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Large energy loss caused by mismatching between the installed power and demanded power, as well as the wasted potential energy, is a serious problem for a hydraulic press. In order to reduce the energy loss, an energy-saving method by balancing the load of operations of presses was proposed based on the analysis of energy flow characteristics of the hydraulic system. In the method, the motor pumps in the drive system are shared in different time by a unit composed of two hydraulic presses so that the energy loss caused by unloading operations can be reduced. Furthermore, these two presses are combined, and the excessive energy from one press can serve as the input energy to the other one during some operations to improve the energy efficiency of the drive system, and the potential energy can be utilized directly. Meanwhile, operation durations of these combined presses are optimized for coordination of working processes. The method was applied to two hydraulic presses in a tandem line, and the energy consumption was obtained by quantifying the characteristics of conversion components. Results indicate that for a single press, 36% of electrical energy can be saved in the investigated forming processes.

Despite the ability of accumulators to smooth out fluctuations in small-scale hydraulic circuits, their use in multi-megawatt power transmission systems remains limited. This is due to the large pressure variations that they experience as their state-of-charge changes when their energy capacity is large. The present work highlights an approach whereby the pressure fluctuations are absorbed by a larger external volume of compressed air. This system has been integrated into a novel floating platform for offshore applications. A thermodynamic model of the gas compression process is developed in order to observe temperature and pressure fluctuations. A brief parametric analysis is undertaken to illustrate the effect of critical system dimensions. This comprises the effect of the external volume with respect to the accumulator volume and the diameter of the umbilical connecting the two components. The system is also simulated in different climates to observe the interaction between the external seawater temperature and the internal gas thermodynamics. A full charge-discharge cycle is simulated and results indicate that around 95% of the energy can be recovered after being stored for a 24-h period. The operational efficiency for a stochastic energy input was also computed and found to be relatively high. Electrical round-trip efficiency was found to be comparable to adiabatic and near-isothermal CAES, but the system can be more advantageous when integrated into the generation-side. The key attribute is the minimization of pressure fluctuations, which results in minimal deviations from the equilibrium temperature. This reduces thermal losses to the surroundings and results in a highly efficient energy storage system.

Computation of stationary and RW fields in the 3D area in the Low Energy Particle Toroidal Accumulator (LEPTA) Penning–Malmberg–Surko trap using the DAISI code and approximation of the RW field are considered.

The present study aims to improve the thermo-chemical conversion behaviours, including reactive transport processes and output performances of an open thermochemical energy storage (TCES) unit. The local thermal non-equilibrium (LTNE) model and the effect of non-uniform porosity are adopted and considered to better elucidate the conversion processes. Cascading the reaction sub-units filled with different thermochemical materials (TCMs), i.e., zeolite, salt hydrate-based composite sorbent, and pure salt of SrBr2·6H2O, to form an integrated storage bed ameliorates the output performance. The numerical results indicate that the maximum temperature difference ranging from 3.5 to 4.9 °C between heat transfer fluid and solid reactants exists during desorption, and the realistic non-uniform porosity facilitates the reactant conversion near the wall compared to the uniform porosity assumption. The cascaded scheme promotes the charging and discharging processes compared to the cases filled with sole TCM, the time required for charging this 10.8 kWh storage model is 16 h. Increasing the charging temperature from 100 °C to 145 °C, the charging time reduced to 6.5 h, saving 59.4%. Boosting the inlet velocity of airflow also accelerates the charging rate. The cascaded storage unit significantly stabilises the output temperature during discharging, warming up the airflow from 20 °C to 35 °C for 24 h with a tiny temperature fluctuation. Airflow with higher relative humidity facilitates hydration but shortens the stable period. Overall power and thermal efficiency of the “thermal accumulator” in charging are 598 W and 92.8%, 164 W and 92.4% in discharging, with a total COP of 0.71. The satisfying performances suggest that the cascaded TCES unit may provide a strategy and reference in the design and promotion of the low-grade energy storage system.

The economic profitability of the operation of gas-steam CHP plants can be improved by using heat accumulators (HA) in them. Thanks to this at the peak of the needs of the National Power System (NPS), an additional amount of electricity will be produced, and in the condition of decreased demand in the NPS load valley, it will be reduced. The total production of electricity in the CHP plant will be at the same level as if there is no accumulator in it. In the article, an innovative methodology in a record with continuous time was used and technical with economic analysis was performed. The reduction of the specific cost of heat production in a CHP plants due to the use of a HA in it is significant and increases the economic profitability of its operation. The N P V a c c u value of the profit with the relatively high price of gas and the low price of electricity may exceed the value of the NPV profit. For the gas price 24 PLN/GJ and the electricity selling price of only 205 PLN/MWh, the profit for the CHP with a HA with V t max = 94 342 m 3 volume is 40 mln PLN greater than without using an accumulator.

With the advantages of high efficiency, clean and renewable energy, the technology of sorption/desorption-based atmospheric water harvesting powered by solar energy has gradually attracted the increasing attention of researchers. In this review paper, through analyzing and summarizing the principles, the performance indexes, the measurements of parameters, the material types, the morphology modification, and the system design and devices of this technology, it was found that the existing research mainly focused on adsorbents, while there are still some imperfections, such as limited application circumstances, instability, discontinuous working and long cycle. Accordingly, the direction of future research is expected to redesign adsorbent materials for higher adsorption-desorption rate and wider range of applications, add heat accumulator and air-driving equipment to make system controllable and flexible, miniaturize devices for convenient utilization, and optimize systems to shorten the water collection cycle and to achieve rapid and continuous working. To follow the direction above, there are also some suggestions for adsorbents and system design.

The fluctuating property of the heat source is a technical obstacle of waste heat recovery, which leads to part-load operation and reduced economics. This work presents a novel system to mitigate the fluctuations by using steam-organic Rankine cycles (RC-ORC) and two-stage steam accumulators. The system can switch between isothermal heat storage and discharge simply by the regulation of water mass flow ( m 2 ) from the low-temperature accumulator (LTA) to the high-temperature accumulator (HTA). In the heat charge mode, m 2 rises when the inlet temperature or mass flow of the heat source increases. The water level of the HTA elevates. Analogously, in the heat discharge mode, m 2 decreases and more water accumulates in the LTA. The RC-ORC operates under the rated condition consistently through the unique structural design. The fundamentals and features of the system are illustrated. Given two typical heat source conditions, the fluctuations in thermal efficiencies are minor (15.63–15.84% and 19.57–19.70%). Thermo-economic estimation of the tanks indicates that the steel cost is roughly 1306 $ and 432 $, respectively. Compared with the single-stage ORC using stream control, the normalized investment cost ( N I C ) is reduced by 888–925 $/kW.

The development of clean and environmentally friendly energy is necessary to address significant energy challenges, and abundant sea current energy, which plays a key role in the decarbonization of our energy systems and has attracted increasing attention among researchers. In the present study, a remote monitoring and diagnosis system was designed in accordance with the requirements of a 50 kW hydraulic transmission and control power generation system. Hardware selection and software function requirement analysis were then performed. The causes of system faults were analyzed, the output fault types of the improved model were determined, and effective monitoring parameters were selected. The accuracy of traditional spectra in diagnosing faults is poor, however, the generalization capability of support vector machines (SVM) is robust. Thus, an improved particle swarm algorithm optimized SVM fault diagnosis model for the hydraulic transmission control power generation system was proposed to rapidly and effectively determine the key parameters. Remote monitoring software for the hydraulic transmission and control power generation system was also developed. The results of remote monitoring and diagnostic tests showed that the software was able to satisfy the functional requirements of the hydraulic transmission control power generation remote monitoring system, and the operation effect was consistent with expectations. By comparing the test accuracy of different diagnostic models, the improved PSVM model has the highest test accuracy with a classification accuracy of 99.4% in the case of normal operation, accumulator failure, relief valve failure and motor failure. In addition, the proposed diagnostic method was effective, thereby ensuring safe and reliable operation of the hydraulic transmission control power generation system.

One of the fundamental issues of the pulse fusion power plants is the appropriate storage of thermal energy during the burn phase and idle phase to ensure the steady-state thermal and flow conditions of the coolant through the turbine. Accumulation of power into the solid heat accumulator is one of the feasible solutions, which, together with its controlled bypass, would allow to achieve steady-state coolant parameters during the burn and idle phases. This paper presents a prototypal model of the solid energy storage. The model is based on the CFD parametric calculations that determine the thermal and flow characteristics of the storage depending on its charge status.

Este documento presenta un marco de evaluación para las cocinas solares con base en tres parámetros: eficiencia energética, facilidad de uso y accesibilidad económica. Cada parámetro evalúa diversos indicadores cuantificables: a) eficiencia energética: potencia de cocción estándar, tiempo de calentamiento, el rendimiento térmico; b) facilidad de uso: la masa en relación al área del colector, orientaciones por hora y capacidad de carga de la olla y; c) accesibilidad económica: el coste por vatio generado y la durabilidad del reflector y/o acumulador térmico. A cada indicador se le asigna una escala máxima y mínima de la evaluación y los datos obtenidos de estos indicadores se integran en un gráfico radial. La suma de los indicadores constituye el aspecto que debe compararse, pero el gráfico también nos permite interpretar las fortalezas y debilidades descritas. Este marco no se puede analizar una sola cocina solar, ya que es una herramienta comparativa que requiere dos o más dispositivos que deseen evaluarse.

An solar battery (SB) efficiency doesn’t exceed 15-25 %. Improvement of SB opertation mode is pos-sible with maximum point power tracker device which is, as usual, a power converter (PC). Conditions of maximum energy picking from the solar battery (SB) which works on PC are analyzed. The accurate con-dition of maximum energy picking for the case of the PC non-linear input current is derived. For a boost converter example the comparative analysis of the derived condition with known one for the converter linear current is performed. The circuits with an accumulator is considered. The simplified system models based non-linear SB characteristic, small current ripple and ideal acuumulator are developed. Three typical system modes with different duty cycle values are considered which are describe different match conditions of the PC and SB. The non-linear differential equation system are solved and maximum energy picking is calculated. Neglectable small of SB energy increasing, smaller than 0.1 %, for the accurate condition in all researched modes is shown. The recommendation of practical implementation the linear current conditions according to its simple practical realization is given. Ref. 11, fig. 4, tabl. 1.

A new hydraulic hybrid excavator potential energy recovery system is proposed in this paper. The energy recovery system uses threechamber cylinders (TCCs) and accumulators to recover potential energy during work cycle. Within this structure, there is no throttle valve in the primary loop, and the recovered energy is stored in the form of hydraulic energy. Hence, energy loss of throttle valve and energy conversion process are avoided, and energy efficiency is improved. The mathematical model is established to analyze dynamic and energy recovery characteristics. From simulation analysis, the usage of accumulators and TCC influences the dynamic response and stability. The increase of accumulator volume weakens the control performance but heightens the stability. When the cross sectional area of the TCC increases, the control performance of the system are improved. In addition, the maximum power and energy consumption of pumps and engine with different accumulator volumes and different TCC diameters are obtained. Also, the maximum power and energy consumption of each pump and engine in different working conditions are obtained and compared with those without potential energy recovery system. According to the comparison, the potential energy recovery system can reduce the maximum power and energy of engine by 50%.

This review will consider the state-of-the art in the storage of mechanical energy for hydraulic systems. It will begin by considering the traditional energy storage device, the hydro-pneumatic accumulator. Recent advances in the design of the hydraulic accumulator, as well as proposed novel architectures will be discussed. The review will continue with a discussion of energy storage flywheels. This will include recent advances in flywheel design and the properties of flywheels, particularly when compared to accumulators, as applied to hydraulic systems. These differences necessitate a discussion of the hydraulic system architectures used to incorporate flywheels, which will cover the various methods that have been proposed for utilising energy storage flywheels in hydraulic systems. The review will conclude by highlighting some of the unanswered questions in this area of engineering research and design.

This paper aims to evaluate the effects of coolant injection into a three-loop Westinghouse plant reactor vessel by the accumulators during small break loss of coolant accident, under severe accident condition. Using RELAP5/SCDAP mod3.4 computer code, a best estimate simulation from initiating SBLOCA event of 2, 3, and 4-in. without active part of the emergency core cooling system, in conditions with and without accumulators, is conducted until the rector pressure vessel failure. The results show that, the actuation of the accumulators lead to postponing the reactor vessel failure. Therefore, although the accumulators are designed for a large break LOCA, their actuation is very effective on the delay of a vessel failure. In this paper, the melt core concrete interaction is analyzed using CONTAIN2.0 code for the 4-in. break size without ACCs case as the most serious cases for the time of lower plenum failure. The result for 52.8 h is reported. The in-vessel molten material retention strategy for this case is studied using RELAP5/SCDAP code. The results show that lower plenum integrity is preserved during the severe accident that causes reactor core melt.

Based on mathematical and logical modeling, a technological support system for changing the battery capacity based on the prediction of voltage variation in measuring the temperature of electrolyte in the volume of the batteries was developed in the com-position of a technological system for battery operation. The developed technology makes it possible: to control operational capacity of the accumulator battery in order to obtain a functional assessment of change in the total charge and discharge voltage; to obtain an integrated reference estimation of change in the charge and discharge volt-age; to develop an integrated system for assessing a change in the voltage of the battery, which enables maintaining capacity of the accumulator battery when measuring the temperature of electrolyte at the input to the battery. The limiting temperature change of electrolyte, – 35 °C, was determined at charging with direct current supply and a limit-ing voltage change for a further charge and discharge was established with a change in the consumption of electric energy. The use of an integrated system for the estimation of voltage change obtained based on the alignment between electrochemical and diffusion processes of discharge and charge makes it possible to take timely decisions on recharg-ing to prevent recharge and unacceptable discharge. Coordination of the electrochemi-cal and diffusion processes that accompany charging and discharging of the battery makes it possible, for example under conditions of functioning of a wind power plant with a capacity of 10 kW, to reduce the cost of production of energy and the payback period of the wind power plant by up to 25 % due to a reduction of the charge period and prevention of gas formation.

The interest in energy storage systems is increasing, since it provides an excellent solution to store the low-cost excess energy from the energy sources, which are available at peak demand hours. This paper presents a new compressed-air storage system that combines ambient air and hydraulic oil, in order to store energy in compressed-air form and benefit from the advantages of both pneumatic and hydraulic systems. The process consists of charging and discharging cycles, however, this paper investigates the discharging cycle, where a new technique of Small-Scale Compressed Air Energy Storage (SS-CAES) system is realised. The new idea in RC-CAHES is to obtain higher efficiency in energy conversion machines during charging and discharging processes with numerous advantages over conventional types of energy storage systems. This study demonstrates the effectiveness of this technique by proving that it has higher efficiency than a similar Compressed Air Energy Storage (CAES) systems.

At present, stirring of flammable liquids in rigid intermediate bulk containers (RIBCs) is allowed only if, firstly, the RIBC is electrostatically protected and secondly either a liquid such us water-based paint is used or the RIBC is inerted. To verify the necessity of these restrictions, several experimental setups were created to investigate the charging of stirred liquids and suspensions. The following questions were answered: 1) Which liquids/suspensions charge the most during stirring? 2) Is ethyl acetate a special charge accumulator? 3) Which safety measures are necessary for safe stirring in RIBCs?

A number of national organizations have recently expressed interest in research to develop materials and devices that achieve greater energy storage capacity, power density and increased energy efficiency on the heels of a report finding that the pneumatic sector of the fluid power industry averages only 15% efficiency. One way of improving efficiency is the use of compressed air storage and recycling devices. The pneumatic Strain Energy Accumulator is a recently developed device that recycles exhaust gas from one pneumatic component, stores it in a highly efficient process, and reuses the stored exhaust gas at a constant pressure to power another pneumatic component. This work analyzes system efficiency increases directly attributable to the implementation of a pneumatic strain energy accumulator by applying an analytical methodology for system level efficiency improvement calculations, experimental validation, and compressed air savings projections. Experimentally determined efficiency increases ranged between 32% and 78%, demonstrating that the pneumatic strain energy accumulator can be a viable part of the solution to the fluid power efficiency challenge.

With the rising penetration of intermittent renewable energy sources (RES) and their variable nature it has become a challenge for distribution grid operators to maintain voltage quality inside the permissible range. It requires the involvement of new distributed resources, such as energy storage devices, to smooth power fluctuations of RES and to avoid long-term voltage rises. To achieve the best results such devices should be located as close to the micro source as possible – behind the meter. Small, distributed energy storage devices could be used to increase self-consumption of generated energy inside microgrids, helping also to flatten the daily load curve of the electrical power system (EPS). This paper discusses the properties of selected energy storage technologies suitable for small-scale microgrids containing renewable energy sources. The properties of small Zinc Bromine (ZnBr) flow batteries obtained in experimental research have been presented and compared to the properties of other energy storage devices similarly classified but at a different level of development. The simple equivalent model of the ZnBr battery has also been developed and described.

There is heightened interest in research to develop materials and devices that achieve greater energy storage capacity, power density and increased energy efficiency. This work analyses the performance of a novel energy storage device, the pneumatic strain energy accumulator (pSEA), which is designed to exploit the advantageous aspects of the non-linear behaviour of elastomeric materials. An analytical method for simultaneously characterising the pneumatic energy and strain energy stored in a strain energy accumulator (SEA), and more generally for pneumatic and strain energy systems, has been employed. Component efficiency along with the expansion and contraction pressures of the pSEA are determined experimentally so that a system level efficiency calculation can be performed. Incorporating uncertainty analysis, the efficiencies of the SEA are measured to be consistently over 93% in over 800 cycles of testing. The steady-state expansion and contraction pressures of the accumulator have steady-stat...

Results of experimental study of the effects of contact condensation of steam–gas mixture on the operation of VVER passive safety systems and steam generator in emergency condensation mode are presented. Contact condensation takes place when subcooled liquid is supplied in the accumulator tank of VVER reactor auxiliary passive core flooding system (the HA-2 system) in the presence of accumulated non-condensable gases. Water supplied to hydro accumulators can be used for increasing the operating time of VVER steam generator in the emergency condensation mode and for ensuring core cooling during longer time. Low liquid outlet velocity (less than 1 m/s) caused by the necessity to ensure safety systems operation in passive mode constitutes the distinguishing feature of the investigated processes. Experiments were conducted on the test facility with parameters typical for the primary cooling loop of the reactor facility 24 h after the accident initiation for different concentrations of gas in the steam–gas mixture. Nitrogen and helium, which replaces hydrogen for the purposes of safety assurance, were used as the non-condensable gases. It was established according to the results of experiments that the increase of concentration of non-condensable gas within the volume of HA-2 hydro accumulator model up to 45% leads to the reduction of intensity of contact condensation of steam from the steam–gas mixture by ∼29% in the experiment with nitrogen and by ∼57% in the experiment with helium. The obtained experimental data can be used for numerical simulation of emergency processes in the VVER reactor facility during operation of passive safety systems taking into account the removal of steam–gas mixture from steam generator by supplying the subcooled liquid jet into the volume HA-2 accumulator tanks.

Hydraulic power system is generally used in off-road vehicles for power transmission such as Heavy Earth Moving Machineries (HEMM). Their energy efficiency and unsubstantial failure becomes an extensive subject of analysis. Various arrangements in the system are compassed along with the utilization of some appropriate components. Application of a hydraulic accumulator is one among them. Benefits of accumulator is its multi-purpose usages like energy saving and pressure surge damping. This paper deals with the control of pressure surges in the hydraulic system and energy saving from the surges by using accumulator. For this purpose, the simulation of the hydraulic system is done in MATLAB/SimulinkR environment and an external disturbance is introduced to generate the pressure surge. The surge absorptivity of the accumulator is studied for different sizes at different pre-charged conditions of the accumulator. The discharge characteristics of different sized accumulators are also analyzed in this paper. It is observed that the ability to absorb the surge and stabilize the system is high in the smaller capacity accumulator. However the energy delivery time of larger sized accumulator is high.

An indirect type forced convection solar dryer using Phase Change Material (PCM) was designed, constructed and experimentally investigated. The dryer consists of a solar air panel for a direct heating of the drying agent, a solar energy accumulator (solar air collector with PCM cavity) and a drying chamber. The solar dryer was tested under no load with and without PCM. The present study is aimed at investigating the feasibility of using a solar air heater with PCM to store the solar energy during the daytime, and to release it during the night. Experiments were conducted to evaluate the charging and the discharging characteristics of the latent storage unit (PCM cavity). The daily energy efficiency of the solar energy accumulator reached 33.9%, while the daily exergy efficiency reached 8.5%. The results show that after using the solar energy accumulator, the temperature of the drying chamber is higher than the ambient temperature by 4–16 °C, all the night. In addition, the relative humidity in the drying chamber was observed 17–34.5% lower than the ambient relative humidity, in the case of the solar dyer with PCM.

The effects of the decay characteristics of a hydraulic accumulator on the responses of the hydrostatic drive system used in mining vehicles are studied in this article. The system considered for the analysis basically consists of a hydraulic pump, hydro-motor, accumulator and a loading circuit. The studies have been carried out with respect to two different sizes of accumulators. The system model has been made in MATLAB/Simulink® environment. The simulation test results are obtained with respect to the hydro-motor speeds and the system pressure at different resistive loads and capacities of the accumulator and they are verified with the experimental test data. Using the validated model, the parametric studies are also made on the speed responses of the hydrostatic drive for different precharge pressures of the accumulator and inertial load on the motor shaft. The studies made in this article may be useful for the selection of proper capacity of accumulators incorporated in the hydrostatic drive system in mining vehicles.

Renewable energy sources such as wind and solar, have vast potential to offer cost competitive power supply and reduce dependence on fossil fuels and environmental issues in the electric sector. However, renewable energy systems often have variable and uncertain energy supply which makes electrical energy storage systems highly valuable for renewable energy applications. Compressed air energy storage is one of the most promising technologies that have received wide attention in scientific community. In this paper, a comprehensive thermodynamic model is developed to investigate the thermal performance of an Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) system. The effect of key parameters including storage pressure, pre-set pressure along with compressor and turbine efficiencies on the system performance is studied. The results show that the storage pressure has a significant effect on the amount of energy stored in the AA-CAES and power generated by the expander. As the storage pressure increases from 2 MPa to 10 MPa, the amount of energy stored increases from 7.8 MJ/m3 to 105.6 MJ/m3 while the output power increases from 4.2 to 63.2 MJ/m3. The results also show that the overall energy conversion efficiency is dominated by the efficiency of the compressor and turbine. As the efficiencies of both compressor and expander increases from 0.65 to 0.95, the efficiency of the AA-CAES system is improved from 35% to 74%. This study provides a deep understanding of operation characteristics of the AA-CAES system and useful information for system design and optimization.

The accumulator is a passive safety injection device for emergency core cooling systems. As an important safety feature for providing a high-speed injection flow to the core by compressed nitrogen gas pressure during a loss-of-coolant accident (LOCA), the accumulator injects its precharged nitrogen into the system after its coolant has been emptied. Attention has been drawn to the possible negative effects caused by such a nitrogen injection in passive safety nuclear power plants. Although some experimental work on the nitrogen injection has been done, there have been no comparative tests in which the effects on the system responses and the core safety have been clearly assessed. In this study, a new thermal hydraulic integral test facility—the advanced core-cooling mechanism experiment (ACME)—was designed and constructed to support the CAP1400 safety review. The ACME test facility was used to study the nitrogen injection effects on the system responses to the small break loss-of-coolant accident LOCA (SBLOCA) transient. Two comparison test groups—a 2-inch cold leg break and a double-ended direct-vessel-injection (DEDVI) line break—were conducted. Each group consists of a nitrogen injection test and a nitrogen isolation comparison test with the same break conditions. To assess the nitrogen injection effects, the experimental data that are representative of the system responses and the core safety were compared and analyzed. The results of the comparison show that the effects of nitrogen injection on system responses and core safety are significantly different between the 2-inch and DEDVI breaks. The mechanisms of the different effects on the transient were also investigated. The amount of nitrogen injected, along with its heat absorption, was likewise evaluated in order to assess its effect on the system depressurization process. The results of the comparison and analyses in this study are important for recognizing and understanding the potential negative effects on the passive core cooling performance caused by nitrogen injection during the SBLOCA transient.

This research work draws an insight into the experimental investigations on a series hydraulic/electric synergy system—a green transportation system. An experimental test rig of the system with all necessary sensors and instrumentation has been developed to study the energy saving through hydraulic regenerative braking. The effect of various system parameters, such as braking time, maximum accumulator pressure, pre-charge pressure of hydro-pneumatic accumulator, volumetric displacement of the hydraulic master pump, and hydraulic regeneration pump on the quantum of regeneration energy, was analyzed. In addition, an AMESim model of the real-time experimental test rig has been developed and validated with experimental results. A set of five different experimental designs (parameter variations) of the system is defined with the available standard component sizes. The best design is selected of the available experimental designs based on the maximum hydraulic regeneration energy and regeneration effici...

CONNEXX SYSTEMS has invented Shuttle Battery™, a paradigm disruptive technology, to enable effective and cost-competitive energy storage for power utilities and consumer applications. Shuttle Battery™ is a patent-granted energy storage technology with an energy density of 7700 Wh/L. This is 14 times higher than the energy density of state-of-the-art Li-ion battery (550 Wh/L) and comparable to fossil fuel (10,000 Wh/L). Shuttle Battery™ generates energy from the reaction between iron and oxygen from air. Thus, the cost per energy of Shuttle Battery™ is reduced to 1/16 compared to Li-ion battery. Enclosure of iron and a small amount of water in the anode side enables continuous generation of hydrogen gas and subsequent reaction between hydrogen and oxygen during discharge. The reverse of these reactions enables iron regeneration during charge, making Shuttle Battery™ electrochemically rechargeable without relying on mechanical swapping of iron fuel. Moreover, unlike Li-ion batteries that use flammable non-aqueous electrolyte, Shuttle Battery™ is intrinsically safe because it is made of nonflammable materials. These characteristics of the new energy technology make it ideal as energy storage for large-scale applications such as power grid energy storage. Deployment of Shuttle Battery™ technology for power grid would enable the effective global energy transformation.

The problem of cooperative optimization of trajectory and main design parameters of spacecraft, equipped with propulsion systems with energy accumulation, during low Earth orbit formation and correction in non-central gravitational field is considered. The working principle of these propulsion systems is a periodic cycle of energy accumulation from the energy source at the passive stages of orbital transfer, and its discharge to supply power to the engine during the active stages of orbital transfer. The special characteristics of propulsion systems with energy accumulation is limited operation time per one switching, which determines by the energy, stored in an accumulator. For design-ballistic analysis, the mass model of the spacecraft with an uncontrollable power-limited engine with energy accumulator is used. The general problem is separated into dynamic and parametric parts. Using averaging mathematical models of motion and Pontriagin's maximum principle, the calculation method of the ballistic characteristics of approximately-optimal orbital transfer is obtained. The method of design-ballistic optimization is obtained as an iterative procedure. It was found, that inclusion of an energy accumulator in a propulsion system provides an increasing of orbital transfer efficiency.

The aim of this paper is to present a comprehensive review of the compressed-air hybrid technology in a passenger and commercial vehicle since the beginning of its discovery to date. Hybrid technology has become popular in the automotive industry since the technology proven to improve the vehicle efficiency, saving in fuel use and green environmental. The well-known hybrid technology is hybrid electric. Nevertheless, the price of the hybrid electric automobile is high, the arrangement is complex, and it is not completely green. These disadvantages have triggered innovation in a hybrid technology called compressed-air hybrid technology. The compressed-air hybrid technology uses a combination of ICE and fluid power components as a propulsion unit and compressed-air energy as a power source. The energy stored in the tank/accumulator. Once the energy in the storage is low, the system utilizes energy losses in braking and recovers into useful energy. This article concentrates on the hybrid compressed-air design, components, latest finding, technology breakthrough, benefit and drawback of the system. The review also encompasses the most recent prototype that has been tested. Based on the study, the literature has shown that the compressed-air hybrid system is proven to work. Nevertheless, further research needs to extend out to resolve a few topics such as amending the energy capability and lightweight system design. The two-subsystem are promising, but nevertheless far from the point of commercialization. However, the three-subsystem has been proven in saving energy and fuel consumption. Although it still needs to be further refined, it has a huge potential to get into the market. The compressed-air hybrid technology in a passenger car is still new. There is a huge room to explore. If the hybrid compressed-air technology is successful, clearly it will benefit the future in the aspect of energy efficiency, cost saving, and reduce the pollution.

With the increase in ocean levels due to global warming, there is a desperate need for clean and renewable energy at this time, more than ever before. Although the economic front of technologies, such as wind and solar power, has shown improvement, the fact remains that these energy sources are intermittently available in nature. This calls for a reliable energy storage technology that can bridge the gap between the supply and demand of electricity, leading us to a world driven by clean and renewable energy. Here, we propose a process for storing electrical energy using engineered osmosis. To store electrical energy, a salty solution is separated into brine and fresh water streams using modified reverse osmosis. When there is a demand for electricity, the chemical potential is converted back into electrical work by mixing the solutions using a modified version of pressure retarded osmosis. With modelling and simulations, we demonstrate that the proposed process can achieve round trip efficiencies of 50–60% and energy densities equivalent to that of a 500 m high pumped-hydro plant. The results demonstrate a promising process to store electrical energy, which, unlike pumped-hydro, is unconstrained by geography.

The active charge accumulator (ACA) is a pressure converter device in a water-hydraulic system that is able to increase and decrease pressure without using a pressure-regulating valve. The basic characteristics of ACAs, however, have not yet been sufficiently revealed. In this paper, we experimentally examined the basic characteristics of ACAs with focus placed on how ACAs reduce pressure. This examination has revealed that the piston stroke of ACAs depends on the load flow rate as well as the valve switching timing. We theoretically analyzed these phenomena using a mathematical model. With an analytic model built taking into consideration the compressibility of the working fluid, valve performance level, and other elements, we made a comparison between the analytic and experimental results to verify the validity of our analysis. This comparison revealed that the pressure waveforms in the low-pressure and pressure-conversion sections obtained through the analysis agreed with those obtained through the experiments, indicating that the analytic model was valid.

With the increased integration of renewable energies in distribution networks comes the need for energy storage systems. Due to its characteristics, the use of hydrogen as an energy vector shows propitious features with this purpose. This study presents a type of storage energy system composed of an electrolyzer, hydrogen accumulator and fuel cells. To model this system, it is necessary to establish a set of physicochemical equations for each component in order to integrate a large number of parameters and variables dependent on the model and operating conditions. This study describes a model for real storage power plants consisting of an alkaline electrolyzer, a PEM fuel cell and a hydrogen accumulator in metal hydrides. A description of some practical tests on each component of the plant is included in order to compare them with the simulated results. All steps and parameters are discussed with the purpose of being used for other plants of similar characteristics.

The present work aims at implementing heat accumulators in real technological processes and poses a problem of practical importance.Heat accumulators have been the subject of laboratory research for a long time. Several authors have obtained certain results while studying such devices, but only few of them have considered their introduction into the industrial practice. In this regard, the present research provides two directions for applying heat accumulators: thermotherapy and methane tanks.The need to stabilize temperature conditions is common to these processes. To achieve this goal, graphene-modified sodium acetate (thermal conductivity ≈5,000 W/(m K))was used herein as heat accumulator with controlled discharge mode (heat dissipation). The possibility of improving the stability of sodium acetate when introducing graphene thereinto was established. Besides,charge/discharge modes were investigated under the operating conditions of thermotherapy and methane tanks.

The functioning of a habitable lunar base requires not only electricity but also heat energy that can be produced from electricity exclusively according to the existing projects. The use of clean solar heat energy faces a number of difficulties in the practical implementation of solar power plants due to the need for its accumulation and storage during lunar night that lasts 14.75 Earth days. The article considers the scheme of a habitable lunar base solar hot water system which is operable during the lunar day and night and includes flat-plate solar collector with hydrogen heat transfer agent and seasonal heat accumulator in the lunar soil filled with crushed regolith to maintain hot water temperature during lunar night. There are presented the results of the estimation of the solar system design parameters and performance analysis based on the developed mathematical model and computer simulations of dynamic modes of operation of the solar system, located on the equator and the middle latitudes of the Moon.

This paper presents the characterization of the hydraulic suspension system of Special Purpose Trailer which is a modular semi-trailer used for carrying heavy commercial equipment’s and heavy cargos. Presently automotive industry is using the knuckle joint hydraulic suspension system for the above mentioned trailer. The study includes the characterization of the hydraulic spring of the system based on the polytropic process and mathematical modelling of the quarter car hydraulic suspension system in MATLAB/SIMULINK. Basically the hydraulic suspension system consists of a hydraulic cylinder ram, pressurized hydraulic circuit, cut off valves, accumulator, and axel-wheel assembly. The study mainly concentrates on the accumulator pressure values as changing the pressure of accumulator directly affects the behavior of suspension system. MATLAB/SIMULINK software is used for obtaining the behavioral pattern of the suspension system on account of different accumulator pressure values. And finally the best possible value of accumulator pressure is obtained under the working conditions of the trailer.

Energy storage becomes more important as mankind switch to renewable energy, away from fossil resources. Traditional way – batteries - offer a limited number of cycles, require regular maintenance; nevertheless gravitational storage, flywheels, compressed air are mainly large scale and expensive methods. The hydrogen as energy carrier and hydrogen fuel cells are possible option to store different amounts of energy for relatively long times with low losses. Different solutions for self-sufficient sun/wind energy objects are analysed - the solar radiation collecting systems, wind power generators, and high pressure electrolysis technologies for hydrogen production and the metal-hydride energy storage. This article describes the development of a versatile technology that can be used to provide continuous power for small and medium-sized self-sufficient objects or their micro-grids using alternative energy and energy storage. The technology uses advanced electrolysis and fuel cells to efficiently store excess energy from sun/wind generation as hydrogen for later use in fuel cells, Хранение энергии становится все более важным в контексте перехода человечества от ископаемого топлива к возобновляемым источникам энергии. Традиционный способ – химические батареи, которые характеризуются ограниченным числом циклов и требуют регулярного технического обслуживания; в то время как гравитационное хранение, маховики и сжатый воздух в основном требуют больших объемов и высокозатратны. Водород в качестве носителя энергии в водородных топливных элементах является возможным вариантом для хранения различных количеств энергии в течение относительно длительного времени с малыми потерями. В работе проанализированы различные решения для автономных энергетических объектов на основе энергии солнца/ветра – фотоэлектрические системы для преобразования первичного излучения солнца, ветрогенераторы и технологии электролиза высокого давления для производства водорода и хранения энергии в металлогидридных аккумуляторах. Описывается разработка универсальной технологии, которая может быть использована для обеспечения непрерывной мощности для малых и средних автономных объектов или их микросеток с применением альтернативных источников энергии и хранения энергии. В технологии применяются передовые разработки электролизеров водорода и топливные элементы для эффективного хранения избыточной энергии полученной из возобновляемых источников, для последующего использования в топливных элементах, Описується розробка універсальної технології, яка може бути використана для забезпечення безперервної потужності для малих і середніх автономних об'єктів або їх мікро-сіток з використанням альтернативних джерел енергії та системи акумулювання енергії. Показано, що технологія використовує передові розробки електролізерів водню і паливні елементи для ефективного зберігання надлишкової енергії, отриманої з поновлюваних джерел, для подальшого використання в паливних елементах

The wave energy converting system (WEC) can convert the unstable wave energy into stable electric power. In this paper, the new WEC which is mainly composed of three hydraulic circuits viz, the commutation, decompression and speed regulation circuit. It is controlled by various electronic valves. A series of experimentations were done to investigate its static and dynamic characteristics under the condition of variable load and variable flow rate, and its influence on the grid was analyzed as well. The experimental result shows that when the flow rate of the system which is controlled by the electro-hydraulic proportional flow control valve varies, the accumulator conserves part of the hydraulic energy and consequently the output power decreases. The revolving speed and working pressure show the different change trend in the response to the variation of the flow rate. However, when the load varies, the revolving speed of the hydraulic motor varies marginally. In the case of identical load change, the amplitude of variation is not the same at different revolving speed. Because of adopting the proportional flow control valve, the new WEC can be regarded as a non-differential control system which may cause the oscillation of the active power. To avoid this, this paper suggests using the variable-speed constant-frequency device or electrical governor.

A new design of a solar dryer for drying fruits is proposed, which includes the use of a flat mirror concentrator to enhance the flow of slant morning and evening sunlight, and a thermal accumulator based on pebble for accumulating over night time the excess heat from the reserve source of energy. This makes it possible to increase economic efficiency of the drying process by 20 %, to reduce energy consumption by 15 %, specific energy consumption by 10 %, direct operating costs by 5 %, electricity consumption by 3,4 kW·h, or 12384 kJ of thermal energy, by using solar energy. We improved a technique of the substantiation of economic efficiency of the developed solar dryer, the basis of which is a simplified mechanism for calculating direct operating costs, economic effect and payback period of the machine depending on the fluctuation of prices for electricity and dried products, linked to a specific territory of the location of a personal peasant farm. The results that were obtained can be used when developing and improving technical means of drying fruits, to improve technological, energy, biological and economic efficiency of the process.

This work deals with the study of influence of additives added to the negative active mass of the lead-acid battery electrode. As additives it were used acryl fibers and TiO2. Acryl fiber were added in amount of 1.4 wt.%. TiO2 was used in an amount of 0; 0.15; 0.46; 0.78; 1.4; 2.65 and 5.15 wt.%. Electrodes ran in PSoC regime and Deep of Discharge cycles (conditioning cycles). The resulting values of the measured voltages and capacitances are shown in the appropriate graphs

In this article, the authors present the implementation of an innovative, automated technological line of powder coating, in a company producing ventilation hoods. Technology of electropainting was applied in painting details, with the use of powder paints and preceding process of preparing details surface, based on innovative technical and technological solutions. By implementing an innovative, technological process of automatic powder coating line in a company, increases its competitiveness in the market, using the best techniques of production. As a result, the authors proposed a system of guaranteed power supply for the purpose of automated technological line of powder coating, which should provide, in case of electricity cut, guaranteed power supply in the form of uninterrupted power supply (UPS)—finish or continue technological operations. The authors determined the requirements of UPS system, together with the sources of accumulators, cooperating with this system. System of guaranteed power supply, using UPS ENERTRONIC I 3-3 with power 200 kVA was determined. Accumulator batteries cooperating with accepted UPS system were calculated and selected.

Extended durations of liquid refrigerant ingestion by the compressor of a vapor compression system (VCS) can lead to damage or failure of this component. While this can be prevented by inserting an accumulator between the evaporator and compressor, this addition of hardware may be undesirable for applications in which the weight or size of the thermal management system is critical. As an alternative, this paper proposes a switched Linear Quadratic Gaussian (LQG) design to quickly recover the presence of a superheated phase at the exit of the evaporator using feedback control. Stability analysis of the closed-loop switched system is presented, and application of the control approach in both simulation and on an experimental VCS testbed demonstrate the success of the control design.

Standalone operation of a photovoltaic generating system under fluctuating solar irradiance and variable load conditions necessitates a storage energy unit. The energy storage system by using battery–supercapacitor combination is an interesting solution. However, batteries have a high energy storage ratio but are limited in the power. In the other hand, supercapacitors can provide high levels of power while they have a much lower energy storage ratio. Moreover, the SC can act as a buffer against large magnitudes and rapid fluctuations in power. In this paper, supercapacitors are used to reduce stresses on batteries and improve their life cycle. In this context, the performance of the RMS current gain in battery, the gain in energy losses, the total energy efficiency and the elimination rate of surge load power are explored, in different operating state conditions. These parameters are also investigated versus the SCs cost. All tests are carried with different number of parallel supercapacitors and the filter constant.

The regenerative hydraulic electric suspension (RHES) is a new type of energy regeneration damper system based on the principle of vibration energy harvesting. This system can recover the vibration energy of suspension dissipated in the form of thermal energy when vehicle travels on the road. In previous studies about RHES system, the vehicle suspension displacement is defined as varieties of periodic waves, such as sinusoidal and so on. The energy harvesting performance of damper system can be explained and evaluated to some extent, but the influence of the actual excitation condition of the road is not fully considered when studying the RHES. This paper builds models of road profiles, quarter car and power regeneration based on the proposed RHES system. Furthermore, the change laws of performance with the varies of road class, motor displacement, accumulator capacity and electrical load are summarized and the corresponding optimization suggestions are proposed, which realize the prediction and evaluation of RHES system performance under the excitation of different road profiles. Simulation suggests that this system can recover 100-400 W of power under road excitation. The findings of system analysis indicate that the component design can satisfy the damping characteristics and power performance required for specific application. The results also show that adjusting the electrical load and accumulator capacity is highly beneficial for controlling suspension behaviours, improving system reliability and increasing power regeneration.

This paper compares the strategies for improving the operational flexibility of combined heat and power (CHP) plants to support wind power integration. Four commonly used strategies, namely cutting off low pressure cylinder, installing heat accumulator, installing electric boiler, and utilizing by-pass device are discussed. An integrated model is proposed to quantify the performance of various strategies in improving the flexibility of CHP plants. A 350 MW subcritical extraction condensing turbine in China is used as an example, to compare the performance of the four strategies from the viewpoint of the operating cost of flexibility enhancement. The maximum flexibility and the scope of applicability can be enhanced.

The German WINNER research project aims at controlling and optimizing local power production, distribution, and consumption in residential areas. Beside residents, who consume electrical energy uncontrollable, there are electric vehicles of a car sharing provider as well. Their charging process can be monitored and controlled. Furthermore, we have a mid-size photovoltaic (PV) power plant on the roof of the residential building. Within this local area, we measure energy consumptions and productions. This paper covers subsequent investigations on the possibility of using different charging strategies of electric vehicles from the view of the grid side. Thus, we have to measure energy consumption and production, calculate the surplus and store this excessive energy in the vehicle accumulator. We aim to be neutral against the local energy grid or at least not unhelpful, i. e., we have to avoid power withdrawal if possible. In this paper, we abstract from real use case with electric vehicles. We are using a simple battery model and make some assumptions on the energy consumption and PV production referring to our measurements. Afterwards, a recurrent approach is used to schedule charging and discharging processes along the day. We consider various charging aims over time, i. e., we vary the charging states and times, at which the aimed battery charging state should be reached. Finally, we use our system to answer the question, if our approach to lower the grid load was worth it. For low PV power days and cloudy days, we found usable strategies. Referring to PV peak days we had to do more intensive investigations.

This article presents an influence of using an energy storage device in order to reduce the oscillation of voltage and power of the underground traction substation and to limit the peak value of power consumed from it. Using the accumulator has an indirect beneficial influence on the environment because of the efficient energy use. In the work a simulation research of the underground traction substation and a substation equipped with supercapacitors was conducted in the communications peak and beyond it. Simulation studies were performed in toolbox Simscape Electrical formerly called SimPowerSystems and SimElectronics from Simulink products family.