User:Mrmaguire
Solar shade analysis[edit]
Solar industry professionals, whether in the thermal or photovoltaic (electrical) solar fields, must survey the physical characteristics of their clean energy production system sites prior to installation to determine the specific sun exposure and shading characteristics. This data is critical to proper design and effective system operations. There are few tools available for measuring these features.
Historically, the Solar Pathfinder™, made by Solar Pathfinder of Linden, TN, was the tool of choice. Comprised of a round plastic casing with a clear polished convex plastic dome, a level and a compass, the Pathfinder houses a sun path chart or diagram. The latitude-specific chart displays the hours of sunlight for every day of the year, divided by month. Mounted on a small tripod, the Pathfinder reflects a panoramic view of the entire site. Using the reflections of trees or other shadow-casting objects in the dome, the user, looking through the clear dome, can either draw a line on the chart outlining the obstructions to sunlight, take a photo for later viewing and analysis, or use related software to determine the hours and times of lost light due to obstructions. (Multiple charts are supplied with the tool.) This information is then used to locate solar panels for optimum exposure.
More recently, an electronic version with companion desktop processing and analyzing software has been developed and is gaining wider use by solar professionals. The SunEye™, made by Solmetric Inc. of Sebastopol, CA, also provides a full analysis of sun exposure and shading impacts for the whole year. However, this device makes field surveys much quicker and easier, reducing the time spent in recording physical conditions and determining the constraints posed by shading objects. It combines the features of the Pathfinder with a camera and fish-eye lens and integrated shade analysis tool. Other features include GPS, designer software and extension kit. Background information is found in Solmetric's Solmetric web site and in the "Understanding the Solmetric SunEye™" Application Note document.
An additional benefit of the electronic solution is the SunEye Extension Kit, a recent enhancement that enables measurements up to 5.4 meters (17.7 feet)from ground level. This is especially useful when roof access is not available, or when the structure is not yet built, for example when planning for raised solar arrays for parking lots. The Solmetric device is placed at the top of the telescoping pole and measurements are triggered by rotation of the pole.
External links[edit]
- http://www.solmetric.com.
- Solmetric SunEye User’s Guide
- "Using Solmetric SunEye in California Solar Electric Programs-6-May-2010" http://www.solmetric.com/newsletters.html.
- SunEye demo part 1 | part 2
- 210 intro
- National Renewable Energy Laboratory, TMY3
- University of Oregon Solar Radiation Monitoring Laboratory, Sun Chart Program: http://solardat.uoregon.edu/SunChartProgram.html and Polar Sun Chart Program at http://solardat.uoregon.edu/PolarSunChartProgram.html.
- Photovoltaic Performance Calculator PVWATTS, by the National Renewable Energy Laboratory
- "Solar Site Evaluation: Tools and Techniques to Quantify and Optimize Production", By Mark Galli and Peter Hoberg, Solar Pro Magazine Dec-2008-Jan-2009