Evaluation of the Performance of Lithium-Ion Accumulators for Photovoltaic Energy Storage

In a context of climate change exacerbated by the increasing scarcity of fossil fuels, renewable energies, in particular photovoltaic solar energy, offer a promising alternative. Solar energy is non-polluting, globally available and the most widely distributed resource on Earth. However, the intermittency of this energy source considerably limits its expansion. To solve this problem, storage techniques are being used, in particular, electrochemical storage using lithium-ion batteries. In this article, we will evaluate the performance of lithium-ion batteries when integrated into a photovoltaic grid. To do this, modelling and simulation of a photovoltaic system connected to a lithium-ion battery storage system will be carried out using MATLAB/Simulink software. A diagnostic of the energy consumption of the Kaya Polytechnic University Centre will be carried out, and the data will then be used in the simulator to observe the behaviour of the PV-Lion system. The results obtained indicate that lithium-ion batteries can effectively meet the centre’s energy demand. In addition, it was observed that lithium-ion batteries perform better under high energy demand than the other battery technologies studied. Successive storage systems with the same capacity but different battery technologies were compared. It was found that these storage systems can handle a maximum power of 4 × 105 W for lead-acid batteries, 6.5 × 105 W for nickel-cadmium batteries, 8.5 × 105 W for nickel-metal-hydride batteries, and more than 10 × 105 W for lithium-ion technology.

Development of hydraulic power unit and accumulator charging circuit for electricity generation,storage and distribution

It is the purpose of the present paper to convert hydraulic energy to electric energy and saves both the pressure and electrical energy for re - use during the next system upstroke using two secondary units coupled to induction motor to drive cylinder loads. During upstroke operation, the variable pump/motor （P/M） driven by both electric motor and the second （P/M） works as hydraulic pump and output flow to the cylinders which drive the load. During load deceleration, the cylinders work as pump while the operation of the two secondary units are reversed, the variable （P/M） works as a motor generating a torque with the electric motor to drive the other （P/M） which transforms mechanical energy to hydraulic energy that is saved in the accumulator. When the energy storage capacity of the accumulator is attained as the operation continues, energy storage to the accumulator is thermostatically stopped while the induction motor begins to work as a generator and generates electricity that is stored in the power distribution unit. Simulations were performed using a limited PT2 Block, i.e. 2nd-order transfer function with limitation of slope and signal output to determine suitable velocity of the cylinder which will match high performance and system stability. A mathematical model suited to the simulation of the hydraulic accumulator both in an open-or close-loop system is presented. The quest for improvement of lower energy capacity storage, saving and re-utilization of the conventional accumulator resulting in the short cycle time usage of hydraulic accumulators both in domestic and industrial purposes necessitates this research. The outcome of the research appears to be very efficient for generating fluctuation free electricity, power quality and reliability, energy saving/reutilization and system noise reduction.

ACCUMULATOR的风险定量问题研究

以深南电与国际投行对赌原油价格的ACCUMULATOR合约为典型案例,通过对此复杂的结构期权重新进行分解和组合,构造出能用布莱克-斯科尔斯模型计算的新期权组合,并具体给出ACCUMULATOR的一种风险定量计算方法。

Characteristics of Cd uptake and accumulation in two Cd accumulator oilseed rape species

Two pot experiments were conducted under greenhouse conditions to investigate the characteristics of Cd uptake and accumulation by two Cd accumulator oilseed rape varieties and one Indian mustard grown on a loamy soil that had been artificially contaminated by different amounts of CdSO\-4(0, 20, 40, 60, 80, 100 mg/kg soil). The relationship between shoot Cd uptake of the two oilseed rape cultivars and the soil Cd concentrations could be simulated via quadratic equations. The curve showed that maximum shoot Cd uptake of Indian mustard was 314.7 μg/pot at soil Cd concentration of 87.8 mg/kg, while maximum uptake of the variety Xikou Huazi was 543.3 μg/pot at soil Cd concentration of 69.1 mg/kg and that of the variety Zhongyou Za-1hao was 576.7 μg/pot at soil Cd concentration of 84.0 mg/kg, suggesting that shoot Cd uptake ability of the two Cd accumulator oilseed rapes was significantly higher than that of the Indian mustard. Xikou Huazi had higher phytoremediation potential for Cd contaminated soil. Shoot Cd accumulation ability of the two Cd accumulator oilseed rapes was correspond and Cd was easier translocated to the shoot than hyperaccumulator Indian mustard as comparation plant. Shoot Cd distribution pattern showed consistent and significant reduction from older leaves to younger ones of two oilseed rapes and Indian mustard. Cd uptake by oilseed rapes in growth prophase was higher than that of growth anaphase.

Use of the finite elements method for modelling the dynamic load impact on hydraulic leg equipped with gas accumulator

Procedures of preparation of numerical analysis,consisting in a simulation of cooperation of three different media: steel,liquid and gas undergoes dynamic load were discussed.Modelling of the initial static load of the mechanical system was presented.By using the MSC.Software products the following exemplary computer simulations were made: dynamic load impact on the hydraulic leg as well as effectiveness of the hydraulic leg protection against overload with help of gas accumulator.

Dynamic characteristics of hydraulic power steering system with accumulator in load-haul-dump vehicle

Using hydraulic power steering system of model EIMCO 922 load-haul-dump vehicle as a simulation example, the dynamic characteristics of hydraulic power steering system in load-haul-dump vehicle were simulated and discussed with SIMULINK software and hydraulic control theory. The results show that the dynamic characteristics of hydraulic power steering system are improved obviously by using bladder accumulator, the hydraulic power steering system of model EIMCO 922 load-haul-dump vehicle generates vibration at the initial stage under the normal steering condition of pulse input, and its static response time is 0.25 s shorter than that without bladder accumulator. Under the normal steering working condition, the capacity of steering accumulator for absorbing pulse is directly proportional to the cross section area of connecting pipeline, and inversely proportional to the length of connecting pipeline. At the same time, the precharge pressure of nitrogen in steering accumulator should be 60%80% of the rated minimum working pressure of hydraulic power steering system. Under the abnormal steering working condition, the steering cylinder piston may obtain higher motion velocity, and the dynamic response velocity of hydraulic power steering system can be increased by reducing the pressure drop of hydraulic pipelines between the accumulator and steering cylinder and by increasing the rated pressure of hydraulic power steering system, but the dynamic characteristics of hydraulic power steering system in load-haul-dump vehicle have nothing to do with the precharge pressure of nitrogen in steering accumulator.

Weld extraction from real-time radiograph based on bidirectional accumulator Hough Transform

An effective approach is presented to extract welds from real-time radiographs, Firstly an algorithm based on an adaptive bidirectional threshold was proposed to segment the gradient image into ternary image, and then the bidirectional accumulator Hough Transform was developed to extract weld edges from the ternary image. Different values of the coefficient proposed in the threshold algorithm were tested, and the proposed approach was applied to extract welds from real-time radiographic images of different types of welds with defects. Results show that the proposed method is adaptive and effective to extract welds from real-time radiographs of linear welds.

Neutral and accumulator species in determining the spatial structure of tree species at different spatial scales

In 2014,a 40-ha undisturbed plot was established in the Beijing Songshan Nature Reserve.The spatial distribution and spatial associations of five dominant tree species of different height classes were examined using spatial point pattern analysis and the effects of these species on local community diversity assemblages were examined using the ISAR method.The dominant species were characterized by an aggregated distribution at spatial scales of 0–50 m.At smaller spatial scales,trees in larger height classes had significant positive and negative effects on the diversity of the lower height classes.However,at larger spatial scales this effect was diminished.At small scales(0–10 m),accumulator species had positive effects on species diversity,maintained an over-representative proportion of diversity in their proximity,and supported the ecological niche theory.At the larger scale(10–50 m),neutral species were dominant and had positive effects on species diversity,though repeller species,which had negative effects on species diversity,also contributed to diversity.Neutral and accumulator species together determined local species diversity,but the relative importance of the two was closely related to spatial scale.A combination of the ecological niche theory and neutral processes together determines species coexistence and biodiversity of an undisturbed pine forest.

CONSTANT WORK-POINT CONTROL FOR PARALLEL HYBRID SYSTEM WITH CAPACITOR ACCUMULATOR IN HYDRAULIC EXCAVATOR

Limitations of various accumulators in hybrid hydraulic excavator are analyzed. A program using capacitor as the accumulator based on constant work-point control is put forward. A simulating experimental system of hybrid construction machinery is established, and experimental study on constant work-point control for parallel hybrid system with capacitor accumulator is carried out using the pressure and flow rate derived from boom cylinder of hydraulic excavator in actual work as the simulating loads. A program of double work-point control is proposed and proved by further experiments.

Accumulator-Based Deep-Sea Microbe Gastight Sampling Technique

The accumulator is used as a pressure compensation device to realize deep-sea microbe gastight sampling. Four key states of the accumulator are proposed to describe the pressure compensation process and a corresponding mathematical model is established to investigate the relationship between the results of pressure compensation and the parameters of the accumulator. Simulation results show that during the falling process of the sampler, the accumulator＇ s real opening pressure is greater than its precharge pressure; when the sampling depth is 6000 m and the accumulator＇ s precharge pressure is less than 30 MPa, to increase the accumulator＇ s precharge pressure can improve pressure compensation results obviously. Laboratory experiments at 60 MPa show that the acctunulator is an effective and reliable pressure compensation device for deep-sea microbe samplers, The success in sea trial at a depth of 2000 m in the South China Sea shows that the mathematical model and laboratory experiment results are reliable.

ANALYSES OF ENERGY LOSSES AND ACCUMULATOR AND PARAMETERS DESIGN METHOD OF HYDRAULIC IMPACTOR MECHANISM

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Reliability evaluation of bladder accumulator with no failure data

As a bladder accumulator is a high reliable and long life component in a hydraulic system,its cost is high and it takes a lot of time to test its reliability,therefore,a reliability test with small sample is performed,and no failure data is obtained using the method of fixed time truncation. In the case of Weibull distribution,a life reliability model of bladder energy storage is established by Bayesian method using the optimal confidence intervals method,a model of one-sided lower confidence intervals of the reliability and one-sided lower confidence intervals model of the reliability life are established. Results of experiments show that the evaluation method of no failure data under Weibull distribution is a good way to evaluate the reliability of the accumulator,which is convenient for engineering application,and the reliability of the accumulator has theoretical and practical significance.

Effects of Accumulator on Stabilization of Direct Acting Poppet Valve and Its System

The effect of vibration attenuation hy installing accumulator for water pressure system with the direct acting poppet valve is studied. The influencing factors of accumulator on the stabilization of direct acing poppet valve and the system are analyzed.

MOTION ANALYSIS AND DESIGN OF ACCUMULATOR FOR HYDRAULIC ROCK DRILL

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Simulation and Experimental Research for Piping Damper with Plunger-type Accumulator

It can be beneficial to reduce vibrations in shipboard piping, so the authors designed a new kind of piping damper with a plunger-type accumulator.Special requirements for the piping damper included low impact displacement, low speed, as well as an appropriate locking speed.Inside the damper, a plunger-type accumulator was installed and on the outside of the piston rod, a tube with exposed corrugations was added.Between the piston and the cylinder, a clearance seal was added.Using mathematical modeling, the effects of the dynamic performance of the damper's impact displacement on vibrations were observed.Changes to the clearance between the piston and the cylinder, the stiffness of the spring in the accumulator, the throttle valve size, and locking speed resistance of the damper were respectively simulated and studied.Based on the results of the simulation, dampers with optimal parameters were developed and tested with different accumulator spring stiffnesses and different throttles.The simulation and experimental results showed that parameters such as seal clearance between piston and cylinder, accumulator spring stiffness and throttle parameters have significant effects on the damper's impact displacement, low speed resistance and locking speed.

Effects of Intercropping with CaryophyllaceaeAccumulator Plants on Cadmium Accumulation ofCyphomandra betacea Seedlings

The pot experiments were conducted to study the effects of intercropping with Pseudostellaria maximowicziana,Malachiumaquaticum and Stellaria media on Cd accumulation of Cyphomandra betacea seedlings.Compared with the monoculture,intercropping with Caryophyllaceae endarachneyllaceae accumulator plants decreased the biomass of C.betacea seedlings,and also reduced the photosynthetic pigment contents in C.betacea seedlings,which involve chlorophyll a,chlorophyll b,total chlorophyll and carotenoid.Intercropping with P.maximowicziana and M.aquaticum increased the Cd contents in shoots of C.betacea seedlings,which increased by 65.02%and 25.61%,respectively,compared with the monoculture.Intercropping with S.media reduced the Cd contents in shoots of C.betacea seedlings,which were reduced by 4.68%compared with the monoculture.When intercropping with C.betacea seedlings,the Cd accumulation amounts of 3 Caryophyllaceae accumulator plants were ranked as S.media>P.maximowicziana>M.aquaticum.Intercropping with S.media could effectively reduce Cd accumulation of C.betacea seedlings under Cd-contaminated soil condition.

Some Aspects of the Analysis during Heating Plastic Tunnel by the Use of Heat from Stone Accumulator

The paper presents the results of research which showed the energy effects when used in foil tunnel heat accumulator. The study was conducted in two tunnels （with and without heat accumulator） and two cycles of growing cucumbers, i.e., in the cultivation of spring and autumn. The heat accumulator is divided into three segments of varying capacity coal deposits （porphyry-type stones）. During the test crops （cucumbers） measured parameters associated with the surrounding climate, microclimate parameters inside the building and parameters of the injected and flowing out air from the accumulator have been monitored and archived by a computer system. The intensity of solar radiation, the technology of cultivation and cultivated species of plants were the same in both the tunnel with heat accumulator as well as the control object. On the basis of the balance of behavior, the heat and mass are described occurring processes related to the exchange of air during ventilation facility. The resulting effects were converted into differences in heat demand between the tunnel and the tunnel with an accumulator of heat. It was found that despite the increase ventilation in adopted arbitrary surface of the foil tunnel, the scope of changes in the amount of heat saved in one of the cultivation is in the range from 0.0015 GJ to over 1.4 GJ of heat.

Optimal Control of a Thermoelectric Generator Attached with a Latent Heat Accumulator

Generally MPPT control (maximum power point tracking) is adopted to control of a thermoelectric generator. However, in the case of generation by use of a heat accumulator MPPT control cannot obtain maximum whole electrical output during the operation period. This is because the amount of heat stored in a heat accumulator is limited and easy to be exhausted rapidly by MPPT. Therefore MEPT (Maximum Efficiency Point Tracking) control should be developed to obtain maximum power from limited heat stored in the heat accumulator. When thermoelectric generator is used for waste heat recovery, conversion efficiency is quite difficult to be measured. This is due to time delay between the change of temperature profile in the thermoelectric generator and the change of heat medium temperature. Decrease of output current is desired to enlarge output because decrease of current decreases Peltier heat and improves efficiency of heat recovery. The experimental results indicate that current fluctuated by MPPT control causes loss of power output. We proposed the optimal control in which current is 10% smaller than one of MPPT control and evaluated it experimentally. We call this control scheme MEPT control. In this evaluation 500 W class thermoelectric generator, latent heat accumulator and the test facilities included 30 kW electric heater are utilized. Experimental result shows MEPT control exceeds MPPT in total electricity recovered from heat accumulator.

Testing Research of Accumulator Performance in the Hydro-pneumatic Suspension of a Vehicle

Taking a 2.5 liter accumulator with hydro-pneumatic suspension in a CXP1032 crane made in Germany as the research object and taking both the overall-road simulative test-bed and the control equipment made by the Schenck Company of Germany as the testing instrument, the structure performance and mechanism are theoretically clarified and the variation of gas states are obtained. This illustrates the accumulating and releasing process of a 2.5 liter accumulator in a 32t crane in the real condition. The preliminary volume and pressure of accumulator would directly affect the stiffness performance of the hydro-pneumatic suspension in a vehicle.

Blockchain state channels with compact states through the use of RSA accumulators

One of the major concerns regarding currently proposed public blockchain systems relates to the feasible transaction processing rate.It is common for such systems to limit this rate to maintain the required levels of security and decentralisation.State channels are an approach to overcome this limitation,as they aim to decrease the required on-chain transactions for a given application and thus indirectly increase the capacity(in terms of applications)of public blockchain systems.In the present paper,we propose a state channel design that,through the use of RSA accumulators,operates on a compact state structure.This scheme is optimal for applications whose state includes large sets of elements.The novel state channel design is presented by analysing all state channel operations and how they have to be revised.The security of the design is discussed,while a practical use case scenario regarding the use of the design for an on-chain asset(e.g.,non-fungible tokens)exchange application is also analysed.