Upgrading C&I rooftop solar installations with spray polyurethane foam

spf diagram

SPF acts not only as an additional barrier to the elements, but it is also incredibly insulative.

As we have continued our expansion in the commercial and industrial solar market (which includes commercial, industrial, municipal, university, school, cold storage, food-processing and hospital buildings), we’ve discovered something. If commercial building owners are not overly familiar with how solar arrays are installed, they have legitimate concerns about the potential effects solar arrays could have on their roofs. For example:

  • Will the racking system, which holds the solar modules in place, harm the roof?
  • Will it have to be penetrated, creating potential pathways for the elements to enter?
  • Will it shorten the longevity of the roof?
  • Will it void the warranty?

In addition, we’ve discovered it’s often not just solar that these building owners want. They are often looking for energy-efficiency measures, too, particularly as property assessed clean energy (PACE) programs allow them to pay for both kinds of upgrades through their property taxes.

At Standard Solar, we take those concerns and desires seriously, and we’ve been searching for an all-encompassing solution — and we believe we have found one in spray polyurethane foam (SPF).

SPF acts not only as an additional barrier to the elements, but it is also incredibly insulative. As a result, building owners who use SPF as an underlayment to their current roofing will reduce energy consumption and save money on their energy bills.

Let’s take a closer look at how SPF works and how it will help you reach your solar and energy efficiencies goals.

Standard Solar ad

Longevity match

One of the strongest arguments for installing a rooftop solar array on a commercial building is to provide electricity for the building for at least 25 years. Many roofing materials can’t match that lifespan, but SPF can — and reduce energy bills by 20 to 50 percent more than fiberglass insulation in the process. When the proper roofing material is wedded to a rooftop solar array, the building owner can stop worrying about either. Instead, they can spend their time counting the savings the electrical system and energy-efficient roof will provide them.

Penetrating protection

In areas with high winds, on metal buildings and other external factors that could adversely affect solar arrays (think earthquakes), arrays must be attached to the roof. To accomplish this, solar installers are often forced to penetrate the roof membrane.

Penetrating installations are the cause of sleepless nights for building owners. After all, the solar installer is asking to poke holes through part of a structure that costs significant money. Any poorly sealed holes will cause problems for the roof itself and potentially allow rain or wind to reach beneath the roof and damage the inside of the building.

Unfortunately, some solar installers don’t know what it takes to seal the penetrations properly, and as anyone who’s ever had a leaky roof knows, locating the problem is difficult by the time the damage is discovered.

RELATED: Why energy density matters — and three ways to maximize it

That’s where SPF can help. We often use SPF to restore roofs under the arrays we install. When you combine SPF with a quality liquid membrane, not only do they self-flash, but they provide a double measure of protection from the weather. Finally, having a sturdy underlayment adds even more strength to the roof, making it an even better investment for the building owner.

The best use of SPF roofing we’ve seen, however, is at building conception. If the long-term plan is always to add a solar array to the roof at some point, SPF roofs allow the construction company to make the building “solar ready” by installing solar stanchions (legs).

Building owners can speed solar installations with such advance planning and get to the fun part of having a solar array — saving money — more quickly.

Perfect pairing

Like a perfectly prepared filet and a well-rounded pinot noir, SPF roofs and solar arrays beautifully complement each other. Combined, they allow commercial building owners to save through solar electricity production and improved energy efficiency with the outstanding insulative properties of SPF and the reflective characteristics of a quality liquid membrane. This collective approach will help companies reach their sustainability goals faster and with greater success.

Though SPF is currently something of a niche product, we believe it is gaining a much wider following with each successful installation, among both solar installers and commercial building owners. In time, we believe it will displace conventional insulation methods, which will be good news for building owners and solar installers alike.

Daryl A. Pilon, M.E., is director of business development for Standard Solar.

— Solar Builder magazine

We shift you not: A ground-mount solar system without piles

nuance energy

On the Osprey platform, load anchors are sent into the earth and pull tested in real-time conditions.

At Intersolar North America 2017, we caught wind of a new fixed tilt ground-mount system developed by Nuance Energy, but at the booth there was no physical system on display. Instead, Founder and CEO Brian C. Boguess handed me VR goggles to look through, which now feels appropriate because it was a glimpse into the future of modular ground-mount solar.

Nuance isn’t trying to play in the cut-throat utility-scale space, where an extra half penny per watt will cause a riot. Instead, the Nuance approach is about nimbly deploying smaller systems much quicker and to the benefit of small- to mid-size contractors and EPCs, increasing their revenue by enabling them to sell more solar quicker and cultivating a more robust, widespread solar industry.

“Where do you find savings? Always in the downstream,” Boguess says. “The upstream value chain has been beating itself up over technology to drive price down but no one paid attention to the downstream value chain.”

It all starts here: Nuance’s Osprey PowerPlatform is a ground-mount system that doesn’t require piles but is strong enough to withstand any load. Instead of piles and foundations, this new system borrows from the super old concept of anchors (5 in.) and cables (stainless steel, 60-in. long) that has been mounting utility poles and holding up retainer walls for a century. Those load anchors are sent into the earth and pull tested in real-time conditions (Nuance requires 1.5 times the worst case scenario for its design load test) and attached to the racking — a unit of four to six adjustable legs that is fully assembled with PV and wiring at ground-level. And yes, this means the entire system, if needed, can be disengaged and moved. We’ll explore those implications at the end.

With that as our starting point, grab a paddle and let’s head downstream.

Good bye geotech

Geotechnical reports are often done months in advance of the installation so a structural engineer can design the ground-mount system per the requirements of the geotech report. All in, this is a couple thousand dollars and a six- to eight-week process. What if you wanted to perform a geotech investigation in the fall? You might not even get the calculations back until the New Year, at a time when delays are equal to death.

As mentioned, the Osprey’s anchors are pull tested on site with a safety factor of 1.5 the worst case design load. This real-time condition test gives engineers the best knowledge of the soil at that time, eliminating the need for the geotech report ordering, process and price. That is just the start of how using the Osprey saves EPCs time and money.

Nuance Energy

Master of your domain

Larger projects are often the realm of larger companies or require a smaller company to rent equipment and wait for a larger company to deliver it. This is a perfectly fine system, but removing piles and removing the large equipment needed to drive them opens up the market even more for a wider variety of contractors, defragmenting the market.

“The small guy gets beat up over concrete and relying on outsourced teams to drive the product in the ground with heavy equipment they rent or lease, which means the equipment is on that company’s time, not the EPC’s,” Boguess says.

Even in the most efficient outcome from order placement to equipment delivery to pile driving, the mere fact of being on another company’s timeline adds extra time to project development and introduces the possibility of delays. The possibility of the delay has its own subtle chilling effect on a contractor’s project pipeline. If a larger project is delayed because equipment is held up at another site, the contractor’s delicate summer and fall project window will be shattered and accounts payable left in the lurch. A system that is fully installed by the contractor using only hand tools gives full control of scheduling back to the contractor.

“If you can’t control your installation schedule, you can’t control your revenues and accounts receivables,” Boguess says. “For small- to mid-size EPCs, a lot of these guys live project to project. If they can’t control cash flow, they are stuck.”

Obviously a larger company working to please investors with timely commissioning and quicker returns on investment would also benefit from the extra control over scheduling, but the savings go deeper, both in actual cost savings and costs avoided. Large developers have slush funds available to cover for unforeseen obstacles under the ground. For example, a developer putting a project in the ground in Florida has to account for the threat of running into limestone — both accidentally cracking it and then working to avoid it if found. Those threats don’t change the installation of an anchor system, which can go in the ground at any angle and avoid any such obstacles, keeping slush funds put and improving profit margins.

Nuance Energy procures its steel from both U.S. and foreign suppliers. This has not affected its model of packaging Osprey units at its regional warehouses and shipping them out with up to 40 units on a truck. Freight costs can be reduced by up to 60 percent.

RELATED: Solar carport developers find low-cost opportunity despite the tariffs

Labor savings

An all-handtool installation for a 5-MW project might sound laborious, but Boguess has compelling evidence of overall labor savings achieved, in less time, with the Osprey vs. a conventional large-scale ground-mount installation.

“One of our first projects with Brad Thomas, senior director of project management [formerly of NEXTracker], was only a 75-kW job. He had forecast three weeks for the installation. The job was finished in five days. He had overcalculated by two weeks, saving $14,000. That’s 18.6 cents a watt on a 75-kW job.”

With minimal training, any local labor crew can be employed to install the Osprey system. The adjustable legs also reduce the amount of site prep and grading needed.

nuance energy

New market: Lift and Shift

The niche for Nuance thus far has been projects in the 10 kW to 5 MW range, but applications within that range extend beyond the conventional. For starters, Boguess has seen a lot of activity in rural residential and small agriculture in the Midwest, less sexy solar locations like Illinois, Michigan and Minnesota.

“The smaller customer is anybody ordering one to 10 units from us, and each unit holds 5 to 6 kW,” Boguess says. “Residential contractors have a cash flow business with three to four install teams out on roofs, and initially they are afraid to take on 20-kW ground-mounts because they think it means taking two crews off a roof. But we can keep them on the roof and get 20 kW installed in four hours.”

Boguess even believes they’ve created a completely new (and catchy!) application category for solar called “Lift and Shift,” born from the fact that the Osprey anchors can be disengaged and the complete PV system above ground can be literally lifted as is and shifted to another location. This opens up totally new areas for PV, such as temporary farm land and mining.

“We had the idea of financing modular ground-mount systems with a PPA in the mining industry,” Boguess says. “This is unheard of because how will you finance a mobile microgrid hybrid solution when you want to move the asset every two years? We enable mining operations or those EPCs in this space to mitigate that risk because when that dig doesn’t find what they want after two or three years, they can lift and shift to redeploy the asset, not leaving it stranded. A stranded asset is what is holding up PPAs.”

Underneath power lines is also a brave new world that’s now possible in California. Just recently Los Angeles Department of Water and Power (LADWP) awarded Nuance Energy 40 50-kWac systems to be installed using the Osprey PowerPlatform.

“Our strategy for keeping costs low is to deploy solar arrays along existing transmission lines, where we already have rights of way, and to handle the installations entirely ourselves with our own crews,” says Francisco Fernandez, the lead electrical engineer in LADWP’s Solar Power Engineering Department. This strategy imposed two special requirements: easy removal when necessary to affect repairs or upgrades to the overhead transmission lines and ease of installation by small crews. “The solution from Nuance Energy met these two requirements.”

With LADWP’s system providing more than 26 million MHh of electricity annually to 1.5 million residential and business customers in the city of Los Angeles’ 472 square miles, the potential for solar energy deployments is substantial.

Added together, the Nuance Energy value proposition is a compelling one, offering several new opportunities for a wide variety of solar contractors and EPCs to grow and solidify their business.

— Solar Builder magazine

Four energy dense solar mounting systems for C&I rooftops

SunModo SunBeam

sunmodo

As a permanent part of the building and roof structure, the SunBeam system eliminates any abrasions, moss build up and need of system removal for roof repair or re-roofing. In addition, it provides shading of HVAC equipment, increasing efficiency and faster temperature response. Twenty-year warranty.

Material: High-grade aluminum and 304 stainless steel hardware. Anchor-only attachment.

How it maximizes energy density: The SunBeam system elevates above obstructions such as HVAC, pipes and vents. By spanning over roof obstructions such as HVAC, pipes and vents, the system takes full advantage of the available roof surface thereby maximizing the PV system size. The system can be easily adjusted to account for the multiple roof pitches on site.

Everest Solar D Dome R²

everest

The D Dome R² system is an east/west commercial flat roof solution. The third generation of this product is now rail-less with only five major components and minimal hardware. It sits at a fixed 10-degree pitch and allows for 3.5-in. inter-row spacing. Twenty-year warranty.

Material: Aluminum, ballast with attachment optional. The ballast blocks sit under the panels.

How it maximizes energy density: Everest Solar Systems believes east/west systems are more efficient south of the tropic of cancer. First, an east/west system practically eliminates inter-row spacing which allows more modules on the roof, thus increasing module density. On one internal study, Everest compared a the production of a 10-degree south-facing system with its east/west system in southern California at different azimuths. The south-facing fit 88 modules and had a 14 percent decrease in at the 225-degree azimuth. The D Dome R² system reached 108 modules in the same space and had less than 0.1 percent change between all azimuth angles.

Solar Mounting Solutions

sms

SMS Racking consists of only three major parts that arrive with all hardware pre-inserted allowing for quick single tool installation. The THRU-ITT integrated wire management system allows wiring to remain organized and protected by running wires east-west and north-south internally. Since this racking design does not rely on the panel for integrity, installers can complete racking and wire installation independent of the panel. Twenty-year warranty.

Material: G90 coated steel and optional galvanized steel, aluminum, powder-coated. Ballast only.

How it maximizes energy density: SMS developed an Excel spreadsheet that determines the optimum row-to-row spacing based on the selected solar module, optimum tilt angle, solar azimuth angle, and the altitude angle all specific to install location. By optimizing the length of row-to-row spacers, the SMS system can greatly reduce the amount of redundant material, which in turn will reduce racking cost and avoid installing the modules in a high shadow region. The racks are designed with minimal distance between modules in the east/west direction to eliminate unused area.

Ecolibrium EcoFoot5D and EcoFoot2+

ecolibrium

EcoFoot5D 5-Degree and EcoFoot2+ 10-Degree speed installation and simplify logistics for flat-roof installs. Main components are: a base, pre-assembled clamps (integrated bonding without washers) and a wind deflector. The system is black, ASA-PC, UL Listed Resin with a 25-year warranty mounted with ballast, attachments or a mix.

How it maximizes energy density: EcoFoot5D 5-Degree delivers 18.4 percent more power than the 10-degree system and lowers cost per watt. The system maximizes roof density while maintaining the ease and simplicity of EcoFoot. The modular base is small at 7 in. x 16.7 in., and inter-row spacing is a dense 9.9 in., creating a tightly packed array. Stackable bases enable up to 290 kW per pallet, resulting in fewer pallets and minimized shipping, storage and onsite crane use.

— Solar Builder magazine

Degrees of Separation: How to mount commercial rooftop PV systems to maximize energy

Ecolibrium EcoFoot system

Ecolibrium EcoFoot system

On commercial rooftops, design trends are all about maximizing energy density. Module selection is a huge factor there, but so are the layout and tilt decisions — figuring out the perfect shape and tilt to mount as many modules as possible without compromising their performance.

Pairing the right racking system with a flat-roof space opens up a world of possible equations. Use a racking system that will position the panels to maximize the energy output, which includes the tilt angle, inter-row spacing and the direction the panels will face. As always, geography matters. For one, the roof’s azimuth, or the direction the pitch faces. For a perfect south-facing system, the azimuth should be 180.

But new systems are tweaking the traditional. East/west systems are becoming popular below the tropic of cancer. Designers are playing more with tilt angles, with the general trend moving toward 5-degree tilt — likely to reduce inter-row shading without compromising the number of modules used or resulting in too much soiling.

“Rooftop energy density is maximized by fitting more panels on the roof using a 5-degree racking system,” said Jonah Coles, product solutions manager, Ecolibrium Solar. “The key to fitting more panels on the roof is to use racking with a small footprint and narrow inter-row spacing. The combination packs in panels, yet the inter-row spacing is wide enough to allow for the working room needed for ease of installation and post-installation maintenance.”

RELATED: Why energy density matters — and three ways to maximize it

But the tilt decision isn’t one-size-fits all. Everest Solar Systems notes tilt angle efficiency correlates to latitude — the higher the latitude often requires a higher tilt. The latitude in Hawaii, for instance, allows a system to be virtually flat, but there needs to be enough tilt to keep the rain from pooling and to keep dust off the modules. Brandon Gwinner, regional sales manager, SunModo, puts that minimum at a 4-degree tilt.

SunModo Sunbeam

“The tilt degree is dependent on the region/location and optimum output based on TSRF,” he says. “The minimal tilt degree racking systems are typically to maximize the number of modules you can get on a roof without your rear post being 8 ft off the roof and to get the most energy density/power density per the project.”

There are also some wind/snow load considerations that can keep tilt below a certain height/tilt degree, as well as parapet walls and billowing of wind. The installer has to find the balance between production and engineering capabilities.

Also, installers looking to maximize production in summer months should consider using lower tilt angles than installers looking to maximize production in winter months. In snowy northern climates, Everest Solar recommends a 10-degree system tilt angle, which is better for shedding snow, plus the wider inter-row spacing allows more room for snow to land without piling up and casting a shadow or covering the modules.

“If you can hit your power goal with a 10-degree system, then 10-degree would be the system of choice. If not, 5-degree racking can enable a successful system when 10-degree wouldn’t fit enough panels to generate enough power,” Coles said.

Commercial installations have significantly more requirements than residential installations, so understanding jurisdictional requirements at the onset of the project will make the process go smoothly. Some states, like Oregon, do not require extra engineering when the tilt is under 18 in. on the back edge of the array, based on a prescriptive path. So, cost analysis vs. ease of permitting is a factor for tilt decisions too.

The inter-row spacing issue

Tilted PV panels cast shadows on the rows of modules behind them, necessitating a gap between rows to minimize the effects of production loss due to shadows cast on panels in anterior module rows. Here are a few ideas to mitigate the impact of this phenomenon on your PV installation via Peter Abou Chacra, engineering consultant, SunModo.

  • Reduce the tilt of your south-facing array. For peak energy production on a per-module basis, PV modules have an ideal incident angle with solar rays emanating from the sun. For some installations, however, it may make sense to reduce the tilt of the modules to a less optimal incident angle. Though this means less production on a per module-basis, it can mean a significant increase in the daily unshaded collection time for the array. This gain in effective collection time can offset the losses caused by a sub-optimal tilt for the module itself. Using software dedicated to modeling and analyzing a system’s performance at a different tilt angle and inter-row spacing should figure out the best path.
  • Locate your system on a south-facing slope. Even a five-degree inclination can have a marked impact on the amount of inter-row spacing required. This can significantly increase the number of modules you can fit in a given area.
  • Consider 3-in-landscape or 4-in-landscape monoslope installations. Coupled with a low tilt, this strategy can reduce inter-row spacing significantly on a given installation since modules on the same structure and slope don’t require significant spacing between them. This can be particularly effective if you can gradually elevate the anterior monoslope PV structures as you work your way north through the site.

— Solar Builder magazine

The Replacements: These solar mounts for tile rooftops cut labor costs, avoid OSHA issues

Quick Mount PV’s Tile Replacement Mount

It’s always reassuring when solar technology moves faster than a federal regulator, even if it is a well-intentioned agency like the U.S. Labor Department’s Occupational Safety and Health Administration (OSHA). In this recent case, a new crop of solar tile replacements that support rooftop mounting systems are eliminating the need for drilling, grinding or sawing cement tiles, an activity that generates harmful dust for workers when not controlled carefully.

Stuck in the Middle

OSHA came down with a new silica rule (29 CFR 1926.55, 1910.1000) in October that limits worker exposure to 50 micrograms of silica dust per cubic meter of air over an eight-hour time-weighted average. Penny-wise-and-pound-foolish solar companies that still choose the cheapest tile hooks requiring them to saw or drill cement tiles now must monitor worker exposure to silica dust and mitigate exposure through practices including mask use, wet-cutting and dust collection. Other more forward-looking solar companies will simply opt for the new tech and cut their BOS labor costs for a net job gain.

Sawing or drilling concrete roof tiles was the standard for installing rooftop PV mounting systems up until a few years ago. Now a number of tile replacement manufacturers say that their products are no more costly than most old-design tile hooks, are faster to install and save a roof tile at every penetration point. Saving tiles for an older roof is no small event. Cement tile costs around $7 per square foot, when a replacement with the same shape can be found, much less with matching fade.

“I’m not sure how much the new OSHA rules will drive the tile replacement mounting market or affect it, because the market will change more as companies see the benefits of saving time and cost,” reckons Andrew Wickham, the marketing manager for SnapNrack Solar Mounting Solutions.

SnapNrack’s tile replacement

SnapNrack’s tile replacements feature a base assembly for simply lagging the base into place and then sliding the riser shaft into position for the tile replacement flashing.

Color Me Impressed

Several replacement tile mount manufacturers suggest that their cement tile replacement product goes on faster than tile sawing or drilling.

“We are a bit more expensive than hooks, but there is far less labor,” says Jordan Pacheco, the director of product management at Pegasus Solar. “An installer that is grinding tiles might use four crews of five men, but we can do five crews of four men with our Lightspeed Tile Replacement.”

The U.S. market for rail-less residential solar mounting systems, the Pegasus specialty, is expected to grow by 67 percent from $240 million in 2016 to $400 million by 2022, according to GTM Research. The Pegasus tile replacement system, available in rail or rail-less mounting configurations, has undergone several refinements in design since it initially launched in 2014.

“The tile replacement technology is definitely faster, and some studies say 20 percent faster than grinding,” says Stri Zulch, the vice president of marketing at Quick Mount PV.

In a time trial in 2016, Quick Mount conducted an in-house test with three different products. The trials were conducted on a test roof, with eight mounts installed for each trial. The installers were third-party contractors, and Quick Mount PV timed and monitored the trials.

“Results showed that the Tile Replacement Mount was 26 percent faster than the Universal Tile Mount and 22 percent faster than Quick Hook,” the company reports. “The Tile Replacement Mount eliminates the need to cut tiles, resulting in the Tile Replacement Mount saving time. Although, there are a number of variables that affect installation times, the Tile Replacement Mount will save on average a minute per mount.”

Quick Mount PV’s Tile Replacement Mount

Quick Mount PV’s Tile Replacement Mounts feature its patented Elevated Water Seal Technology for optimal waterproofing

Quick Mount’s Tile Replacement Mount comes with a 25-year warranty and features a universal base mount, which works with three flashing profiles including a flat tile, S-shaped tiles and W-shaped curved tiles.

“Once you see more of these large-scale installs, it will drive the market for tile replacements,” says Brandon Gwinner, the western region sales manager for SunModo. One of his customers using SunModo’s tile replacement on a large cement tile project in Hawaii with 2,800 support points, reports cutting project labor costs in half — with no tile breakage.

The SunModo tile replacement can be attached either by a single bolt into a rafter, like most tile replacement designs, or by four screws into the sheathing, in cases where a rafter is not reachable. The industry is now trending toward the sheathing-attached method since it is more reliable and is now proven, Gwinner notes. While his company specifies no less than 1/2-in. oriented strand board (OSB) sheathing, many home builders or roofers opting for cement tiles are upgrading the sheathing by using thicker OSB, if not structural-grade 5-ply plywood, he notes.

Here Comes a Regular

After the construction downturn resulting from the recession in 2008, roofing is on an upturn and expected to reach a global value of $95 billion by 2024, according to a September report by Global Industry Analysts.

Cement tile is the fastest growing segment of the global roofing market, with an estimated combined average growth rate of close to 7 percent by 2020, according to a recent study by Technavio. Recent hurricanes and other adverse weather have helped demonstrate the durability of cement tiles over asphalt shingles and over clay tiles, which are much lighter than cement tiles.

In the U.S. South and Southwest, where daily temperature highs and lows range widely, and air conditioning is a major use of electricity, cement tiles are a favorite because they can be used for cool roofs as well as for evening heat retention.

Tile replacements for cement tiles already are highly waterproof and manufactured with formable aluminum. But cement tiles also are evolving via nanotechnology. Nanotech coatings for cement tiles will provide additional benefits for protection against heat, mold, mildew, fungus and algae, according to Global Industry Analysts.

Overall, signs indicate that the U.S. adoption rate for tile replacements should accelerate. However, at the heart of the market is installer awareness and preference. “For the market to grow, installers will need more education about the advantages of tile replacements,” suggests Stella Sun, the marketing director for SunModo.

Charles Thurston is a freelance writer covering solar energy from Northern California. He is not to blame for all of the Replacements song references.

— Solar Builder magazine