Concentrating Photovoltaics CPV
Solar sensors are crucial during the phase of development and operation. Even at high sunny places, the composition and variability of the atmosphere strongly affects the solar spectral distribution and will impact on the energy yield and the decision on which cell type to use. The pyrheliometer in combination with the spectral radiometer for DNI measurements accurately pinpoint the solar prospect for certain sites, the spectral impact on the performance and efficiency of the module.
Once a PV system has been designed and planned it will be realised in the field along with adquate PV monitoring equipment. PV monitoring systems keep a close watch on the PV system performance and monitor individual components, such as inverters and module strings. Usually, a PV evaluation system tells the operator accurately how much performance assessments is larger than ever before. In the highly competitive module market, module manufacturers want to demonstrate the real- world performance of their products to point out their competitive advantage.
The performance of a PV module is measured at the factory under the so called Standard Test Conditions, described in IEC 60904. This is a convenient test method that can be integrated in routine production procedures. However, the indoor measurement of the PV performance at STC reveals the power production of the module at only one, particular measurement condition, as defined in the norm. So, these STC performance values do not automatically reveal the PV power production at the site-specific meteorological conditions. When using the PV module at higher latitudes and at relatively high temperatures the module label values might be misleading and might over-estimate the PV power production at this location.
Concentrated Photovoltaics systems convert solar irradiance into electrical power similar to conventional PV systems, however those make use of an optical system to concentrate solar energy. A large area of sun light is focussed by primary and secondary optics on a small spectrally enhanced photo cell which makes the energy conversion very efficient. Different from PV cells CPV cells must be mounted on a 2-axis sun tracker to capture the direct beam.
Depending on the technology used solar energy can be concentrated from 10 - 1000 suns (1 sun = 1000W/m2). In practice two different optical systems are used, a mirror type or fresnell lens type, with the same goal to focus solar light on small photocell and get more energy from less photovoltaic material.
Nowadays CPV solar systems are a viable alternative to conventional PV systems. Systems perform at a higher efficiency (~30%) rate, due to an alt least triple cell architecture that covers the solar band up to 1700nm. Higher energy yield per surface area due smaller modules compared to PV. Give extended high Energy yield during daytime since the solar direct is captured. On top of that tracker and cell materials are relatively inexpensive and less bulky.