Experimental study into the influence of straw content in fuel on parameters of generator gas

The objects of this research are double-sided stationary vertical photovoltaic modules (PV-modules) with an “East–West”-oriented solar panel. The tilt angles of the Sun’s rays on PV-modules at a latitude of 50° were determined, and the installation efficiencies of both double-sided stationary vertical PV-modules with an “East–West” oriented panel and PV-modules installed at an angle of latitude with a “South” oriented panel were compared. The horizontal azimuth of the fall of the Sun’s rays during the day when using PV-modules with an “East–West”-oriented panel reaches a minimum at noon. The vertical azimuth of the Sun’s rays remains constant throughout the day and can vary from 66.55° to 113.45°. The weighted average daily installation efficiency of PV-modules with an “East–West”-oriented panel has the same value as that of PV-modules with a “South”-oriented panel, and can vary between 45.87 and 50% on different days. However, these installation options have a “mirror” value of the cosines of the Sun’s rays falling on the surface of the PV-modules and can have values from 0.917 to 1. The results can be used as a basis for evaluating the efficiency of double-sided vertical stationary solar PV-modules with an “East–West”-oriented panel.

This study presents the experimental results obtained from hybrid filtration combustion using biomass pellets. The experiments were carried out using a porous media gasifier filled with pellets and inert material. The gasifying agent used was an air–steam mixture, with 40% being steam. The dependence of the temperature in the gasifier’s reaction zone from the volume percentage of inert porous material in the gasifier, the specific heat capacity of this material, as well as the air–steam blowing rate, was investigated. The multifactor experiment method was used. A maximum temperature of 1245 °C was achieved using 28 vol% of porous material with a heat capacity of 1000 J/(kg·°C) and at a blowing rate of 42 m³/h. The maximum hydrogen content in the syngas was 28 vol%. This was achieved at an air–steam blowing rate of 42 m³/h and 40 vol% porous material, with a heat capacity of 1000 J/(kg·°C). The calorific value of the syngas was 12.6 MJ/m³. The highest CO content in the gas was 28 vol% and was obtained at 20 vol% porous material with a heat capacity of 1000 J/(kg·°C) and a blowing rate of 42 m³/h. The obtained information is applicable in the design, management, and control of gas production by way of a hybrid filtration combustion process in a downdraft gasifier.

The object of this study is photovoltaic modules in various installation options. The physical model of the Earth's illumination by a parallel flow of solar rays has been refined. The dependence of the cosine of the angle of incidence of the Sun's rays on the angular length of the day, as well as the average annual efficiency of the installation of photovoltaic modules, both fixed and with various tracking options, was determined. Refinement of the physical model implies determining the angle of inclination as the angle between the inclined axis of the Earth and its projection on a vertical plane, perpendicular to the line connecting the centers of the Earth and the Sun. This line passes through the center of the Earth. The concept of the average annual efficiency of the installation of photovoltaic modules is introduced as the annual weighted average value of the cosine of the angle of incidence of solar rays on the plane of the photovoltaic module. Various options for installing photovoltaic modules were analyzed: fixed horizontal on the equator; stationary, installed at an angle to the horizon; one that performs tracking in horizontal (vertical) planes; with full tracking. The efficiency of installing a photovoltaic module at each latitude can be equal to the efficiency of installing this module at the equator, that is, 47.93 % when installing the module at an angle of inclination to the horizon equal to the latitude. Tracking in the vertical plane makes it possible to increase the efficiency of the photovoltaic module installation by up to 50 %. Compared to full tracking, tracking in the horizontal plane at an angle of latitude makes it possible to obtain the efficiency of the installation of the photovoltaic module at the level of 97.93 %. The results could be used as a basis for evaluating the efficiency of the installation of photovoltaic modules at different latitudes with different techniques of their installation, as well as for the subsequent generation of electricity

The object of this study is photovoltaic modules with different options for the angle of their installation to the horizon at different geographical latitudes. The scientific problem to solve was determining the dependence of the average annual efficiency of solar photovoltaic modules on the mounting angle of photovoltaic modules and the value of geographical latitude. It has been proven that the efficiency of installation of solar photovoltaic modules can be increased by reducing the angle of their inclination to the horizon depending on the value of the geographical latitude at which they are installed. The average annual efficiency of photovoltaic modules with different mounting angles to the horizon at different geographical latitudes was determined as the annual weighted average value of the cosine of the angle of incidence of solar rays on the plane of the photovoltaic module. The maximum of the average annual efficiency of photovoltaic modules corresponds to a smaller value of the angle of their installation to the horizon than the value of the geographical latitude. So, with a latitude value of 10°, 20°, 30°, 40°, 50°, and 60°, the mounting angle of photovoltaic modules to the horizon will be 9.5°, 18.8°, 28°, 37°, 45.8°, and 54°, respectively. A dependence was derived that allows determining the mounting angle of photovoltaic modules to the horizon dependent on the value of the geographical latitude at which they are installed. A mathematical expression was also constructed that makes it possible to determine the average annual efficiency of photovoltaic modules depending on the angle of their installation to the horizon for different values of geographic latitude. The results could be used in calculating the average annual efficiency of photovoltaic modules based on the adjusted values of the angle of their installation to the horizon at different geographical latitudes

The object of the present research is a machine-tractor unit based on a tractor consisting of an energy (high-energy tractor—EM) and a technological (additional traction axle—TM) module. This tractor uses three-row crop cultivators, each with an operating width of 4.2 m. One of these cultivators is attached centrally to the technological module, and the other two are connected to the sides of the energy module in its front part. The research aimed to determine the influence degree of such a unit scheme and design parameters on the stability of its movement in the horizontal plane. The theoretical analysis was performed using amplitude (AFC) and phase (PFC) frequency characteristics obtained based on the developed mathematical model of the modular unit movement when it processes a disturbing effect. The difference in traction resistances of the unit’s side cultivators was adopted as the latter. Finally, it was established that blocking the vertical hinge of the TM contributes to a significant increase in the unit motion stability. The practical implementation of this method of joining EM and TM in the horizontal plane allows the unit to work out a disturbing influence in the frequency range 0.65–5.50 s⁻¹ to eliminate the resonant AFC peaks and reduce their value. When the TM hinge is locked at a torque oscillation frequency of 2.5 s⁻¹, the AFC is 2.82 times less than when it is free. Blocking the TM vertical hinge increases the delay in the unit’s response to a disturbance. At an oscillation frequency of the latter of 1.5 s⁻¹, this delay is 0.6 s, and at a frequency of 0.5 s⁻¹, it increases by more than three times, reaching a level of 1.9 s.