This paper included analysis the conversion efficiency in photovoltaic panels. The tests were done between February and June at a test stand equipped with three commonly used types of photovoltaic panels: poly- and monocrystalline silicon and with semi-conductive layer made of copper (Cu), indium (In), gallium (Ga) and selenium (Se) (CIGS). Five days of each month were selected for a detailed analysis. They were close to the so-called recommended day for calculations in solar power engineering. Efficiency, calculated as the yield of electrical energy in relation to solar radiation energy reaching the panels was made conditional upon solar radiation intensity and ambient temperature. It was found that as solar radiation intensity and ambient temperature increase, the efficiency of solar radiation conversion into electricity is reduced. Correlation dependence was determined for the test data obtained, describing temperature change of panels depending on climatic conditions. It was found that as panel temperature increases, the conversion efficiency is reduced. Within the tested scope of experiment conditions, the efficiency was reduced in the range between 20.1 and 22.8%. The authors also determined the average efficiency values in individual test months together with average ambient conditions of the environment where the process of solar radiation conversion took place.

This paper presents the results of the analysis of thermal issues and energy efficiency of three types of accumulators; namely stone-bed; water and phase change. Research experiments were carried out during April–October 2013 in a standard commercial semi-cylindrical high plastic tunnel with tomato cultivation of 150 m². A stone-bed accumulator; with an area of almost 75 m² was installed in the tunnel below ground level; while a water accumulator with a volume of 4 m³ was installed outside the tunnel. A phase change material (PCM) accumulator, with a volume of 1 m³ containing paraffin, was located inside the tunnel. The heat storage capacity of the tested accumulators and the energy efficiency of the process were determined based on the analyses of the 392 stone-bed charging and discharging cycles, the 62 water accumulator charging cycles and close to 40 PCM accumulator charging and discharging cycles. Dependencies in the form of easily measurable parameters; have been established to determine the amount of stored heat; as well as the conditions for which the effectiveness of these processes reaches the highest value. The presented analysis falls under the pro-ecological scope of replacing fossil fuels with renewable energy. As a result of the analysis; it was found that; in the case of a stone-bed; such an accumulator shows higher efficiency at lower parameters; that is, temperature difference and solar radiation intensity. In turn; a higher temperature difference and a higher value of solar radiation intensity are required for the water accumulator. The energy storage efficiency of the PCM accumulator is emphatically smaller and not comparable with either the stone-bed or the water accumulator.

The essence of the research was to model the actual energy storage system obtained from photoelectric conversion in a phase change accumulator operating in a foil tunnel. The scope of the work covered the construction of four partial models, i.e., electricity yield from solar radiation conversion for three types of photovoltaic cells (mono- and polycrystalline and CIGS), energy storage in a PCM battery, heat losses in a PCM battery and energy collection from photoelectric conversion in PCM battery. Their construction was based on modelling methods selected on the basis of literature review and previous analyses, i.e., artificial neural networks (ANN), random forest (RF), enhanced regression trees (BRT), MARSplines (MARS), standard multiple regression (SMR), standard C&RT regression trees (CRT), exhaustive CHAID for regression (CHAID). Based on the analysis of the error values (APE, MAPE, ΔESR_t), the best quality models were selected and used in the further part of the work. Based on the developed models, a simulation of the influence of the size of the photovoltaic power plant and the type of cells on the process of storing energy from photoelectric conversion in a PCM battery was carried out. For the battery under study, a PV power output of 9 kWp for mono and polycrystalline panels and 13 kWp for CIGS panels is recommended for reasons of energy storage efficiency. The obtained results made it possible to develop a model determining the amount of energy stored in a phase change battery depending on the power of a photovoltaic power plant and variable solar conditions. In order to store the greatest amount of energy, we should choose a source with a capacity to produce at least 70 kWh of electricity per day. In the final stage of the work, the indicators of solar radiation energy storage in the tested phase change accumulator were determined. For the battery tested, the solar energy storage efficiency can reach 12–13% for mono and polycrystalline panels and less than 7% for CIGS panels.

Understanding perception about nature is paramount to understanding human behavior and decision making on the environment. We performed a survey-based study in Brazil and Poland to better understand the perception of land sparing for nature and the perceived value of nature. The countries were selected by intentional sampling and given their importance for local and global biodiversity conservation, and complex socio-ecological context of conservation versus agroforestry business. We performed an online questionnaire (N = 1030) in Brazil and face-to-face interviews in Poland (N = 322). We found that Brazilian respondents demonstrated more pro-environmental attitudes than Polish survey participants. Regarding the question: “How much nature that is left should be spared?”, nearly 51% of Brazilians answered “everything”, compared with 13% of Polish respondents. Just under half of the respondents from Poland (45.6%) indicated that half of the nature that is left should be spared. Brazilian respondents also perceived the intrinsic value of nature to a greater extent compared with Polish respondents; in total, 76% of Brazilians respondents entirely agreed that “Nature, its plants and animals have a value on their own, independent of their usefulness for us” versus 25% of Polish respondents. Our study contributes to a better understanding of the leverage points driving pro-environmental attitudes in both countries.

The aim of the study was to analyse the energy needs of selected consumers and to select the PV installed capacity in the east and west panels orientation (E-W). The analysis was carried out for two variants. The first concerned the impact of the installation power of a PV source on the contracted power in its symmetric east and west position. The second variant was the result of previous observations and studies of the authors of this paper. Thus, in this variant, the unbalanced power of PV E-W in relation to the S azimuth has been analyzed, taking into account the characteristics of the recipients' needs and the variation of the PV power installed. The analyses show that an increase in meeting the energy demand for two of the tested plants at symmetrical power distribution to the east and west occurred only when the installed power was increased to the level of approx. 1.4-1.6 of the contracted power. However, the power distribution in the E-W direction has a very strong effect on the energy amount that is generated in the power plant and cannot be used due to the lack of demand in the plant.