How To Build A Better Solar Tracker
How To Build A Better Solar Tracker Utilities want quality tracking systems with zero down-time, a long life and low Total Cost of Ownership. Here’s how successful manufacturers can achieve it. The list of solar manufacturers meeting their demise continues to grow. This is no different in the solar tracker sector, where much of it is due to Total Cost of Ownership (TCO). TCO consists of capital, operational and maintenance costs, the last of which is probably the least considered but most important. TCO is a major consideration in tracker selection for utilities around the world. But many out-of-business companies have failed the TCO litmus test. In photovoltaic systems, trackers help minimize the angle of incidence (the angle that a ray of light makes with a line perpendicular to the surface) between the incoming light and the panel, which increases the amount of energy the installation produces. So when a tracker isn’t working, not only is a project losing money in paying for labor to repair components, but also in less-optimized energy production and therefore diminished revenue. Sometimes the plant must be shut-down completely. Deploying labor and replacement components to the project site are often an overlooked expense on the front side of a solar project’s development, too. A leading cause of solar tracker malfunction is that, many times, their components Solar tracker components must be able to stand the are not made to effects of harsh environments. The inferior components in this photo have corroded over time. survive the often harsh environments of solar sites. When trackers are made with such inferior, sub-standard components, replacements become necessary and TCO rises. Root Causes Of Inferior Tracker Components Solar trackers must work for more than twenty years in tough conditions, often on barren government land. For example, the Ivanpah solar project is in California’s Mojave Desert, which has an arid climate where temperatures in some parts
can extend above 120°F and below 0°F. This area also faces daytime humidity between 80% to 100% and nighttime moisture-laden condensation, not to mention rain, dust, snow and sleet. Saline-laden ocean breezes near shorelines can also corrode components.
The effects of condensation and dust ingress, due to poor ingress moisture protection, is evident in a motor.
Utility Expectations Utilities are looking for a tracker equipment life of 20 years or more. These companies want the tracker that will perform the best in their application and has the lowest TCO and lowest cost per watt. The responsibility to assure that electrical equipment meets these expectations rests with the component manufacturer, while the lowest TCO is a shared responsibility between all partners engaged in engineering the solar tracker. All companies involved in tracker engineering should begin with a mutual understanding that environmental conditions must be studied and integrated into the design. Application specification must include not only the mechanical and electrical function, but also the target component costs. An electrical component manufacturer may achieve these goals by focusing on these areas:
©2016 Dunkermotoren. All Rights Reserved. Information subject to change at anytime.
reason, low-friction gears are essential to prevent the possibility of gears fusing into one another because of the intense heat. Cable Termination: The cables and cable components exiting from the motor and controller must be protected from water ingress and ultraviolet light.
This fully-sealed solar tracker motor from Dunkermotor is a potential solution for a corrosion protected unit.
Insulation: Electric motors driving the solar tracker must have a higher class of insulation to withstand temperature extremes -4°F to +185°F. Lubrication: Planetary and worm gearbox assemblies require durable lubrication. The lubricant must remain stable over the 20-year tracker life, withstanding the full high and low temperature range. It also must be suitable for low rotational speeds and high torques (usually twice the nominal rated values). Moisture-Out Membrane: All electric assemblies, including electro-optical, must be moisture-free. Moisture, which results from condensed daytime humidity, will get trapped inside the motor housing or the electro-optical enclosure, likely damaging the electrical components. High Ingress Protection: Electro-mechanical and electro-optical equipment must be protected from penetrating dust, rain and snow. It’s best to seal equipment completely. At a minimum, the equipment should meet an IP54 rating, but it is preferable to seal the enclosure to a higher degree of protection, such as IP65 or IP67.
Manufacturer Qualification Support Tracker manufacturers should conduct qualified tests to ensure the highest protection of equipment from long-term environmental exposure. Additionally, manufacturers should also have third-party independent laboratories conduct tests on their products. Such tests should include: • First Article Inspection (FAI) • Life expectancy projection tests • Shock and Vibration tests to EN61373:1999 • Highly Accelerated Test (HALT ) • Highly Accelerated Stress Screen (HASS ) • Failure Mode and Effect Analysis (FMEA ) • On-site data collection • Product compliance to CE, cUL, CCC, ISO 9001:2008, ISO14001:2004 + 1:200 Successful solar tracker manufacturers know that their companies’ survival depends on producing quality systems and have worked to ensure zero down-time, a 20-year life and low TCO. By: Dee Chatterjee, Regional Manager – Western Region; and Jonathan Doyle, Application Engineer, at Dunkermotoren (USA), a brand of AMETEK Precision Motion Controls.
Enclosure Corrosion: Electrical motors and gearbox enclosures should be protected from corrosion. The corrosion protection must include all metal surfaces. Coating materials with varnishes, electroplating or anodizing to prevent exposure to corrosive elements is a must. If plastic enclosures are used, they, too, must have an equivalent field life. The materials should have excellent UV environment inhibitors. Low-Friction Gears: High torque and low speed are operational characteristics of solar tracker designs. The high torque will cause heat build-up inside the gearbox. Low gear turning speed/motion causes poor heat dissipation. For that
©2016 Dunkermotoren. All Rights Reserved. Information subject to change at anytime.
can extend above 120°F and below 0°F. This area also faces daytime humidity between 80% to 100% and nighttime moisture-laden condensation, not to mention rain, dust, snow and sleet. Saline-laden ocean breezes near shorelines can also corrode components.
The effects of condensation and dust ingress, due to poor ingress moisture protection, is evident in a motor.
Utility Expectations Utilities are looking for a tracker equipment life of 20 years or more. These companies want the tracker that will perform the best in their application and has the lowest TCO and lowest cost per watt. The responsibility to assure that electrical equipment meets these expectations rests with the component manufacturer, while the lowest TCO is a shared responsibility between all partners engaged in engineering the solar tracker. All companies involved in tracker engineering should begin with a mutual understanding that environmental conditions must be studied and integrated into the design. Application specification must include not only the mechanical and electrical function, but also the target component costs. An electrical component manufacturer may achieve these goals by focusing on these areas:
©2016 Dunkermotoren. All Rights Reserved. Information subject to change at anytime.
reason, low-friction gears are essential to prevent the possibility of gears fusing into one another because of the intense heat. Cable Termination: The cables and cable components exiting from the motor and controller must be protected from water ingress and ultraviolet light.
This fully-sealed solar tracker motor from Dunkermotor is a potential solution for a corrosion protected unit.
Insulation: Electric motors driving the solar tracker must have a higher class of insulation to withstand temperature extremes -4°F to +185°F. Lubrication: Planetary and worm gearbox assemblies require durable lubrication. The lubricant must remain stable over the 20-year tracker life, withstanding the full high and low temperature range. It also must be suitable for low rotational speeds and high torques (usually twice the nominal rated values). Moisture-Out Membrane: All electric assemblies, including electro-optical, must be moisture-free. Moisture, which results from condensed daytime humidity, will get trapped inside the motor housing or the electro-optical enclosure, likely damaging the electrical components. High Ingress Protection: Electro-mechanical and electro-optical equipment must be protected from penetrating dust, rain and snow. It’s best to seal equipment completely. At a minimum, the equipment should meet an IP54 rating, but it is preferable to seal the enclosure to a higher degree of protection, such as IP65 or IP67.
Manufacturer Qualification Support Tracker manufacturers should conduct qualified tests to ensure the highest protection of equipment from long-term environmental exposure. Additionally, manufacturers should also have third-party independent laboratories conduct tests on their products. Such tests should include: • First Article Inspection (FAI) • Life expectancy projection tests • Shock and Vibration tests to EN61373:1999 • Highly Accelerated Test (HALT ) • Highly Accelerated Stress Screen (HASS ) • Failure Mode and Effect Analysis (FMEA ) • On-site data collection • Product compliance to CE, cUL, CCC, ISO 9001:2008, ISO14001:2004 + 1:200 Successful solar tracker manufacturers know that their companies’ survival depends on producing quality systems and have worked to ensure zero down-time, a 20-year life and low TCO. By: Dee Chatterjee, Regional Manager – Western Region; and Jonathan Doyle, Application Engineer, at Dunkermotoren (USA), a brand of AMETEK Precision Motion Controls.
Enclosure Corrosion: Electrical motors and gearbox enclosures should be protected from corrosion. The corrosion protection must include all metal surfaces. Coating materials with varnishes, electroplating or anodizing to prevent exposure to corrosive elements is a must. If plastic enclosures are used, they, too, must have an equivalent field life. The materials should have excellent UV environment inhibitors. Low-Friction Gears: High torque and low speed are operational characteristics of solar tracker designs. The high torque will cause heat build-up inside the gearbox. Low gear turning speed/motion causes poor heat dissipation. For that
©2016 Dunkermotoren. All Rights Reserved. Information subject to change at anytime.
