Facade Retrofit Transforms 3M's Single-Glazed Window Wall System for Enhanced Thermal Comfort
INOVUES has collaborated with 3M and Grid Catalyst for an energy-efficiency retrofit project at 3M’s global headquarters in Maplewood, MN. The project consists of transforming an existing single-glazed window wall system into a high-performance, energy-efficient system, using INOVUES non-invasive insulating glass retrofits (IGRs) without any removal, replacement, or disruption. The goal is to evaluate INOVUES' patented technology's impact on window performance, energy savings, and thermal comfort.
Transforming Single-Glazed into Double-Glazed Window Wall System
The pilot project involved upgrading windows as large as 5 by 10 feet located at the visitor center, 3M Building 222, into a high-performing, low-e coated, double-glazed system. The non-invasive retrofit was done in-place from the exterior of the building.
Thermal simulation of the windows with and without the retrofits showed that the retrofitted units deliver up to 300% improvement in thermal performance, with the existing windows' center-of-glass (CoG) R-value increasing from R1 to approximately R3.
After installation, heat images were taken to compare the performance of the retrofitted lites next to the original single-glazed windows. According to John Morrow, Insights Lead, Strategic Business Development for 3M, "these pictures show a pretty significant temperature difference between the test windows with the inserts and the current windows."
The thermal images show a 15-degree Fahrenheit difference in outside surface temperature between adjacent retrofitted (-27.5 deg. F) and non-retrofitted (-12.1 deg. F) windows, indicating that the retrofitted windows are much better at keeping heated, conditioned air inside the building.
The lower outside surface temperature recorded at the retrofitted window (first image, -27.5 deg. F) demonstrates its improved insulating properties in comparison with the adjacent original window (second image, -12.1 deg. F). Note: when the thermal images were taken, the two large windows on the right were fully retrofitted, while the small units on the bottom were only fitted with the INOVUES spacer frames, visible as purplish-pink outlines.
Understanding Thermal Performance and R-Value
The R-value represents thermal performance and measures how well a material resists the flow of heat. The higher the R-value, the more effective the material is at insulating against heat flow. To provide an example, imagine two identical offices in a building. One has a single-pane glass window with an R-value of 1, while the other has a double-glazed window with an R-value of 3. On a cold winter day, when the room temperature is approximately 70°F and the temperature outside drops to 30°F, indoor temperature near the single-pane window trends towards the outside temperature of 30°F, causing the room to feel colder. This can create discomfort at the perimeter of the building and force the heating / HVAC system to work harder to maintain the desired temperature. On cold winter days when the outside temperature is significantly lower than the inside temperature, frost and ice have also been observed to build on some single-pane glass windows.
In contrast, the temperature near a well-insulated double-glazed window is closer to the indoor set temperature of 70°F, providing a more comfortable and energy-efficient environment. Thus, the difference between a glass window with an R1 value and one with an R3 value is that the latter provides better insulation, keeping the indoor temperature more consistent and reducing energy consumption. Today, R-value of over R10 can be achieved with INOVUES IGRs by incorporating more advanced glass technologies, such as vacuum insulated glass (VIG).
Improvement Beyond the Glass R-Value : Framing, Aesthetics, and Innovation
To install as quickly as possible, the project was divided into two phases. Thanks to the split structure of INOVUES’ IGR system, the temperature-sensitive part of the system could be installed in the fall of 2022. When the specialized glass became available, the team returned to 3M in the winter to complete the project.
Grid Catalyst’s Nina Axelson noted that "INOVUES had the highest interest of any of the startups that were in our pitch program. The partner that selected them first was 3M."
Grid Catalyst, who facilitated the pilot, is the only clean energy accelerator focused on energy efficiency and decarbonization solutions for cold climates. Its goal is to provide climate-tech startups with project opportunities to prove out technologies in real-world applications, with the long-term goal to accelerate regional sustainable manufacturing and job growth.
John Morrow, Insights Lead, Strategic Business Development for 3M, added: "Thermal images show a significant temperature difference between the test (INOVUES) windows and the current windows without the inserts. We look forward to obtaining some interesting and useful insights from this pilot."
Anthony Watry, Senior Manager at 3M Facilities Operations, noted that when he reviewed the windows upfit, the temperature outside was 10-15 degrees Fahrenheit, and the retrofitted glass “felt significantly warmer to the touch than the original single-pane windows."
In addition to insulating the 3M facade glazing, new interior trims were added to create a finished look that blends with the existing frames. They are also contributing to the overall thermal performance of the retrofitted windows.
Impact for Climate-Tech
The pilot project at 3M's headquarters is an example of the potential for non-invasive window and facade retrofit technologies to help buildings achieve carbon reduction and meet ESG and Net Zero goals. It also highlights the importance of innovation and collaboration, in this case between INOVUES, 3M, and Grid Catalyst, in addressing climate change.
The project also showcases the potential of Minnesota's specialized manufacturing industries, particularly in glass and windows. Sustainable growth and innovation in these industries can create new opportunities for related industries and support the state’s development efforts.
Overall, the project demonstrates the potential for non-invasive window and facade retrofit technologies to help buildings, which are responsible for 40% of greenhouse gas emissions, reduce their carbon footprint and contribute to a Net Zero future. As climate-tech continues to gain momentum, collaborations between startups and established companies will be crucial in driving innovation and achieving global sustainability goals.
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