Energy-efficient Mode Research Articles

Investigation of Low Velocity Impact Behavior of Aluminum Honeycomb Sandwich Structures with GFRP Face Sheets by Finite Element Method

The aim of this study is to examine the low velocity impact behavior of aluminum honeycomb sandwich structures with glass fiber reinforced plastic (GFRP) face sheets with the help of finite element method. In the study, low velocity impact tests were carried out in the LS DYNA finite element program to examine the effects of face sheets thickness, core number, wall thickness, impact location and impact velocity on maximum contact force, absorbed energy efficiency and damage mode. Progressive damage analysis based on the Hashin damage criterion and the combination of Cohesive Zone Model (CZM) and the bilinear traction-separation law was performed using the MAT-54 material model. At the end of the study, it was determined that the face sheets thickness in sandwich structures had a significant effect on the impact resistance up to a certain impact energy. It has been observed that as the impact velocity gradually increases, there is a decrease in the contact force after a certain threshold value. As the impactor velocity increases, the energy absorption efficiency also increases. It has been determined that the location of the impact is very effective on peak force and energy absorption efficiency. The effect of the number of core layers depends on the face sheets thickness. When the face sheets thickness was not damaged at first contact, the peak force value increased in parallel with the number of layers. It was determined that the dominant damage mode after impact was matrix damage. It has been observed that as the energy level of the impactor increases, damage also occurs on the back surfaces.

ANALYSIS OF THE ENERGY EFFICIENCY OF TECHNICAL SOLUTIONS OF THE HEAT-DRIVEN SHIP EJECTOR REFRIGERATION MACHINE FOR OBTAINING SUB-ZERO TEMPERATURES

Marine refrigeration machines are responsible for large amounts of electricity consumption, as well as direct emissions of high global warming potential (GWP) refrigerants, so they need to be gradually upgraded. The possibility of using a ship ejector refrigeration machine with two-stage compression, consuming waste heat, as well as a cascade compression-ejector refrigeration machine to obtain the temperatures of minus 28–27 °C was analyzed. It was shown that the traditional indicator of the efficiency of heat-driven refrigeration machines COPtherm ot be recommended for the selection of energy-efficient modes of operation of ejector refrigeration machines that consume waste heat. As a criterion for the energy efficiency of ejector refrigeration machines that consume waste heat, it is proposed to analyze COPmechTot, which takes into account the electric power of pumps, fans, as well as units that provide “feeding” the refrigeration machine with waste heat. A two-stage ejector refrigeration machine that consumes waste heat with a temperature of 95–45 °C and is intended for the operation of a ship ice generator (boiling temperature — 28 °C) loses to a traditional vapor compression refrigeration machine in terms of energy consumption: COPmechTot = 1.266 vs. COPmechTot = 1.52. A cascade vapor compression ejector refrigeration machine that consumes waste heat with a temperature of 85–95 °C and is designed to provide refrigeration (boiling temperature — 27 °C) of ship provision chambers is more attractive than a traditional vapor compression one: COPmechTot = 2.37 vs. COPmechTot = 1.82. An alternative technical solution for the production of sub-zero temperatures on ships, which the authors plan to consider in further research, is a refrigeration machine with two-stage compression. It uses a compressor in the first stage and an ejector in the second stage. Bibl. 26, Fig. 7, Tab. 1.

Scientific and practical basis of cephalopods dehydration processes

Nowadays, it is relevant to solve the problems of adapting optimal resource- and energy-efficient modes to technologies for processing food raw materials. The work is focused on the analysis of the prerequisites to find similar features in the dehydration of food capillary-porous colloidal materials by means of various methods. The authors have studied the patterns of cephalopods dehydration using the example of octopus and squid under different heat treatment regimes. It has been proved that there is only one critical point characterizing the transition from moisture with a lower binding energy to moisture with a higher one, and an equation has been proposed for finding the critical humidity during dehydration of the objects been studied. A generalized mathematical model has been developed to determine the duration of the process at the current moisture content of the food material based on dimensionless similarity criteria characterizing the phenomena been investigated. The dependences of the moisture removal rate for different heat treatment methods of cephalopods are given according to their initial moisture content, the specific surface area of the material and the operating factors that determine the process. The obtained dependencies and patterns open up unique opportunities for labor-saving design in the food industry using rational operating modes of industrial enterprises, optimization of heat treatment processes in general and the creation of energy-efficient equipment new designs.

Optimizing mixing efficiency of anaerobic digesters with high total solids concentrations using validated CFD simulations

In this article, viscosity dependent mixing in anaerobic digestion (AD) towers is analysed using finite volume based computational fluid dynamics (CFD) simulations validated with ultrasound particle image velocimetry (uPIV). The study focuses on improving mixing characteristics for enhanced biogas production resulting from increased organic loading. Mixing of fluids with viscosity ranges found in real-life AD is investigated using the multiple reference frame (MRF) method. The aim is to increase the energetic efficiency of AD by reducing the energy demand required for sufficient mixing such that microorganisms and organic substrates are homogeneously distributed. The distinguishing feature of this work is the implementation of less power-consuming helical ribbon stirring devices (HRSD) for enhanced mixing in different reactor designs. It is demonstrated that HRSD become progressively effective for increasing total solids concentrations (% TS) ranging from 2.5 % TS to 12.1 % TS, particularly in cylindrical reactors. In comparison with conventional propeller-based mixers, innovative HRSD operation reduces dead volume (DV) by up to 22 %. Additionally, HRSD cause less shear forces and require less power due to lower rotational speed. The most energy-efficient mode of operation reduces the power demand by 9.29 % at 12 rpm, while still providing decreased DV of 13.38 % for the most viscous fluid investigated. The outcome is a more efficient and cost-effective mixing approach, which holds strong potential for mixing applications involving highly viscous fluids.

Energy Efficiency of the Extrusion Process and its Effect on Output of Biogas during the Fermentation of Maize and Rape Straw

The purpose of the research is determining the influence of pre-treatment by extrusion of rape and maize straw on the output of biogas and the energy efficient mode of the extrusion process. The set goal is achieved by solving the following problems: pre-treatment of rape and maize straw by grinding and various versions of extrusion; carrying out experimental researches of the fermentation of rape and maize straw in the mesophilic mode of fermentation for 42 days; carrying out numerical modeling to determine the power inputs on the process of extrusion during change the frequency rotation of screw conveyer of the extruder. The most significant results: it was experimentally proven that the output of biogas from rape and maize straw increases when the size of their particles is reduced to a certain value, which is reached after 2-times extrusion, and further reduction of the size of the particles does not give a positive effect and, vice versa, reduces gas release. Extrusion provides not only grinding, but also thermo-baro processing, which additionally grinds lignin-cellulosic raw material. It was determined that the energy efficient mode of operation, the necessary level of pressure and temperature in the die, which exclude the burning of organic raw materials, is ensured at the rotation frequency of screw conveyer of the extruder at 110 r/pm. The significance of the obtained results is that the extrusion with the proposed technological and mode parameters of the extruder can be used as an effective method of pre-treatment of lignin-cellulosic raw material to increase the productivity of bioreactors and biogas output.

The Impact of the Digital Economy on Regional Carbon Emissions: Evidence from China

As a high-tech, energy-efficient mode of economic development, the digital economy has a strong impact on regional carbon emissions and sustainable development. With a sample of panel data from 30 provinces in China ranging from 2011 to 2021, this study employs an expanded STIRPAT model to examine the impact of the digital economy on regional carbon emissions. The results reveal that the digital economy significantly inhibits regional carbon emissions, and specifically, a 1% increase in the level of digital economy development leads to a decline of approximately 1.09% in total carbon emissions. The heterogeneity analysis indicates that the digital economy has a more significant inhibitory effect on carbon emissions in the eastern region and areas with a higher level of development of the digital economy. The mechanism analysis shows that the digital economy can inhibit regional carbon emissions by affecting energy efficiency and changing the energy structure. A further study shows that the digital economy has a spatial spillover effect on the reduction in carbon emissions. Therefore, the government should fully leverage the potential of the digital economy to promote carbon emission reduction, promote the development and innovation of carbon emission reduction technology, continuously improve energy utilization efficiency, and achieve the mutually beneficial goal of economic benefits and emission reduction.

Experimental Study of the Skip Pneumatic Hoisting Plant Model

It has been established that the problem of skip centering relative to the axis of the shaft of pneumatic hoists is solved on the basis of establishing patterns that connect the energy-efficient mode of operation of the guide device with its design parameters and dynamic loads acting on it. The developed and researched model of the skip movement in the systems of the pneumatic lifting plant made it possible to establish the patterns of interaction between the «skip – guiding devices». During the operation of pneumatic hoists, electricity is spent only on lifting the load, and the lowering of the skip occurs without energy consumption under the action of gravity. It was revealed that the maximum dynamic loads on the guiding devices from the side of the skip of the pneumatic hoists during its movement are determined depending on the mass of the loaded skip, the displacement of its center of mass and the dynamic coefficient. The adequacy of the emerging dynamic loads on the directing devices is confirmed by experimental studies of the model of a skip pneumatic hoist. An objective function has been obtained to determine the dynamism coefficient, which determines the energy-efficient mode of operation of the electric drive of the pneumatic hoist and leads to energy saving of the hoist as a whole.

EFFICIENT USE OF ELECTRIC ENERGY WHEN OPERATING A BALL MILL WITH A CONSTANT ROTATION SPEED

Link for citation: Zakamaldin A.A., Perevoshchikov F.V., Shilin A.A. Efficient use of electric energy when operating a ball mill with a constant rotation speed. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 115-127. In Rus. The relevance. Ball mills are widely used in industry for grinding bulk materials, as well as in the last stages of ore crushing, where the required optimal particle sizes are achieved for enrichment. Although ball mills have a relatively simple design and cover extensive research, the industry is still struggling with the very low energy efficiency of the grinding process. As the retrofitting heavy equipment is the costliest approach, process optimization through control system is the most suitable for energy consumption reduction. As a rule, the feed rate is the main control variable for a mill with a constant rotation speed. Due to insufficient information content, outdated methods of analysis and control of the internal dynamics of the mill, control systems keep the target value of feed rate at a deliberately low level in order not to overload the mill. This article provides an explanation of how, in such a case, an increase in mill feed rate could affect the energy efficiency of grinding. The main aim: study of energy efficient modes of operation of stations; verification of models and confirmation of experimental data: the relationship between door loading and power consumption indicators; construction of buildings for energy efficient control of ball towers. Objects: the process of grinding in a ball tower with a constant rotation speed. Methods: mathematical description of the behavior of the electromechanical part of a machine that consumes current and works on a load in the form of spherical furniture; simulation modeling of the operation of the door electric drive; statistical analysis of production indicators. Results. The paper demonstrate the tendency to increase electricity consumption with a decrease in feed rate and vice versa, respectively for ball mills with a synchronous drive of 2500 kW based on modeling and experimental data. Increase in feed rate in the range of 10–40 t/h, there is a drop in active power by 0,48–1,57 %. The values of the specific power consumption of ~5–8 kWh/t during the grinding of apatite ore were obtained. An increase in productivity by 5 t/h on average leads to a decrease in the specific power consumption by 0,12 kWh/t. It is necessary to increase productivity in the operation of ball mills only after integrating measuring instruments into the control system of the mill, which allow an accurate assessment of the state of loading of the mill drum.

Energy-Efficient Modes of Dehydration of Pome Fruits during Microwave Treatment in Combination with Convection

The aim of the work is to significantly increase the efficiency of the dehydrating process of fruits with seeds, by treating it with microwaves in combination with convection. To achieve the purpose, an electrical installation was designed, produced, tested, optimized and implemented, which applies the combined technological treatment method in the dehydration process. Pears were selected as the object of the research in particular, because currently the production of these seeded fruits is not fully exploited, but they are of an increased interest for the agricultural producers and for specialized enterprises, and their dehydration by the methods currently used is difficult, especially because of the browning effect that occurs in the heat treatment process. The essential results obtained based on the research carried out, regarding the application of the elaborated installation, are: reduction of electricity consumption and treatment duration, increase in productivity and quality of dehydrated fruits. At the same time, the developed installation is simple in construction, has low cost and is easy to use, and during fruit processing it allows strict monitoring of the technological parameters, and researches demonstrated a high level of safety in operation. The significance of the obtained results lies in the solution to a series of problems, which are currently faced by the enterprises specialized in fruit processing, in particular by significantly increasing the efficiency of the process of dehydration of pears, based on the proposed method of combined treatment, predominantly with increasing the speed of dehydration, energy efficiency, quality of final products and profitability.

Энергоэффективное управление системой отопления для зданий с циклическим режимом работы

Lack of energy can be a significant factor holding back the country's economic growth. At the level of objects of energy consumption, this problem can be solved by developing systems for energy efficient management 
 of the consumption of energy resources, taking into account the peculiarities of the functioning of specific objects. There is considered a heating system of the building of the OSTROVskiy shopping center (SC) (Astrakhan). There has been made engineering evaluation analysis of energy saving and energy efficiency measures of the building. Engineering evaluation analysis of the building and the heating system of the SC as a control object was carried out, the main regulated, regulating and disturbing quantities were identified. A functional model of a SC as a thermal facility has been developed. To calculate the air temperature inside the building, a thermal model of the object was built based on the thermal characteristics of the building envelope. The correspondence of the model to the real thermal characteristics of the building is shown. A control system for the heating point of SC was developed using the Totally Integrated Automation Portal software. The interface of the control and management system for the heating point of SC has been developed. An algorithm for the heating system functioning in an energy-efficient mode is proposed, taking into account the cyclical mode of operation of SC. A comparative evaluation of the effectiveness of the proposed control system for a thermal substation in the modes of constant performance, variable performance with manual control, variable performance with automatic energy-efficient control has been carried out. It is shown that the use of the proposed method of energy efficient control makes it possible to reduce the consumption of thermal energy by 21.7% compared to the constant performance option used.

Three-Dimensional Ultrasonic Reverse-Time Migration Imaging of Submarine Pipeline Nondestructive Testing in Cylindrical Coordinates

Submarine pipelines are a safe and energy-efficient mode of gas transport. However, due to the complex manufacturing process and harsh operating environment, submarine pipelines are subject to fatigue cracks under long-term cyclic loading. A comprehensive and high-precision characterization strategy for submarine pipelines can effectively prevent potential safety hazards and have significant economic and social repercussions. As a matter of fact, pipeline defects cannot be reliably detected with current traditional 2D methods. On the other hand, in ultrasonic testing, cylindrical geometry increases the complexity of the 3D wave field in the submarine pipeline space and significantly influences the accuracy of the detection results. In this paper, we put forward a novel method for 3D ultrasonic image testing that is suitable for cylindrical coordinates. In order to accurately simulate the ultrasonic signal received from pipelines, we generalize the 3D staggered-grid finite-difference method from Cartesian coordinates to cylindrical ones and simulate the full wave field in the 3D pipeline space. Then, signal processing is performed on the ultrasound simulation records, and 3D reverse-time migration imaging of submarine pipeline defects can be effectively achieved using the reverse-time migration method and cross-correlation imaging conditions. The results obtained from simulations and real field data show that the proposed method provides high-quality 3D imaging of defects in pipelines, taking into account multiple scattering and mode conversion information at the bottom of the defects.

Simulation Model for Operational Planning of City Cargo Transportation by Trams in Conditions of Stochastic Demand

A city’s transport and distribution system requires the effective organization of urban freight deliveries that take into consideration the economic, ecological, and social impact. Implementation of the concept of green logistics necessitates the use of environmentally friendly and energy-efficient modes of transport, which consider the existing infrastructure and the possibility of its development. The aim of this work was to facilitate the transfer to rail transport, using the existing tramway infrastructure, those shipments which previously entered the city center by road. The paper proposes a simulation model for small consignments delivered by freight trams in the city of Poznań, Poland. Operational planning is carried out in conditions of uncertainty and risk. The uncertainty is due to the stochastic nature of the demand for products. The risk is characterized by the probability that, due to technological and technical limitations, a given customer will not be fully served from the distribution center. The authors provide a decision support tool for evaluating the possible locations of tram depots and for route planning. The assignment of the routes, with the criterion of minimizing the costs for the carrier, and with a limitation on tram operating time, is based on the use of genetic algorithms, which makes it possible to obtain a solution that is close to optimal, within a reasonable time period. As a result of a series of simulation experiments and statistical data processing, the distribution laws and expected average values of the technological parameters were determined for the functioning of the city transport and distribution system under conditions of uncertainty and risk.

Забезпечення енергоефективних режимів роботи в системах електрозабезпечення промислових і цивільних об’єктів шляхом регулювання напруги

The development of voltage regulation methods in the energy supply system of industrial and civil facilities using continuous and discrete sources of reactive power, tap-changer of GPP transformers and PBZ of shop transformers is an urgent task. It allows maintaining energy-efficient modes of powerconsuming equipment, elements of power supply and power consumption systems and reduce financial expenses for payment for electric energy. The article presents approaches to solving the task of determining energy-efficient voltage levels at different hierarchical levels of the power supply system and ensuring them by using voltage regulators (TAPs) of GPP transformers, PBZ switches of workshop transformers, as well as power regulation of reactive power sources. For the calculation of energy-efficient voltages, an appropriate algorithm has been developed, which provides the separate execution of operations for calculating the parameters of the current mode of the power supply system and its optimization. This allows to monitor the state of the power supply system and ensure the maximum efficiency of the use of voltage regulation devices. A method of determining the static load characteristics of asynchronous motors by voltage is proposed, taking into account their design features, mechanical load characteristics and magnetizing currents. A method of de termining the static characteristics of the load by voltage at the levels of the shop transformer, RP and GPP has been developed. With the use of the MATLAB/SIMULINK package, calculation studies of static characteristics by voltage at different levels of the hierarchical power supply system were carried out. The selection of the method for calculating the modes of shop and distribution electric networks of an industrial enterprise was reasoned. The static characteristics of the load according to the voltage, the action of the voltage regulators of the GPP trans formers, the position of the PBZ of the shop transformers, the power of the reactive power sources were taken into account. Algorithm for controlling discrete and continuous sources of reactive power and voltage regulators of GPP transformers was proposed taking into account static load characteristics to ensure energy-efficient operation modes of shop and distribution electrical networks of an industrial enterprise.

Modified Ant Colony Optimization as a Means for Evaluating the Variants of the City Railway Underground Section

The railway is one of the most energy-efficient modes of transport, helping to enhance the environment and public health in cities and agglomerations. In this paper, the authors raise the issue of the construction of an underground railway route in Wrocław (Poland) to allow the organization of the suburban rail system in the agglomeration. There are many concepts for the construction of this route, but so far none has been realized. Therefore, it is important to design the route properly. Here, five options for this tunnel are considered and evaluated. To make such an evaluation, the authors construct a modified ant colony optimization algorithm (ACO). The "classic" algorithm considers the determination of the shortest route. The modification of the algorithm will allow a more accurate analysis of the issue, taking into account more parameters than just the length of the route. These are the location of traffic generators in the city center, the number of inhabitants neighboring the stations, and the number of tram or bus lines integrated with the railway. The presented method and exemplary case study should allow for the evaluation, introduction, or development of the city railway.

Method development for determining the energy-efficient mode of air-cooling devices’ operation

When ensuring the normative limit of the heat of the gas transmitted to the main gas pipelines by means of air cooling devices of the gas transmission compressor station, the modes of parallel operation of the fan motors of the air cooling device system are considered. At the same time, a comparison was made of methods for adapting air cooling devices to factors affecting energy-efficient operating modes. As a result, based on a mathematical model of the combustion operating mode through a gas-air cooling device, the possibility of regulating the engine speed and increasing the energy efficiency of the system, taking into account seasonal and temperature changes, is shown. The main parameters for saving energy sources are introduced into the technological processes of gas compression and cooling.

Optimization of the operating mode of a squirrel-cage induction motor

THE PURPOSE. The presented work aims to optimize the operating mode of an asynchronous motor (AM) with a short-circuited rotor. To implement energy-efficient modes of operation of AM, operating in the resources of a rational electric drive, it is necessary to determine the numerical values of the parameters of the AM equivalent circuit, the currents flowing through the circuit element. There is no significance to this important definition of squirrel-cage currents, in accordance with the identification of the allocation of squirrel-cage rotor currents, which requires a solution along with the determination of the parameters of the IM equivalent circuit.METHODS. To analyze the work of AM in technical and educational formulations, equivalent circuits are presented, which turn into circuits with serial and analytical connections of active and inductive connections. For the established and transient operating modes of AM, it is important to determine the stator and rotor currents, their active and reactive components. In this regard, it is proposed to present the IM equivalent circuit in the form of conductivities connected in parallel, which will allow determining the components of IM currents without complex mathematical models. The replacement circuit of AM consisting of a series and parallel connection of active and inductive resistances has been converted into a circuit consisting of conductances. When converting the AM equivalent circuit, no additional dependencies and coefficients were introduced, and all assumptions that are accepted for IM equivalent circuits refer to the circuit under consideration. RESULTS. It was decided to use the equivalent circuit of one phase of AM, expressed in terms of the conductivities of the stator and rotor. According to the found dependences of conductivities, for the proposed equivalent circuit, the corresponding currents and powers of the AM phase are determined. Formulate the basic principle of optimal frequency control of AM, according to the criterion of energy saving. As an indicator of the efficiency of AM operation in steady-state operating modes, the minimum value of the total losses of the engine, the value of which is determined by the ratio of the product of the active conductivity of the rotor circuit q2s and the active conductivity of the phase q to the square of total conductivity y.CONCLUSION. Based on the results of the analysis of the characteristics of an asynchronous motor, the following conclusion was drawn: the motor will operate with minimal losses if the amplitude of the supply voltage is changed so that the slip of the asynchronous motor is equal to the critical value sξ for a given frequency. For the investigated engine AIR100S4, the critical value is sξ=0.0613 at a network frequency of 50 Hz. The method proposed in the work allows to reduce the loss of active power by 3-5% in the motor windings.

A nonlinear fractional-order dynamical framework for state of charge estimation of LiFePO4 batteries in electric vehicles

An efficient state of charge (SOC) estimation for LiFePO4 batteries in electric vehicles (EVs) has been an open problem so far, largely due to its non-measurable nature. This paper tackles this problem by presenting a fractional-order (FO) dynamical framework to unravel and understand the inherent dynamics of the LiFePO4 battery which leads to an improved estimation of SOC. First, a FO model (FOM) is proposed where the parameters are introduced as nonlinear functionalities of SOC. It has been observed that the FO defined as a nonlinear function of SOC is crucial in identifying its progression during the weakly measurable flat, open circuit curve of the battery; a property the integer order models (IOMs) fail to capture. Second, a fractional order estimator (FOE) is designed incorporating the SOC based nonlinearities of the model parameters. The FO derivative being a memory-based operator improves estimation as it can store historical information of the speed profiles of the EV. The proposed framework of nonlinear FOM and FOE design is validated through both simulation and experimental results. Precise estimation of the battery parameters using the proposed framework can be applied to protect the battery management system, mitigate overcharge or discharge, prevent hazardous accidents, and enhance battery life, eventually leading to an energy-efficient mode of green transportation.

Improving the energy efficiency of tractors in agricultural operations

The article proposes and substantiates a method for indirect determination of the energy parameters of the operation of an agricultural tractor engine, which makes it possible to calculate and establish the most energy-efficient mode for performing an agricultural operation. The proposed method for determining the energy parameters of the engine operation by measuring the turbocharging pressure, with high accuracy, is highly informative and has a number of advantages compared to traditional methods for instrumental control under the working conditions of agricultural tractors and machines.

MATHEMATICAL MODEL OF THE DYNAMIC MODES OF THE MICROCLIMATE SYSTEM IN THE LIVESTOCK BUILDING WITH A HEAT EXCHANGER

The article determines the relevance of research options for the use of heat exchange equipment for the utilization of the heat of the exhaust air of livestock building. It has been analyzed that for the efficient functioning of heat-utilizers, it is necessary not only to choose optimal design parameters, but also to implement rational energy-efficient modes. It was determined that for the synthesis of the system of automatic control of the thermo-humidity mode in the room, it is necessary to determine the dynamic characteristics of the control object based on the mathematical model of dynamic modes. The analysis of the existing heat utilization systems is presented and it is stated that they have only analytical dependencies for their description, which describe the stationary regimes of heat utilization systems that determine the statics of heat and mass exchange (moisture condensation on the surface) processes. In the considered works, the combined functioning of the heat recovery unit and the livestock building in non-stationary mode is not considered. On the basis of the analysis of the heat-moisture regime of the livestock building, the ventilation system of which is equipped with a recuperative type heat recovery unit, a mathematical description in the form of differential equations of the heat and material balance of the livestock building with the heat utilization ventilation system was compiled. Mathematical models of the heat and material balance for the livestock building have been developed in the form of a system of three differential equations, which contain two interrelated parameters: temperature and air humidity. But since the parameters of the air in the room with the waste ventilation air heat utilizer depend on the parameters and mode of operation of the heat exchanger, the equation of the thermal regime of the room was developed with the equations that determine the non-stationary thermal regime of the heat utilizer. The formulated mathematical model describes the non-stationary process of heat exchange in the microclimate creation system and can be used to justify the design and operating parameters of the heat exchanger regardless of design features. The mathematical model defines the transition process in the "room-heat-utilizer" system and can be used to create a system for automatic temperature-humidity control.

Controlling of Electric Vehicle to with Different Hybrid Systems

Electric vehicles (EVs) are currently regarded as one of the most energy-efficient modes of transportation, emitting no tailpipe emissions. 3 million electric vehicles are already on the road, and that number is expected to reach 100 million by 2030 . Notwithstanding, the execution of the proposed plan interest for tremendous charging foundation and gigantic electrical energy. Also, EVs must be economical when the electrical energy expected for charging is created from inexhaustible and practical energy sources. However, shifting emissions from vehicles to power plants through the use of fossil fuels for electricity generation does not reduce emissions. Accordingly, the utilization of sustainable power hotspots for power age can totally take out the emanation and gives a natural advantage. Solar photovoltaic (PV) based generation is the most feasible option for EV charging out of the various renewable energy sources that are available, such as wind energy, hydro energy, fuel cell-based energy, and solar photovoltaic (PV) array.