Low-cost all-iron flow battery with high performance towards long-duration energy storage

Long duration energy storage(LDES)technologies are vital for wide utilization of renewable energy sources and increasing the penetration of these technologies within energy infrastructures.Herein,we propose a low-cost alkaline all-iron flow battery by coupling ferri/ferro-cyanide redox couple with ferric/ferrous-gluconate complexes redox couple.The designed all-iron flow battery demonstrates a coulombic efficiency of above 99%and an energy efficiency of~83%at a current density of80 m A cm^(-2),which can continuously run for more than 950 cycles.Most importantly,the battery demonstrates a coulombic efficiency of more than 99.0%and an energy efficiency of~83%for a long duration(~12,16 and 20 h per cycle)charge/discharge process.Benefiting from the low cost of iron electrolytes,the overall cost of the all-iron flow battery system can be reached as low as$76.11 per k Wh based on a10 h system with a power of 9.9 k W.This work provides a new option for next-generation cost-effective flow batteries for long duration large scale energy storage.

Whole system value of long-duration electricity storage in systems with high penetration of renewables

Energy storage is a key enabling technology to facilitate an efficient system integration of intermittent renewable generation and support energy system decarbonisation.However,there are still many open questions regarding the design,capacity,and value of longduration electricity storage(LDES),the synergy or competition with other flexibility technologies such as demand response,shortduration storage,and other forms of energy storage such as hydrogen storage.This paper presents a novel integrated formulation of electricity and hydrogen systems to identify the roles and quantify the value of longduration energy storage holistically.A spectrum of case studies has been performed using the proposed approach on a future 2050 netzero emission system background of Great Britain(GB)with a high share of renewable generation and analysed to identify the value drivers,including the impact of prolonged low wind periods during winter,the impact of different designs of LDES,and its competitiveness and synergy with other technologies.The results demonstrate that high storage capacity can affect how the energy system will evolve and help reduce system costs.

Hybrid planning for LEO long-duration multi-spacecraft rendezvous mission

For the low-earth-orbit （LEO） long-duration multi-spacecraft rendezvous mission, a mixed integer nonlinear programming （MINLP） model is built with consideration of the , perturbation and the time window constraints based on lighting condition. A two-level hybrid optimization approach is proposed. The up-level problem uses the visiting sequence, the orbital transfer duration and the service time after each rendezvous as design variables, and employs the mix-coded genetic algorithm to search the optimal solution; the low-level problem uses the maneuver time and impulses in each rendezvous as design vari- ables, and employs the downhill simplex method to search the optimal solution. To improve the solving efficiency of the low-level problem, a linear dynamic model with J~ perturbation is derived, and the approximate strategy of the low-level prob- lem is then proposed. The proposed method has been applied to several numerical problems. The results lead to three major conclusions： （1） The MINLP model for LEO long-duration multi-spacecraft rendezvous mission is effective, and the proposed hybrid optimization strategy can obtain good solutions that satisfy time window constraints; （2） The derived linear dynamic equations are good first-order approximation to the long-duration rendezvous trajectory under ,J2 perturbation; （3） Under J2 perturbation, the long-duration rendezvous problem has multiple local minimums either in the duration of multiple orbits or in a single orbit, and it agrees with the problem＇s characteristic to use the mix-coded genetic algorithm.

Seismic evaluation of frequency influence and resonant behavior for lead rubber bearing isolated rigid rectangular liquid tanks

The seismic behavior of a partially filled rigid rectangular liquid tank is investigated under short-and longduration ground motions.A finite element model is developed to analyze the liquid domain by using four-noded quadrilateral elements.The competency of the model is verified with the available results.Parametric studies are conducted for the dynamic parameters of the base-isolated tank,using a lead rubber bearing to evaluate the optimum damping and time period of the isolator.The application of base isolation has reduced the total and impulsive hydrodynamic components of pressure by 80 to 90 percent,and base shear by 15 to 95 percent,depending upon the frequency content and duration of the considered earthquakes.The sloshing amplitude of the base-isolated tank is reduced by 18 to 94 percent for most of the short-duration earthquakes,while it is increased by 17 to 60 percent for the majority of the long-duration earthquakes.Furthermore,resonance studies are carried out through a long-duration harmonic excitation to obtain the dynamic behavior of non-isolated and isolated tanks,using a nonlinear sloshing model.The seismic responses of the base-isolated tank are obtained as higher when the excitation frequency matches the fundamental sloshing frequency rather than the isolator frequency.

Effect of high-pressure detonation products on fuel injection and propagation characteristics of detonation wave

The effect of high-pressure detonation products on fuel injection and propagation characteristics of detonation wave has been investigated in the form of ion voltage by varying the equivalence ratio(ER),air mass flux,and operation duration with hydrogen-air mixtures.It has been shown experimentally that the ion voltage decays gradually during the initial stage of rotating detonation wave(RDW).The attenuation of ion voltage is a general phenomenon,and the decay rate of ion voltage and its peak value of the trough state are related to the equivalence ratio and air mass flux.The analysis of interaction between the combustor and hydrogen plenum indicates that the feedback of high-pressure detonation products leads to the attenuation of ion voltage.In addition,the long-duration tests show that the ion voltage will recover to a steady state with the extension of reaction time,when the purgation(products leaving plenums)of detonation products is greater than feedback(products entering plenums)of detonation products in the hydrogen plenum.The recovery of ion voltage starts earlier at the higher equivalence ratio and air mass flux,and the peak value of ion voltage in the steady state also increases with the increase of equivalence ratio and air mass flux.A low frequency oscillation about 10 e12 Hz occurs in the RDW at some operation conditions.This low frequency oscillation is related to the interaction between the combustor and hydrogen plenum,and can be eliminated by either increasing the equivalence ratio or decreasing the air mass flux.

Fast optimization of impulsive perturbed orbit rendezvous using simplified parametric model

A novel simplified parametric model for long-duration impulsive orbit rendezvous is proposed.Based on an existing fast estimation method,the optimal impulses and trajectory can be expressed by only ten parameters whose initial values can be easily determined.Then,these parameters are used to predict orbital deviations with a target orbit.A simple correction process is designed to sequentially update the parameters based on the J_(2) perturbed analytical dynamic equations of circular orbits.Finally,an iteration loop is formed to obtain the precise parameters and optimal trajectory.The simulation results confirm that the simplified parametric optimization method can be applied to elliptical orbits of small eccentricity and adapts well to both analytical and high-precision dynamics.The deviations could always converge within five iterations and the calculation was more efficient than the existing methods.