Additional Power Source Research Articles

Energy Efficiency and Limitations of the Methods of Controlling the Hydraulic Cylinder Piston Rod under Various Load Conditions

The article is an overview of various methods of braking and controlling the movement of the piston rod under various load conditions. The purpose of this review is to systematize the state of the art in terms of efficiency, energy consumption and limitations of each method. The article discusses systems with different types of hydraulic actuators, operating under passive, active and variable load during the duty cycle of the piston rod. The existing literature was analysed in terms of applicability, reduction of energy consumption of the systems and even the possibility of energy return. Attention was paid to the costs and the need for additional power sources, as well as the problems and limitations of the presented methods. Based on the simulation model, energy consumption tests were carried out in systems with an actuator loaded with a variable force. There is a comparison of all methods in terms of actuator type, load, energy consumption and the possibility of energy recovery.

Triboelectric nanogenerator-enabled fully self-powered instantaneous wireless sensor systems

The wireless sensor networks (WSNs) play an important and essential role in modern society. However, the requirement for huge distributed energy for sensors and wireless transmission modules has become a bottleneck in the development of WSNs. Various energy harvesting technologies have been explored for developing self-powered sensors, however they either need a long duration for energy collection and storage, leading to not real-time sensing, or require additional power sources to run the WSNs. Here we report a novel triboelectric nanogenerator (TENG)-based fully self-powered instantaneous wireless sensor system. TENG is integrated with an RLC sensing circuit, enabling spontaneous generation of oscillating signal with encoded sensing information. Additionally, by using an electronic switch, the frequency and amplitude of the signal become extremely stable and immune to the environmental variations. An innovative impedance-modulated signal analysis method is also developed to extract the sensing information for resistive, capacitive as well as inductive types of sensors. The sensor system is then applied for real-time tire pressure and speed monitoring for a bicycle. Results showed that the self-powered wireless tire pressure sensor system is able to monitor tire pressure and speed of the bicycle, with a resolution of 5.5 kPa and a precision of about 97% respectively, demonstrating its excellent potential for general applications.

A novel solar-powered milk cooling refrigeration unit with cold thermal energy storage for rural application.

This experimental study analyzed the use of solar photovoltaic energy for operating a novel twin-circuit DC milk chiller without batteries using water-based cold thermal energy storage for different seasons in Chennai, India. HFC-134a and HC-600a were used as refrigerants in the two individual circuits. For each season, the test was conducted continuously for 18days to analyze the quantity of generated ice that could be utilized to chill 10 L of milk in the morning and in the evening. The average quantity of ice formed per day in the ice bank during monsoon, winter, and summer seasons was found to be 3.61, 19.75, and 27.97kg, respectively. Thus, it is evident that the use of solar energy with thermal energy storage is effective for operating the milk chilling unit for two seasons, namely winter and summer. However, the system requires an additional power source for continuous operation during the monsoon season. It is noteworthy to mention that the use of a solar milk chiller instead of a conventional milk chiller resulted in 91.15% lesser CO2 emission with 27.6% less LCC. In this study, solar photovoltaic power was observed to be a good choice for chilling milk in the context of global warming and energy consumption. The use of thermal energy storage also allows the initial cost to be reduced.

Study of Operation of the Thermoelectric Generators Dedicated to Wood-Fired Stoves

Thermoelectric generators are devices that harvest waste heat and convert it into useful power. They are considered as an additional power source in the domestic sector, but they can also be installed in off-grid objects. In addition, they are a promising solution for regions where there is a lack of electricity. Since biomass heating and cooking stoves are widely used, it is very appropriate to integrate thermoelectric generators with wood-fired stoves. This paper shows the experimental analysis of a micro-cogeneration system equipped with a wood-fired stove and two prototypical constructions of thermoelectric generators dedicated to mounting on the flue gas channel. The first version was equipped with one basic thermoelectric module and used to test various cooling methods, while the second construction integrated four basic thermoelectric modules and a water-cooling system. During the tests conducted, the electricity generated in the thermoelectric generators was measured by the electronic load, which allowed the simulation of various operating conditions. The results obtained confirm the possibility of using thermoelectric generators to generate power from waste heat resulting from the wood-fired stove. The maximum power obtained during the discussed combustion process was 15.4 W (if this value occurred during the entire main phase, the energy generated would be at a level of approximately 30 Wh), while the heat transferred to the water was ca. 750 Wh. Furthermore, two specially introduced factors (CPC and CPTC) allowed the comparison of developed generators, and the conclusion was drawn that both developed constructions were characterized by higher CPC values compared to available units in the market. By introducing thermoelectric modules characterized by higher performance, a higher amount of electricity generated may be provided, and sufficient levels of current and voltage may be achieved.

სისტემაწარმომქნელ ქსელში შერჩეული რეაქტიული სიმძლავრის დამატებითი წყაროს ოპტიმალური გადანაწილება მანაწილებელ ქსელში

An additional (generation) source of reactive power may be required in a backbone network node (𝑈௡ ≥ 220 𝑘𝑣) which has a heavy reactive load. When solving this problem, in a technical-economic sense, it is advisable to place this additional source of reactive power not in the mentioned node of a backbone network, but in the nodes of a distribution network (𝑈௡ ≤ 110 𝑘𝑣) connected to this node. This problem specifically involves: optimal rescheduling of total power of the additional reactive power source selected according to a voltage criterion in a backbone network node between the distribution network nodes connected to this node. The relevant optimization equations created in the article and the obtained mathematical model allow us to solve this problem effectively and successfully. The condition for optimality here implies the best economic returns, while the objective function is to minimize active power losses caused by nodal reactive powers. That was why we used the economic criterion as the main criterion in solving this problem.

Film-Sponge-Coupled Triboelectric Nanogenerator with Enhanced Contact Area Based on Direct Ultraviolet Laser Ablation.

Triboelectric nanogenerators (TENGs) recently have emerged as applicable and eco-friendly harvesting devices. Numerous studies have been actively conducted to fabricate a flexible and robust TENG with high-output performance. Herein, a film-sponge-coupled TENG (FS-TENG) is proposed using direct ultraviolet laser ablation, as a method for surface modification of a polyimide (PI) film. This state-of-the-art method has advantages of accuracy as well as time efficiency in creating the pattern on the surface; thus, the pre-designed patterns can be precisely constructed within only a minute. In the laser-ablated PI film, the structural design and chemical modification on the surface are investigated related to the triboelectric output performance. Thereafter, a sponge is fabricated based on non-woven polyamide and silicone rubber, which can fully contact with the micro-/nano-scaled structure on the surface of the PI film. After an optimization, the FS-TENG exhibits 48.19 V of open-circuit voltage and 1.243 μA of short-circuit current, which shows approximately 3 times enhanced electric performance compared to the FS-TENG using a pristine PI film. The FS-TENG device demonstrates its robustness through both mechanical stress and flexible stress by showing less than 5% degradation after 50,000 cycles. On the basis of the high flexibility and stability of the FS-TENG, a self-powered scoreboard is successfully developed for lighting a scoreboard in a soccer field. This feasible lighting system can be operated by harvesting the kinetic energy of a soccer player without an additional power source. The novel FS-TENG, thus, provides remarkable potential for a self-powered indoor harvesting system.

IMPROVING THE METHOD OF DETERMINING THE VALUE OF WATER LEVELS IN VERTICAL WELLS OF GROUP WATER COLLECTION

Purpose. Reconstruction of water supply systems to meet the increased water needs of consumers is a complex, time-consuming and expensive task. Reconstruction options include expanding existing water intakes or building new ones anywhere in the existing water supply network. The variety of options is accompanied by changes in water consumption in the sections of the networks and, importantly, in the flow distribution. The introduction of additional sources into the existing water supply systems requires a detailed study of the factors affecting the technical characteristics of the systems and responsible for the economic component of the project. Methodology. The influence of the determining factors on the total head losses in the water distribution network during the reconstruction of the water supply system is analyzed. An algorithm for finding the optimal network points for connecting an additional power source is proposed, which includes determining the optimal flow distribution and the corresponding technical changes for each selected option; total capacity of pumping stations and heads; analysis of the complete set of the water supply system of the accepted options; an economic analysis of the construction investment and operating costs that will accompany the operation of the water supply system design options. Findings. The choice of the optimal connection points for additional power sources depends on the amount of water flow in the network sections and the flow distribution. It is shown that the nodes of the end sections of the network most correspond to the conditions for searching for optimal points and can be fed from different directions, depending on the amount of additional flow. With an additional water flow rate no more than two nodal flow rates, the total head losses in the network sections are minimal. When an additional flow rate of more than two nodal flows enters the final node, an increase in head losses is observed, which can have critical values depending on its increase. The introduction of additional water flows into the network, which exceed two nodal ones, requires the use of intermediate network nodes located at sections with a higher throughput as connection points. Originality. The analysis of the factors influencing the choice of points of connection of additional power sources of the water supply network during its expansion is carried out. The analysis of the points was carried out with limited ranges of the values of water consumption of additional feeding − less and equal to the nodal ones, two and three times larger than the nodal ones. The ways of finding the optimal option for choosing a network node as a point of connection of additional power are shown. Practical value. The use of the analysis results will make it possible to most effectively search for the optimal variant of reconstruction of water supply systems, take into account the influence of determining factors on the characteristics of networks with changes in water consumption and flow distribution. The use of the analysis results will make it possible to most effectively search for the optimal variant of reconstruction of water supply systems, take into account the influence of determining factors on the characteristics of networks with changes in water consumption and flow distribution.

The Nickel Mass Distribution of Stripped-envelope Supernovae: Implications for Additional Power Sources

Abstract We perform a systematic study of the 56Ni mass (M Ni) of 27 stripped-envelope supernovae (SESNe) by modeling their light-curve tails, highlighting that use of “Arnett’s rule” overestimates M Ni for SESNe by a factor of ∼2. Recently, Khatami & Kasen presented a new model relating the peak time (t p) and luminosity (L p) of a radioactively powered supernova to its M Ni that addresses several limitations of Arnett-like models, but depends on a dimensionless parameter, β. Using observed t p, L p, and tail-measured M Ni values for 27 SESNe, we observationally calibrate β for the first time. Despite scatter, we demonstrate that the model of Khatami & Kasen with empirically calibrated β values provides significantly improved measurements of M Ni when only photospheric data are available. However, these observationally constrained β values are systematically lower than those inferred from numerical simulations, primarily because the observed sample has significantly higher (0.2–0.4 dex) L p for a given M Ni. While effects due to composition, mixing, and asymmetry can increase L p none can explain the systematically low β values. However, the discrepancy can be alleviated if ∼7%–50% of L p for the observed sample comes from sources other than radioactive decay. Either shock cooling or magnetar spin-down could provide the requisite luminosity. Finally, we find that even with our improved measurements, the M Ni values of SESNe are still a factor of ∼3 larger than those of hydrogen-rich Type II SNe, indicating that these supernovae are inherently different in terms of the initial mass distributions of their progenitors or their explosion mechanisms.

A flexible electrostatic nanogenerator and self-powered capacitive sensor based on electrospun polystyrene mats and graphene oxide films

Electrostatic nanogenerators or capacitive sensors that leverage electrostatic induction for power generation or sensing, has attracted significant interests due to their simple structure, ease of fabrication, and high device stability. However, in order for such devices to work, an additional power source or a post-charging process is necessary to activate the electrostatic effect. In this work, an electrostatic nanogenerator is fabricated using electrospun polystyrene (PS) mats and dip-coated graphene oxide (GO) films as the self-charged components. The electret performances of the PS mats and GO films are characterized via the electrostatic force microscopy phase shift and surface potential measurements. With a multilayer device structure that consists of top electrodes/GO films/spacer/electrospun PS mats/bottom electrodes, the resultant device acts as an electrostatic generator that operates in the noncontact mode. The nanogenerator can output a peak voltage of ca. 6.41 V and a peak current of ca. 6.57 nA at a rate of 1 Hz of mechanical compression, and with no attenuation of electrical outputs even after 50 000 cycles over a 13 h period. Furthermore, this as-prepared device is also capable of serving as a self-powered capacitive sensor for detection of tiny mechanical impacts and measurement of human finger bending. This results of this work provides a new avenue to easily fabricate electrostatic nanogenerators with high durability and self-powered capacitive sensors for the detection of small impacts.

CORRECTION OF THE METHOD FOR MEASURING THE AMPLITUDES OF THE CURRENT OF THE IMPULSE ALONG THE LONG EARTH ELECTRODE

An improved method for measuring the amplitude reduction of the lightning current impulse as it flows from the beginning to the end of long horizontal earthing arrangement using ferromagnetic recorders has been substantiated. Two existing methods of pulse amplitude measurements at high voltages, the magnetic recording method and the method using a shunt, are used in justification. It is noted that in a number of cases it becomes necessary to determine the decrease in the pulse amplitude as it flows on a long object. This leads to the need to develop a method for performing such measurements. As an example, a long horizontal earth electrode was investigated when a lightning current pulse moves on it. Based on experimental studies in natural conditions, an improved method for measuring the decrease in the amplitude of the lightning current impulse along a long earth electrode is proposed. The proposed method has a measurement error not exceeding 10 %, and allows simultaneous measurements of the amplitude of the current strength at given points of the object, which can amount to tens or even hundreds. This method is implemented in a simple design and has an affordable manufacturing cost. The results of the experiments performed make it possible to recommend the corrected measurement method for practical use on existing electrical installations. The use of ferromagnetic recorders for recording and measuring the lightning current in areas of complex earthing arrangements is relevant for practical reasons, which include the possibility of measuring during a long wait and long-term storage of measurement results, does not require additional power sources and provides the possibility of synchronous measurements at various points of the grounding device. An important feature of the method is safety for technical equipment and personnel.

WSN Smart Irrigation System and Weather Report System

This paper proposes a cost-effective system that can be used by farmers easily. In these modern times also, we find farmers going to their fields to check the water level and to see that no cattle are present near the field. Even if there are cattle he can’t do anything at that moment. So, we proposed a system where he can be notified if there is any animal or if the water content is low on his registered mobile number. In this system, an irrigation-based Wireless Sensor Network (WSN) using Raspberry Pi and the solar panel is implemented, Raspberry Pi being used as Coordinator node and Arduino as an end node, nRF24L01 as a transceiver. The sensor input values such as soil moisture level, PIR; the temperature is collected by the Arduino and is wirelessly sent to the Raspberry Pi. The water pump can be turned on based on sensor values using the Raspberry Pi web server and those values are also posted on the webpage. For temperature and humidity detection, we used the DHT11 sensor and the solar panel is used as an additional source of power. A PIR sensor is used to check if there are any animals present near the field.

The influence of load distribution along a line on power and place of connection of a photovoltaic system

Distributed generation in the electrical network causes a redistribution of power and leads to a reduction in technological losses and a decrease in voltage deviations for consumers. The installation of additional generators of electric energy based on the use of wind generators and photovoltaic systems has become widespread in the world energy industry, and has now received development in the Russian Federation. It is shown that the connection of an additional source based on photovoltaic systems can reduce losses in a supply line. According to results of the analysis of a possible location of the connection of an additional power supply on a line with a uniformly decreasing or increasing load, it is proved that the greatest reduction in the level of losses in a line is achieved when additional power supply is connected to it in the case of increase in the load from the beginning to the end. Analytical expressions for determination of economically expedient capacities and a place of connection of an additional source for linearly decreasing or increasing specific load of a supply line are presented. There was determined the optimal power of an additional power source in the form of a photovoltaic system and the optimal point of its connection on a line to reduce power losses during power transmission.

DEVELOPMENT OF MEASURES TO IMPROVE THE OPERATIONAL EFFICIENCY OF AUTONOMOUS LIGHTING COMPLEXES FOR UKRAINIAN HIGHWAYS

Reducing highway hazards through the creation of modern lighting systems is an important practical task that currently has some difficulties. The rapid development of renewable energy makes it possible to use off-the-shelf solutions to create autonomous lighting complexes for unregulated pedestrian crossings. The analysis of peculiarities of design, constructive structure and operation of autonomous lighting complexes, which are located in Kharkiv region and use renewable energy sources and energy storage systems to power lighting devices and flashing signal lights, is carried out. The analysis results showed that the lighting complexes under investigation are not capable of supplying sufficient energy for themselves and of functioning properly at low insolation and low ambient temperatures. The reasons for the unstable operation of autonomous lighting complexes have been identified, with the main one being the insufficient accuracy of taking into account the actual climatic operating conditions of facilities when forming design solutions. Measures have been developed to improve the efficiency of the autonomous lighting complexes under study, involving the use of off-the-shelf technical solutions based on modern tools and technologies. A criterion for sufficiency of the developed measures to solve the problem of autonomous power supply of lighting complexes for highways is proposed. The sign of the resulting capacity of the complex over the calculation time period is taken as a sufficiency criterion. The practical use of the developed criterion confirmed the feasibility of the proposed measures to improve the operational efficiency of the investigated autonomous lighting complexes for highways. Calculations have shown that it is not sufficient to use solar panels alone to supply highway lighting complexes located in regions with unstable levels of insolation. The feasibility of hybrid power supply systems for autonomous lighting complexes that use additional power sources such as wind turbines and systems with electromechanical converters in addition to solar panels has been quantitatively confirmed.

ИССЛЕДОВАНИЕ АСИНХРОННОЙ ЭЛЕКТРИЧЕСКОЙ МАШИНЫ С КОРОТКОЗАМКНУТЫМ РОТОРОМ ДЛЯ ВОЗОБНОВЛЯЕМОЙ ЭНЕРГЕТИКИ ПРИ НЕСТАЦИОНАРНОМ КОНДЕНСАТОРНОМ ВОЗБУЖДЕНИИ

Актуальность. Доля электроэнергии, вырабатываемой установками на основе возобновляемой энергии, постоянно растет, в связи с чем потребность в развитии систем питания и автоматического управления электрическими машинами, лежащими в основе ветро- и гидрогенераторов, не теряет актуальности. В составе таких генераторных установок переменного тока применяют синхронные электрические машины, асинхронные машины с фазным и короткозамкнутым ротором. Преобразователи частоты, устанавливаемые в статорные и роторные цепи асинхронных машин переменного тока, позволяют управлять процессами их возбуждения, однако для начала генерации требуется использовать дополнительные внешние источники питания. Благодаря остаточному намагничиванию в магнитопроводе можно обеспечить процесс гарантированного самовозбуждения асинхронной машины с помощью подключения батарей конденсаторов к ее статорным обмоткам без применения дополнительного внешнего источника питания. Предложенный способ нестационарного конденсаторного возбуждения позволяет обеспечить адаптацию генераторной установки к изменению режимов работы в условиях децентрализованного электроснабжения. Цель: исследовать предложенную систему стабилизации напряжения асинхронной машины с короткозамкнутым ротором с варьируемым конденсаторным возбуждением в составе источника возобновляемой энергии. Методы: теоретические – теория дифференциальных уравнений, методы численного решения обыкновенных дифференциальных уравнений, теория электропривода, теория электрических машин, численные методы аппроксимации данных, и экспериментальные – проведение испытаний асинхронной электрической машины с нестационарным конденсаторным возбуждением на разработанном испытательном стенде с целью получения нагрузочных характеристик и осциллограмм напряжений на обмотках статора асинхронных машин с короткозамкнутым ротором в различных режимах работы, методы исследования. Результаты. Разработана и изготовлена оригинальная экспериментальная установка с узлом, имитирующим работу турбины. Электромеханический преобразователь энергии выполнен в виде асинхронной машины с короткозамкнутым ротором с нестационарным конденсаторным возбуждением. Блок управления установкой выполнен в виде интегрированного с силовым блоком гальванически развязанного модуля во влагостойком исполнении с применением беспроводного интерфейса связи Bluetooth. Описан и протестирован способ коммутации батарей конденсаторов с применением тиристоров в качестве управляемого ключа с двухсторонней проводимостью. Анализ полученных нагрузочных характеристик показывает принципиальную возможность обеспечить гарантированную выработку электроэнергии со стабилизацией напряжения в допустимых пределах изменения мощности нагрузки. Примененная в составе экспериментальной установки система автоматической коммутации конденсаторов с варьируемой в зависимости от потребляемой мощности емкостью позволила обеспечить приемлемое время динамической реакции на возмущающее воздействие при нестационарной нагрузке.

Analysis of Electrical Cell-to-Cell Communication Using the Aggregate of Model Cells

When muscle cells are excited electrically, the membrane potentials of entire cells change simultaneously from a resting potential to an action potential. For smooth muscles, depolarization caused by pacemaker cells spreads to neighboring cells via gap junctions.1) Because Ca2+ or K+ flows through gap junctions between neighboring cells, a local circulating current is generated between the two cells. A change in membrane potential from resting to action potential therefore propagates through the muscle tissue. The same propagation mechanism is assumed to occur in cardiac muscle tissue. The propagation of electric signals among neighboring cells within the cell aggregate has been proposed based on the local circulating current. Voltage-sensitive dyes have been used to monitor partial membrane potentials of single living cells, because it is difficult to simultaneously measure the membrane potentials in multiple places. In addition, because it is almost impossible to simultaneously monitor the changes in the membrane potentials of multiple cells in a given tissue, a detailed propagation mechanism of the action potential among multiple living cells has yet to been clarified yet. On the other hand, K+ and Na+ channels play important roles in nerve conduction. We have proposed a new propagation mechanism for action potential in nerve conduction using model systems composed of multiple liquid-membrane cells.2) Ligand-gated Na+ channel in a synapse behaves as electric power sources that propagate changes in membrane potential toward the synaptic terminal, and voltage-gated Na+ channels on the nerve axon serve as supporting electric power sources to assist with directional propagation of the action potential. In addition, action potential appears to be caused by an external electrical stimulus. The circulating current generated in the model-cell system partially provokes a change in membrane potential from a resting potential to an action potential, and the action potential propagated to neighboring cell systems sequentially. In this study, signal transmission among multiple cell bodies was elucidated by constructing a model-cell system composed of multiple liquid-membrane cells that mimic the function of K+ and Na+ channels. Signal transmission among model-cell units caused by activation of a given model-cell unit or an external electric stimulus was investigated by analyzing the relationship among the respective membrane potentials and the currents flowing through the respective liquid-membrane cells. To imitate tissues such as muscles, cardiac muscles, and brains, liquid-membrane cells mimicking the function of K+ and Na+ channels were made. Action-potential propagation within the cell aggregate model constructed by multiple model cells was investigated. When the action potential was generated at a given cell, the cell behaved as an electric power source and a current partly flowed through neighboring model cells. Influx and efflux currents caused hyperpolarization and depolarization, respectively, on the surface of neighboring model cells, and the action potential was generated at the depolarized domain of the neighboring model cells. The action potential then spread over all the model cells one after another. When an external electric stimulus was applied to the cell aggregate model system, most cells were simultaneously excited as if they were synchronized. By measuring the electric currents and membrane potentials of respective cells, a mechanism for action-potential propagation among multiple cells has been suggested. The initial depolarized cell behaved as an additional electric power source, and the current locally flowed the outside. According to Kirchhoff’s law, the sum of electric currents flowing through each cell is zero, and the inward and outward currents are equivalent. Considering the relationship between the membrane current and the membrane potential on the channel function of the plasma membrane, an inward current causes hyperpolarization and an outward current provokes depolarization. Because the depolarization at one part of a cell activates neighboring voltage-gated Na+ channels in sequence, the membrane potential of the whole cell is then depolarized. The excited cell behaves as an additional electric power source and propagates the action potential to neighboring cells. It is clear that action-potential propagation to distant cells is delayed by resistances according to the distance between the excited cell and the objective non-excited cell. Thus, external electric stimuli can induce action-potential propagation more smoothly.References1) M.J. Berridge, J. Physiol., 2008, 586, 5047-5061.2) O. Shirai, Y. Kitazumi, and K. Kano, Electroanalysis, 2017, 29, 2656-2664.

Boosting a Power Performance of a Hybrid Nanogenerator via Frictional Heat Combining a Triboelectricity and Thermoelectricity toward Advanced Smart Sensors

AbstractThe demand for a well‐equipped healthcare system is increasing due to the requirement of instant treatment in emergency situations. Particularly, patients are advised to employ fall‐detection sensors and touch‐activated emergency alarms to reduce the mortality rate arising from unexpected falls and emergency conditions. Herein, smart sensors are successfully developed by scavenging the human motions and heat energy with the combination of a triboelectric nanogenerator (TENG) and a thermoelectric generator (TEG). The frictional heat energy produced from the contact and separation of TENG can be utilized as an input source for TEG. Thus, the hybrid tribo‐thermoelectric nanogenerator (HTTNG) generates two electrical outputs with a single primary input. As evidence of this, the flexible HTTNG delivers high output due to the synergistic effect of two generators, that is, through the high output voltage and current in TENG and TEG, respectively. The feasibility of HTTNG as a touch‐activated emergency alarm and a human fall‐detection sensor is successfully demonstrated. Furthermore, the HTTNG can be a promising self‐powered sensing device without any additional power source as well as a power supplier in the Internet of Things era. This hybrid nanogenerator can pave the way for efficient utilization in healthcare systems.

Model prediction-based battery-powered heating method for series-connected lithium-ion battery pack working at extremely cold temperatures

The degraded performance of lithium-ion batteries at low temperatures is a key obstacle to the development of battery energy storage system applied in extremely cold environment. Therefore, this paper proposes a heating method based on model prediction to support the low-temperature operation of battery pack without additional power sources. Battery pack model is developed based on Thevenin equivalent circuit model. A co-estimator is established to update model parameters and state-of-charge online using adaptive recursive least squares and extended Kalman filter. The permissible discharging current of pack is predicted based on multiple constraints to prevent over-discharge. Then, the battery-powered heating structure, control circuit, and heating strategy are designed. The strategy contains a preheating process for cold-start and a holding process for stabilizing cell temperature. The method is verified experimentally through systematic battery-in-the-loop tests at the environmental temperature of – 40 °C. Results show that the method can uniformly preheat all in-pack cells from − 40 °C to − 20 °C in 330 s consuming 4.7% of nominal capacity. In holding process, it is energy-efficient to raise cell temperature continuously and then maintain at 5 °C, which makes 68.3% of nominal capacity available when loading a modified federal urban driving schedule.

Simulation of Heat and Mass Transfer Characteristics for the Optimal Operating Conditions of a Gas-to-Gas Membrane Humidifier with Porous Metal Foam

The shell-and-tube type gas-to-gas membrane humidifier used with air supply to polymer electrolyte membrane fuel cell supplies heat and vapor through a membrane and does not require an additional power source. Packing porous metal foam in the flow path of the membrane humidifier can result in higher heat and mass transfer efficiencies due to heat conduction through metal. In this study, the influence of various operating conditions and types of porous metal foams on the transport characteristics of the membrane humidifier are evaluated by simulation. The main factor causing the improvement of heat and mass transfer is the high conductivity of the porous metal foam, which is significantly correlated with the type of material used, compression ratio, and pore diameter. Additionally, the heat and mass transfer changes significantly when the flow velocity and channel size change due to the effect of the metal foam becoming more pronounced.

Control algorithms for a Range Extender vehicle with an combustion engine

The combination of two drive sources: the internal combustion engine and the electric motor in the hybrid drive system requires an appropriate control system to manage their operation. It relies on many variables, and the greater the degree of drive hybridization the greater is the degree of interdependence of the parameters involved. The article presents solutions of electric drive control algorithms with an additional power source in the form of an internal combustion engine (Range Extender). The results of simulation analyzes in the AVL Cruise program are presented, taking into account three control algorithms and two driving cycles. The obtained results indicate the necessity to take various input quantities into account in order to optimize the use of the combustion engine

Flexible single-electrode triboelectric nanogenerators with MXene/PDMS composite film for biomechanical motion sensors

The increasing demand of portable electronics requires modern power sources to be flexible, wearable, durable, and waterproof. This work reports a flexible single-electrode triboelectric nanogenerator composed of MXene/polydimethylsiloxane film. The effect of (MXene) content (wt%) and compressive force on the output performance of the as-prepared devices are systematically studied. A peak-to-peak open-circuit voltage of 225 V, short-circuit current density of 30 μA cm −2 , and a maximum power density of 10 mW cm −2 on a load resistance of 100 MΩ are obtained by periodically hand hammering a 2 × 4 cm 2 smart textile-based composite. The high output directly powers 80 green light emitting diodes connected in series without any additional power source. In addition to its application as a triboelectric nanogenerator, the textile-based composite is also implemented as a human motion sensor, detecting various human motions such as finger tapping, hand clapping, and hand hammering. Such lightweight smart textiles provide potential opportunities for multifunctional power sources and hence have promising applications in self-powered wearable electronics. • The flexible single-electrode triboelectric nanogenerator was successfully fabricated. • The STENG device with area of 2×4 cm 2 under the periodic hand hammering can light up at least 80 LEDs. • The as-prepared device can behave as a human motion sensor.