Dissertation for obtaning the Doctor of Technical Sciences degree in specialty 05.14.08 — Transformation of renewable energy. Institute of Renewable Energy of the National Academy of Sciences of Ukraine, Kyiv, 2021.
The thesis considers the actual scientific and applied issue of the development and improvement of methods for analyzing the electrothermal state of photovoltaic panels, solar collectors, photothermal modules and power supply systems based on them, in which interconnected processes of various physical nature occur. Scientifically based technical solutions and standard and technical documentation have been designed that provide an increase in energy efficiency and reliability.
The analysis of electrothermal state of photovoltaic panels, solar collectors and photothermal modules was performed based on the electrodynamic models of solar radiation absorption using Maxwell’s equations system, transformed into canonical form of hyperbolic and parabolic equations. Using the method of complex amplitudes, data on the spatial distribution of solar radiation intensity during absorption and the spatial distribution of volumetric heat release rate were obtained. The data showed a sharply inhomogeneous distribution of these parameters, as well as the distributions of temperature and temperature gradients dependent on them. These results enabled to create new heat sinks from composite materials for photovoltaic panels and solar collectors.
According to I. Prihogine's methodology, taking into account the experimental dependence of active elements characteristics (in particular electrical conductivity) on temperature and spatial coordinates, analysis of interrelated processes instability (thermal, electrothermal, thermal diffusion, etc.) was performed regarding the probability of spatially inhomogeneous structures formation and the occurrence of self-oscillating modes in time, which lead to degradation of functional materials characteristics and, accordingly, to a decrease in the basic equipment reliability and resource.
For "photovoltaic panels-autonomous load" systems of different types (resistance, DC motors, etc.), taking into account the nonlinearity of the current-voltage characteristics, the conditions for maximum use of the electric power of photovoltaic panels with load have been determined.
The obtained results were used to develop 18 state standards of Ukraine in the field of solar energy.
Key words: solar power, energy transformation processes, solar power supply systems.
