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Net-Zero Townhomes Benefit From Solar Garden Roof

Green Team at Green Roof Technology, - Saturday, November 30, 2019
Net-Zero Townhomes Benefit From Vegetated PV Roofs
This suburban Washington, D.C., project proves there's no need to choose between a green roof or a photovoltaic roof



Developer-builders Jessica Pitts and John Miller of Flywheel Development had a goal and a problem with their Perry Street Townhouses project. Their goal was to build affordable net-zero townhomes in suburban Washington, D.C. Their problem was stormwater management: Rules in Prince George's County, Maryland, required them to detain the runoff from heavy rainstorms on-site, rather than divert it into municipal storm drains. The poorly draining site soils and the tight site precluded traditional ground-based stormwater best management practices, so they looked to a vegetated rain-detaining roof for a solution. But Pitts and Miller also had other plans for the roof: They needed solar power to meet their ambitious energy goals.

In the end, Pitts and Miller reached both of their objectives with an innovative combination: a vegetated roof whose growing medium captures significant amounts of rainfall, with solar arrays mixed in with the plants and supported by modular frameworks that are anchored and ballasted by the green-roof growing medium. Manufactured by German firm Optigrün, the PV array support system is imported from Germany, and the pair say this was the first time it had been deployed commercially in the United States. But Miller says the idea is a "no-brainer" financially: "Because the solar racking is ballasted by the green roof media and the plants that keep it from blowing away, that percentage of the green roof that is ballasting the panels is also eligible for the federal tax credit for PV." The roof is also effective as a stormwater management system.

"The solar green roof is designed to detain between 1.8 and 2.4 inches of rainfall," Pitts says. "There is little to no runoff from a small storm of about 1.2 inches or less, and runoff increases as the rainfall increases."

The process started during the design phase. Says Pitts, "This can go on any sort of deck. Our structures are wood framed. But you have to account for the load that you’re going to be carrying with the engineering, so it’s important if you do this, to have a mind to do it at the beginning."

"Wind uplift is a critical calculation on the solar," Pitts continues, "and the depth of the green roof media is determined by wind uplift calculations. We actually had a 3-foot parapet wall on three sides of the roof, and the PV system is down below that level and is protected from wind uplift on three sides, which reduced the depth of the green roof media that we needed to install."

The green roof media would help to protect the building's EPDM roof from sunlight and weather. But the green roof and solar would also impede any needed repairs or maintenance down the road. So Pitts and Miller decided to install a leak detection system before laying down the roofing.

"We thought it was prudent to install a leak detection layer—it's a metal mesh that goes underneath the roof membrane," says Pitts. "What that allows you to do is that if you ever get a leak, you can identify the exact location of it."

The thin stainless steel mesh comes in rolls and is installed directly to the roof deck before protection board and roofing are installed. "It looks like chicken wire," says Pitts. "There are two leads that you can run up the side of your parapet wall and hang out at the top. And you can test even before you put the green roof on. We had the people come out and test the membrane as soon as it was in place. They wet down the roof and apply an electrical charge and they look for places where you get a connection."

Miller explains that the leak testing crew uses a detector that looks like a push broom with metal bristles. "They found five or six little pinprick holes that you never would have noticed, and we patched them," he says. "All you have to have is a roofer maybe bends over and maybe one of the metal brads on their jeans pokes a hole in the roof, or they drop their utility knife, and you would never know. The leak detection crew will circle this spot with a Sharpie, and you’re like, 'Wait a minute, that’s a hole?' But this way you know on day one that your roof is leak-free. And if you have a future problem, then you can find it."

Next comes the layers of the green roof, which are integrated into the high-density plastic bases for the solar array racks. "You have your plastic protection layer, which keeps the roots from growing down into the actual roof itself," Pitts says. "Then you have a protection mat, which is kind of like a felt material. That’s for protecting the roof membrane from the roughness of the growing medium. Then you have a geotextile mesh, and the mesh that we were using has large holes in it—it’s a loose weave—and that goes on top of the bases that the green roof ballasts down."

The mesh wraps under and around metal edging at the roof perimeter, and it runs over the PV rack bases. An L-shaped metal bar is installed into each of those bases, and then the rack is accepted into those metal L bars, according to Pitts. Each grouping of panels is also tied together. "We had four individual systems on top of each of the four individual homes," Pitts says. "So each panel grouping becomes linked together, and then they all become linked together through the geotextile mesh."

Next it was time to place the growing medium. "It’s very common to have drainage trays and things of that nature to help reduce the depth of green roofs, but we wanted it to be thicker because we are using the weight of it to hold down the solar," Pitts explains. "We had a green roof media company (Mulch Solutions of Falls Church, Va.) come and blow the media up onto the roof with its blower truck."



There were two types of media: a larger, heavier drainage medium as a base layer, then a layer of growing medium on top of that, separated by a layer of fabric. The entire placement with the blower truck took less than a day. Besides the efficiency, says Pitts, another advantage to the blower truck is that it avoids creating point loads on the roof during the application of the growing medium.

"And then the plants arrived," says Pitts. "There are two different types of green roof plants. There are ones that grow in sun, and there are ones that grow in shade. So we had to demarcate the locations behind and beneath the panels, and allocate the shade plants to those locations; and the sun plants went everywhere else. And then we got all the PV equipment, and the PV panels came up last."

The Perry Street Townhouses were completed in spring 2017, and the plants on the roof are spreading nicely over the growing surface. "Green roofs really require a lot of care and feeding in their first couple of years to get them to establishment," Miller says.

Flywheel Development is currently working on two more affordable net-zero developments in Washington, D.C., Stack Eight and Cycle House, slated for delivery in 2020 and 2021, respectively.





Germany breaks 3 solar power records in 2 weeks

Green Team at Green Roof Technology, - Saturday, June 21, 2014

Germany breaks 3 solar power records in 2 weeks

  

More about the German record breaking Solar News at Treehugger

Since 5 years Green Roof Service LLC / Green Roof Technology is desperately trying to convince North Americans of the combination Solar and Green Roof.

Whether it is the world’s famous Universities, the world’s biggest corporations, the National Roofing Association or the Green Roof Association of North America, none of them seems the future of combined modern technologies.

Short term profits, ignorance and greed semm to blind North America - it isn't the sun blinding. These egoistic behaviors are reasons why North America is losing more and more ground in the technology sector, respect in the world and last but not least Millions of jobs.

I hope there is an App for it …. Well, without power it might not help.

 

 

Solar Gardens Made Easy

Green Team at Green Roof Technology, - Thursday, September 12, 2013

Here at Green Roof Technology we are actively helping commercial, municipal and not-for-profit clients generate renewable energy and control stormwater for a cleaner tomorrow.

The Solar Garden Roof System is rapidly growing in popularity.  The benefits of our combined solar and green roof system are unmatched.  Additionally, the Solar Garden Roof System can be 50-60% less expensive than a 4" extensive green roof.

We provide a number of services for our clients.  They include the following:

  • Provide professional designs and engineering,
  • Maintenance programs for your Solar Garden Roof,
  • Secure 25 year Roof and Solar Warranties,
  • Help secure commercial solar financing,
  • Offer SREC brokerage,
  • Perform leak detection,
  • Assess roof membrane condition.
  • Utilize local professional labor resources,

Call us today for a Free Estimate & Analysis:

Using satellite imagery, we analyze factors that affect your Solar Garden Roof design such as south-facing roof location, shaded areas and available roof space.  We will also study your monthly energy usage and future energy plans so that we can create the best system for your needs.

Additionally, business owned PV systems are eligible for tax advantages, such as accelerated depreciation and a thirty percent Federal solar investment tax credit.

Call us today to see if a Solar Garden Roof System is right for your roof.  


Green Roofs Protect Solar Panels and Micro-Inverters

Green Team at Green Roof Technology, - Thursday, September 05, 2013

Randall's Island, NYC.  The Solar Garden Roof System is uniquely designed to grow plants under PV Panels - protecting the panels and microinverters from extreme rooftop heat.  Our system produces more energy and prolongs the life of your solar equipment.  

Over the holiday weekend a massive 11-alarm blaze erupted at the Dietz & Watson distribution center in South Jersey.  The very destructive fire burned for nearly a day due to a peculiar reason - the 300,000 square foot building had more than 7,000 solar panels on its roof.  Instead of being able to tackle the fire from close range, firefighters were forced to fight the fire from a distance in order to avoid any risk of electrocution from the solar panels.  Most solar panel arrays do not have a simple on/off switch, or a master breaker.  So long as the sun is shining, the panels are producing electricity.  Individually, a solar panel does not create enough volts to harm a person, but when solar panels are strung together to a single converter, the power of each panel is accrued, creating a deadly situation for anyone near the array during an emergency situation. 

While no specific forensic evidence has been issued yet, experts in the field of roofing and solar panels already agree that the fire may have started due to the intense heat that is created between low-lying solar panels and reflective white roofing membrane.  Extreme rooftop temperatures can be effectively controlled by installing green roofs below solar panels.  Countless studies have shown that the surface temperature of extensive green roofs rarely exceeds 86°F.  When solar panels and green roofs are integrated, i.e. a Solar Garden Roof System, rooftop and solar panel temperatures are significantly reduced.  Lower rooftop temperatures means greater energy production and may potentially save your building from destruction.

Visiting 1st Solar Garden Roof

Green Team at Green Roof Technology, - Wednesday, August 14, 2013

A vast experimental roof top garden is located on the New York City Department of Parks and Recreation Building on Randall’s Island.  A few years ago the department opened its roof top up to companies to display their latest innovations in green roofing.  Over the years several dozen technologies have been installed, making the roof top home to hundreds of kinds of plants.  From lightweight extensive green roofs, to vegetable farms, to solar garden roofs, all kinds of green roofs are open for public tours.

During the early spring of 2012 we had the pleasure of installing four of our Sun-Root™ Modules on the roof, making the department’s building home to the first Solar Garden Roof System in the United States.  Super Storm Sandy made landfall only 6 months after installation and the system was successfully wind tested with maximum sustained winds at 85 mph with some gusts reaching 92 mph. 

Jörg recently visited the roof top and came back with some beautiful pictures we wish to share with you all. The system is engineered to support healthy plant growth under the PV panels - unique and brilliant! Ask us for details and investment options.

 Solar Garden Roof

Nation’s largest Solar Garden Roof

Green Team at Green Roof Technology, - Wednesday, July 03, 2013


Photo courtesy of Elkus Manfredi Architects and BHC Architects.

Green Roof Technology is proud to announce their partnership with BHC Architects to design the largest Solar Garden Roof in North America.  The Solar Garden Roof will rest atop the new, soon-to-be build Exelon headquarters in Baltimore, MD. 

Exelon’s office tower will be the tallest building in the upcoming Harbor Point multi-use business park, scheduled for completion in Fall 2014.  

The Exelon headquarters rooftop will house a 40,000 sf green roof and an estimated 400 Sun-Root™ Modules, which will generate approximately 120,000 kWh’s a year.  This will be the largest Solar Garden Roof in North America.

For more information about the Solar Garden Roof System and to see a short video of how it all comes together, please visit:  http://www.greenrooftechnology.com/solar-green-roof.


New Sun-Root™ System Installed

Green Team at Green Roof Technology, - Tuesday, June 25, 2013

By Samantha Yurek

Last Wednesday, June 19th, Green Roof Technology traveled to Northern Virginia to help install a green roof demonstration project, complete with a Sun-Root System™. Being the latest achievement in sustainable design, the Sun-Root System™ effectively combines solar power with vegetated roofs.

Working with the company Prospect Solar, we were able to help preserve the environment and promote renewable energy. Prospect Solar was established in 2010 by the well-known Prospect Waterproofing Company. One of the leading specialty roofing companies in the DC area, they have been successful for over twenty years. Prospect Solar has been following in their footsteps, creating more sustainable alternatives to the traditional roofing practices. 

A Solar Garden Roof for Non-Profits

Green Team at Green Roof Technology, - Friday, June 21, 2013

By: Ryan Miller

Renewable energy is an attractive tool that businesses can use to offset rising energy costs. What makes renewable energy so attractive are the Federal and State incentives that cover over 30% of the costs to install the system. An investment today in a Solar Garden Roof creates a path of energy independence where your rooftop is producing the power necessary to run your building, instead of the local power plant.

So how does a non-taxable entity like a non-profit organization (NPO) take advantage of the plethora of incentives to produce energy for their own building? Fortunately there is an investment option tailored for NPO's called a Power Purchase Agreement (PPA). PPA's are used in situations where a site host does not desire to outlay the capital required to purchase a system, or is not able to take advantage of the tax benefits available due to being a non-tax paying entity. Through the PPA, the NPO will have no upfront investment nor carry any of the ongoing operations and maintenance obligations. The NPO will then enter into an agreement to purchase the energy produced at a rate below current energy rates.

With this setup, the NPO will make uniform, monthly payments at a reduced cost when compared to the current energy bill. After a set period of time, the NPO can decide to purchase the array from the investors at an agreed upon price. From there the system is paid off and the NPO is enjoying free energy, thanks to the SUN!

Green Roof Service/Green Roof Technology works with NPOs and investors to tailor the right PPA for an investment in a Solar Garden Roof.

Green Roofs are Standard on Passive Houses

Green Team at Green Roof Technology, - Friday, June 14, 2013

By: Samantha Yurek


Photo Source: Wikipedia

In the past few decades sustainable building practices have come a long way. Many designers are striving to use the latest technologies to create more environmentally friendly conscience structures. Some of the best examples of sustainable buildings are considered Passive Houses. Germany is at the forefront of this trend, having been researching and developing specific environmental design principles since the early 1990s. These principles surpass LEED™ certifications and are overall less expensive. Energy consumption of a Passive House is between five to ten times lower than an average (LEED™) building, decreasing the environmental footprint two to five times. 

These houses are designed with many modifications. Exterior walls tend to be two to three times thicker when compared to conventional home. Natural and controlled ventilation systems are also prominent, helping to keep temperature balanced throughout the entire building. All these modifications make Passive Houses almost completely airtight and soundproof. Many of these houses are designed to include a green roof or solar powered system


Photo Source: Wikipedia - as you can see, this passive house on the right

In 2010, there were over 25,000 Passive Houses in Germany and around 13 in the United States. In Urbana, Illinois, the first Passive house was erected in America, back in 2003.

Ryan Miller featured in Solar Power World Magazine

Green Team at Green Roof Technology, - Tuesday, May 14, 2013

Ryan Miller was recently interviewed for the Solar Power World Magazine, focusing on our Solar Green Roof Sun-Root™ System. Solar Power World is written with a focus on technology, installation and development, reaching tens of thousands of industry professionals. "Four Questions with Ryan Miller of Green Roof Technology" is featured in the May issue of the Solar Power World Magazine. The online version can already be viewed on their website.

Here is a snippet of the article with Ryan:

SPW: What is the concept behind the Sun-Root™ System?

Miller: As a green-roof company for more than 30 years, we have seen many innovations to modern green roof technology that makes it more marketable and affordable. When you sit down with clients, they want to know how much they are spending and what is their return. The payback of a green roof lies somewhere between 15 years to 25 years in most cases, and for many building owners that is not something  that excites them. So we look for ways to shorten this payback period while still meeting our goal of increasing the world's green spaces.

If interested, please learn more by watching a video of the solar panel green roof combination.


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