Due to the initiative of the student working group Renewable Energies, a PV system was put into operation in 1994 under the direction of the institute. The goal was to scientifically supervise the operation through long-term investigations and to offer students an insight into this technology in the form of laboratories and student research projects and diploma theses.
The solar generator has an installed capacity of 1.8 kWpeak. At the location Hannover-Königsworther Platz this corresponds to an annual yield of approx. 1300 kWh. The design of the generator corresponds to the annual energy requirement of a family of 4 with rational energy use. The system consists of 18 monocrystalline modules (MIS-I technology) from Nukem, two of which are uniaxially passive, i.e. without additional energy. The self-commutated inverter with MPP tracking from the company UfE has an output of 1.6 kW.
The solar plant is equipped with a comprehensive measurement technology, which allows a detailed long-term investigation of the plant. The measured values recorded every quarter of an hour are divided into three categories:
- The electrical values provide information about the yield of the system and allow a comparison of the fixed modules with the tracking modules. For this purpose, the voltage as well as the currents and power of the fixed and the tracked level are measured.
- The meteorological parameters show the dependence of the yield on weather influences such as solar radiation, wind and temperature.
- The system parameters, these are mainly the temperatures in the junction boxes and the transistors of the inverter and some digital state variables. These serve to ensure the fault-free operation of the plant.
The measured values are recorded by suitable sensors and, if necessary, further processed by measuring amplifiers, digitized and fed to the measured value recording computer on a universal two-wire bus system. All measured values are recorded, stored and evaluated with programs developed by the institute in order to obtain information about the operation of the plant. For example, the development of the efficiency or the yield advantage of the module tracking over the fixed modules is evaluated over the entire operating time.
