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February 23, 2017

Meet The Men Who Put Solar Shingles On The Roof

Originally published on CleanTechnica

Solar shingles are now gaining increasing traction in the renewable energy landscape. They are architecturally distinctive, more so than traditional rooftop photovoltaic panels. Solar shingles provide an integrated building product providing both roofing security and solar electricity in one package.

As PV Magazine’s Charles W. Thurston has stated,

“The nascent field of U.S. solar shingle manufacturers is beginning to expand from its small base in building-integrated PV (BIPV), leveraging their systemic reductions in installation costs, their improved roof and solar integration, and their continuing march-out of newer materials.”

Two of this industry’s solar shingle pioneers are Robert and Gary Allen, brothers and partners in Rochester, Michigan-based Luma Resources. The two men answered my questions about their innovative building-integrated photovoltaic (BIPV) products and provided these helpful photographs.

Solar shingle basicsBack side of Luma solar shingle

SONY DSC

Structurally, a polycrystalline photovoltaic tempered glass module is adhered to a custom formed metal shingle. A premium plastic edge protector surrounds the glass to provide added durability.

The junction box located on the back is positioned in the center of the shingle, allowing equal length wires to run in either direction.

For starters, take a look at this remarkable finished roof, as shown below:

The Bermuda Roof from Luma solar shingles

The Bermuda roof from Luma Resources
Our conversation begins:

Meyers: In short, what factors led to the development of your solar shingles?

Robert Allen: It all started with a phone call. I knew a man who worked for a German company, Rheinzink. He knew that our roofing company (Allen Brothers) excelled in specialty roofing and sheet metal. He’d gotten a call from then solar-leader, United Solar Ovonics (USO). Rheinzink was doing a lot of business with USO in Germany. USO asked him if he had any ideas on how USO might gain entrance into the residential solar market. He told them he didn’t have a clue, but based on their area code — being the same as mine — they should call us. They called just before Christmas in 2006.

Meyers: Where was your first product launched, and can you describe the performance successes and drawbacks?

Robert Allen: We showed our product for the first time at the International Roofing Expo in Las Vegas. We had a 10 x 10 foot booth along with a smaller display in the new products pavilion. Thousands of contractors from all over the world walk the Expo. There they see about 50+ new products being introduced into the roofing and construction market for the coming year. During the Expo, attendees are asked to vote for the best new product of the year. Our Luma Solar Roof took first place. When asked why they voted for Luma: they saw it as something they could add to their product offerings back home and make money with.

Meyers: How about system performance?

Gary Allen: The performance success has been very nearly flawless. Our biggest challenge has been helping educate interested parties about rooftop solar versus traditional rack-and-frame. For example, we actually enhance the roof’s strength as opposed to traditional rack-and-frame solar that weakens it. The general public does not yet fully understand, but that is changing with all the press and growing demand about roof-integrated solar.

Designers of the Luma solar shingle

Robert and Gary Allen
Meyers: Who were the product developers, and did this effort generate interest from other companies?

Robert Allen: Gary was the key developer of the Luma Solar Roofing system. His 30 years of experience in the roofing and sheet metal industry doing some of the most challenging projects in our market area paid off big. When we were asked by USO if we could figure out a way to make their thin-film solar laminate work on a residential roof he saw the solution in his mind right away. Three days later he had the prototype shingle finished.

As to the question of our product generating interest from other companies, the answer is yes. Within a year, Dow came out with the Power House Solar Shingle, and a small company called BIPV Solar came out with its product. Dow has closed down its solar shingle division with its most recent merger with DuPont. BIPV was private labeled by Saint-Gobain (French conglomerate) through its CertainTeed division, they now call it the Apollo Tile. Saint-Gobain approached Luma ahead of BIPV Solar but we weren’t looking for a partner and turned them down.

Meyers: Describe some of your solar shingles demos, locations, and comparative costs.

Robert Allen: Although we have been involved in demos in the past, in a certain way every Luma job is a roofing demo, in a sense. Our product is first a fully weatherproof roofing system complete with its own R listing (R for roofing) at Underwriters Laboratories. When we add the solar component to the top of the metal roofing shingle it also becomes a solar roofing system. Luma Solar Roofs are located throughout the United States, Canada, and the West Indies.

Luma solar shingles

Gary Allen: We currently have two active Luma demos for purposes of R&D. One is located in Detroit on the campus of NextEnergy. They are a 501(c)(3) nonprofit organization established in 2002 to drive advanced energy and transportation investment and job creation. The second demo is on the campus of Western Michigan University in their “Solar Garden.” They will be using it as part of their clean energy degree program.

Robert Allen: Luma’s “comparative cost” can only be looked as it relates to the cost of the roof and the cost of the solar. Luma is the original, and to date, only complete solar roofing system. We cover the entire structure’s roof with either the Luma Metal Shingle or Solar Metal Shingle. Others use a patchwork method. Roofs are sold on a certain price per square foot. Solar is sold on a certain price per watt. Luma’s “comparative cost” would be equivalent to a high-end custom roof that is fully weatherproof and powers your house, as well as beautifying it.

Meyers: While the roofing system is architecturally attractive, how do longevity and performance fit?

Installing splice plate on solar shingle

Gary Allen: The 24-gauge painted galvanized metal that Luma uses to form its shingle has a 30-year warranty on the paint finish. The metal shingle itself is a lifetime product. The solar laminate has a 25-year power generation warranty. Interestingly, some of our systems still function after surviving multiple hurricanes, hail storms and other acts of nature.

Meyers: Who are some of the champions for your company and your solar shingles product?

Robert Allen: Here are some: PV Technical Services, Ontario, Canada 50 + – Luma Solar Roofs; Yale Acres Subdivision, Meriden, Connecticut; Home Land Builders, Ann Arbor, MI; Teddington Farms Eco Tourism Retreat, Portland Perish, Port Antonio Jamaica. Two off-grid Eco Tourism Lodges completed, five more to go.

Luma solar shingles

Mr. John Sarver, former head of the Michigan Department of Energy and first Luma customer post-UL listing. John is the current head of Great Lakes Renewable Energy Association (GLREA). He’s a strong solar advocate and sought after public speaker. John loves to tell the story that he wanted to put solar on his roof for decades (before Luma) but his wife wouldn’t let him. She hated the way traditional solar would make her beautiful house look. That is, until he showed her the Luma Solar Roof.

On site training of solar shingle installers

Thanks to Robert and Gary Allen for the time they have provided. I look forward to learning more about solar shingles and projects from Luma Resources.

March 10, 2016

ETFE Football Stadium Will Soon Be Minneapolis Showcase

Originally published on Green Building Elements

When it opens this summer, US Bank Stadium in Minneapolis will feature the only ETFE (ethylene-tetra-fluoro-ethylene) roof on a sports facility in the United States. This resilient and transparent material, long used in Europe, will now provide Minnesota Vikings football fans with a comfortable experience inside the stadium and a clear view outside, even if the outdoor temperature is far below zero degrees Fahrenheit.

us bank stadium logo shutterstock_306699017In contrast to the preponderance of opaque domed stadiums in this country, some 60% of the Vikings’ facility has been covered with ETFE, not only letting in daylight, but allowing fans to gaze skyward and enjoy the view. Add to this, this dramatic stadium features five of the world’s largest operable glass doors, which can be opened if the weather outside is pleasant. These gargantuan doors measure 55 feet in width, angling from 75 feet to 95 feet in height, and weighing approximately 57,000 pounds each. Of note, the large door system also contains five smaller doors which can be used when the large doors re closed due to inclement weather.

Journalists were invited to sample

GRM Vikings ZT__8035As the stadium nears completion, a diverse group of journalists — specializing in everything from architecture to sports — had the opportunity to visit this 1.75 million sq. ft. structure, including 248,000 sq. ft. of ETFE roof, and listen to very articulate presentations from many on the design and development team, including leadership from the Minnesota Vikings.  I found no shortage of good stories to report, most which will follow later this month. Here I report on the old stadium, the new stadium, and this remarkable material, ETFE.

In other stories, I will report about:

  • Sustainability practices in design and construction
  • Strategy behind  this projected $1.1 billion inner-city facility
  • Economic impact & surrounding development
  • This development is a showcase for others to follow

The old stadium model

Minneapolis, known for its very cold winter weather, previously featured the Hubert H. Humphrey Metrodome, built downtown in 1982. It was the ninth oldest stadium in the NFL, featuring a fiberglass fabric roof, self-supported by air pressure. It was the third major sports facility to have this feature (the first two being the Pontiac Silverdome and the Carrier Dome).

vikings metrodome shutterstock_108070454

Preparation for the demolition of the Metrodome began the day after the final home game for the Minnesota Vikings on December 29, 2013. Demolition began January 18, 2014.

For those wanting a glimpse, here is how the roof to the Metrodome came down.

The new stadium model

usbankstadiumOwned by the Minnesota Sports Facilities Authority (MSFA), the multi-purpose US Bank Stadium is scheduled to host Super Bowl LII in 2018 and the NCAA Final Four in 2019. Some leap from the starting line!

Designed by Dallas-based HKS Architects, the US Bank Stadium features the largest transparent ETFE roof in North America, spanning 240,000 square feet. This will be the only stadium in the nation with a clear ETFE roof.

Vikings ETFE & cane IMG_6142Because of the angles of the roof, ETFE material on the south side accounts for 60% of the entire roof, while hard metal deck on the north side will account for the remaining 40%. 

ETFE basics

ETFE is a co-polymer resin which is extruded into a thin film. The light-weight material is transparent but can be treated to be translucent. It is durable and resistant to corrosion. In an architectural application ETFE is typically used in a multi-layer pneumatic system.

Longevity of ETFE

Vikings ETFE IMG_6211

ETFE beginning layer

This material does not degrade with exposure to UV light, atmospheric pollution, harsh chemicals, or extreme temperatures. The material has withstood extensive testing within extreme environments and is expected to have a 30 to 50-year life expectancy, requiring minimal maintenance. Presently, the true life-cycle of ETFE is not known as the oldest applications are just hitting the 30-year mark with little to no replacement of system components.

ETFE weight & strength

us bank stadium 2 Berg-150707-0965Despite its light weight (1/100 the weight of glass) ETFE is reported to handle snow/wind loads well. In sheet form, it can stretch three times its length without losing elasticity. Support rods are used with the stadium roof panels.

Cleaning ETFE

The surface of the foil is non-stick and non-porous, which allows the natural action of rain to clean the surface. Deposits of dirt, dust and debris remain unattached and are washed away in the rain, meaning ETFE effectively self-cleans with virtually no need to clean externally.

As Amy Wilson has written on Architen, “Originally invented by DuPont as an insulation material for the aeronautics industry, ETFE was not initially considered as a main-stream building material, its principle use being as an upgrade for the polythene sheet commonly used for green house polytunnels.

“The advantages of its extraordinary tear resistance, long life and transparency to ultra-violet light off-set the higher initial costs and 20 years later it is still working well. It wasn’t until the early 1980s, when German mechanical engineering student, Stefan Lehnert, investigated it in his quest for new and exciting sail materials, that its use was reconsidered.”

Indeed! Just take a look at this showcase taking place near the Mississippi River.

Images: Metrodome via Shutterstock; usbank stadium sign via Shutterstock; all other images via the Minnesota Vikings

January 28, 2016

NREL: Solar Cell Defects Might Improve Solar Cells

Originally published on CleanTechnica – January 20th, 2016 by Glenn Meyers

The time-honored adage that we sometimes learn best by the mistakes we’ve made is now being applied by scientists at the National Renewable Energy Laboratory (NREL) in their study of defects in solar cell defects, stating the results may lead to improved performance.

The study reports about certain defects in silicon solar cells which may eventually improve their overall performance. The findings run counter to conventional wisdom, according to Pauls Stradins, the principal scientist and a project leader of the silicon photovoltaics group at NREL.

NREL cell defect 20160111-solar-defectNREL cell defect 20160111-solar-defect
Schematic of a ‘good’ defect (red cross), which helps collection of electrons from photo-absorber (n-Si), and blocks the holes, hence suppresses carriers recombination.The findings run counter to conventional wisdom, according to Pauls Stradins, the principal scientist and a project leader of the silicon photovoltaics group at NREL.

Deep-level defects frequently hamper the efficiency of solar cells, but NREL’s theoretical research suggests such defects with properly engineered energy levels can sometime improve carrier collection out of the cell, or “improve surface passivation” of the absorber layer.

NREL researchers conducted simulations to add impurities to layers adjacent to the silicon wafer in a solar cell. Specifically, they introduced defects within a thin tunneling silicon dioxide (SiO2) layer that forms part of “passivated contact” for carrier collection, and within the aluminum oxide (Al2O3) surface passivation layer next to the silicon (Si) cell wafer. In both cases, specific defects were identified to be beneficial.

According to NREL press information, the research by Stradins, Yuanyue Liu, Su-Huai Wei, Hui-Xiong Deng, and Junwei Luo, “Suppress carrier recombination by introducing defects: The case of Si solar cell,” appears in Applied Physics Letters.

Finding the correct defects to examine

The researchers state finding the right defect was key to their research process.

“To promote carrier collection through the tunneling SiO2 layer, the defects need to have energy levels outside the Si bandgap but close to one of the band edges in order to selectively collect one type of photocarrier and block the other. In contrast, for surface passivation of Si by Al2O3, without carrier collection, a beneficial defect is deep below the valence band of silicon and holds a permanent negative charge. The simulations removed certain atoms from the oxide layers adjacent to the Si wafer, and replaced them with an atom from a different element, thereby creating a “defect.” For example, when an oxygen atom was replaced by a fluorine atom it resulted in a defect that could possibly promote electron collection while blocking holes.”

The referenced defects were then sorted according to their energy level and charge state. It is believed more research is needed in order to determine which defects will ultimately produce the best results.

A recent study by the same authors has shown that the addition of oxygen could improve the performance of those semiconductors. For solar cells and photoanodes, engineered defects could possibly allow thicker, more robust carrier-selective tunneling transport layers or corrosion protection layers that might be easier to fabricate.

The research was funded by the U.S. Department of Energy SunShot Initiative as part of a joint project of Georgia Institute of Technology, Fraunhofer ISE, and NREL, with a goal to develop a record efficiency silicon solar cell. The SunShot Initiative is a collaborative national effort that aggressively drives innovation to make solar energy fully cost-competitive with traditional energy sources before the end of the decade.

Graphic via NREL

December 3, 2015

Advanced Infrared Camera Can Photograph Methane

Originally published on CleanTechnica

A new camera has eliminated the guesswork about where greenhouse gases are being emitted. It can photograph and film methane.

This technology has been released by a team of researchers from Linköping and Stockholm Universities who have demonstrated how this remarkably advanced camera can record methane in the air around us.

Importantly, this technological advance can play an important role in global efforts to measure and monitor greenhouse gases.

camera shoots methane inventors104304_web

According to a press announcement, the camera has been developed by a team that combined knowledge from many different fields of expertise, including astronomy, biogeochemistry, engineering and environmental sciences.

“This gives us new possibilities for mapping and monitoring methane sources and sinks, and it will help us understand how methane emissions are regulated and how we can reduce emissions,” said David Bastviken, Linköping University professor at Tema Environmental Change,  and principal project investigator. “So far the camera has been used from the ground and now we’re working to make it airborne for more large-scale methane mapping,”

So much for the dubious notion, “If you can’t see it, it’s not there.” Now it will be visible for all to see.

The news release reports several questions surround the powerful greenhouse gas methane, including its rapid but irregular increase in the atmosphere. There is also considerable uncertainty regarding methane sources and sinks in the landscape.

The new camera may help address these issues. The utility of the camera to both photograph and film methane has been demonstrated in a study that was recently published in Nature Climate Change.

“The camera is very sensitive, which means that the methane is both visible and measurable close to ground level, with much higher resolution,” said Magnus Gålfalk, Assistant Professor at Tema Environmental Change, Linköping University, who led the study.

The hyperspectral infrared camera weighs 35 kilos and measures 50 x 45 x 25 centimeters. It is optimized to measure the same radiation that methane absorbs, and which makes methane such a powerful greenhouse gas.

The camera can be used to measure emissions from many environments including sewage sludge deposits, combustion processes, animal husbandry, and lakes. For each pixel in the image the camera records a high-resolution spectrum, which makes it possible to quantify the methane separately from the other gases.

Longstanding complaints of methane leaks from natural gas production and distribution can also be recorded. It will be very interesting to report on the results.

Image via Linkoping University

September 30, 2015

Solar Light Bulb Inventor Might Make Kerosene Obsolete

It is estimated that almost 1.6 billion people on this planet live without electricity. To have light in the darkness, toxic fuels like kerosene are used to fuel lanterns. While they provide much needed light, they also pollute habitats and endanger the health of those living inside.

A Denver inventor, Stephen Katsaros, appropriately named the solar light he developed Nokero, short for “no kerosene.” The solar battery powered LED-type solar-powered bulb measures 70mm by 125mm and emits light for two to four hours, depending on the charge. Such a clean, low-cost technology might eventually make lighting fuel like kerosene obsolete. The Nokero website states that 5 percent of the average user’s income is spent of fuel for lighting. The price of a Nokero bulb and charger package is $15.

The story about this innovation has been featured on National Geographic and Denver television station, KCNC-4 , among a growing list of interested media.

(more…)

December 4, 2014

Books for Change: Real Goods Solar Living Sourcebook – 14th Edition

Filed under: Books,Innovation — Tags: , , — Glenn @ 12:11 pm

Here is an updated book on solar living we look forward to receiving.

Real Good Solar Living Sourcebook: Your Complete Guide to Living Beyond the Grid with Renewable Energy Technologies and Sustainable Living 14th Edition – Revised and Updated  

by John Schaeffer

Real goods image001

The 14th edition of Real Goods Solar Living Sourcebook  is now available. This comes thanks to New Society Publishers. We have featured other books from them.

This top-selling guide by John Schaeffer has been in publication 1982.  Now in its 14th edition, the Real Goods Solar Living Sourcebook is the definitive guide to renewable energy, sustainable living, alternative transportation, natural and green building, homesteading, energy conservation and off-grid living. This completely revised 14th edition, written by experts with decades of hands-on experience, contains expanded information on permaculture, biodynamics, the Transition Movement, urban homesteading and emergency preparedness.

Contents in this work include:

  • Relocalization
  • Land and Shelter
  • Sunshine to Electricity
  • From Panel to Plug
  • Emergency Preparedness
  • Energy Conservation
  • Water Development
  • Water heating
  • Water and Air Purification
  • Composting Toilets
  • Grey Water Systems
  • Off Grid Living, Farming and Homesteading
  • Sustainable Transportation
  • The Real Goods sustainable living library
  • Natural Burial

 

We look forward to providing a review upon receipt of this new book. For anyone wanting more information, contact the publisher.

June 16, 2014

Solar Roadways

Filed under: Innovation,Sustainability — Tags: , — Glenn @ 5:27 pm
Energy Innovation: Solar Roadways and Solar Sidewalks (via Green Building Elements)

PV-powered roads and walkways being tested in U.S. Federal Highway Administration research program Get to know a solar-to-electricity system that isn’t stuck on the rooftop. Thus is s story about tenacity in renewable energy research and a long-range…

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June 10, 2014

Compost-Powered Water Heater

The Compost-Powered Water Heater – Books to Buy (via Green Building Elements)

Gaelan Brown’s new book, The Compost-Powered Water Heater, is a work that demands being read by anyone interested in learning more about all the free energy available to renewable energy stewards who also happen to be composting champions. Brown provides…

(more…)

April 16, 2014

New Prefab Book of Note: Prefabulous World

New Prefab Book of Note: Prefabulous World (via Green Building Elements)

As we have been writing a series about green prefab homes, the timing could be no better for the release of “Prefabulous World – Energy Efficient and Sustainable Homes Around the Globe,” a new book by Sheri Koones. As we have been writing a series…

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September 9, 2013

First Uses of New Solar Energy Technology: Killing Germs on Medical and Dental Instruments

From Green Building Elements By: pressroom

A revolutionary new solar energy technology that turns water into steam without boiling the entire container of water has become the basis for new devices to sanitize medical and dental instruments and human waste in developing countries, scientists said here today.

Rice logo

 

Prototypes of the devices, which need no electricity or fuel, were the topic of one of the keynote addresses at the opening of the 246th National Meeting & Exposition of the American Chemical Society (ACS), the world’s largest scientific society. The meeting, which features almost 7,000 reports on new advances in science and other topics, continues through Thursday in the Indiana Convention Center and downtown hotels.

Naomi Halas, D.Sc., pointed out that almost 2 billion people live in areas of the world without a regular supply of electricity. That electricity is key to using machines called autoclaves, which produce scorching-hot steam to sterilize medical and dental instruments. Without that basic machine, doctors must rely on chemicals, which can be costly and difficult to transport, to prevent the spread of germs and disease from medical and dental instruments.

“We have developed a solution, our solar steam technology,” Halas said. She is with Rice University. “It is completely off-grid, uses sunlight as the energy source, is not that large, kills disease-causing microbes effectively and relatively quickly and is easy to operate. This is an incredibly promising technology.”

Halas and colleagues have prototypes of two solar steam machines. One is the autoclave for sterilizing medical and dental instruments. The second is an autoclave for disinfecting human and animal wastes, which are another major source of disease transmission in developing countries and other resource-limited areas. The technology could be expanded to provide steam for direct use in purifying dirty or salty water for drinking and cooking — with the solar-generated steam simply allowed to condense into pure distilled water. Possibilities also exist for adapting the technology to produce steam to spin small electric turbines to generate electricity.

Their tests showed that the prototype autoclaves produced steam at temperatures ranging from 239 to 270 degrees Fahrenheit. Steam production adequate for sterilization began within about 5 minutes. It continued for periods of time long enough to sterilize liquid and solid materials placed inside the device, consistent with U.S. Food and Drug Administration sterilization guidelines. The heat and pressure produced by the steam was great enough to kill the most heat-resistant living microbes, and also viruses and the tough spores that microbes form to survive hostile environmental conditions.

The autoclaves are the first practical applications of a new solar energy technology described earlier in 2012 in ACS Nano, one of the ACS’ more than 40 peer-reviewed scientific journals. Metallic nanoparticles — bits of material so small that hundreds would fit inside the period at the end of this sentence — go into a container of water. Sunlight focused into the water quickly heats the nanoparticles, which scientists are terming “nanoheaters.” A layer of steam forms on the nanoheaters and buoys them up to the water’s surface. They release the steam and sink back down into the water to repeat the process.

“Nanoheaters generate steam at a remarkably high efficiency,” Halas said. “More than 80 percent of the energy they absorb from sunlight goes into production of steam. In the conventional production of steam, you would have to heat the entire container of water until it boils, with the bubbles rising to the top to release steam. With nanoheaters, less than 20 percent of the energy heats the neighboring liquid.”

The prototype autoclaves consist of a dish-like mirror that focuses sunlight into a container of water with the nanoheaters.

A video on the solar heater technology is available here.

Halas recently formed a company that is working on moving the devices from the prototype stage to commercial products. She and her collaborators are seeking ways to make them more rugged and at a more reasonable cost. They are also exploring even more applications for the technology.

Source: AAAS EurekAlert

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