SIMULATION OF UNCOVERED PHOTOVOLTAIC THERMAL COLLECTOR IN MATLAB/SIMULINK

Abstract

The combination of a photovoltaic module and a solar thermal collector into a photovoltaic thermal (PVT) collector allows implementing the principle of cogeneration and, thereby, increasing the efficiency of solar radiation conversion into thermal and electrical energy. The task for optimizing the designs and operating modes of such collectors requires modeling. The paper proposes a simulation model of an uncovered photovoltaic thermal collector implemented in the Matlab/ Simulink software. An equivalent thermal scheme of the collector representing the processes of heat transfer from the photovoltaic module to the liquid coolant and the processes of heat exchange between the structural elements of the collector and the environment has been developed. Based on the thermal and electrical schemes a simulation model of an uncovered PVT collector which allows determining the generated thermal and electrical power, energy conversion efficiency and temperature of structural elements under stationary and variable environmental conditions for different operating modes of the photovoltaic module was created using Simscape blocks. The SUNSYSTEM PVT 240 collector was chosen as a sample, and the structural parameters of this collector were used as the basis for calculating the values of the Simscape blocks. A simulation of collector tests in stationary external operating conditions was carried out. The heat loss coefficient and maximum thermal efficiency were determined based on the obtained heat performance curve. A comparison of these parameters obtained by simulation with the values from the collector specification showed a discrepancy of less than 5%. The deviation of the electrical power values obtained by simulation under different temperature operating conditions from the calculated ones does not exceed 3% which indicates the correctness of the proposed model. The simulation for variable operating conditions showed high efficiency of uncovered PVT collectors for the Ukrainian climate. Developed model can be used to optimize the construction of uncovered photovoltaic thermal collectors, determine their operating modes for different climatic conditions, and also be the basis for substantiating the economic feasibility of implementing generation systems based on photovoltaic thermal collectors.