Radiation sensors are used to get an indication of the efficiency of photovoltaic systems. These sensors are intended to be used at any time to reproduce the actual gained solar yield of the PV system.
This paper deals with the different ways to capture solar radiation, and is intended to show what methods can reproduce the performance of the system best. It will be shown that the radiation sensors do not usually reproduce the actual energy output of the facility because they do not work with the same parameters of the plant itself. These parameters include the different spectral sensitivities of the various solar cells, as well as the different temperature behavior of the sensors. Even the unequal reflection behavior of different materials, that are used as surface protection, have an influence on it. Different environmental factors such as aging, pollution and damage to the sensor have a role in determining the efficiency of the system. With solar sensitivity, does it have to be taken into consideration, which wavelength of the light spectrum has more or less influence on the different solar cells? This also results in a different behavior at different times of day, which results in the following question: "Which sensor works in which plant types?" The most commonly used systems are based on the basis of thermoelectricity. With this type of measurement the relationship between temperature and spectral sensitivity of the sensor has to be considered in more detail. By the effects of aging, solar cells will also change their efficiency. This can be achieved by varying the speed of the aging Process at different solar modules to produce a different income between the sensor and the system. With the reflection properties of a sensor, one must pay attention to the reflection of light rays through the surface protection, as well as on the surface condition of the cell itself. Here it must be noted that the structure of the cell as well as the color will change the properties of the PV system.