## 2 Materials and Methods
described in the next part. The measurements were performed in two ways. At first, temperatures in the different parts of model object were detected without installation of the photovoltaic module on the model roof. The second experiment was focused on the temperature measurements after installation of the photovoltaic module on the model roof (Figure 1c). For measurements, we used two different types of PV modules. Monocrystalline PV module [39] type SZ-50-36M (Solarfarm, Utrecht, The Netherlands) and polycrystalline PV module [40] type SPP50-10/3a (Victron energy, Almere, The Netherlands). Temperature measurements were performed by temperature sensors REED TP-01 (REED Instruments, Newmarket, ON, Canada) with the accuracy of measurement \(\pm\) 0.75% [41]. A measuring device was set up to measure the temperature 24 times per hour. Temperature sensors were placed with transparent tape from the upside of the roofing, and also from the downside of the roofing and photovoltaic module. One temperature sensor was located between the photovoltaic module and roof sheet. The next one was placed near the roof of the model cowshed. The function of mentioned sensor was detection of the ambient temperature. Measurements were carried out in the interior of the model cowshed by 12 temperature sensors. The temperature sensors were arranged in three levels: The 1 st level-up (S1), middle-the 2 nd level (S2 and S3), and the 3 rd level-down (S4). The levels are illustrated in Figure 2a with red dots. Real positions of sensors are shown on Figure 2b. The sensor distances are given in Table 1. Temperature sensors in the group were spaced 150 mm apart. The layout of the temperature sensors allowed measuring the temperature across the whole model cowshed. The data processing was applied on the measurement results obtained for every season during the year, but detailed results are presented for three model days with similar weather conditions. The model day was extracted from the data obtained for every season (e.g., autumn) by comparison of experimentally obtained day data, and then the average values were calculated for every time point. A correlation analysis was applied on the experimental data. The model day was selected for the best correlation between the data measured during the whole evaluation period and average values for the same period. For every evaluated day the obtained parameters (ambient temperature, relative air humidity, wind speed, intensity of solar radiation) were compared with the monthly average for each point of graphical dependencies. The model day of the season had a high degree of correlation with the average monthly parameters. In particular, the ambient temperature was approximately the same during the day. Measured data for data analysis were selected in the time range from 12 p.m. to 3 p.m. The mentioned time was chosen because the maximum intensity of solar radiation is reached in this period. The next reason for the selection of the mentioned time range was the fact that the PV system produces the maximum energy, and the last reason was the greatest thermal stress of animals in this time interval, which has a direct influence on the THI (THI reaches the maximum). The experiments were performed continuously during the day and night, but no measurable effect on the interior conditions after the PV modules installation  
Figure 2: (a) Layout of temperature sensors; (b) installed temperature sensors inside the model cowshed. at night was found. From the solar radiation intensity point of view, the PV modules installation on the cowshed roof was not considered as significant for night conditions. Monitoring of cow behavior was not performed.