Grantee Research Project Results
Final Report: Smart Solar Windows – A Step Towards Carbon Neutral Buildings
EPA Grant Number: SU835940Title: Smart Solar Windows – A Step Towards Carbon Neutral Buildings
Investigators: Patrick, David L.
Institution: Western Washington University
EPA Project Officer: Hahn, Intaek
Phase: II
Project Period: October 1, 2015 through September 30, 2017
Project Amount: $75,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2015) Recipients Lists
Research Category: Sustainable and Healthy Communities , P3 Awards , Pollution Prevention/Sustainable Development , P3 Challenge Area - Sustainable and Healthy Communities
Objective:
The goal of this project was to develop and demonstrate a cost-effective smart solar window technology based on a new transparent photovoltaic solar concentrator able to simultaneously produce power and reduce HVAC building loads as a step toward carbon-neutral buildings and communities. An interdisciplinary team of chemistry, engineering, industrial design, environmental studies, and business students designed, built and demonstrated the new technology, participated in a business plan competition based around their product concept, and participated in a variety of public outreach activities.
Summary/Accomplishments (Outputs/Outcomes):
The project began with an intensive visioning effort, as the team examined a range of ideas for potential new applications, new features for the window technology , market opportunities, and technological and business constraints. This included a critical assessment of the feature set proposed in the Phase II grant, which ultimately led to a revision of the concept, based on a commercial “curtain window” design. Curtain windows are a common element in modern commercial construction, providing the appearance of a glass wall or façade. The team met frequently to discuss ideas, research the ideas, and debate alternatives. Prof. Miller served as a moderator/guide in these discussions, drawing on his experience in technology development.
This process led to some revisions and improvements to the window design proposed in the Phase II application. In the final design, electrical power generated by the window is put into the building wiring, using a novel approach to connect windows to one another, along with an array of microinverters converting the DC output from photovoltaic cells into AC power compatible with building power. To accomplish this, the team developed a new window frame with integrated electrical and data connections, allowing windows to be linked directly together, forming a water-tight seal on a building exterior. The system was designed to be fully compatible with industry-standard “curtain window” architecture, which is the system of windows and framing used to construct many modern glass-clad buildings. Calculations based on this new design indicated it should meet or exceed the per-unit-area electrical power generation target set out in our Phase II application. The new design does away with motorized open and closing capabilities. Upon further investigation into the value and costs of this feature, the team determined that a better approach is to direct all power produced by the window into the building’s wiring using the new frame design, enabling it be put to the most efficient distributed use, whether for HVAC, lighting, electrical outlets, or other demands.
All team members participated in this design process, each contributing from their own area of expertise. After the design revisions were decided upon, several subteams were formed to work in parallel on component elements: The electrical engineering subteam examined power consumption and efficiency models for various combinations of solar cell wiring, inverter technologies, and whole-building wiring, i.e., the pattern of connecting windows together, and on the basis of this analysis designed and produced all the circuitry and photovoltaic cell connections used in the window. The chemistry team continued work developing and testing low Cadmium content and Cadmium-free alternatives for use in the luminescent solar concentrator (LSC) window pane, and scaled up the synthesis to provide larger quantities required for the prototype. The chemistry team also constructed a set of luminescent solar concentrator (LSC) panes used in the window, as well as additional panes for testing purposes. The industrial design team considered alternative frame designs and examined cases for residential versus commercial buildings. They fabricated the aluminum frame and oversaw final assembly and testing of all the components. They also designed and produced a range of visual materials such as posters and back-drops used to help explain the technology to non-technical audiences. The business team examined market opportunities, cost considerations, and led development of a business plan.
Conclusions:
Working at first in subgroups, and then coming together at the end as described above, the team succeeded in fabrication and assembling all window components to produce a functional prototype. The chemists prepared and characterized a series of 3”x3” and 6”x6” LSC panels based on low-Cd content CuInS2 nanocrystals. These are new luminophores introduced by the team with the goal of both reducing or eliminating Cd, and of shifting the absorption and emission spectra to the near infrared, to both increase the overall energy efficiency of the window and render it more color neutral. The final prototype included six 6”x6” LSC panes. Additionally, numerous other LSCs were fabricated during the project for the purposes of developing and testing optical coupler designs. Optical coupler development was led by the industrial design subteam, who developed a mirrored acrylic waveguide to efficiently couple light from the LSC pane to edge-attached solar cells, as well as approaches for perimeter sealing compatible with long term outdoor exposure. The same subteam also developed CAD models for the final window structure and mapped out the assembly process. The electrical engineering subteam developed a low power inverter circuit, tailored for solar window applications, to enable placing the electricity produced onto a building’s electrical grid. The MBA student team worked on a sustainable business plan and online information dissemination.
The team’s work culminated in their participation in the Alaska Airlines Environmental Innovation Challenge (EIC), hosted by the University of Washington’s Buerk Center for Entrepreneurship. This competition draws university-based teams from across the region, and is the most prestigious (and competitive) event of its kind in the area. The WWU solar window team finished by winning the grand prize at the competition (and $15,000 in prize money, shared between them), a fantastic conclusion to the project. In the course of the competition, team members met with entrepreneurs, technology business executives, attorneys, investors, window manufacturers and other professionals, and gained a great deal of knowledge and experience beyond the science and engineering of the window itself. The team also engaged in extensive outreach activities, including display booths at community events, for K-12 students, and through numerous meetings with members of the community. These included meetings with WA State Governor Jay Inslee, US Senator Maria Cantwell, US Representative Rick Larson, and many others, helping to draw attention to the importance of renewable energy. Near the end of the project WWU signed a licensing agreement for the underlying technology with the company UbiQD, which is actively developing practical solar window technologies for eventual sale. This successful transfer of university discoveries to the private sector was aided by the attention the team help bring.
Work continues on solar window technologies in the Patrick group, with two team members (undergraduates Amy Morren and Star Summer) remaining actively engaged in nanophosphor development, LSC prototyping, and testing.
Journal Articles:
No journal articles submitted with this report: View all 3 publications for this projectSupplemental Keywords:
Solar Energy, Green Buildings, Solar WindowsProgress and Final Reports:
Original AbstractP3 Phase I:
Smart Solar Windows – A Step Towards Carbon Neutral Buildings | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.