Energy balance of the photovoltaic system is influenced by many factors. In this article the effect of tilt and azimuth angle changes of the photovoltaic system energy production is analyzed. These parameters have significant impact on the amount of solar radiation which hits on the photovoltaic panel surface and therefore also on the energy absorbed by the module surface. The main aim of research was identification of the optimal position of photovoltaic system installation in the southern Slovakia regions. The experimental apparatus had two setups consisting of polycrystalline photovoltaic modules. The first setup was used for identification of the tilt angle changes in the range (0–90°). The second one was focused on the detection of the azimuth angle effect to the energy production. The measurement results were statistically processed and mathematically analyzed. Obtained dependencies are presented as two-dimensional and three-dimensional graphical relations. Regression equations characterize time relations between the tilt or azimuth angle and the energy produced by the photovoltaic system in Southern Slovakia. Obtained simplified mathematical model was verified by analytical model. Presented models can be used for the dimensioning and optimization of the photovoltaic system energy production.

Thermal characteristics represented by thermal parameters are very important for wood and wood-based products. They are influenced by internal and external factors such as: structure, temperature, moisture content, etc. Based on these factors the main aim of this article is the presentation of...

This paper is focused on the temperature measurements which can detected the influence of temperature changes on the microclimate in animal production building after the installation of photovoltaic (PV) modules. The first series of experiments were performed on a specially designed model cowshed. For the data comparison and verification, the same measurements were realized in real conditions of the animal production object. The temperature balance was identified by measurements of the temperatures in the different parts of roof, PV modules, and the most important were measurements of the ambient temperature and temperatures in three levels of the cowshed interior. For the confirmation of results, measurements were done in two cowsheds, which had the same azimuth orientation and roof slope. The first cowshed was without installation of the PV modules on the roof and the second building had installed PV modules. By the data analyzed from experimentally obtained time-temperature dependencies, it was found that the installation of PV modules on the cowshed roof had a positive influence on the interior temperature balance. The installation of PV also had a positive effect on the cowshed microclimate, which was declared by calculation of the Temperature—Humidity—Index.

Due to expansion of utilisation of photovoltaics in ordinary households, the question arises how this phenomenon affects the electric power of photovoltaic modules. The article deals with the electric power analysis of photovoltaic modules as a function of two very important factors. The first examined factor was partial shading, and the second factor was the intensity of reflected radiation. In order to determine the dependence of module power on the aforementioned parameters, a measurement system under laboratory conditions has been prepared. For identification of the reflected radiation effect on the power of the photovoltaic module, a series of measurements was performed on 7 different surfaces with the same radiation source. It is evident from obtained experimental result that the ratio of reflected irradiation on the solar module power is 1.29%. By simulation of partial shading of photovoltaic module, the decrease of 86.15% in its output power was identified.

The article deals with the impact of selected external factors on the temperature of photovoltaic module surfaces. Primary aim of this research is creation of temperature model for photovoltaic module, which would be usable under the real climatic conditions in Central Europe region. Fully autonomous measuring system was designed and created for temperature monitoring of different parts of photovoltaic modules. The measuring system consists of 24 temperature sensors, voltage inverter, control unit, transfer modules, receiver modules and temperature measuring module. The experiments were performed on photovoltaic modules installed on the roof of the University of Life Sciences in Prague during summer 2018. The temperature of photovoltaic modules significantly depends on the climatic conditions, which were monitored by the weather station. The temperature and the solar radiation dependencies for polycrystalline and monocrystalline photovoltaic modules were obtained in experiments conducted. The temperature relations were measured for different parts of photovoltaic module – active parts of photovoltaic module, frame, non-active parts of photovoltaic module, as well as ambient temperature. Final mathematical description of polynomial graphical dependencies was obtained after application of fitting procedure and regression analysis.

The primary purpose of this study is to create a thermal model of a photovoltaic module which is usable under real climatic conditions in the Central Europe region. The system for temperature measurements of the photovoltaic module was designed and built at the Department of Physics SUA in Nitra. The climate data utilized in the present study were obtained from a weather station. The measurements were performed during the summer on PV modules. The results obtained indicate that the response of the module temperature is dynamic with changes in irradiance and module temperature, particularly during the periods of fluctuating irradiance. Mathematical descriptions of the obtained time-temperature and time-irradiance relations were made on the basis of the experimental results obtained. A second-degree polynomial function was established for every graphical relation obtained with relatively high coefficients of determination. The temperature model of PV modules was generated after fitting the experimental results to real dependencies and correlation analysis values.