Building-integrated solar energy devices based on wavelength selective films

Loading...

View/Download File

Ulavi_umn_0130M_13907.pdf (9.17 MB)

Persistent link to this item

https://hdl.handle.net/11299/157236

Statistics

View Statistics

Journal Title

Journal ISSN

Volume Title

Title

Building-integrated solar energy devices based on wavelength selective films

Authors

Ulavi, Tejas U.

Published Date

2013-06

Publisher

Type

Thesis or Dissertation

Abstract

A potentially attractive option for building integrated solar is to employ hybrid solar collectors which serve dual purposes, combining solar thermal technology with either thin film photovoltaics or daylighting. In this study, two hybrid concepts, a hybrid photovoltaic/thermal (PV/T) collector and a hybrid `solar window', are presented and analyzed to evaluate technical performance. In both concepts, a wavelength selective film is coupled with a compound parabolic concentrator (CPC) to reflect and concentrate the infrared portion of the solar spectrum onto a tubular absorber. The visible portion of the spectrum is transmitted through the concentrator to either a thin film Cadmium Telluride (CdTe) solar panel for electricity generation or into the interior space for daylighting. Special attention is given to the design of the hybrid devices for aesthetic building integration. An adaptive concentrator design based on asymmetrical truncation of CPCs is presented for the hybrid solar window concept. The energetic and spectral split between the solar thermal module and the PV or daylighting module are functions of the optical properties of the wavelength selective film and the concentrator geometry, and are determined using a Monte Carlo Ray-Tracing (MCRT) model. Results obtained from the MCRT can be used in conjugation with meteorological data for specific applications to study the impact of CPC design parameters including the half-acceptance angle θ_c, absorber diameter D and truncation on the annual thermal and PV/daylighting efficiencies. The hybrid PV/T system is analyzed for a rooftop application in Phoenix, AZ. Compared to a system of the same area with independent solar thermal and PV modules, the hybrid PV/T provides 20% more energy, annually. However, the increase in total delivered energy is due solely to the addition of the thermal module and is achieved at an expense of a decrease in the annual electrical efficiency from 8.8% to 5.8% due to shading by the absorber tubes. For this reason, the PV/T hybrid is not recommended over other options in new installations. The hybrid solar window is evaluated for a horizontal skylight and south and east facing vertical windows in Minneapolis, MN. The predicted visible transmittance for the solar window is 0.66 to 0.73 for single glazed systems and 0.61 to 0.67 for double glazed systems. The solar heat gain coefficient and the U-factor for the window are comparable to existing glazing technology. Annual thermal efficiencies of up to 24% and 26% are predicted for the vertical window and the horizontal skylight respectively. Experimental measurements of the solar thermal component of the window confirm the trends of the model. In conclusion, the hybrid solar window combines the functionality of an energy efficient fenestration system with hybrid thermal energy generation to provide a compelling solution towards sustainable design of the built environment.

Keywords

Building-integrated solar

Hybrid

Solar window

Wavelength selective film

Description

University of Minnesota M.S. thesis. June 2013. Major: Mechanical Engineering. Advisor: Dr. Jane H. Davidson. 1 computer file (PDF); ix, 124 pages, appendices A-B.

Related to

Replaces

License

Collections

Master's Theses (Plan A and Professional Engineering Design Projects)

Series/Report Number

Funding information

Isbn identifier

Doi identifier

Previously Published Citation

Other identifiers

Suggested citation

Ulavi, Tejas U.. (2013). Building-integrated solar energy devices based on wavelength selective films. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/157236.

Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.