The article deals with the study of a balanced agroecosystem on the production of crop products, livestock products and biofuel with respect to its energy autonomy with ensuring its environmental safety. The structure of straw use in agroecosystem and its influence on humus balance and level of electric and thermal energy supply is investigated. The balance of humus in crop rotation was chosen as the criterion of ecological safety. The criterion of energy autonomy is the level of providing the agroecosystem with electric energy and thermal energy through the use of biofuels of its own production. The coordination of environmental safety, energy autonomy and economic efficiency was taken as the basis for the functioning of the agroecosystem. In a balanced agroecosystem on the production of crop products, livestock products and biofuel up to 41% of straw should be used to maintain the balance of humus in the soil. Up to 22% of straw can be used to produce heat and electricity for own needs. Up to 37% of straw can be used to produce electricity for sale according to the green tariff.

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.

In this paper, a new technical solution is introduced for the substrate mixing in a digester. The novelty content lies in the direction changes of the gravitational forces that influence the movement of organic and mineral biomass fractions. Digester case is designed as a horizontal cylinder rotating around a horizontal axis. Digester rotates in water that is in the outer casing. This design creates a lift force for rotating digester which reduces the load on the bearings. The friction is reduced and therefore it reduces the energy loss of digester rotation and mixing of the substrate.

In this work, a study was performed on the influence of the ratio of height to the diameter of the reduction zone of a small-size downdraft gasifier as well as of the fuel fraction sizes on the gas quality (the quality was evaluated for CO content). The ratio of a full side area to the volume of a fuel fraction (SVR) was used as a fuel parameter. The maximum CO concentration was observed when using a small fuel fraction with SVR—0.7–0.72 mm⁻¹ and when adhering to the ratio of height to the diameter of the reduction zone H/D—0.5–0.6. The maximum electric power for gasoline generators (nominal power equaled 4 kW) when using the gas received from the fast-growing hybrid willow biomass equaled 2.4 kW. This power is 37.5% lower than when using gasoline and 7.0% lower than when using the gas received from the hardwood biomass. The emissions of harmful gases into the atmosphere by the gasoline generator engine equaled 0.12–0.14% CO and 24–27 mln⁻¹ C_xH_y. The emissions were 64.8 times less for CO and 8.5 times less for C_xH_y when compared with using gasoline.