Applied Solar Energy最新文献

The work presents a technological diagram of a heliopyrolysis device with a parabolic concentrator for the thermal processing of biomass and organic waste to produce alternative fuel. An experimental heliopyrolysis device was created and its main characteristics were substantiated. The results of experimental studies of the temperature regime and material balance of pyrolysis of biomass and various organic wastes are presented, taking into account the intensity of solar radiation in the conditions of the city of Karshi. An analysis of the material balance of pyrolysis of biomass and organic waste using concentrated solar energy was carried out. It has been established that through the use of a parabolic solar concentrator as the main heater of the reactor, it is possible to create the required temperature regime for pyrolysis within the temperature range of 350–500°C. The cycle duration of the biomass pyrolysis process averages 180–240 min. The conducted studies show that during the daytime in sunny weather, three or four cycles can be carried out in the proposed unit. As a result, it becomes possible to compensate for the thermal energy that is consumed for the device’s own needs with solar energy. It was concluded that with slow pyrolysis of biomass and organic waste, the intensity of the yield of gaseous fuel increases from 10 to 30% with an increase in temperature from 100–350°C; the yield of liquid pyrolysis products in the temperature range of 150–350°C increases from 5 to 22%. The analysis of the temperature regime and material balance of the heliopyrolysis device shows the feasibility of its use for the producing alternative fuel from biomass.

The spectral and angular distributions of the intensity of diffusely reflected and transmitted solar radiation fluxes in the atmosphere, resulting from multiple Rayleigh scattering on air molecules, have been studied. Additionally, calculations of the spectral distribution of total fluxes of diffusely reflected, transmitted, and unscattered solar radiation exiting the atmospheric layers have been performed. It is demonstrated how the redistribution of these fluxes across the spectrum occurs depending on the angle of illumination. The calculations of diffuse radiation intensity were carried out within the framework of the theory of Chandrasekhar’s (X,Y) functions theory, developed using the factorization method.

Global warming driven primarily by human activity, underscores the urgency of reducing reliance on fossil fuels and curbing greenhouse gas emissions. The construction sector alone accounted for a staggering 37% of all carbon emissions in 2021. The application of solar architectural principles is emerging as a key strategy to reduce the carbon footprint of civil buildings. This approach includes passive and active solar techniques, alongside energy-efficient measures. Passive strategies include optimal building orientation, envelope improvements to minimize heat exchange, and the use of shading devices. Active measures include the integration of renewable energy sources. In a practical demonstration, a residential building in Russia’s Kaliningrad region illustrates the implementation of these principles. Using passive solar measures and rigorous energy calculations, the building achieved an A+ energy saving class. In addition, the integration of active solar elements, including a 4.5 m² evacuated thermal collector and 3.56 kW photovoltaic panels, along with an air-to-water heat pump, resulted in a 72% reduction in annual energy consumption for heating, hot water, and electricity—from 27.695 to 7.697 kWh. This results in a significant reduction of 10 tons of carbon emissions per year. This illustrates the potential of solar architecture in advancing sustainable building practices.

In solar technology mirrors are used with an outer and rear coating of a reflective layer. The reflection coefficient of mirrors with an external coating is greater than that of mirrors with a rear coating, but over time it decreases due to the destructive effects of the external environment. Therefore, solar technology began to apply mirrors with an external coating and a protective film to protect them from the effects of the external environment. The paper presents the results of computer simulation of protective films for aluminum mirrors. It is shown that dielectric films with a refractive index from 1.38 to 1.8 have practically no effect on the reflectance of an aluminum mirror if their thickness does not exceed 15 nm. To protect the surface of an aluminum mirror, SiO₂ + Al and ZnS + MgF₂ mixed films with a thickness from 10 to 15 nm with a SiO₂ and ZnS concentration of 10% are recommended. Of interest is a MgF₂ + ZnS film with a MgF₂ concentration of 43% and a thickness of 10–15 nm. The film reduces the reflection coefficient of the mirror by no more than 2% and has no internal stresses.

Throughout this article, we explore several generations of photovoltaic cells (PV cells) including the most recent research advancements, including an introduction to the bifacial photovoltaic cell along with some of the aspects affecting its efficiency. This article focuses on the advancements and successes in terms of the efficiencies attained in many generations of photovoltaic cell and discusses the challenges of each generation. Monocrystalline silicon dominates the solar cell market, and other technologies are still being developed in order to commercialize them. As an illustration, recent solar cell technology, known as the fourth generation and containing graphene, has been discussed. To determine if the damaged solar panel pieces would function or not, a test was conducted, it showed that even after being cut into small pieces, the open circuit voltage had not changed. The bifacial photovoltaic technology has been briefly reviewed in the review, including the substrates used, cell texturing, antireflection coating, cell reflectors, etc. Bifacial photovoltaic (PV) performance will continue to profit from studies on higher conversion efficiencies linked to monofacial PV cells. It is important to do studies within the area of bifacial PV modules in order to boost their performance, efficiency, and market value globally.

Several researchers tended to study and develop vortex technologies to generate clean electric power, it generates a vortex updraft air stream while operating at a moderate temperature scale. The conventional solar air collector with a vortex engine has been shown to be insufficient for starting and maintaining updrafts by a previous model. So, this research sought to propose and design a new solar vortex engine system and improve the system by conducting a set of calculations carried out by the ANSYS 2020 R2 simulation program. The research focuses on increasing the performance of the proposed model by changing the angle of the Guide Vane to increase the vortex force generated where four angles are proposed. Where four different angles were proposed that are close to the angles of previous studies (10°, 15°, 20°, and 25°). The air intake speed has been changed on each proposed angle. The proposed model was validated by its general behavior, which is similar to previous studies in performance. After a comparison was made between the results of the proposed models, it was found that the angle of 20 deg gives the highest performance of the model that was designed and tested using the ANSYS program.

Sb_xSe_y thin films were obtained from precursor of pure antimony and selenium granules evaporated in the temperature ranges from 980 to 1025°C for Sb and 415 to 470°C for Se by chemical molecular beam deposition method on glass substrates. It was found that the films consist mainly of the Sb_xSe_y phase and have a different Sb/Se ratio in the range from stoichiometry to 0.89. Controlling the fraction of components allows to change the orientation of crystallites, which, in turn, leads to changes in electrical conductivity.

In this study, the efficiency of air velocity on solar panels during cooling was studied based on temperature and solar radiation in the environment where the panels are located. When the panels cool down, the temperature of the rear panel decreases and, accordingly, the idle voltage of the panels increases. Currently, the most significant losses in panels are associated with an increase in the temperature of the panels, depending on solar radiation and outdoor temperature. The article presents mathematical modeling of turbulent natural air convection in a heated photovoltaic solar panel. The considered problem, despite its relative simplicity, contains all the main elements characteristic of currents near the wall caused by buoyancy forces. A significant disadvantage of the algebraic Reynolds-Averaged Navier—Stokes (RANS) turbulence models for solving this problem is that for them it is necessary to set the transition point from the laminar to turbulent mode from the experiment. Therefore, the work uses the modern Spalart—Allmares (SA) turbulence model, which has a high rating in the NASA database. In order to verify the model, the obtained results are compared with known experimental data. It is shown that the SA model describes the turbulence zone well. The paper shows that an additional force arises as a result of the temperature gradient, which plays an important role in describing turbulent natural convection. The results show good agreement with the experimental data.

This article analyzes various methods and installations for heat removal from the surface of solar photovoltaic modules (PVMs). The distribution of solar energy in a PVM is theoretically substantiated. A cooler has been developed, consisting of a body and two fittings through which the coolant flows. Experimentally, an increase in the efficiency of solar PVMs by 9.3% using the developed cooler was revealed, and it was proven that the use of such solar photovoltaic stations near pumping stations gives an increase in efficiency.

Solar thermal power generation has broad development prospects in China’s energy market due to its excellent power quality, continuous power generation, low manufacturing costs, and no pollution to the environment. Based on the theoretical support of computational fluid dynamics, structural strength theory, and Monte Carlo ray tracing method, ray tracing analysis on parabolic trough collector were carried out, to ensure that the concentrating efficiency of collector under the specified wind speed stays within the standard range. Based on the existing parameters, the collector is three-dimensional modeled. The size of the fluid domain was calculated. The calculation model was meshed, and the boundary conditions were set, according to the change of the wind force on the collector under different working angles. The best danger avoidance attitude and the most appropriate maintenance attitude of the collector are obtained, use the data transmission interface between ANSYS and Fluent software to perform a unidirectional fluid-structure coupling analysis on the collector, and pressure-transmit the surface wind pressure of the collector analyzed by Fluent software. Calculate the displacement deformation and equivalent stress distribution of the collector under the effect of wind pressure, Analyze and evaluate its structural strength. The ray tracing software Trace Pro is used to calculate the concentration efficiency under different wind speeds and working angles. Obtain the changing law of the collector efficiency under different wind speeds and different working angles, analyze whether the working efficiency meets the requirements under the two conditions of the design work.