Motivation of a material of the sensitive element of an electronic system for determination of the global solar radiation

In this study the requirements have been analyzed for the material and for the selective coating properties of the sensitive element of a low-cost electronic system for measuring the total solar radiation. The key problems for achieving the desired error in measuring total solar radiation, as well as the ways to solve them, are described. A criterion for estimation of the absolute error of pyranometer have been defined, depending on the properties of the sensitive element and its selective coating. A specialized software application has been developed, implementing the developed criterion for estimation. With its help a simulation was performed, that uses the thermal properties of different materials and selective coatings. The results from the simulation show that out of the investigated materials, the most appropriate is aluminium, and the requirement for the selective coating is that it reflects less than 10% of the solar energy. Under these conditions the device would have an absolute error e ±10W.m^-2