Commercial Install and Non-intrusive Demonstrations of Optimal Window Systems (Comm-INDOWS)
Institute of Gas Technology dba GTI Energy
Recipient
Davis, CA
Recipient Location
$172,228
Amount Spent
Active
Project Status
Project Update
The project team has begun initial technology assessment and market characterization including conducting a market survey of relevant window technologies in support of techno-economic analysis of different window types. The team has also begun laboratory evaluation and modeling of multiple secondary window system technologies including baseline window and calibration transfer standard testing, and thermal and solar-optical performance modeling. The team is preparing to move to the field validation portion of the project and conduct a demonstration of the technology at a commercial building.
The Issue
High-performance windows, such as triple pane and vacuum insulated glass windows (VIG), are commercially available but represent less than 2% of the U.S. window market, limited by technical and cost challenges with replacing existing windows. Replacing existing windows with code compliant windows to meet energy efficiency goals is disruptive, expensive, with difficult economics for building owners, often resulting in a “do nothing” approach. This causes a significant missed opportunity for improvement in energy savings in commercial buildings.
Project Innovation
Secondary window systems (SWS) are an alternative to full window replacement, attaching to the interior or exterior of an existing (i.e., primary) window. Currently, SWS employs a single-pane or double-pane of glass. This project will evaluate the impacts of improving glazing systems using a triple-pane thin-glass secondary window technology in existing commercial buildings as a gas demand reduction strategy. The project aims to address key benefits and challenges with this novel retrofit solution by reducing costs, improving performance, and being less disruptive to occupants in order to maximize commercialization and deployment opportunities.
The demonstration will occur in a commercial building with existing single-pane glass windows. The SWS will serve as a validation of thermal performance, energy impact, ease of installation, and manufacturing costs, while reducing concerns around condensation potential.
Project Goals
Project Benefits
This project benefit IOU ratepayers by creating a new affordable window retrofit option for commercial and residential buildings and demonstrating the potential energy savings and cost-effectiveness of the technology in a specific application. Window improvements are one of the most challenging barriers to energy savings in the existing building stock. Yet improvements to such windows are essential for meeting California’s long-term energy efficiency and decarbonization goals. Increasing the number of options available to building owners greatly increases the likelihood of voluntary action being taken without necessarily relying on stronger building codes for additions and alterations. Proven savings can also justify incentives from IOUs for novel window technologies, further improving cost-effectiveness.
California’s commercial sector consumes 1,989 million therms of natural gas per year for three major natural gas IOUs (PG&E, SDG&E, and SoCalGas) in California, with 44% or 875 million therms used for space heating. This contributes to 4% of total GHG emissions. Modeled analysis has shown in residential applications that a R-7.17 window can achieve 10% therm savings annually in California Climate Zone 3 and 12% therm savings in Climate Zone 12. Commercial applications with a window-to-wall ratio between 25% and 30% could proportionally achieve similar results as residential buildings and could potentially save between 79–96 million therms annually. However, demonstrations on commercial buildings are needed to validate these savings potential. Analysis from PG&E confirms these savings with an estimate of total savings potential of 84.5 million therms annually, roughly the equivalent of a 200 MW natural gas fired power plant.
Affordability
Demonstrate installation easy and lower cost of implementation compared to current practices, with installed cost premiums ≤$5 per square foot.
Energy Security
Demonstrate increased energy performance (e.g., higher energy efficiency) according to the research goals of the project and decreased HVAC energy consumption by at least 15% compared to current HVAC energy use with existing single pane windows.
Key Project Members
Kaushik Biswas
Subrecipients
Match Partners
Northwest Energy Efficiency Alliance
Southern California Gas Company (SoCalGas)
U.S. Department of Energy
