Site Surveys and Preplanning

Key

•The installer should meet with each customer to discuss available PV system options.

•Information gathered during a site survey should be carefully documented.

•A variety of testing and measuring devices and marking equipmentis used during site surveys.

•The density of the module arrangement in an array affects the accessibility and the area required to produce a certain amount of power.

•Roof slope is measured with an angle finder or calculated from the rise and run.

•A compass is used to determine the orientation of a sloped roof surface.

•The potential loss in receivable solar radiation from non-optimal orientations may not be significant.

Recall

  1. Why is it in the customer’s best interest to have dense array arrangement vs open array arrangement?

More power can be produced in a smaller area.

•Directional bearings from magnetic compasses must be adjusted for magnetic declination.

•Magnetic declination varies by location and changes slightly over time. Up-to-date maps are used to determine the necessary declination adjustment.

•Shading of PV modules and arrays can cause disproportional reductions in power output.

•Most of the daily solar radiation occurs between 9 AM and 3 PM, so avoiding shading during this period is high priority.

•A sun path calculator is used to evaluate shading at potential array locations.

•When the sun is in the northern part of the sky, shading can be caused by obstructions immediately north of an array.

•The Solar Pathfinder™ analyzes shading for potential array locations by comparing the reflections of potential obstructions on the horizon to a sun path diagram of the solar window.

•Marking the solar window obstructions on the removable sun path diagram creates a permanent record of shading for a particular location.

•A newer, electronic tool for shading analysis is the SolmetricSunEye.

Hypothesize

  1. Your home is facing north and a solar company pitches to you that if you add more panels on your roof, you will generate just as much electricity as a southern facing roof. Is this correct?

This is not true in most cases. Some homes simply do not have the roof design to house solar panels on the south facing roof. Instead, designers will add the panels to the western or eastern face of the roof. Panels on the northern end of the home will produce less power because of the orientation of the home in relation to the sun path.

  1. Take two minutes to connect this information on sun path and orientation to what we need to know about your home.

Answers may vary, but students should make the connection between the orientation of their home to the sun path visualizing which way the panels should face.

•Roofs should be inspected for signs of deterioration.

•The thickness of roof decking and covering can be determined by inspecting the edge of the roof under the eaves.

•Noticeable dips on roof surfaces may be a sign of underlying structural defects.

•Inverters and other system components should be located as close together as possible.

•A site layout drawing shows basic building dimensions and locations of major components.

•A load analysis is part of an energy audit, which is used to evaluate a customer’s energy use for stand-alone system sizing.

•Data monitoring may involve simple display panels or web sites interfaced with sophisticated data acquisition systems.

Reflect

  1. Take two minutes to summarize what you have learned in 4-6 sentences.

Answers may vary.