Single Axis VS. Dual Axis Solar Tracking
In today’s market you’ll find two types of solar tracker systems, single axis, and dual axis trackers. Single axis trackers will track the sun from east to west on a single pivot point. Dual Axis trackers track east to west and tilt for north to south tracking.
Dual axis trackers are more complex in design, using additional motors and sensors to track the sun. Dual axis also use an “eye” sensor which visually follows the sun, while the single axis tracks the sun using a predictable pattern based on the time of year.
On a cloudy day you’ll find dual axis trackers pointing all over the sky, while the single access tracker points directly where it should be – at the sun. This eliminates any unnecessary tracking movements which only result in additional wear and tear, and loss of power.
Strathcona Solar exclusively uses the Lorentz single axis tracker system for various reasons, which we’ll explain below.
First, let’s take a look at each system.
Single Axis Trackers
- Track the sun from east to west using a single pivot point
- Increase solar yield up to 34%
- Simple, effective design
- Low maintenance
- Lower cost compared to dual axis
- Minimal points of failure
Dual Axis Trackers
- Track the sun from east to west, and north to south using two pivot points
- Increases solar yield up to 37%
- Complex design – more motors and sensors
- Higher maintenance
- Higher cost due to additional parts and installation time
- Additional points of failure
Studies have shown dual axis trackers may only provide an additional 3% solar harvest. With the added cost of equipment, higher maintenance costs, and high potential downtime, dual axis trackers may actually be less productive in the long run.
Dr David Lubitz, Assistant Professor, University of Guelph, School of Engineering studied 217 solar tracker sites across North America and wrote a scientific paper based on his findings. He found the difference gained by using a dual axis tracker instead of a single axis was relatively limited, barely 3-4%. A graph with the results of Dr Lubitz’s study is located below.
When you’re looking for a reliable, low maintenance solar tracker, single axis trackers are the best way to go.