The U.S. government plans to produce a buyer's guide to power-converting roofing materials.
The government tests cars for gas mileage. Now it's testing roof tiles for wattage.
Photovoltaic shingles (in blue) can be installed in the same way as conventional shingles. About 500 square feet of them produce three kilowatts during peak sunlight, enough for most residences. Currently, they're still darker than conventional roofing materials. (Courtesy of United Solar Ovonic.)
Homeowners have long been able to partially power their homes with sunlight, but it meant clumsily mounting photovoltaic (PV) panels on the roof. Now the latest generation of PV panels look and act much like ordinary roofing tiles or shingles. And the National Institute of Standards and Technology (NIST) is evaluating nine of these commercial PV roofing products in hopes of providing an easy way for consumers to judge the panels' power potential.
"A lot of people are considering the use of PV products on their homes and businesses, and in order to make decisions on whether it's a worthwhile investment you need to predict their performance," says Hunter Fanney, head of NIST's Heat Transfer and Alternative Energy Systems Group in Gaithersburg, MD. "We are collecting detailed performance data to validate those models."
The roofing materials, which use various types of solar-to-electricity conversion, are being tested for 15 months. Fanney hopes to use the data to build a computer program and database with, among other things, average flat-surface solar radiation readings for neighborhoods across the United States (as measured by the weather service at the nearest airport). Punch in the performance characteristics of the roofing product you want to use, plus your location, roof orientation and slope, and other data, and -- bingo -- you'll know what kind of wattage you can expect from your roof.
According to Fanney, roofing tiles and shingles with embedded solar converters have been on the market for about three years. They look like regular roofing materials, keep out the sun and rain, and can be installed in much the same way. But by generating electricity, these tiles and shingles save consumers money.
Around 500 square feet of PV tiles can produce three kilowatts of electricity, according to Subhendu Guha, president and chief operating officer of United Solar Ovonic, a maker of PV shingles in Auburn Hills, MI -- and most roofs are several times that size. His company's version is dark blue and can blend with ordinary shingles of a similar shade. Or a builder might devote an entire sunny section to PV materials.
"A south-facing roof on a three-bedroom home could supply 20 to 30 percent of the home's electrical needs," says Paul Maycock, a consultant and head of PV Energy Systems in Williamsburg, VA.
Researchers are working on solar cells that use a novel organic dye.
Guest (Marco)
How do you overcome the dramatic loss of power generation capability when the panel is covered with layers of dirt, dust a urban grime? until this problem is solved Solar Power will remain a Sci Fi confidence trick on the poor consumer.
Guest (alfranco)
Test conditions and PV maintenance
My concern is that the NIST test site pictures show the panels variably shaded at the test site and I haven't received a reply from
Brian Dougherty (sent 7/1) questioning the validity of this siting.
As for PV, it's like your windshield it works best if periodically washed and cleaned. No problemo.
Guest (John)
If you look at the diagram on http://www.bfrl.nist.gov/863/pvsolar/NISTs_PV.htm, the large building (the Administration Bldg.) is aligned north-south. It looks like the solar panels should be in the sun most of the time?? However, I wonder if the panels are laying flat (horizontal); most residential roofs are not.
Guest (John)
I would think there is data from current installations in Europe and
Japan?? Also, I understand the top surface may be a fluoropolymer film, maybe that would help to reduce adhesion of city grime? Or perchance create a new industry (chimney sweeps to roofing sweeps)?
Guest (Leon Viveros)
Maybe its a good opportunity for a new kind of job... PV Cleaners...lol
Guest (Mike)
Suppose for a moment that you treat these panels just like a car - say wash them once in a while with soap and water. Then rinse. With newer nano surfaces that repel water they may even be semi-self cleaning. GE has a new plastic that has this capability.
Reply to MARCO - Re: Solar Panel Electricity
I think you're just too lazy to realize that you're saving fuel (fossil) which when burned create CO2 and then ruin the environment by creating the greenhouse effect and thsu global warming - please, Marco, see outside your 4 walls (no pun intended)!
Guest (Em)
cleaning PV's and sloped roofs
As you clea your eves, you can hose your PV's now and then.
As for slope: for best results you want to have the sun light coming perpendicular to your panels. Sloped roofs work better than flat roofs (get more light).
And this changes with latitude.
If builders start including this in their desings, house orientation and roof shapes and slopes will be designe for the local condition to optimally make use of the sun in each particular location.
Guest (Ron)
Open Energy makes solar roofing tiles
One company makes both solar roofing tiles and PV panels. The efficiency is up to 20%. I hope they get included in the testing.
site is www.openenergycorp.com . There is some other interesting things there as well.
Guest (arnold)
do these shingles hold up well in the deep south of the east and coast areas, is humidity an issue?
they do, if i understand you right. as a matter of fact, normally coastlines have more sunhours that on the land, so for solar coast is perfect. it depends a little whether you place the panels very near by the sea or not. very near means a salty film on the panels which should be affoided to my believe.
PV solarpanels are good to use anywhere, don't understand me wrong. even in canada or norway. i live in the netherlands where we have very diffuse light now and then, but no problem for solar, using poly-crystalline solar modules. these are perfect for that kind of conditions.
a rule of thumb is; the hotter (not about light) a climate is the better you should use thermal-electro solar power, since PV panels don't like their working surface very (VERY) hot. at the end, its all about efficiency and how much you want to matter with that, because we are talking about percents power more or less... writing this, i think i wouldn't care about it too much. just put the panels there and shout it out! so that others hear it and do the same!
Solar power for our homes sounds great...until you start to add all the other expensive items.
It would be helpful to know the full expense plus all the maintenance needs and failure rates. Also, in the tropics (like Guam), air conditioning is the real energy hog. A solar system for this might be unaffordable for most people. And then there are the typhoons....
Re: Solar - - the bigger picture
concerning solar-energy in the tropics; it is known that photo-voltaic solar panels (PV) are less efficient when the working temperature is high (that is the temp on/in the panel itself). for tropical conditions it is, efficiency-wise, better to invest in thermo-electro solar energy. here the sun heats oil in pipes that runs a generator. the efficency is very high. don't know whether this is technique ready to use on home-roofs, though.
Re: Solar - - the bigger picture
You have mentioned temperature being a factor on the use of solar shingles for electricity. What are the specs? I live in TX and we see 20-40 100 degree F days per year in addition to hail storms usually once per year. I love the idea for weening my corner of the world off petrol, but these questions concern me.
look here! new energy techniques
for anyone interested in new energytech, including foil-solar and stuff, but also many different other projects and ideas, go to; http://peswiki.com/energy/Main_Page
Guest (solar jon)
Sadly, the current administration "studies" new technology like solar panels, while it "funds" old technology like coal and oil.
Solar shingles is an awesome idea, but I'm sure that just like solar panels, they're expensive. I looked at solar panels a while back and they were $1000+ each! Then I finally stumbled upon this site that shows you now only how to build your own solar panels, but wind turbines as well. It cost me just a little over $100 each per solar panel, which is more than twenty times less that some solar panels. For more info visit http://8ac8d615gjld9o63blzc8m0teg.hop.clickbank.net/?tid=EARTH4
Does anyone know whether the clay tile BIPV has been rated for typhoon winds of 170mph or greater?
Kiernan
I think that these new "shingles" would work. Looks are very important to people and that includes their home. Who wants an ugly solar panel on their house. But in order for these to be successful they will have to produce. If they are not producing at a high enough level then no one will buy them. Residential solar panels are becoming very popular. Everyone is looking to save a dollar in this economy.
As one who as of April 2009 has 500 square feet of solar panels producing an average 720 kilowatt-hours of power per month, I produce twice the power predicted for shingles. In 10 years I will likely change out my 25 year panels with an improved panel producing four times the current shingle production. Try that option with shingles. As a technical person, I think panels are not unsightly (the shingles do not match very well either) but display the thoughts of someone willing to invest for both financial benefit and to protect the environment.
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Guest (mike)
Solar Panel Buyers Guide
Great Idea! Maybe this type of Consumers Reporting will boost the use of the newer solar solutions. My main concern - 15 months? These things are supposed to last many years. The testing should also include variables like Cold testing, snow and ice tests, etc.
Reply
Guest (josh wood)
solar panels
how do you know if your in the right location, and which system is the best in oklahoma and whats the prices like
Reply
hiofarwa
4 Comments
Re: solar panels
hi, it doesn't really matter where you are. just direct your PV panel to the south (or somewhere in between SO - SW). that should do the job. when you have a sloping roof on the south it is perfect. a flat roof is good too, then you need a panel-base made of plastic or alluminium frame.
do you live in a very sunny place then choose mono-crystalline solar modules. when you have a lot of diffuse light, then use poly-crystalline solar modules.
Reply