solar panels. I was instantly enchanted and could not stop myself from tweeting a picture.
But transparent solar panels are less exotic than we would expect. During production less cells are incorporated leaving more room between them. The absence of a backing layer leaves the panel largely transparent and the cells they contain seem to float.
Less solar cells off course mean less capacity in comparison to a standard solar panel of the same size. Therefore the choice to use transparent solar panels is mainly made from an esthetic point of view.


MODULE DATASHEET

Every solar panel has it’s own datasheet. I like to call it a panel passport. Amongst other things the datasheet will state which standards the panel meets, which is the maximum capacity it can deliver and which warranties apply. It has proven to be difficult for many people to get a good understanding of the many abbreviations and descriptions. What follows is a summary of commonly found descriptions on a datasheet.

High Module Efficiency: Maximum capacity of the panel measured per square meter as per STC (Standard Test Conditions). In short this means that the maximum capacity can be achieved according to the specifications of the STS on the 41st parallel north or otherwise said, at the level of New York, California, Nebraska, Illinois, Ohio, Barcelona, Rome and Istanbul.

Positive Power Tolerance: The amount the capacity can deviate from the stated value, expressed as a perecntage. Usually +3% or +5%. Never a negative value.

Robust frame to up 4.500 Pa load: Indicates the force per area the panel can withstand. Indicates the resistance to weather conditions like snow, storm and hale.

Outstanding Performance at Low Irradiance: Indicates that the panel performs above average in low sunlight conditions.

High Energy Yield at Low NOCT (Nominal Operating Cell Temperature): Modules are tested in more ideal conditions than the ones they will eventually be used in. With this description the manufacturer wants to make clear that the panel will perform well in less ideal circumstances.

EL Screening (Electro Luminescence): During manufacturing the cells are tested for defects before laminating.

Current Binning: With this technique any minute interruptions within the electrical circuit of the cell, which could interfere with the current, are removed.

Accredited Salt Mist / Ammonia Resistance: Indicates resistance to a coastal/marine environment.

25 Years World Wide Coverage: Manufacturer’s warranty for 25 years.

100% Warranty Term Coverage: The manufacturer is entirely responsible for the mentioned coverage during the warranty period.

Providing Third Party Bankruptcy Rights: In case of bankruptcy of the seller the customer will be covered by the manufacturer’s warranty.

Non-Cancellable: The warranty cannot be revoked unilaterally.

Insured by Two World top Insurance Companies: The manufacturer has deposited the warranty with two major worldwide insurance companies. If the company would go out of business these insurances will remain active.

IEC – 61215: Satisfies the International Electrotechnical Commission standard regarding aging by weather conditions.

IEC – 61730: Satisfies the International Electrotechnical Commission standard regarding safety.

IEC – 61701: Satisfies the International Electrotechnical Commission regarding corrosion in marine environment.UL1703: Underwriters Laboratories standard regarding absorption of light intensity.

ISO 9001: Standar by the International Organisation for Standardization regarding quality management in organisations.

Cell Type: Indicates monocrystralline or polycrystalline cells. The amount of busbars is also mentioned.


Cell Arrangement: Number of cells in a module including the specific arrangement.

Dimensions: The module’s hight, width and depth.

Weight: The total weight of the module.

Front Cover: Thickness and type of glass cover.

Frame Material: Specifies the material the frame of the module is made of.

J-Box: The type of junctionbox at the back of the panel.

Graph I-V Curves: The current/voltage ratio.

ISO/TS 16949: A type of quality management certification.

ISO 14001: Indication that the product satisfies environmental standards.

QC080000 HSPM: Indication that the product satisfies standards regarding use and disposal of hazardous substances.


OHSAS 18001: Meets British operational health and safety standards.

Pmax: Maximum nominal power.

Vmp: Voltage at maximum power.

Imp: Amperage at maximum output.

Short circuit current: The maximum current expressed in amperes.

Module efficiency: The power output that is converted from absorbed sunlight.

Operating temperature: Temperature range in which good working order is guaranteed.

Maximum system voltage: Maximum voltage load in configuration with the transformer.

Maximum series fuse rating: Maximum load of the panel in ampere.

Application Classification: Indicates the class of panel. Summary of qualities and certification.

by ARJAN EIKELENBOOM / via Eikelenboom

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