Solar collectors can be used anywhere on earth thanks to solar trackers. It does not matter the amount of sunlight received. As long as the collector can be made to maneuver around so as to collect the little there is, the higher efficiency will produce more energy.
Introduction to solar trackers
As the name suggests, it’s basically a tracking device as used in police and army intelligence. The only difference is that the sun is made to be the suspect here. PV cells rely on sun to produce energy. The sky is generally bright during day time but the sun is always the brightest spot that yields more energy. For this reason, it is more efficient to track the position of the sun and let the collectors adjust accordingly so that at any particular time, the system is producing its maximum energy. The PV cells will be made to function at their level best to produce more electricity.
Other dual-axis trackers observe the rule of seasons. With the shifting of the sun to either the equator, north or south hemisphere, these trackers are able to adjust to the relevant direction at the appropriate angle.
How trackers work
The action of following the sun is not that easy. It requires incorporation of different technologies. Generally, technologies employed are of two types. These are;
- Passive trackers – uses differential heating theory to respond to the location of the sun. Compressed gases are filled in tubes and then placed on the east and west sides of the solar collector. When the sun rays hit these tubes, temperature changes will be detected. As expected, the gas fluid will have to move to one direction and by doing so, the collector is also adjusted. Hydraulics is the technology adopted here and no other technical systems. There is hence no power consumption with this technology.
- Active trackers – there are more technicalities added in these trackers. There are gear and motor trains run by electrical circuits. Photo sensors are also used in this design to direct the solar collectors to the direction detected to be fit. Due to the electrical components making up these trackers, some electricity produces by the solar system is consumed internally by the tracker.
What happens on cloudy days?
On cloudy days, the sunlight is blocked. Your solar collectors will not have much work to do. Two types of light exist; the direct light (90%) from the sun and the ambient light (10%) usually reflected. On cloudy days therefore, direct light will be missing. The reflected light will however be present. For this reason, the tracker will still adjust the collector to the positions where there is maximum reflected light. Until when the sunlight appears again, the collector will keep on orienting in search for maximum ambient light.