Search

The hollow fiber membrane energy accumulator (HFMEA) and the flat membrane energy accumulator (FMEA) were designed. Dynamic mathematic models of the heat and mass transfer in the full-scale membrane energy accumulators (MEAs) were built in order to consider the membrane-to-membrane interactions and boundary effect in MEAs. The reliability of mathematic models has been verified by the experimental results. The maximum relative deviations of the mass transfer flux and solution temperature were 14.9 % and 14.6 %, respectively. The change rate of LiBr mass fraction in the FMEA was 1.38 times of that in the HFMEA. The hollow fiber membrane bundle in HFMEA is more conducive to the mass transfer process when the arrangement of the fibers is triangular. When the length of the membrane channel increased from 50 mm to 160 mm in HFMEA, the mass transfer per membrane surface area decreased by about 5 %. With increasing the vapor inlet pressure from 700 Pa to 1500 Pa, the mass transfer flux was tripled. And the average temperature of the solution increased by more than 3.75°C in 10 minutes. If the membrane filled density increased from 1.4 % to 2.1 %, the mass transfer flux increased to 2.04 times in FMEA.

An experimental platform was set up to test the heat and mass transfer performance inside the membrane energy accumulator (MEA). Hollow fiber MEAs (HFMEAs) and flat MEAs (FMEAs) were designed and tested. Compared with HFMEAs, FMEAs have higher mass transfer efficiency. The average mass transfer speed of the water vapor increased by 108.34% when the evaporation temperature increased from 4.5 °C to 12.3 °C for HFMEA. When the evaporation temperature increased from 7.88 °C to 19.51 °C, the change in mass fraction of lithium bromide (LiBr) in FMEA increased by 62.36%. Compared with a 60% solution, the average mass transfer rate of water vapor molecules in a 70% LiBr solution increased by 49.83% for FMEA. In addition, the water vapor absorbed by the 70% LiBr solution in 30 min increased by 18.63% compared to that of the 60% solution for FMEA. The effect of the initial solution temperature on the mass transfer rate is closely related to the mass fraction of LiBr. Both the mass transfer rate and crystallization melting process of the LiBr solution will accelerate by increasing the initial mass fraction and evaporation temperature.

Objective. In the case of a coupled supply of heat in a heat supply system, engineering structures act as a heat accumulator. Therefore, when calculating the premises cooling time in case of accidents in a heating network, it is necessary to take into account not only weather conditions, but also a decrease in the flow of heat from the heat supply system, since at low outside temperatures the heat loss in premises is greater than the heat supply, which will lead to the accumulation of moisture in materials of the structures. Methods. To build a model of internal conditions in premises when the heat supply system operates in emergency mode, the humidity potential theory was applied, which allows calculating the humidity mode of engineering structures under various non-periodic exposures. Results. A method for calculating moisture accumulation in outer walls of residential premises using the moisture potential theory is proposed. Conclusion. The impact of moisture accumulation on heat accumulation in outer walls and the dynamics of internal air temperature in premises under emergency conditions of the heat supply system operation has been determined.

The article considers the features of the method of research of fuel economy and environmental performance of vehicles with engines converted to run on gas fuel, which are equipped with a thermal training system based on a thermal accumulator phase transition, which is based on the implementation of system interaction of three interconnected components: information, analytical and energy. The schematic diagram of the system of thermal preparation and the information system of estimation of ways of maintenance of thermal preparation of vehicles in the conditions of operation by means of system of thermal preparation on the basis of an onboard complex (Intelligent transportation system) are presented. The peculiarity of the proposed system is that the subsystems create a common information field of the vehicle monitoring system with the heat treatment system, but operate separately from each other, based on the characteristics of the tasks they perform. Improved is the method for determining and calculating fuel consumption and emissions in exhaust gases of vehicles with engines converted to run on gas fuel, equipped with a thermal accumulator phase transition in the processes of pre-start and post-start heat treatment based on the selected model of the engine "Neutralizer". To ensure thermal preparation of vehicles with engines converted to run on gas fuel, equipped with a thermal training system based on a thermal accumulator of the phase transition, a cycle of thermal preparation in operating conditions has been developed. The influence of the thermal preparation system with the heat accumulator of the phase transition of a vehicle with an engine converted to run on gas fuel on the fuel efficiency indicators and environmental indicators in the pre-start and post-start-up processes is established.

The article proposes a matching device between an accumulator battery and a voltage inverter in electric energy storage systems based on a reversible DC-DC converter with improved weight, size and cost indicators. Lithium-ion batteries are subject to tough operational requirements. The discharge of such batteries is not recommended to exceed their three-fold capacity (C), while the charge is limited to 0.5C, and low-frequency ripple components should not be present in the charging current. These requirements can be fulfilled with the help of the proposed matching device which is characterized by smaller dimensions and cost achieved due to the choke unit. The article proposes the calculation of the converter circuit and presents the simulation results obtained in the Psim simulation environment (the PowerSim environment). An economic assessment of the converter has been carried out.

Experience of structure development, manufacture, and testing of a pneumatic pressure shell accumulator with a volume of 25 dm3 is presented. A binder composition for “cold” hardening based on ED-20 epoxy resin and Etal-23X cycloaliphatic amine is developed. In terms of rheological and physicomechanical properties the binder proposed is suitable for manufacturing shells by a “wet” winding method with low energy consumption for hardening.

Well-known problems that take place at a start diesel of generators, at subzero temperatures, and unsatisfactory state of accumulators. From one side, complications arise up due to that at subzero temperatures substantially the moment of resistance increases on the billow of diesel. It contingently thickening oil, decline of temperature in a combustion chamber. As a result the starting turns of knee billow increase on 15-20%. On the other hand, at subzero temperatures the charged accumulator can lose to 60% of the capacity. Both factors unite, and the assured start of diesel of generator does not take place. Application of movable device that is capable after 3-10 min to charge super condenser from a network 220 In is offered, and to provide a feed a starter diesel of generator. Transformation of electric energy takes place without the use of inductive elements that gave possibility substantially to improve it massoverall indexes. Most effective a device becomes at presence of a few the diesel of generators. In case to the unsuccessful start, a device by turns is delivered to each the diesel to the generator, joins output terminals directly the terminals of accumulators and executed start. Exchange of energy from super condenser to the accumulator, on this stage does not take place, as internal resistance of super condenser and starter, on an order less from resistance of accumulator. Of necessity sub charge of device is executed from the low-powered network of 220В. Starting processes the diesel of generator is described by the system of differential equalizations that gives an opportunity to get optimal correlations depending on a type diesel of generator. The got mathematical dependences allow optimizing a starting process, by the use of magnetic energy that accumulates in the inductive elements of starter. Taking into account the small values of internal resistance of starter, accumulator, super condenser and comparatively large inductance of starter (anchor puttee and puttee of excitation), it is possible to attain a shake process of starting. At that rate, energy is accumulated in the inductive elements of starter on the initial stage, his rotation will additionally support. Similar technology of starting will allow to improve the mass overall indexes of mobile charge device.

The pipe isolation tool (PIT) demonstrates remarkable advantages in safety and efficiency compared with traditional plugging devices. However, its utilization in plugging operations is limited by the operation duration. In addition, the existing energy recovery system has low energy saving efficiency. In this paper, a real-time control energy-saving system of the PIT was designed based on a reinforcement learning algorithm. First, an experimental device for energy-saving was designed. Secondly, the energy distribution scheme of a hydraulic pump and accumulator based on experimental data was proposed. Finally, the reinforcement learning algorithm was used to adjust the opening of the hydraulic pump and the accumulator valves in real time during the plugging process to improving energy saving efficiency. The results verify that the energy saving efficiency of the PIT control system based on reinforcement learning could reach 23.71%, which satisfies the objectives of energy-saving and environmental applicability.

Based on the analysis of the Russian market of basic materials for phase-shifting heat accumulators (FPAT), including the issue of pricing policy, an attempt was made to reveal the dependence of the cost of a heat accumulator for a solar thermal supply system on operating and design parameters. In turn, to determine the latter, the method was used, which makes it possible to design FPAT with the given design and technological parameters, at a given minimum temperature of the coolant at the outlet of the accumulator, the known thermophysical characteristics of the coolant and heat storage material (TAM), including the phase transition temperature.

Theoretical analysis of construction technologies and features of use of natural accumulators of thermal energy in the near-surface layers of the Earth, both in soil and in aquifers is given. The general economic analysis of investment attractiveness of introduction of the heat pump systems using as a primary source low-potential renewable energy of near-surface layers of the Earth is executed. A comparative analysis of the efficiency of using a geothermal heat collector consisting of vertical ground heat exchangers and a hydrothermal heat collector consisting of two wells: the first for water intake, which plays the role of a heat carrier for the heat pump system; the second - to return the waste water to the aquifer. The current model of the hydrothermal experimental heat pump system developed and constructed in IVE of NASU is presented. The method of conducting research is described. The characteristics of the measuring equipment installed on the model of the experimental installation and the software used for archiving and visualization of the data received in the course of carrying out of researches are resulted. The results of scientific work obtained in the course of theoretical calculations and experimental studies of the efficiency of heat pump systems, depending on the system of primary thermal energy selection, are presented. The dependences of the heat pump transformation coefficient on the type of thermal energy collector are given. The dependences of the heat pump system efficiency on the parameters of the primary source of low — potential heat and design features of the heat supply system are substantiated. It is concluded that the open-type hydrothermal heat pump system is more efficient than the geothermal one and further studies of the possibility and efficiency of using the aquifer as a natural heat accumulator to stabilize the generation of thermal energy from renewable energy sources in different seasons.

Generally, during the accelerating process of construction machinery large inertia hydraulic swing system, a lot of kinetic energy is accumulated, and it will be eventually dissipated through the relief valve orifice during the decelerating process, which results in serious energy waste and large overflow loss. In order to solve this problem, a new dual source hydraulic motor with non-uniform flow distribution is proposed, which can drive high-frequency swing mechanism efficiently. The new dual source hydraulic motor has two groups of oil inlet and outlet, corresponding to two groups of different displacement. The two groups of inlet and outlet are respectively connected with the energy recovery unit and the main driving unit. During the starting process, the energy recovery unit assists the main driving unit to drive the swing mechanism together, so that the main drive unit output torque and overflow loss are reduced; during the braking process, the energy recovery unit recovers the braking energy. Finally, the integrated control of braking energy direct recovery and utilization is realized. In the research, the 38 t hydraulic excavator is taken as the research object. Firstly, the multi-body dynamics electro-hydraulic simulation model of the dual source integrated driving hydraulic excavator swing system is established, and the accuracy of the model is verified by experiments. Then the effects of the accumulator working pressure and the dual source hydraulic motor displacement ratio on the working performance of the system were simulated. The simulation results show that with the displacement ratio increasing, the accelerating time, the maximum angular velocity and decelerating time increase. Compared with the original system, when the displacement ratio $\alpha $ is 0.6, the comprehensive performance of the system is the best, and the hydraulic pump output energy is reduced by 48.6% and 46.6% respectively in the process of full load and no-load operation.

Many power grid facilities require heating in winter. For their heating, they usually install a system of electric heaters, connect mini gas boilers or use the thermal emissions of working electrical installations, since these objects are often located away from the sources of central heating. This leads to additional costs for the organization's own needs. It is proposed to accumulate the excess heat generated by using a ground heat accumulator, which will allow you to accumulate heat in warm periods of the year and when there is an excess of thermal energy in the system, and then use the thermal energy of the accumulator to heat the object. (Research purpose) The research purpose is in developing a ground heat accumulator capable of accumulating excess heat energy generated during the operation of high-power transformers and, if necessary, to transfer the accumulated heat to the heat supply system of energy facilities. (Materials and methods) The article considers the advantages of introducing heat storage in the heat supply systems of various facilities. Authors conducted a literary analysis of various methods of heat accumulation. (Results and discussion) The article presents the justification for the choice of a ground heat accumulator. Authors have completed the description of the proposed battery and the technology of its creation. The article describes the method of calculation of the main elements of the selected type of heat accumulator and the quantitative characteristics of the accumulator on the example of real objects. The article describes the operation of the battery in interaction with a heat pump and a horizontal ground heat exchanger. (Conclusions) The use of a heat accumulator as a backup source for energy facilities allows organizations to reduce the cost of heating premises and equipment. Additional functions that the ground heat accumulator is capable of performing are identified.

The article briefly describes the processes carried out during the operation of the gas hydrate accumulator (GHA) at the automobile gas-filling compressor station (AGCS): formation of natural gas hydrates, their accumulation and storage, and melting with the release of natural gas at high-pressure р = 25MPa, sufficient for full refueling gas cylinders. The circuit-constructive solution of filling with compressed natural gas in AGCS-GHA is offered, and the principle of its work is described in a good example. It is shown that during AGCS-GHA operation with four compression stages and ACG compressed gas accumulators, the gas from GHA to ASG moves in the connecting pipeline at adiabatic conditions at subcritical speed, i.e., below the speed of sound, because the pressure ratio рASG / рGHA coefficient is more critical. Calculations performed for these conditions by thermodynamic equations of gas flow in the subcritical mode of motion, without losses, showed that the velocity in a pipe with a diameter of d = 15 mm has a value of w = 793 m / s. This will ensure a specific gas supply from GHA to ASG at the level of m = 0.178 kg / s. It is proposed to use the coefficient efficiency of refueling to characterize the energy efficiency of refueling vehicles with compressed natural gas in AGCS-GHA. According to the results of calculations, it is evident that the energy efficiency of refueling vehicles with compressed natural gas in AGCS-GHA is 6% higher than in traditional AGCS at the same conditions: the corresponding values of coefficient refueling efficiency = 0.47 and = 0.41. The article also illustrates that in the process of melting gas hydrates in GHA at a temperature of t = 26-28 0C, one can get compressed natural gas at a pressure of р = 30-35 MPa, which will use AGCS-GHA without additional compressor equipment for refueling mobile gas stations (PAGZ), in which the optimal values of the maximum pressure are in the range of 32-35 MPa.

It is an essential and most abundant energy resource on earth. Solar energy can be caught and utilized in a few different ways and as a sustainable energy source is a significant part of our virtuous energy future. Its technology can be passive solar or active solar depending on how it can store excess energy and converting into solar power the storage of solar energy require a storage medium or accumulator. It can help to store excess solar energy for future use. One of the best methods to store heat energy from the sun is by making use of phase change material (PCMs) due to a huge ton of captured latent heat and isothermal kind of PCM during heat expansion and dismissal during phase change. PCM becomes an ideal candidate for a thermal energy storage medium in building applications. Now a day PCM gained special attention in building applications like water and air heating application, building-integrated system (ceilings, walls, and floor), H.V.A.C/solar absorption system for building, and other useful applications PCM concrete, PCM shutters, solar cooker, and solar dryer. In this paper, an attempt has been made to provide an overview of the progress and application of PCM in solar thermal energy.

The development of renewable energy sources in Ukraine is characterized by rapid pace. As of September 2020, the installed capacity of wind station (WPP) and photovoltaic (FPP) stations is about 6 GW, which corresponds to almost 20% of the maximum load of the power system at the current time. Therefore, today the problem of accumulation of stochastic electricity supply of wind farms and power plants in the power system, due to the inconsistency of schedules of generation and consumption of power, is becoming relevant. The idea of using pumped storage hydro station (PSH) to store stochastic energy input of wind farms and power plants is beginning to find its practical implementation. In Spain, a wind-diesel power station has been operating for several years to supply water to the 11 MW PSH battery pool. The experience of operation of this complex has shown a significant reduction in its energy efficiency due to the stochastic nature of wind energy. Therefore, it is time to solve the problem of determining the energy efficiency of the process of converting the kinetic energy of wind into potential energy of water accumulated in the accumulator pool, taking into account the presence of wind speed pulsations. In this work, the energy efficiency of a powerful hydraulic pumping station when powering pump motors from a wind power plant is evaluated, taking into account the pulsations of wind speed and the number of hydroelectric units in the station. The determination of quantitative values of the estimated parameters was based on the results of mathematical modeling of the dynamics of loading modes of operation of the wind pumping station taking into account the stochastic change of wind speed. The mathematical model is a system of nonlinear differential equations that describes the interaction of two inertial components of a single aero-electro-hydro-dynamic system. The rational ratio of the number of hydraulic pumps in the pumping station to achieve the maximum values of the utilization factor of the installed capacity of the wind pumping station is determined. Ref. 29, fig. 6.

There are needed energy (heat) accumulators to increase the efficiency of solar installations, including solar collectors (water heaters, air heaters, dryers). One of the tasks of designing heat accumulators is to ensure its minimal heat loss. The article considers the problem of determining the distribution of temperatures and heat losses by convection and radiation of the heat insulation-accumulating body (water) system for a ball heat accumulator under symmetric boundary conditions. The problem is solved numerically according to the program developed on the basis of the proposed «gap method». (Research purpose) The research purpose is in determining heat losses by convection and radiation of a two-layer ball heat accumulator with symmetric boundary conditions. (Materials and methods) Authors used the Fourier heat equation for spherical bodies. The article presents the determined boundary and initial conditions for bodies and their surfaces. (Results and discussion) The thickness of the insulation and the volume of the heat accumulator affect the dynamics and values of heat loss. The effect of increasing the thickness of the thermal insulation decreases with increasing its thickness, starting with a certain volume of the heat accumulator or with R > 0.3 meters, the heat losses change almost linearly over time. The dynamics of heat loss decreases with increasing shelf life, but the losses remain large. (Conclusions) Authors have developed a method and program for numerical calculation of heat loss and temperature over time in a spherical two-layer heat accumulator with symmetric boundary conditions, taking into account both falling and intrinsic radiation. The proposed method allows to unify the boundary conditions between contacting bodies.

This paper presents the development of a low-power electronic system powered by a thermoelectric generator, based on Peltier cells, which takes advantage of daily temperature variations in the environment using a tank with 6 liters of water as a thermal accumulator. The generator works both day and night, since it uses a dc-dc boost converter with bipolar input. The system avoids using batteries because it charges a 0.1 F supercapacitor module between 2.40 and 3.15 V, so the useful energy in each charging cycle is 208 mJ. This energy is sufficient so that the system can measure the ambient temperature, represent it on a display and record it along with the date and time on a memory card when there is enough stored energy. The PSpice model and the simulation of the generator is also presented and experimental results of its operation are presented for two days. It is derived that in that period, with a maximum temperature difference of 10 °C, the system is able to charge the supercapacitor thirteen times per day, which means a daily useful energy of 2.7 J. Finally, results of the autonomous system performance for four days are presented.

Целью исследования является разработка новой конструкции саморегулируемого водяного аккумулятора теплоты с температурной стратификацией воды, исключающей перемешивание греющего и нагреваемого теплоносителей, поступающих в аккумулятор из контуров зарядки и разрядки на основе естественного расслоения воды в баке под влиянием объемных (архимедовых) сил в условиях принудительной циркуляции теплоносителя. На основе анализа мирового опыта разработки конструкций водяных аккумуляторов теплоты с температурной стратификацией воды и устойчивости стратифицированного (расслоенного) течения теплоносителя в объёме аккумулятора предложена новая конструкция саморегулируемого водяного аккумулятора. Рассмотрены преимущества использования саморегулирующихся стратификационных водяных тепловых аккумуляторов в системах солнечного теплоснабжения. Показано, что использование стратификации для кратковременного и долгосрочного накопления тепла приводит к увеличению использования солнечного тепла на 15-20% по сравнению с полностью перемешивающимися аккумуляторами. В системах горячего водоснабжения эти аккумуляторы могут обеспечить более раннюю подготовку горячей воды с требуемой температурой для потребителей.

This monitoring system is used to monitor currents and voltages from Solar Power Plants (PLTS) with solar cell capacities of 50WP, 80WP, and 100WP. PLTS used is an active type of solar tracker, where solar cells used can find the maximum solar irradiation position by determining the upper and lower voltages as the reference voltage in the Arduino program. After PLTS can produce energy, then the energy can be used to turn on AC and DC electrical loads. From the energy used, here of course there are currents and voltages starting from the output of the solar cell, the accumulator output, the input at the AC load, and the input at the DC load. The monitoring results that have been carried out subsequently will be automatically sent to the Thingspeak application by using the SIM800L Module. This thingspeak application will send data in the form of numbers and graphs in real time. By comparing the value of the measurement results on Arduino and the thingspeak application, we get the size of the percentage of reading errors on the measuring instrument.

The hydraulic power take-off (HPTO) is considered as the most promising method to convert wave power to electrical power. This paper presents an experimental assessment of the power conversion of a wave energy converter using HPTO. Based on the experimental results, a modification of accumulator pre-charged pressure and a control strategy were proposed to improve the system performance. System design, the working principle and mathematical model of all components were described. The proposed method was verified based on both simulation and experimental tests. The results showed that the system always works at an optimal condition under different input wave conditions.

The accumulator is a crucial component of the hydraulic power for servomechanisms of the launch vehicle, which has a significant effect on the performance and the mass power. Traditional design methods are mostly based on empirical formulas, which do not meet the requirements of the fine design of aerospace products. The physical model, the mathematical model of the accumulator and joint simulation model of the energy and the control loop are established, and parameters satisfying the extreme flight operation profiles are obtained, including the discharge volume, charge volume and charge pressure. The flight data of third-stage servomechanisms of the Long March 3 series Launch Vehicle were analysed, which is consistent with the simulation data, indicating that the accumulator has exerted the maximum capability in the extreme flight condition, and the maximum mass power has been realised.

An open center system (OC-System), which is one of the major hydraulic architectures for excavators, has been improved in the world to reduce fuel consumption for global environment conservation and lower operating costs. However, the total system efficiency, including the internal combustion engine (ICE), has not been thoroughly considered. In contrast, a constant pressure system (CP-System) enabling the engine to be driven optimally is developed, but is not accepted in the industry owing to the complexity of the required components. Thus, in this research, a hybrid system combining an OC-System with a CP-System is proposed to improve the total system efficiency. An accumulator, which is used to provide flow rate to actuators, is essential for the new hybrid system, and it is vital to consider the nominal gas volume and pressure level for the accumulator in terms of energy savings and initial cost. Therefore, the influences of accumulator volume and pressure level are discussed in this paper.

The hydrogen sorption characteristics of La1–xCexNi5 alloys (x = 0, 0.1, 0.2, 0.25, 0.5) were studied in the temperature range 298–363 K. The optimal compositions of intermetallic compounds were determined for use as hydrogen sorbents in reusable accumulators: compounds La0.9Ce0.1Ni5 and La0.8Ce0.2Ni5. Based on them, a metal hydride hydrogen accumulator was designed and manufactured and its technical and operational characteristics were found. The developed devices are proposed to be applied in electric energy storage systems using hydrogen as an energy carrier.

The purpose of the study is the reduction of the time of hydraulic couplings slipping by optimization of hydraulic accumulator discharge pressure. When operating tractors with hydroshift transmission at loads close to the nomi-nal values, there is a problem of slipping of the friction coupling during gear shift without interruption in torque de-livery. There is a critical scientific problem of reducing the slipping of hydroshift transmission during the operation of major tractors. Theoretical prerequisites for increasing friction force due to the reduction of slipping via the re-duction of gear shift time and influence of oil pressure in the booster of the released drive are justified. Procedure and results of study of gear shift in transmission of tractor «Kirovets» with the use of both standard and constant discharge pressure hydraulic accumulators are given. The process of gear shift was investigated on the new gear-box with standard hydraulic accumulator, on the box with standard hydraulic accumulator worn to the limit provided, and on the new gearbox with constant discharge pressure hydraulic accumulator. It has been established that dur-ing operation of a new transmission with standard hydraulic accumulator the 0.2MPa discharge pressure exceeds the optimal value, which leads to an increase in the duration of the shift from 0.915...0.920 s at a pressure of 0.45...0.46 MPa to 1.395...1.04 s at a pressure of 0.65...0.66 MPa. The installation of a constant discharge pressure hydraulic accumulator on the new transmission reduces the discharge pressure to 0.48...0.49 MPa, which reduces the gear shift process to 1.034...1.040 s, that is only 4.2...6.6% higher than the optimal value. Recommendations are given to optimize the gear shift process in the transmission of the «Kirovets» tractor.

The article deals with the analysis of the peculiarities of starting diesel engines of generating sets in the conditions of warfare, which are related to the state of batteries. In particular, problems with reliable start-up of diesel engines occurred at their frequent start-ups. This is caused by a decrease in the charge of the starter batteries and the lack of sufficient time to recharge them. Disruptions to the power supply of weapons and military equipment can cause military missions, the loss of personnel, and the destruction of military installations. Therefore, it is relevant to conduct research aimed at improving the efficiency of start-up diesel engines systems of mobile power plants in combat conditions. Existing start-up facilities do not provide cold starts for diesel engines at low-temperature generators, and pre-warm-up methods take a long time to prepare the engine for start-up. Therefore, it is advisable to use molecular electric energy storage units together with rechargeable batteries as part of the engine's electric start system to ensure efficient starting of the engine at low temperatures. This should increase the starting power of the engine's electric start system twice and increase the capacity of the power source by half. Schematic solutions of existing methods of starting diesel generators of military units that are deployed in the war zone, analyzed in the work. An approach to the estimation and justification of the use of complex power sources in diesel power plants is proposed in the article. This approach can be used to select the parameters of a complex source of electrical energy, consisting of a battery and a molecular accumulator of electrical energy, as well as the design of systems for the electric start of diesel engines of generating sets. Based on the analysis, proposals for the use of molecular energy storage have been developed. This will allow the use of molecular electric energy storage units in conjunction with starter batteries in diesel power plants of power systems of complexes of armament and military equipment in combat conditions.

Problem statement. Starting internal combustion engines for a large car fleet at ambient temperature of less than 5 ºС requires considerable time; it leads to increased wear of the components of the connected engine pairs, increased fuel consumption during start-up and warm-up and increased emissions of harmful substances into the atmosphere with exhaust fumes. Therefore, prestart warming up of car engines is given great attention. Actual scientific researches and issues analysis Recently, this problem has been solved by using heat accumulators, moreover, heat accumulators with heat storage material of a phase transition are given preference. The engine exhaust gases (temperature 600-700 ºС) or the engine cooling liquid (water, tosol cooling agent) are used as a heat transfer agent. Given the negative impact of high temperatures on the heat storage material, the metal of the heat storage structure and overheating (boiling) of the engine coolant, the first way has certain disadvantages. In this regard, we consider it more promising to use a liquid cooling engine as a coolant for a heat accumulator. High temperatures have no positive affect on the heat storage material, the metal of the heat storage structure and these are a cause for boiling a coolant –cooler of the engine. In this regard, we consider more promising to use a cooling fluid of the heat accumulator as a heat transfer agent. The aim of this work is to develop a new design of a heat accumulator for pre-starting warming up of a car engine, to make the experimental installation to research its work and conducting researches in order to find the time of charging and discharging of the heat accumulator, to construct operating modes during charging and discharging, to determine the necessary mass of the heat-accumulating material and the battery size. Base material The experimental installation was a closed system: the heat accumulator — a passage of the VAZ 2109 car engine cooling system. Taking into account the work peculiarities of the heat accumulator in the cooling system of the car engine, unlike other areas where all mass of the heat storage material constantly is in contact with the substance which the heat storage material giving up heat, in our case, the engine cooling liquid is located in the heat accumulator and in the cooling jacket. They mixes before starting the engine, while its temperature decreases. The time of charging and staying of the heat accumulator in the charged state has been determined, the operating modes during charging and discharging have been constructed, the necessary mass of the heat-accumulating material and the battery size has been determined. Conclusions The experimental model of the heat accumulator of the pre-starting system of worming up of the engine of the car has been developed. This experimental model is included in a closed circuit with engine cooling system. On the model the researches of charging and discharging process of the heat accumulator have been conducted. The required time for these processes has been determined and on this basis the modes of operation of the heat accumulator - engine cooling system have been constructed. The temperatures of tosol cooling agent in the cooling system were calculated and it allowed finding mass (volume) of heat storage material of the heat accumulator and it served as the basis for determining the size of the heat accumulator. Establishment of a computerized control system on/off control of the heat accumulator in order to maintain the desired temperature of the engine coolant liquid using of heat storage material of phase transition and controlling this system using supplements to phones.

Electric vehicles (EVs) are limited by the on-board batteries in terms of driving range and charging duration. In this paper, the driving range of electric vehicles (EVs) charged by wireless power transfer (WPT) systems is investigated. Specifically, a force-based vehicle model is coupled with a simple extended battery model to simulate the impact of wireless charging on the state of charge of the accumulator sub-system. In total, three different scenarios, i.e., urban, highway and combined driving are presented. The trade-off between having a standalone charging option versus combined dynamic and quasi-dynamic wireless charging is outlined and minimum system requirements, such as charging power levels and road coverage, for unlimited range are established. Furthermore, the effect of external factors such as ambient temperature, battery age and wireless transfer efficiency is investigated. It is shown that employing combined charging at medium power levels is sufficient to achieve unlimited range compared to high power requirements for standalone charging. Finally, safety concerns regarding human exposure are addressed with lower charging powers.

As a research result, characteristic indicators of the efficiency of using various heat sources in combined heat supply systems were determined. During the study, various schemes for integrating heat accumulators in heat supply systems were considered. Water was used as a battery, which also acts as a coolant. Mathematical modeling of processes in combined heat supply systems using intermittent heating is carried out. The characteristic operating modes of the elements of heat supply systems that take into account the operating modes of heat consumers are determined. Mathematical modeling was carried out using a software package that allows to obtain the distribution of heat power of the heat supply system by its main elements and its characteristic operation modes. According to the research results, a coefficient of thermal power reduction and a coefficient of efficiency of using the heat accumulator volume were proposed. These coefficients allow to evaluate the efficiency of heat sources and the efficiency of using the volume of the heat storage tank. Based on the obtained data, the task was set to optimize the daily load of the heat source, taking into account the installation of the storage tank. The research results can be used for the reconstruction of heat supply systems of buildings with a two-period operation mode (operation duty) using both traditional and renewable heat sources. This will significantly increase the efficiency of the use of elements of the heat supply system, even out the daily heat generation schedule and increase the service life of the main equipment

The heaving buoy wave energy device is popular for wave conditions with small wave heights and short periods. This paper presents the design of a wave energy converter composed of a gyro buoy, a hydraulic power take-off, and an electricity generation system. The energy accumulators are used to improve the output power with different control strategies. The quantity relations between each component are established using theoretical methods. The simulation model describes the energy conversion and calculates the operation time, energy capacity, and output power of the device under different initial pressures, release pressures, and electric resistances. As a result, the capacity is determined by the electronic load, and the maximum output power can be obtained when the accumulators are turned on and off at the same time. This study investigates the factors influencing the electric energy production and can be used to guide the optimization of this type of device.

The development of an intelligent energy storage management system is an up-to-date scientific and technical challenge. This system should ensure maximum efficiency of energy storage in power networks for various purposes. The article discusses the use of energy storage in distribution networks of an industrial enterprise and substantiation of the vector control method of the inverted synchronous motor of the energy storage SPENE-1, shows a block diagram of the vector system for controlling the energy accumulator motor and the results of its simulation in MatLab.

The heavy earth moving machineries (HEMM) like hydraulic excavator play a major role in construction and mining industries. In this context, the energy saving strategies in hydraulic excavator needs to be addressed considering its vital importance. Since the hydraulic excavators are subjected to heavy loads, hence the opportunity to harness the potential gravitational energy (GPE) remains a key area which can be effectively explored in order to minimize the energy consumption in consideration with hydraulic excavator. In the projected system, the potential energy is stored as pressure energy in hydro-pneumatic accumulator. The upward movement of the boom is executed with the help of prime mover during the starting of the first duty cycle. In the latter duty cycles, the stored pressurized energy is utilized together with the prime mover energy capable to execute the upward movement of the boom. The position of the boom cylinder is controlled by using the conventional PID controller using proportional flow control valve (PFCV) and accumulator. The error between the actual position and demand position of the linear actuator is minimized along with attainment of superior controlled performance while utilizing Model Predictive Controller (MPC). The pressurized accumulator with PFCV has been utilized to cater the different position demands. This has been also justified both experimentally and analytically with the error in the permissible range of 2%. It has been observed that the proposed system is 10% more efficient in contrast to the conventional system.

A trolleybus is the most economically advantageous transport because it is cheaper to operate than a bus, and it has no CO2 emissions, which makes it an eco-friendly vehicle. However, it does have one major drawback, such as the limited mobility that is caused by the connection to the power grid and the line along which it is laid. Therefore, in this case, it is advisable to use a traction system to which a high-voltage battery is connected. The capacity of such a battery is not large compared to the electric bus, so the cost of such a vehicle is low. The structure and modeling of the traction system with a high-voltage battery is developed. The main difference between this scheme and the usual trolleybus is that it can move part of the route autonomously. The energy to power the actuator is taken from a constant voltage source. In this case, the rectifier is required to prevent the emergency mode from occurring when the polarity of the connection can be confused. After the rectifier goes the DC link is a capacitor. The link is connected to a 3-phase inverter, which generates a 3-phase voltage on the motor. The main disadvantages of this scheme is that during start-up power, which is drawn from the network much more than in the steady state. Also, when braking occurs, the energy cannot be transmitted back to the network, because the rectifier does not allow the energy to go back. In this case, an active rectifier consisting of transistors can be used instead of a rectifier. This allows the energy to be recovered back into the grid. For the most part, trolleybus networks are not designed for energy recovery and, as a rule, such circuits install a brake resistor that connects to the DC link during braking. increase in current, but in this case all the useful energy that could be used is dissipated on the resistor. In this case, it is advisable to use an additional converter, which itself will consume this energy and then it can be used when starting the engine. Such a converter is required to charge the battery with the energy released during braking. And after the energy has been accumulated, it is reused to reduce grid load during engine start-up. The control of the actuator and the converter is consistent. When the actuator is braking, it causes an increase in the voltage in the DC link and this excess energy, which caused this increase, must go into the accumulator for energy storage., У статті розглядається система електроживлення транспортного засобу з високовольтним акумулятором. Показано переваги використання такої системи електроживлення та досліджено режими її роботи і порівняно зі звичайною схемою електроживлення тролейбуса. Визначається ШІМ модуляція для оптимального режиму роботи. Для живлення електроприводу у разі відсутності мережі буде використовуватися акумулятор. Перетворення енергії відбувається за допомогою перетворювача з двостороннім передаванням енергії. Такий перетворювач потрібен для того, щоб заряджати акумулятор енергією, яка виділяється при гальмуванні. Накопичена енергія, повторно використовується, щоб знизити навантаження на мережу під час пуску двигуна.

The process of heating a dewatered object in an infrared solar drying plant (with paraffin on the bottom) with solar energy storage is considered. To solve this problem, it is assumed that the heat capacity of paraffin exceeds the heat capacity of the dehydrated object. Infrared rays fall on the upper layer, and heat exchange takes place due to heat and mass transfer with the surface air located between the metal plate and the object to be dehydrated. The equations of thermal conductivity for a dewatered object are given, its relationship at the phase interface is determined using the equality of temperature and heat flow. For an exposure of overheating with a period of 6.5 h, the time of passage of the phase boundary in accordance with the law of motion of the spreading (hardening), was determined according to the formula of ξ = α √6,5 h ≅ 12 h.The optimal thickness of the accumulating paraffin layer was ascertained. On the basis of the theoretical studies, experiments were conducted to study the temperature field of various heataccumulating materials in the laboratory of Tashkent State Technical University. It was found that of all heat-accumulating materials, paraffin has the best heat retention ability when its thickness is of 2–4 cm. The optimal variant of a solar accumulator drying plant with a heat accumulator, viz. paraffin has been designed. In particular, 2–4 cm of paraffin layer with a mass of 50 kg with a corresponding flat surface in terms of specific heat of evaporation is 2400 kJ/kg. The specific melting value of paraffin (150 kJ/kg) allows additional evaporation of 5.8 l of moisture when drying objects. The proposed solar accumulator drying plant can be used for dehydration of medicinal herbs.

Introduction: there is much concern about power supply to small and remote villages and industrial facilities, such as crude oil and gas fields, in the present-day power industry. Systems using renewable energy sources are the most innovative solutions to this problem. The need for electric energy storage units complicates the use of renewable energy sources. Versatile types of storage units, working on different principles, are in use now. Flywheels, working on the principle of mechanical accumulation of energy, are of particular interest.Methods: both traditional and advanced designs of electric energy accumulation systems are analyzed in the article. Recent advancements in machine building, power engineering and structural materials are contributed into structural elements of an electric energy accumulation system.Results and discussion: basic strengths and weaknesses of electric energy storage units were identified in the course of the analysis. The author substantiated the need for new effective electric energy storage units working on the principle of mechanical accumulation of potential and kinetic energy. The conclusion is that advanced engineering solutions, such as flywheels and energy efficient reversible electric machines, can boost the efficiency of electric power storage systems. The solution underlying the design of an energy efficient storage unit is offered to electric power industry players.Conclusion: the storage unit under development has flywheels and energy efficient reversible electric machines. It improves the energy efficiency of both classical power generation systems and those using renewable energy sources.

A combined numerical approach featuring an immersed boundary and a cut cell method was implemented to discretize the conservation equations that model the discharge period of a solar energy...

Approaches to the technical description of maintenance processes, storage, rules of putting into storage batteries (batteries) into operation, ways of charging of the battery are outlined. The main focus is on the study of the storage process of the battery during the winter period of operation. The ways of monitoring the condition of the battery in the State Border Service of Ukraine (STSU) and the processes of maintenance of starter batteries used on cars have been determined. The model of the control-renewable charge-discharge cycle of the accumulator taking into account the residual resource is offered. The model is aimed at increasing the battery life and improving the efficiency of its operation during the entire period of operation.

Recently researchers are focus on evaluation of hydraulic regenerative braking systems for improving fuel economy and reducing pollutant emissions. Present work is oriented to study effects of variation in vehicle speed at braking, accumulator initial pressure and pump displacement on regeneration efficiency of hydraulic regenerative braking system (HRBS) on the school van conveyance in Vadodara city. The results show that the HRBS regeneration efficiency improves between 1.7 to 10% with reduction in initial pressure from 110 to 90bar. Increase in pump displacement from 16 LPM to 23 LPM results in rise in regeneration efficiency of the HRBS between2.6 to 16.7%. While increasing initial speed at braking from 20 to 35 KMPH, regeneration efficiency of the HRBS system rises by 48%. This is the maximum rise in regeneration efficiency while varying the initial braking speed.

A new type of charging valve with electro-hydraulic closed-loop feedback is designed, and a wet multi-disc dual-circuit service brake is built based on AMEsim. The charging and discharging characteristics of the accumulator are studied. The results show that under the condition of a medium-flow constant current source, the dual-circuit accumulator responds quickly, and a single charging can smoothly provide multiple stable discharge output. The response to the pressure output caused by the static structural parameters of the tandem braking valve and the pedal signal is studied. The results show that: the pedal signal can significantly change the brake pressure output, but the preload of the return spring is not apparent; the change of the cross-sectional diameter of the rear axle spool will cause the spool opening lags, and the difference in the spool diameter will cause the spool closing lags. The time response performance of single-axle braking and dual-axle braking is studied. The response from environmental factors such as road adhesion coefficient, slope, load, and brake cool modes to braking distance, braking deceleration, and braking temperature is studied. We establish a parameter ranges of braking safety zone and braking safety comfort zone. This study provides a comparison and reference to the design of a new charging valve and the performance test of the service braking system of heavy vehicles.

Traditional excavators driven by diesel engine have poor emissions and low energy efficiency. Pure electric driven excavators have high cost and limited endurance. Therefore, at present, hybrid power train system is an ideal candidate for excavators to realize energy-saving and emission reduction. In this paper, a novel series hybrid hydraulic excavator based on electro-hydraulic composite energy storage, which provides the average power of the system through the diesel engine, and the battery and accumulator are used as the intermediate energy storage devitalize the output current of the battery, and improve the service life of the battery, is proposed. Advantages of high energy density of battery and high power density of hydraulic accumulator are synthetically utilized. A 7-ton crawler excavator is taken as the research object, according to typical load spectrum, through analysis method and modeling method, and using dynamic programming (DP) to optimize the parameters of the novel series power train system. The control strategy of the power system is further studied, and the AMESim and Simlink co-simulation models of the transmission system is established to verify the feasibility of the system. At last, the experimental platform is built. Experiments are conducted to verify the effectiveness of the power train system.

Im Rahmen des vom BMWi geförderten Projekts „Phi-Factory“ am Institut für Produktionsmanagement, Technologie und Werkzeugmaschinen (PTW) der Technischen Universität Darmstadt wurden, angesichts des steigenden Anteils fluktuierend einspeisender Stromerzeuger, technische Potenziale zur energetischen Flexibilisierung von Produktionsanlagen und Industrieprozessen untersucht. Im Bereich der Kühlung von Werkzeugmaschinen bietet der Einsatz von innovativen Phasenwechselmaterialspeichern die Möglichkeit, Lastflexibilisierung auf Maschinenebene umzusetzen, ohne den Fertigungsprozess zu beeinflussen. Zur experimentellen Untersuchung dieser Speicher wurde ein Demonstrator aufgebaut an dem ein parallel entwickelter „digitaler Zwilling“ validiert wurde. Within the framework of the BMWi-funded project „Phi-Factory“ at the Institute for Production Management, Technology and Machine Tools (PTW) of the Technical University of Darmstadt, technical potentials for the energetic flexibilization of production plants and industrial processes were investigated in view of the increasing share of renewable energy sources. In the field of cooling of machine tools, the use of innovative phase-change material storage systems offers the possibility of implementing energy flexibility at machine level without influencing the production process. For the experimental investigation of these storages, a demonstrator was built on which a parallel developed „digital twin“ was validated.

To reduce the cost of materials in a thermal energy accumulator, the use of water as a substitute for a mass fraction of paraffin wax was considered in the present study which evaluates the thermal behavior of a combined sensible and latent heat storage system that used a beverage can containing paraffin wax and water in different proportions for experiences of thermal energy accumulation and discharge. Unlike other applications that consider the forming of emulsions, there will be two phases within the containers. In a second stage, energy discharge experiences were realized within a 12 cans laboratory scale energy accumulator to analyze its thermal behavior. Replacing 25% of paraffin wax decreases the accumulated energy by only 12%, retaining similar energy discharge times relative to a 100% paraffin wax configuration. Shorter energy loading times and higher heat removal were observed for configurations with a higher water content. No major differences in energy discharge efficiency were found for the same wax/water content, using air velocities of 1.3 m/s and 2.6 m/s. However, in the first 60 min differences up to 25% in the heat removal were observed. Heat transfer coefficients between 18.0 W/m2K and 26.8 W/m2K were determined experimentally.

A regenerative fuel cell (RFC) is a hydrogen accumulator which is charged via an electrolyzer (electricity conversion into H2) and discharged via the fuel cell (H2 conversion into electricity), where the storage media is pressurized hydrogen. The also generated oxygen is mostly not stored in terrestrial applications. There are discrete RFCs (DRFC) consisting of two separate stacks (electrolyzer and fuel cell) and unitized RFCs (URFC) with one single stack working during charge in electrolysis mode and during discharge in fuel cell mode. URFCs show a high specific energy up to 1500 Wh kg−1. Furthermore, it is possible to optimize the power and energy of the system independently, which is important for seasonal storage of larger amounts of energy. In contrast to conventional electrochemical accumulators the discharge power of RFCs is unaffected by the state-of-charge of the system. But unfortunately, due to the long conversion chain with associated losses, RFCs generally have low levels of efficiency compared to conventional electrochemical accumulators. The high specific energy of URFCs makes the system interesting for niche applications in military and space areas where efficiency and related costs are not primary parameters. For civil terrestrial applications, however, costs and electrical efficiency are mostly primary parameters. DRFCs are preferred since the individual stacks (EL, FC) can be better optimized. However, for the time being, there are existing no commercial applications of RFCs, as they are not really competitive, especially not with electrochemical accumulators. In the future could be electricity storage with RFCs possible in off-grid or island applications in which a high level of autonomy is required but also in grid application with high share of renewables to stabilized power supply. In a broader sense are power-to-gas storage systems identically with DRFCs. Power-to-gas technologies and therefore also electrolyzers currently are developing strongly which will decreases the costs and increases the efficiency of RFC as well. The RFC technology is in the moment proton exchange membranes based, but they are relatively costly caused by use of platin group metal catalysts. Alkaline-RFCs could reduce the cost by using non-platin group metal catalysts. Because Alkaline–RFCs show an unsatisfactory performance and poor cyclability, therefore, the development is still in an initial stage. The efficiency of PEM-RFCs (URFC max. 35%, DRFC max. 40%) is relatively low. Higher efficiencies, however, show SO-RFCs. SO-URFCs already reach today in an early development state ca. 45% efficiency and could be used also in terrestrial applications.

Bangladesh secured the third position in freshwater fish and fisheries product producing country where around 4.134 million metric ton of fish is extracted annually. Fish transporting in traditional method reduces fish freshness and thus causes serious economic loss. Further, for live fish transportation, maintaining water quality is a challenge, with the course of time, oxygen, pH and temperature of water deteriorate. Considering this issue, a study was undertaken to construct simple, low energy consumed aerator-cum-oxygen accumulator for live fish transport. A 12-volt 3-ampere DC motor operated 1100 GPH bilge pump was modified with the venturi principle to construct the aerator. The experiment was conducted to evaluate its performance for live fish transport and compared with the results in a condition of with and without an aerator. 45 (forty-five) numbers of Rohu fish (Labeo Rohita) with an average weight of 378 g were put in a tank of 650 liters for this experiment. After six hours of the test, different parameters were measured in both conditions. With the device, dissolved oxygen and pH level were found as 9.3 mg/l and 7.8 and without the device, dissolved oxygen and pH level were found 6.2 mg/l and 7.1, respectively in six hours of operation. On the other hand, without the device, the dissolved oxygen level decreased from 6.5 mg/l to 2.2 mg/l and pH level increased from 8.30 to 9.70 in six hrs of the test. Besides, by using, the device mortality rate of fishes was zero but without the device, the mortality rate was 11.11%. Water temperature changing was insignificant during the experiment. Results indicate that for reducing losses of fish and increase the income of fisherman, this device might be suitable for live fish transport. J Bangladesh Agril Univ 17(4): 592–598, 2019

Modern thermal power is built based on three components: generation, transmission, and distribution of thermal energy. In this industry, another fourth element which was previously virtually absent is energy storage. Energy storage completely change our usual heat supply system. Heat storage is a serious factor in saving energy and improving environmental safety. The introduction of autonomous high and low potential heat storage systems is a real opportunity for the development of Intelligence Smart Grid heating systems. Therefore, the study of mobile heat storage batteries and the choice of methods for their design calculation and performance is an important task of modern science and technology. For this purpose, a study was conducted to determine the charging and discharge time of a mobile heat accumulator, depending on the type, volume, and temperature of the heat storage material. Types of thermal energy accumulation, classes of thermal accumulators, range of operating temperatures for a thermal accumulator were analyzed, design features of accumulators, operating time and methods of calculation of design parameters were considered. It is concluded that the method of calculation of MTA depends on the selected type of heat storage material. Although, phase transition materials have a higher heat storage density than liquid solutions, the design of liquid thermal batteries is much more attractive regarding technological, technical, and economic parameters. As a result of the study, the dependence of the MTA charging rate on the heat source power was obtained, the required amount of heat was determined, the average battery cooling time from the volume of the heat storage material, and the heat losses through the MTA body was analyzed. The results obtained must be taken into account when choosing the design and capacity of the battery.