Energy March/April 2022

March 8th, 2022 by Nathan Hobbs

Technology

Power-Producing Coating Makes Waves

Energy codes and regulations continue to drive demand for more energy-efficient windows. So imagine a power producing low-E coating and how that would change the energy equation. Ubiquitous Energy, a developer of photovoltaic technology that converts light into electricity using semiconductor materials, while maintaining visible transparency, says they created exactly that. Andersen Corp. announced a major investment in the technology in January 2022, for use in its residential and commercial products.

Miles Barr, Ubiquitous Energy chief technology officer and co-founder explains how it all works. “Think of this as a power producing low-E coating,” he says. “An active solar element is included directly within the low-E coating on the window glass. That coating captures solar energy and converts it into electricity, which is fed out of the window with wires.”

But how much power? “It’s enough to power lots of things,” says Barr. “An average size residential window could produce over 60 watts, which could power room lighting, mechanization, or other types of electronics.”

Ubiquitous Energy CEO Susan Stone sees a few crucial paths in the residential space. In addition to Barr’s suggestion, she says the technology isn’t just an energy-producing unit. “We also create a self-powering window unit that integrates with all these smart features for a home,” she says. “We can power blinds, window venting, security features—all kinds of features that you can imagine. It’s a high value-add for homeowner comfort and makes a home more energy-efficient. It can be installed just like a window because our technology produces the electricity at the source.”

For new construction, she points out that these power-producing windows can be married with a rooftop residential solar system as another way to generate solar energy.

Executives at Andersen are excited about the possibilities, and that includes Prabhakar Karri, director of Ventures at Andersen Corp. With a variety of technological investment opportunities, Karri stated what made this one stand out.

Among all the technologies we look at, there are always tradeoffs. For this one, we don’t have to make major changes to our production lines—and it looks like regular glass.”

“This uses the same processes, the same tool set, the same energy requirements that are really identical to what is used for low-E. It’s no different than your standard window,” adds Karl Halling, treasurer at Andersen Corp.

Currently, the maximum size offered in pilot projects is 14 by 20 inches. “As we move to full scale manufacturing we will be able to do floor-to-ceiling glass,” says Stone. “As we really move toward manufacturing, if everything holds we will have a product coming out in early 2024.”

She adds that there is a lot of work to be done to meet that 2024 date but the company is up to the task.

-Tara Taffera

Energy Star

EPA Introduces Draft 2 of Energy Star 7.0

The U.S. Environmental Protection Agency (EPA) released details for Draft 2 of Energy Star 7.0, including several updates for doors and windows. Officials tell [DWM] changes to the proposed criteria result partly from industry comment, but also from fresh data gleaned from a new version of Energy Plus, the modeling software used to make program calculations. EPA is maintaining the same prescriptive window criteria proposed in Draft 1 of Version 7.0, but revised the proposed equivalent energy performance levels based on updated modeling analysis. As a result, prescriptive pathways have been updated with new combinations of U-factor and solar heat gain coefficient (SHGC) ratings.

Requirements for Draft 1 were established using Version 8.9 of the Energy Plus software and while officials say they were aware of a newer version amid development, Version 9.5 arrived midway through the process. At the same time, researchers felt the changes presented in Version 9.5 would have little to no impact on performance requirements and calculations for
energy savings, but numerous manufacturers begged to differ, prompting an upgrade. Initial analysis also relied on older population census data, which is used to weight results for energy costs by zone. New census data released in 2020 was used for Draft 2 calculations.

In the process, impacts to energy savings were calculated across 132 cities, comparing 288 products and more than 600,000 modeling runs, officials tell [DWM]. Cities were then grouped to establish average energy savings per climate zone. New calculations primarily impacted solar heat gain coefficient (SHGC) ratings, prompting updates for Draft 2.

As part of Version 7.0, proposed criteria retains base requirements, plus energy equivalent tradeoffs, which allow for higher U-factor ratings in the Northern climate zone in instances where SHGC ratings allow for greater use of solar energy (additional solar heat gain). New modeling supported changing prescriptive requirements, officials say, to what they suggest is a “similar, but easier to meet” set of criteria. While Draft 1 called for U-factors ranging from 0.23 to 0.26 and corresponding SHGC ratings that graduated by 0.05 over four prescriptive combinations, Draft 2 requirements call for just two SHGC ratings, including 0.35 and 0.40, over the same U-factor increments. (See the corresponding chart.) Additionally, EPA is backing off of its suggestion that sliding glass doors be grouped with the same requirements for windows. With Draft 2, officials opted to group sliding (glass) doors with swing style patio doors “that are mostly glass.” Sliding, glass patio doors now fall under the same category and requirements as swing doors with greater than one half lite of glass. Requirements for those doors were previously proposed at a U-factor of 0.28, while sliding glass doors were required to be 0.22. In Draft 2, both are required to be U-factor 0.25. That number, officials suggest, will be significantly easier for manufacturers of sliding doors to meet, though tougher for some swing style doors.

Following publication of Draft 2, officials say there will be another period of comments and responses, but the data used to develop the latest requirements will not be revisited or recalculated, they tell [DWM]. Following the comment period, a final draft with finalized specs is expected to be released in June 2022, after which updated program requirements are expected to be deployed a year later.

If all goes as planned, manufacturers will need to be prepared for rollout in July 2023.

EPA encourages stakeholders to provide comments on this draft via email to windows@energystar.gov by March 28, 2022.

To view the laid-in version of this article in our digital edition, CLICK HERE.

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