Sun Tracking Solutions for CSP and PV Solar Plants for Improved Efficiency

To generate maximum power from the solar PV modules, the solar panels must be pointed in the right direction so as to capture most of the energy from the sun rays. A solar panel collects the maximum solar radiation when the sun rays strike it exactly at 90 degrees. Any misalignment will lower down the energy being captured by the modules.

It has been observed that on average, plants with single axis solar tracking roughly produce 20 to 25% more than solar plants without tracking provision. Benefits from dual axis tracking (for CSP plants) are even more. CSP plants with dual axis solar tracking produce 40 to 45% more energy than plants without tracking.

As it can be observed in the graph below, the percentage of lost output steeply increases as the misalignment between the module and incident radiation increases.

In order to ensure that the solar radiation falls normal to the solar panels for the most of the time CSP and PV solar power plants use two primary methods: solar tracking and seasonal tilt. Solar tracking is a sophisticated dual axis tracking system, mostly used by CSP plants where the Fresnel modules are rotated in 2 axes so that they are always facing the sun. Where in seasonal tilt method, depending on the seasons, the PV modules are varied twice or four times every year so as to ensure efficient operation. As even a slight misalignment affects the power generation significantly, in both of above methods, the Plant operators need precise and accurate tools to ensure proper alignment.

Tilt Sensors: The perfect solar tracking solution for CSP plants

It is a common misunderstanding that the solar energy is available only during the noon times. Many studies show that a considerable amount of radiation energy is present even during the mornings and the evenings. If CSP systems are provided with a solar tracking provision, the output of the plant significantly goes up.

Tilt sensor from Aeron can be effectively used for solar tracking application. Tilt sensors are based on MEMS technology accelerometers. Another technology, which is used for solar tracking is optical encoders. Optical encoders have a disc with slits of different sizes and shapes on it at different angles. The light pulse coming through this slit is monitored to find out the angle of orientation. As the motor moves the shaft, the disc also rotates and as a result, the light pulse varies. This variation is used to find out the angle of rotation. In case of dual axis tracking, two separate motors are used and two optical encoders are installed to calculate elevation as well as azimuth angle. Here are some points of comparison between tilt sensors and optical encoders:

  1. Tilt sensors are compact, easy to install and use and affordable. Their costs are significantly lower than the cost benefits one reaps out of them, justifying their use for this application. On the other hand, optical encoders are difficult to install, bulky in nature and maintenance heavy. Any mis-alignments during the installation can produce a permanent error in the output unless corrected.
  2. Tilt sensors provide digital output which can be fed directly to controllers to actually control the orientation of the collectors. The output remains accurate over the period. In case of optical encoders, since they are relative angle sensors, operation over the period can introduce a small error in the output which may gradually increase.
  3. Tilt sensors provide absolute angle whereas optical encoders are relative angle sensors.
  4. Tilt sensors are rugged and hence, withstand heat, rains and other extreme weather conditions. When compared with tilt sensors, optical encoders having moving components and hence, are subject to wear and tear. Dust and dirt also affect their performance. This system is not only costly, but is also maintenance heavy and many errors like fixed offset distort the output in long run.

Aeron manufactures high accuracy dual axis tilt sensor, TS2D for this application. A low cost version is also available, named TS2L which is highly suitable for the solar tracking application.

Inclinometers: Tool for accurate alignment of PV panels

As we discussed above, PV panels are mounted at a fixed tilt angle which is changed either two times or four times every year as per the seasonal conditions. It is needless to say that accuracy of the tilt angle is highly crucial as it significantly affects the output. It has been observed that many plants make use of instruments like spirit levels for this activity. Spirit levels are not very accurate and are highly subject to the human error. Many a times, the installation activity is carried out during the nights and spirit levels output is not visible therefore resulting in errors.

Inclinometers from Aeron are highly recommended to be used while giving tilt to the solar panels for following reasons:

  1. Highly accurate and precise measurement. No scope of human error as output is displayed digitally. Users can set up their own alarms or permissible angle brackets to further eliminate the human error and ensure accuracy. Inclinometers also come with a laser beam to facilitate easy alignment.
  2. The inclinometers are battery operated and the battery can be charged using the standard cell phone charger. They are compact in size and lightweight.
  3. Aeron inclinometers come with graphics LCD display with backlight , a required feature for night installations.
  4. The inclinometer can be easily calibrated by the user on site. The tear feature ensures easy alignment on tilted terrain and platforms as user can find out relative angle with respect to the terrain or platform on which the panels are being mounted.
  5. With all the above mentioned features, Aeron inclinometers are highly cost competitive.

From the above comparisons, it is quite clear how our products, Tilt Sensors and Inclinometers are handy and useful for solar plants. Both the products can be easily ordered online through Amazon will be shipped to your location within a short span of time.