Monday, April 12, 2010

McCluney Presents Results of Awning Study

The Attached Awning Rating Feasibility Research Project Monitoring Task Group gave a presentation to close the first day of NFRC’s Spring Membership Meeting. The presentation focused on the Project Awnings Shading Rating Strategies Feasibility Study by Ross McCluney, Ph.D. and Willie duPont. The study was funded by the Professional Awnings Manufacturers Association (PAMA).

During the presentation, Dr. McCluney discussed several aspects of rating the energy efficiency performance of awnings.

One of those considerations involved opaque awnings. McCluney said only shadowing calculations are needed. He added that this produces an important metric called the un-shaded fractional area and its complement, which is called the shaded fractional area.

McCluney added that because attachments would be rated in NFRC by reference to any of several base case windows, there will be a different pair of SHGC (w) and SHGC (aw) for each direction of incident flux and for each base case window.

Additionally, McCluney said rating awning energy performance only makes sense if multiple directions of solar incidence are considered in addition to any strong spectral selectivity effects.

Finally, McCluney explained that there is much strategic work that needs to be done to effectively rate the energy efficiency of awnings. Among the points that need to be addressed are the following:

• Asking NFRC to include projecting awnings in rating program
• Writing more detailed descriptions of research projects
• Determining how much of this work is Lawrence Berkeley National Labs (LBNL) is planning and doing.
• Get estimates of when the LBNL may be ready to take on this kind of work
• Eliminating the choices one does not want, thereby narrowing NFRC’s scope of work
• Determining how much of the ratings work be done by the awning industry
• Finding funding for additional research and engineering work needed to complete the ratings.

The study recommends the following future research and engineering work:

• Develop awning shadow protection projection algorithms based on existing papers on the subject plus extra work
• Investigate awning cover materials optical properties
• Investigate new optical equipment investigation
• Organize a project to put this all together (i.e., to develop an awning rating methodology)

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