Frameless modules are becoming more than just an aesthetics-pleaser on residential roofs. There are many benefits to them — better fire protection, better moisture barrier, no grounding needed — but there are also many installation aspects that take some getting used to. How are they mounted? What about wire management? What are the extra costs? Solar Builder hopes this crash course helps answer some of the basics.
Jing Tian, product manager at Trina Solar
Trina Solar manufactures the PDG5, a 60-cell dual glass module. It comes in at around 255 W, has a 15.2% module efficiency and is UL certified. Trina offers a 30-year warranty on the product.
SB: What is a dual glass/frameless module?
JT: A traditional module is a silicon sandwich. There’s glass with a silicon cell in middle, and the backsheet is typically polymeric with a frame around to ensure the mechanical integrity of the product.
With a dual glass module, we replaced the backsheet with another sheet of glass, so it’s a glass sandwich without a frame. The cells are encapsulated in glass.
SB: What are the advantages of a frameless module?
JT: Glass is much less flammable than polymeric materials. From a fire safety perspective, that’s why we passed as a Class A fire-rated module. One of the common concerns with a silicon module is a microcrack. Having a glass panel, front and back, gives better mechanical protection during transportation and installation. There’s also no grounding for the frame because there is no metal for the modules.
SB: What type of customer wants a frameless module?
JT: These modules target any customer. There’s an industry adoption curve for people to get used to dealing with a dual glass panel [like] handling of the module, the installation process. What really appeals right now to early adopters is aesthetics, fire safety and high wind load. Because there’s better mechanical integrity, it provides better resistance to wind loads.
SB: Are special parts needed to install frameless modules?
JT: Trina developed our own clamps that mate with most commercial rails. For ground-mounting, [we’re] continuing with a C-clamp-type of solution. But we have been working with mechanical BOS companies, from ground-mount to roof-mount, to work with their existing solutions to work with our modules. We’re working with partners to make it easier for installation.
John Williamson, engineering manager for Array Technologies Inc.
Array Technologies Inc. (ATI) manufactures fixed-mounting and tracking systems. The company recently developed a new design for both its DuraTrack HZ tracker and DuraRack fixed rack to accommodate frameless modules.
SB: Did Array need to redesign its systems for frameless modules?
JW: Array designed a custom tracker structure, including a brand-new racking system designed especially for frameless modules. The racking system was extremely rigid to prevent module damage. However, it included a well-thought out assembly system that allowed rapid deployment and installation on-site and minimized materials as much as possible using custom-designed rails and clips to keep structural costs down, and assembly tools to reduce installation time on-site.
SB: How does securing frameless modules differ from traditional modules?
JW: Though the backbone of the tracker structure remains the same, ATI uses a completely different system for racking both kinds of modules. Framed modules don’t require special supports and custom designed clips for attachment to a structure. Frameless modules require special clips to support them at specific locations. To install these at the lowest possible price point, custom racks must be designed for the individual frameless module to support them properly.
SB: Can installers adapt to installing frameless modules pretty quickly?
JW: Workers can be trained in less than a day on how to properly install frameless modules. There are different instructions and tools needed. We have full documentation that we provide our customers for install, as well as an excellent project management team who will train customers on best practices and installation techniques.
SB: Why incorporate frameless modules into your systems?
JW: We incorporated frameless modules due to the demand of our customers. As a leading ground-mount solutions provider, it is our policy to work with customers to find the most effective configuration of our tracker to bring lowest LCOE, fastest installation and the most reliable product possible. If that requires designing new racking systems or other subcomponents for large projects, we will happily take on the engineering challenge.
SB: What is your outlook on frameless modules in the industry?
JW: Frameless modules are becoming somewhat popular because they are cheaper than framed modules by themselves. However, removing the frames requires the racking company to support the frames in special ways with more expense, often requiring special clips that are expensive to manufacture and install. I think in certain cases projects can be less expensive than framed modules, but it often requires a development partnership between the module company and racking company to get there. If cost simply shifts from the modules to the racking, it doesn’t save the customer any money and can slow down a typical project.
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