Determining Sun Paths and Intensity Levels – Solar Training
If you’re considering installing a solar system for your home or business, you will definitely want to consider some site-specific factors that will greatly influence the efficiency of your solar system’s performance. Two of the most important factors associated with solar efficiency are solar intensity and the sun’s path. Keep reading to find out how these two factors impact how well your system will perform.
Identifying Your Location’s Sun Intensity
The sun’s intensity, which is alternately called solar irradiance (SI) or insolation, is the measure of the power of electromagnetic radiation over a given surface area. More simply, it is the intensity of the sunlight reaching a particular location.
Generally speaking the SI is measured in terms of watts per square meter (W/m2) or kWh per square meter per year (kWh/(m2 * y)) and is based on the intensity of the sun and the particular location in question. This measurement is important when doing a solar site assessment as it indicates the potential kWh per square meter available for harnessing into solar electricity.
In most cases, as long as you have an exact address or the latitude and longitude of your location, you can use online calculation tools to estimate the solar intensity of your property. Online mapping programs will also aid in this exercise by giving you aerial views of the site for determining whether there are obstructions that would impede solar energy collection.
Identifying Your Location’s Sun Path
The sun’s path on your particular location is also important when doing a solar site assessment. A sun path indicates the relative position of the sun as it tracks through the sky and from season to season. The sun’s path will vary by time of year and throughout each day.
For instance, during winter months in the northern hemisphere, the sun will rise in the southeast, peak above the southern horizon on a low angle (depending on latitude), and then set in the southwest. Conversely, for those in the southern hemisphere, the sun rises in the northeast, peaks approximately overhead, and then sets in the northwest.
Knowing the latitude and location-specific solar path differences is tremendously critical for estimating and modeling annualized solar system performance. You can find an excellent online sun path estimator via the University of Oregon Solar Radiation Monitoring Laboratory. All you need to do is enter your location’s latitude, longitude, zip code, and time zone. The system will output a sun path chart and other useful site-specific data to aid in your solar site assessment.
When working with online tools like those provided by the University of Oregon, you will see that they provide elevation view of the sun path for your location. By viewing the changes in elevation from month to month, this type of graph will show you firsthand how much the sun path can vary from season. It is important to note that your site will receive the most sunlight when the sun is at its highest point (the highest elevation), with diminishing returns as the elevation decreases.
Another useful view provided by the University of Oregon online tool is the overhead view of the sun path. This view illustrates how the sun moves across a targeted site from month to month and throughout the day. From this, you will see that sites located in the northern hemisphere will experience longer days during summer months and shorter days during winter months. Knowing the actual number of sunlight hours your site receives throughout the year is also useful when determining a site’s solar potential.
The work of mathematically modeling a site’s solar energy potential is complex but highly interesting for those interested in a solar career. If this kind of work intrigues you, you should definitely consider receiving some solar training to find out just how much more there is to learning the best methods for location a solar energy system.