For the case of solar-concentrating collectors, some form of tracking mechanism is usually employed to enable the collector to follow the sun. This is done with varying degrees of accuracy and modes of tracking, as indicated in Figure 2.10.
Tracking systems can be classified by the mode of their motion. This can be about a single axis or about two axes (Figure 2.10a). In the case of a single-axis mode, the motion can be in various ways: east-west (Figure 2.10d), north-south (Figure 2.10c), or parallel to the earth's axis (Figure 2.10b). The following equations are derived from the general equation (2.18) and apply to planes moved, as indicated in each case. The amount of energy falling on a surface per unit area for the summer and winter solstices and the equinoxes for latitude of 35° N is investigated for each mode. This analysis has been performed with a radiation model. This is affected by the incidence angle, which is different for each mode. The type of model used here is not important, since it is used for comparison purposes only.
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Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.