
The Earth receives more energy from the Sun in one hour than the whole World uses in a whole year. Time to tap into that. Solar power is used to power everything from calculators to Coast Guard buoys to highway signs to the International Space Station.
You have read Are Solar Panels for me? and Solar Panel Installation – Planning and are ready for more details. Photovoltaic Solar panels were invented at Bell Labs in 1953. They have evolved over the years and several different types of solar panels exist, and choosing between then is confusing. No one vendor will have access to all products, so you will have to do some shopping around to find the best solar panels.
Monocrystalline or Polycrystalline Panels
These solar panels are made either from single crystal cells or stringing ribbon of multiple crystals. They are the classic version of solar panels and are rated for good efficiency, around 12-13% power conversion, and a Long lifespan, possibly 30 years+? Sunpower has a model with a very high 19.3% efficiency. Monocrystalline panels are less efficient in hotter climates and work best in unobstructed sun. A panel’s power will drop by 50% if a even one cell on the panel is half shaded. Temperatures typically above 75 degrees F cause most solar panel power generation to decrease. Solar panel suppliers include: Sharp, Hitachi, Mitsubishi, Kyocera, Schott, SolarWorld, SunTech, Sunpower, bp solar.
Thin Film Panels
Less efficient than the Crystal Panels, but they much thinner and easier to make. Less efficient than monocrystalline, at 10-12% efficiency. They work better when you have slight shading and are not affected by hot weather as much as monocrystalline. Major Drawback of performance degradation over time. Possible lifespans of 10 years. Suppliers include: Nanosolar, Unisolar
Hybrid Panels
Hybrids of single crystalline silicon surrounded by ultra-thin amorphous silicon layers. Produces 10% or more electricity (kWh) than conventional crystalline silicon solar panels at the same temperature. Good efficiency levels of 16%. Hybrid Solar Panel Suppliers include: Sanyo
Solar Panel Power Ratings
Solar Panels are rated by Maximum power generated or Pmax that they produce in Watts when exposed to full sun. The rating may be calculated at STC - Standard Test Conditions at the factory or PTC – Practical Test Conditions which are more real world. PTC numbers are almost always lower than STC numbers. Most spec sheets will also show how much power they make with varying current and voltage. To calculate total system power, you need to compare Apples to Apples. Power output of solar panels decrease with time. Many panels are rated for 80% output for 25 years, 90% output for 10 years.
Also look for the negative tolerance rating of solar panels. This number reduces the PTC rating, so a high PTC rating with a high negative tolerance is not good. A 200 watt PTC panel with 10% negative tolerance could produce only 180 watts.
Look for the installer to quote a minimum warranted power rating for solar panels.
Total Solar System Power in CEC AC Watts output = Number of Panels X PTC Power rating of each Solar Panel X Inverter efficiency.
3456 watt CEC AC Rating = 3.4 kw = 12 panels X 300 Watt PTC Rating x 96% Inverter efficiency
This is a real world power output ratings of a solar electric array.
Solar Panel Inverters
Inverters convert DC power from the solar panel to AC power you can use. Look for brand name inverters from Sunny Boy. Target inverters with 95% or higher efficiency and 10 year warranty. Options include web interface to get statistics, SD Card for holding data, or even WiFi access.
Solar Panel Warranty
Look for a solar panel that has a long warranty. The longer the warranty, the more reliable the vendor feels the solar panel is. 20 or 25 years is not uncommon. Life expectancies of up to 40 years are now being seen. Watch out for dealers that promise warranties that may outlive their firms.
Solar Panel Rebates
Most rebates have lists of qualified solar panels. This can help narrow down what you can buy. California has a list.
The solar panel that is right for you, depends on your budget, location, and power needs. Some installations may need different types of panels for different locations, especially for areas of no shade and partial shading. Consult a local expert to find what is right for you.
Beware of the latest technology, you do not want to pay thousands of dollars and be a beta tester.
Filed under: Alternative Energy, Eco Friendly, Effort, Green, Hard, Home, Shopping, Solar, Sustainability | Tags: Hybrid Panels, Monocrystalline, Polycrystalline, Solar Panels, Sun Power, Thin Film Panels |
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