Your Questions About Solar Panel Efficiency

Sandy asks…

Why are solar panels effected by operating temperature?

The colder a solar panel gets the more efficient it seems to be. As the panel warms, it loses some efficiency. Why is this so? Please explain in a way you would expect a high school kid to understand it, as I am a high-schooler and i have to explain this to other high-schoolers.

ssadmin answers:

Absolutely temperature matters. So what do higher temperatures do to solar photovoltaic panels? As temperatures rise, the efficiency of solar panels decreases. Heat causes electrical resistance to the flow of electrons. On days where the temperature is more than 75 degrees, the electrical resistance makes the voltage fall thereby producing less kilowatts per hour. Your roof is much hotter than temperatures on the ground. That’s why solar panels are not mounted flat to a roof. There’s usually a few inches of spaces between the panels and roof so air flow can easily pass through and cool the panels down.

There are some photovoltaic panels that are designed specifically to operate in hotter temperatures. These panels have a higher temperature coefficient. This is especially important in high heat climates like Arizona or New Mexico, but probably wouldn’t make too much of a difference in New England (except maybe this year). If someone lives in one of these areas, they should speak to a solar installer to make sure they are using they right equipment for their region.

Please note: Solar thermal panels used to heat water can withstand high temperatures without any degradation. In fact, hotter temperatures would actually be better for these types of modules.

Ruth asks…

How many kilowatt hours of electricity will the solar panels generate in 20 days?

A house with a south-facing roof has photovoltaic panels on the roof. The photovoltaic panels have an efficiency of 10.3 % and occupy an area with dimensions 3.35 m by 8.55 m. The average solar radiation incident on the panels is 305 W/m2, averaged over all conditions for a year. How many kilowatt hours of electricity will the solar panels generate in 20 days?

ssadmin answers:

Area is 28.64 m²
incident power is 305 W/m² x 28.64 m² = 8740 watts
output power = 8740 watts x 0.103 = 900 watts

900 watts x 24 hr/day x 20 days = 432000 watt-hour / day or 432 kW-hour / day

.

Lisa asks…

Help Solar Panel Project do soon!?

I'm doing a shcool porjet on solar panels I need to know all this informatio can some one help me?:Research and Support Your Opinion 1. Many companies that sell solar energy products advertise on the Internet. Do a search for these Web sites and make a list of sources. 2. Use these sources to find information about the cost and efficiency of solar heating products and designs. 3. Make a list of solar options that could be used in your home. For each one, list its approximate cost and its advantages and disadvantages. 4. Do you think solar energy is a practical option for your home? Write a paragraph summarizing your opinion. Make sure to support your opinion with facts from your research.

ssadmin answers:

These arent so difficult. If I had access to google when I was in school, it would have been a breeze 😀 .
I assume your teacher is asking about Photovoltaic products .
1. Http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=rQr&q=solar+energy+products+photovoltaic+&btnG=Search
2.http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla:en-US:official&hs=YoW&ei=vqG6SarRGYnYsAO84tFG&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=solar+energy+photovoltaic+efficiency&spell=1
3.http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=vqW&q=solar+energy+%22in+the+home%22++%22pros+and+cons%22&btnG=Search
4. YES. The rest is all you Kido . But I would say something about helping the environment , also not being (as)dependent on grid power or gas for heating or electricity. Good Luck=D

Nancy asks…

For solar panels, if the wattage is 280 wp(watt peak) and the efficiency is 14.5%, what is the wattage?

do you just multiply it by the percentage or leave it?

ssadmin answers:

280 means the max power

14.5% means the transfer rate from light to electricity.

William asks…

Judge my theory on solar panels, are we on the verge of limitless power?

Ok, here's my theory:
In a few years, scientists will figure out a way to make solar panels with a good efficiency at low cost.
When a certain efficiency – I'll call it the ‘profitability point' – is reached, everyone will want one because you make money out of it in the long run.
Eventually everyone will be able to provide themselves with energy.

Is there a flaw in my theory or are we going to see energy utopia in a few years?

ssadmin answers:

I think we have already reached the point where solar electricity is cheaper than grid electricity, in some areas. Where I live in California is an example. As prices continue to fall, business should pick up even more.

However, there are two lessons from history:

1) People don't do what's mighty good for them. Since the 80's, it's been widely known that adding insulation to homes will pay for itself in just a few seasons, and save money thereafter, but few people did the retrofit. Efficiency standards evolved, but people don't like to change or think.

2) Business will always try to maximize profit. In the 30's, they were talking about hydroelectric power, so abundant that it would be too cheap to meter. We see what happened to that. The power grid would need to be reworked to incorporate large amounts of solar, but then, someone would find a way to run the price up to the maximum someone was willing to pay. Maybe connection fees to the grid would skyrocket.

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