What is a Dual Axis Solar Tracker?
A solar tracker is a device that orients photovoltaic panels, concentrators or reflectors towards the sun. Trackers are used in solar power schemes to maximize energy production over the course of the day. They do this by ensuring the solar collectors are kept in a constant alignment with the moving sun. There are two basic types of solar trackers – single axis and dual axis.
Single Axis vs Dual Axis Tracking
Single axis trackers rotate the panels around a horizontal axis, allowing them to follow the east-west path of the sun across the sky. Dual axis trackers have the added capability of tilting the panels to follow the sun’s elevation angle as it moves lower on the horizon during mornings and evenings. By varying the panel angle in two directions rather than just one, dual axis trackers are able to maintain a closer alignment with the sun throughout the day. This results in 20-30% more energy generation compared to fixed tilt or single axis tracked systems.
Working Mechanism of a Dual Axis Tracker
A typical Dual Axis Solar Tracker consists of a metal pole attached to a base platform anchored in the ground. Mounted on top of the pole are the solar panels fixed to a rotating assembly. The assembly allows the panels to pivot around both a horizontal and vertical axis driven by motors. Sensors are mounted on the panels to detect the angle and position of the sun. A controller uses the sensor feedback to precisely position the panels to face the sun by sending signals to the two tracking motors. As the sun arcs across the sky and changes elevation levels over the course of a day, the dual axis tracker continuously orientates the panels to maximize light exposure.
Improved Solar Radiation Capture
By maintaining an optimal angle to the sun, dual axis trackers are able to capture the direct beam component of solar radiation much more efficiently compared to fixed solar panels. The direct beam forms the most concentrated portion of sunlight and accounts for 50-70% of total solar radiation received on earth. Dual axis tracking results in more of this high energy radiation being absorbed by the panels over time as opposed to some of it reflecting or bypassing at wide angles. This increased effective solar capture allows for generation capacity gains of 20-30% from the same physical panel area.
Greater Energy Yield Throughout the Day
Due to their enhanced ability to track the sun, dual axis systems experience less drop off in solar intensity levels especially during early morning, late afternoon and winter months. Fixed panels see a rapid decline once the sun passes by azimuth angles beyond a certain threshold. Dual axis trackers can maintain high irradiance for extended durations into the shoulder periods of the day by compensating for the lowering sun angle. Similarly in winter, they are better equipped to utilize the available sunlight. This leads to generation being distributed more evenly over long hours instead of short intense bursts seen with other methods. Overall annual energy production is significantly higher as a result.
Higher Energy Density with Concentrated PV
Dual axis tracking can additionally be combined with solar concentration technologies. Concentrated photovoltaic (CPV) systems focus sunlight onto smaller, more efficient multi-junction solar cells using lenses or mirrors. Higher concentration ratios above 500X are only possible if the receiver assembly is continuously guided on dual axes to capture the directed sunlight. Without precise tracking, excess heat build up from misdirected concentrated beams could damage the cells. For this application, dual axis trackers enable cost effective generation at utility scales using CPV. They make full use of the increased energy densities achievable through optical concentration.
Improved Performance in All Climates
Unlike location specific improvements from fixes tilt and seasonality corrections by single axis trackers, dual axis technology delivers consistent advantage under any climate conditions. Be it tropical, arid, temperate or polar regions, the sun’s diurnal and seasonal variances are effectively counteracted. Not only is energy generation boosted but it is stabilized and made more predictable. Areas with low insolation levels see greater utilization of the available sun hours. Performance is maintained throughout the year without degradation. This universal optimization is very important for a smooth return on investment.
Enhanced Lifetime Value and Lower Levelized Cost of Energy
As a result of augmented annual yields, dual axis solar trackers enhance the lifetime value and affordability of photovoltaic projects. Higher electricity volumes generated recoup the initial capital cost in a shorter timeframe. Economies of scale lower financing, operations and maintenance expenses on a per kWh basis. The levelized cost of energy, a key industry benchmark, is reduced substantially making solar competitive against conventional generation options. For commercial and utility installations pursuing maximum returns, dual axis tracking emerges as a cost effective way to reduce tariffs and speed up break-even.
Overall Dual Axis Trackers Enable Optimal Solar Harvesting
By precisely aligning collectors with the moving sun throughout each day and over all seasons, dual axis trackers allow solar resources to be harvested at their fullest potential. None of the sunlight is squandered due to misalignment. This innovative technology ensures solar panels, reflectors or cells remain exposed to maximum direct beam radiation for sustained high energy yields. Dual axis tracking facilitates substantial electricity generation gains over fixed and single axis alternatives in any geographic setting. It makes solar power optimized, predictable and affordable on an industrial scale.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
