ASSET-Mac Acme Solar Site Evaluation Tool - Mac Version
Wiley Electronics ASSET-Mac Acme Solar Site Evaluation Tool - Mac Version
The ASSET is a patent pending system for evaluating shading at a site. The ASSET allows the user to efficiently analyze and document installation sites. In use, the ASSET is positioned to take a series of pictures at the intended site. The software assembles the pictures into a panorama with the path of the sun superimposed. One can easily see the times when the sun will be shaded.
The complete survey can be done much more quickly than with past methods, so it is easy to optimize installations. In addition, the software incorporates the PVWatts program, written by Bill Marion of the National Renewal Energy Laboratory (NREL) under contract to the Department of Energy (DOE). The program uses hourly historical data from the TMY2 data set to calculate energy captured by the array. All information is available for editing in an Excel spreadsheet.
The ASSET consists of a precise positioning system, a digital camera, and software.
The above image shows the ASSET in an upright position, as if mounted on a camera tripod. Note the bull's-eye type bubble level for leveling the positioning system. The compass is used to point the system towards the equator (south in the northern hemisphere) because the path of the sun appears in that portion of the sky. The compass has an inner ring which may be used to correct for local magnetic declination. The camera is facing east in the picture and set to an angle of 22.5 degrees. The system may be positioned to take a series of 7 pictures from east to west.
The pictures below are a set of digital photographs taken at the seven positions. Note that the array will not be mounted on this building, this building represents a possible obstruction for the pole mounted array (which was eventually installed on the other side of the parking lot from this building).
The following image shows a composite panorama assembled from the seven photographs. Superimposed on the panorama is the path of the sun averaged over each month of the year. The yellow numbers on the grid represent the hours of the day, 6am to 6pm, reading left to right. The months of the year are also indicated in yellow on the lower left of the panorama. As can be seen, the site has some morning and evening shading, especially during winter, but midday is mostly unobstructed. Exposure is excellent during the summer.
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