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Technical Terms
| SOLAR TECHNICAL TERMS AND ASPECTS: |
Definitions: Terms Used in Solar Site Evaluation INSOLATION: The incident solar radiation on the earth's surface in a given time window, typically expressed in kWh/m2/day. SOLAR ACCESS/SHADING: Solar access is the ratio of the insolation in a given location, including shade, to the insolation available at that location without shade. Solar access is typically expressed in percent for a given time period, such as a month, season, or year. OPTIMUM TILT AND ORIENTATION: For any location, the optimum tilt and orientation is the specific fixed tilt and orientation for solar arrays that absorbs maximum solar energy over the course of one year. ORIENTATION FACTOR (TOF): TOF is the solar insolation at the actual tilt and orientation divided by the insolation at the optimum tilt and orientation, expressed in percent. TOTAL SOLAR RESOURCE FRACTION (TSRF): TSRF is the ratio of insolation available accounting for both shading and TOF, compared to the total insolation available at a given location at the optimum tilt and orientation and with no shading. TSRF is also expressed as a percentage. TSRF = solar access x TOF MAGNETIC DECLINATION: Magnetic declination is the azimuth offset between magnetic north and true north, expressed in degrees east or west. TYPICAL METEOROLOGICAL YEAR (TMY ): TMY is a collection of weather information that includes data about insolation for every hour of a typical year computed using historical weather data. |