Hamamatsu News 3 / 2019

News 2019 Vol. 3 12 Applications of High Resolution Digital Cameras in Solar Tower Plants Collection of solar energy Solar irradiation serves as a major energy source for renewable electrical energy. This solar energy can be collected either by direct or indirect methods. Direct methods convert radiation energy directly into electrical energy, most commonly through photovoltaic effects. Photovoltaic modules consist of a semiconductor material, which generates voltage and current when light is absorbed in its bulk material. Indirect methods instead use solar-thermal technologies, where sunlight is focussed onto an absorbing material that transforms the radiation energy into thermal energy. The thermal energy is then used to power steam turbines, in the same way as fossil-fuel or nuclear power plants. Solar Tower Plants (STPs) rely on a conceptually simple method of energy generation. However, maximizing their performance and thereby providing an efficient method of energy generation requires knowledge of important parameters such as solar extinction. Let us show you an example of how scientific cameras have been used during the design and operation of STPs, in order to enhance the efficiency of indirect solar power collection. Solar tower plants In STPs, solar irradiation is reflected and focussed by an array of mirrors, called ‘heliostats’, onto a receiver installed on an elevated structure, the power tower. The heliostats feature a tracking system in order to focus solar irradiation onto the receiver throughout the day. The receiver absorbs the concentrated solar irradiation and the result­ ing heat is passed to a heat transfer fluid, which is used for consecu­ tive power generation [Zhang 2013]. Figure 1 shows the layout of an experimental STP at Plataforma Solar de Almería (PSA) in Spain. Solar extinction measurements Upscaling the power of STP is conceptually straightforward but a couple of pitfalls have to be avoided. In a best-case scenario, all of the direct irradiation from sunlight captured by the heliostats would be utilized for power generation. A complication of increasing the size of STPs is a comparative increase in solar extinction between the heliostats Figure 1: Aerial view of the experimental CESA 1 facility at Plataforma Solar de Almería Application Report Figure 3: Solar extinction is routinely measured at PSA.