• Energy Research
• engineering and technology close
• 6. Clean water close
• UA close

The concept and a new method for the shielded development of bottom gas hydrates have been proposed, the technological phases and constructive elements of their implementation have been substantiated. The research provides for the realization of the idea suggesting the simultaneous dissociation of the vast areas of a gas hydrate deposit, management of the targeted process of the penetration of methane recovered from gas hydrates into water space and its accumulation under the extensive gas-collecting shield wherefrom it is removed by bottom pipe transportation facilities. To do hydraulic fracturing, a well is drilled into the plane of the junction of the surface of a gas hydrate deposit and the rocks of a roof, the open system of fissures in the rocks of a roof is made through which produced gas is released to a gas-collecting blanket in a water.

The mathematical model of heat flow and transfer in roof rocks of underground gas gasifier during coal gasification is developed and tested. In terms of geological conditions in the Olkhovo-Nizhnee site (industrial region in Donbass), in Mathcad environment, convective and conductive components of heat flow from reaction channel to upper-lying aquifer are determined. The change in the heat flow from the reaction channel and in the ground water temperature is estimated depending on impermeable layer thickness and water well yield. It is found that after underground coal gasification, water-bearing sandstones accumulate more than 60% of heat migrating from gasifier to enclosing rock mass. It is shown that withdrawal and use of water heated during underground coal gasification will enhance efficiency of the process by 18–25% subject to thickness of partition layer.

Due to urbanization, large portions of vegetated territory have been replaced by waterproof surfaces. The consequences are greater outflows, lower infiltration, and lower evapotranspiration. Pavement systems made with permeable surfaces allow the infiltration of water, ensuring reduction of runoff volume. In this paper, the methods of analysis of the hydrological and environmental performance of the pavement systems are reviewed in the context of urban drainage and regarding their durability. The purpose is to present an overview of the studies published during the last decade in the field. The Pubmed and Web Science Core Collection electronic databases were used to conduct the scientific literature survey. This generated 1238 papers, of which only 17 met the criteria and were included and discussed in this review. The evidence drawn from the knowledge on which the document is based provides useful critical interpretations of existing studies to progress the current understanding on hydrological performance and environment impacts in terms of conventional pollutant removal efficiency and the current permeable pavement systems.

We have tested the microwave device of continuous operation for the thermal treatment of plant materials, which was developed and designed to implement microwave technologies in the industry. The purpose of the tests was to assess the effectiveness of the microwave device by the indicators of quality of the obtained material and energy consumption determined by the efficiency of the conversion of microwave energy into the internal energy of the material. The effects of microwave treatment of a straw substrate for tree-destroying fungi were studied. The treatment quality was determined by the yield of Oyster (Pleurotus) mushrooms, grown on the obtained substrate. Microwave treatment was carried out in various modes, which differed in the value of specific power. When analyzing the effectiveness of microwave treatment, the results were compared with the data obtained during the application of the traditional technology of straw sterilization. It was shown that the harvest of Oyster mushrooms increased by 11 %. It was found that under the optimal mode, specific power was q v =8.68·10 5 W/m 3 , final temperature was t=96 °С, duration of treatment was 180 s. Based on the thermal calculations, the values of the microwave chamber efficiency η c were calculated; under the optimal mode, η c =62 %. The influence of the microwave treatment on the sowing characteristics of seed wheat grain was studied. The effectiveness of the microwave treatment was determined by the values of laboratory germination and seed germination energy. Under the optimal mode, the output power of magnetrons was ΣP out =0.6 kW, the grain consumption was G=2.1·10 -2 kg/s. The study of the microwave device operation showed that for this design, in order to ensure stable and uniform movement of the material along the product pipeline, it is necessary to maintain the movement speed that is not higher than 0.5 m/min. It is recommended to apply the tested microwave device of continuous operation on specialized farms

Electrodialytic desalination of cheese whey was carried out using a pair of polymer cation exchange (Nafion 117) and inorganic membranes. The ceramic separator was modified with nanocomposite containing hydrated zirconium dioxide and basic bismuth nitrate. This amphoteric filler provides anion exchange ability of the composite membrane. This property is realized when at least one side of the membrane is in contact with an acidic solution. Ion transport through the membranes was shown to be determined by current, whey acidity, and also by composition of the solution in the concentration compartment of the electrochemical cell. It was shown that whey desalination occurred under overlimiting current. Acidification of whey and decrease of the acid content in the concentrate suppress ion transport. The electrodialysis of whey and nanofiltration permeate allowed removal of up to 80% of the mineral components in 5 h and 40 min, respectively. Preliminary ozonation of the permeate increased the rate of desalination.

Absorption refrigeration units (ARU), which are part of absorption refrigeration devices (ARD) with a natural working fluid (water, ammonia and hydrogen) have a number of unique qualities. These qualities include: noiselessness, high reliability and long life; the possibility of using several energy sources in one device. At the same time, ARDs have increased energy consumption compared to similar compression models, and this does not allow them to expand their presence in the market of household refrigeration equipment. The ARU evaporator provides a predetermined temperature level in the chambers of the refrigeration appliance and the required cooling capacity. In this regard, it is relevant to search for the operating modes of the evaporator that provide the ARU maximum energy efficiency, which is the aim of this work. The thermal conditions of the direct-flow three-pipe design of the evaporator are simulated. The calculated ratio for a once-through evaporator is obtained taking into account the assumption of the adiabaticity of the evaporation process, when all the heat of the phase transition is used to cool the incoming flows of the purified vapor-gas mixture (VGM) and liquid ammonia to a minimum temperature. The analysis of the results of calculating the operating modes of the evaporator made it possible to determine the directions of ways to increase the energy efficiency of both the evaporator itself and the ARU in general: a) preliminary cooling of the purified VGM flow at the inlet of the adiabatic section of the evaporator with an under-recovery of up to 5 °C and up to 10 °C; b) preliminary cooling of the liquid ammonia flow at the inlet of the adiabatic section of the evaporator with an under-recovery of up to 5 °C for all ARU types; c) increasing the purification degree of the VGM flow in the absorber allows increasing the temperature of the purified VGM flow at the inlet of the adiabatic section of the evaporator by 4...6 °C, i. e. to reduce the costs of useful cooling capacity for pre-cooling by 10...15 %

Study region: Eight main river basins covering the major part of Ukraine. Study focus: The main aim of this study was to provide an assessment of climate change impacts on water availability across Ukraine using global hydrological models. Six global hydrological models were evaluated for their performance in the historical period in the basins under study. Future river discharge was simulated by using the best performing model and all available models driven by bias-corrected GCM projections from the ISIMIP project under the RCP 2.6 and RCP 8.5 scenarios. New hydrological insights for the region: The results show precipitation increase up to 10 % under RCP 2.6, and variable changes from -14 % to +10 % under RCP 8.5 by the end of the century. The projections show the decreasing mean annual river discharge in the majority of basins for the middle (2040–2070) and far future (2071–2100) periods under both RCPs, and the decrease is stronger under RCP 8.5. The seasonal changes are characterised by a decrease in summer and a small to moderate increase in winter months in most of the basins. The highest reduction of mean annual discharge was projected for the Pripyat, Southern Bug and Dniester basins, reaching up to -30 % to the end of the century under RCP 8.5.

Optimization of the water flow distribution is an important problem in the field of the operative control over technological processes in water supply systems. In this article we describe the comparative analysis results showing the efficiency of various methods used to optimize flow distribution in water supply systems with a large number of active sources. The research has shown that the Hooke and Jeeves method of the direct search is the most efficient in terms of the cost of computer time and the amount of used memory.