Vol 55, No 1 (2019)

Dependences of the evaporation temperature and the growth rate on minimal condensation temperature of polycrystalline CdS films in chemical molecular-beam deposition are discussed. The effect of the evaporation rate and the substrate temperature on the morphology of films has been studied.

The possible improvement of the morphology of the CH₃NH₃PbI₃ perovskite layers by adding toluene in the process of obtaining absorber layers under different conditions is studied.

The photogalvanic cells are rechargeable device with the sun light in which surfactant solutions are potentially important for efficient energy conversion and storage. Here, effect of cationic cetyltrimethyl ammonium bromide (CTAB), anionic sodium dodecyl sulphate (SDS) and non ionic tween 80 surfactants on the electrical output of the cationic oxazine dye brilliant cresyl blue (BCB)-fructose (redox couple) system in photogalvanic cells have been studied. For this, the photopotential and photocurrent for different cells having BCB-fructose system without and with surfactant (CTAB, SDS and tween 80) in the alkaline medium have been measured. The total 30 different cells have been prepared for optimizing the concentration of electrolytes corresponding to the higher electrical out put. Generally, the electrical output increases in presence of a particular surfactant, due to increase in solubilization and stabilization properties of dye molecules in the water. The amount of enhancement in electrical output of BCB-fructose system was highest with SDS and lowest with tween 80, i.e. the order for BCB-fructose system with different surfactants in photogalvanic cells is: BCB-fructose-SDS > BCB-fructose-CTAB > BCB-fructose-tween 80. This order for electrical output was good agreement with the stability order of BCB-SDS/CTAB/tween 80 system, on the basis of spectrophotometric study. Hence, among these surfactants, SDS has stronger capacity, (due to opposite charge on BCB and SDS) to stabilize the BCB-fructose system leads to enhancement in electrical output of photogalvanic cells. Therefore, dye and surfactant, having chemical structure, like BCB and SDS, has a great importance of improvement of electrical performance to photogalvanic cells in the future.

This article presents the results of computational experiments aimed at determining the influence of the ambient temperature (\({{t}_{a}}\)), wind speed (v), average working temperature (\({{\bar {t}}_{{avw}}}\)), and emissivity of light-absorbing heat-exchange panels (LAHPs) \(\left( {{{\varepsilon }_{p}}} \right)\) on their thermal losses through the translucent coating (TC) of the case of flat-plate solar water heating collectors (FSWHC) with a single-layer TC.

This work is done to propose a model sufficient to predict in different contexts of global solar radiation on a horizontal plane and other inclined area. This is very important for a variety of applications of solar energy conversion. Indeed, the lack of data before, we will not know what will be the solar potential before to ensure such feasibility or function. After this study, the development of a suitable model for the Biskra site for five angles of inclination, of any solar project was made through an experimental study. The experimental results show, that the values obtained, give a good estimate of the solar radiation and are in good agreement with those given by the elaborate model, which is in agreement with that of Perrin de Brichambaut, also more particularly for an incident on an inclined area.

In this work, the new photovoltaic modules, including the photodetectors and concentrators, providing the effective transformation of solar energy into thermal and electric energy are considered. The creation of the algorithm of the design calculation of the thermo-photo-electric module with the set power parameters with the use of laws of geometrical optics, and also heat and mass exchange are mathematically modelled. When using similar modules, at the heart of which there is a paraboloidal concentrator and a photodetector with the heat carrier’s channel system, the creation of the cogeneration installations for the development of electricity and heat is possible. In the course of the research, a solar module with a parabolic trough concentrator and a line photodetector with a triangular profile, which is supplied with the heat carrier channel system, is developed for the first time and the physical and mathematical models are developed, based on which, the following aspects are developed: the design data of the module; distribution of sunlight concentration across the width of the photodetector; dependences of the thermodynamic values of heat conductivity, the viscosity of the heat carrier (water) on temperature and their ratio from the distribution of the heating of the heat carrier across the profile of the photodetector; distribution of the temperature of the heating of the heat carrier; distribution of the heating energy of the heat carrier; the time of the heat carrier’s heating; and the heating of the heat carrier’s mass per unit of time; the thermal power of the heat carrier and the thermal efficiency of the module (coefficient of efficient use of power of solar radiation), which adequately reflect real parameters of the functioning of the manufactured SB solar modules. It is shown that the thermal efficiency (and, respectively, other power parameters) of a module with a photodetector with a triangular profile at any distribution of the illumination exceeds the thermal efficiency of a module with a photodetector with a rectangular profile. The model samples, developed by such a technique are investigated at the corresponding stands, and are tested in natural conditions. The solar module with the asymmetric parabolic trough concentrator with a line photodetector of a triangular profile of the concentrated radiation with the heat carrier channel system ensures the water heating temperature (ranging from 38 to 60°С) with the reduction of water consumption (from 11.1 to 5.5 l/h), at an illumination of ~850 W/ m², and the thermal efficiency changes within 49–65%.

Integration of a distributed energy generation with several sources is the most promising model for isolated power systems. The integration, where generation occurs due to renewable energy sources (RES), adds new dynamic elements to the distribution networks because of the stochastic indicators of the renewable energy sources. In order to ensure the normal functioning of the power system, it is proposed to develop an algorithm for its functioning.

The problem of preparing a compensated material is solved by the radiation technology method (by irradiating the silicon single-crystal with fast neutrons), which makes it possible to intentionally change the photoelectric parameters of silicon. The changes in the photoelectric parameters of the compensated samples are monitored by measuring the R_d/R_l ratio, and the possibility of creating photo and thermal sensors with identical characteristics, operating within the temperature range of 30 to 100°C, is shown.

A report on the computer software developed for determining actinometric data based on the long-term observations from satellite and terrestrial measurements for the regions of Uzbekistan. The program is created in the Delphi environment for 32 and 64-bit Windows systems.