Electrical Regeneration Research Articles

An Integrated Heat Recovery System Design for a Fuel Cell Buggy With Hydrogen Preheating and Thermoelectric Generator

ABSTRACTThis study presents an integrated heat recovery‐proton exchange membrane (IHR‐PEM) fuel cell system designed for lightweight vehicles powered by a 2 kW PEM fuel cell. The IHR system captures waste heat through multiple heat exchangers and integrates thermoelectric generator (TEG) modules for electrical regeneration and hydrogen preheating, enhancing PEM fuel cell performance. Utilizing the temperature gradient between the fuel cell's exhaust and the ambient environment, the system effectively converts waste heat into electrical energy, improving energy efficiency. Experimental evaluation under various operating parameters, including cruising speeds, PEM fuel cell loads, rejuvenation conditions, and electrical regeneration strategies, demonstrated the system's effectiveness. Results revealed waste heat absorption of up to 8.5 W and hydrogen preheating by 19°C, leading to an 11.5% increase in electrical power production and a maximum PEM fuel cell efficiency improvement of 11%. This study advances waste heat recovery (WHR) technologies in fuel cell‐based transportation, significantly improving energy efficiency and reducing carbon emissions. The findings provide valuable insights into the integration of regenerative WHR systems for lightweight vehicles, fostering the development of sustainable and energy‐efficient transportation solutions.

Advances in conductive hydrogels for neural recording and stimulation.

The brain-computer interface (BCI) allows the human or animal brain to directly interact with the external environment through the neural interfaces, thus playing the role of monitoring, protecting, improving/restoring, enhancing, and replacing. Recording electrophysiological information such as brain neural signals is of great importance in health monitoring and disease diagnosis. According to the electrode position, it can be divided into non-implantable, semi-implantable, and implantable. Among them, implantable neural electrodes can obtain the highest-quality electrophysiological information, so they have the most promising application. However, due to the chemo-mechanical mismatch between devices and tissues, the adverse foreign body response and performance loss over time seriously restrict the development and application of implantable neural electrodes. Given the challenges, conductive hydrogel-based neural electrodes have recently attracted much attention, owing to many advantages such as good mechanical match with the native tissues, negligible foreign body response, and minimal signal attenuation. This review mainly focuses on the current development of conductive hydrogels as a biocompatible framework for neural tissue and conductivity-supporting substrates for the transmission of electrical signals of neural tissue to speed up electrical regeneration and their applications in neural sensing and recording as well as stimulation.

Extreme Monovalent Ion Selectivity Via Capacitive Ion Exchange

Capacitive deionization (CDI) is an emerging technology applied to brackish water desalination and ion selective separations. A typical CDI cell consists of two microporous carbon electrodes, where ions are stored in charged micropore via electrosorption into electric double layers. For typical feed waters containing mixtures of several cations and anions, some of which are polluting, models are needed to guide cell design for a target separation, given the complex electrosorption dynamics of each species. An emerging application for CDI is brackish water treatment for direct agricultural use, for which it is often important to selectively electrosorb monovalent Na+ cations over divalent Ca2+ and Mg2+ cations. Recently, it was demonstrated that utilizing constant-voltage CDI cell charging with sulfonated cathodes and short charging times enabled monovalent-selective separations. Here, we utilize a one-dimensional transient CDI model for a flow-through electrode CDI cell to elucidate the mechanisms enabling such separations. We report the discovery that an asymmetric CDI cell with a chemically functionalized cathode induces electric charges in the pristine anode at 0 V cell voltage, which has important implications for monovalent cation selectivity. Leveraging our mechanistic understanding, with our model we uncover a novel operational regime we term “capacitive ion exchange”, where the concentration of one ion species increases while competing species concentration decreases. This regime enables resin-less exchange of monovalent cations for divalent cations, with chemical-free electrical regeneration.

Heuristic-based optimization framework for customizable design of long-haul data center interconnect networks

With the widespread deployment of data centers, Internet service providers are expecting more efficient design strategies to build long-haul data center interconnect (DCI) networks. In this paper, we propose a heuristic-based optimization framework to design these networks. Through this framework, network designers can obtain a site-type design scheme that arranges customized site types such as in-line amplifiers, dynamic gain equalizers, optical terminal multiplexers, and electrical regenerators, and three strategies are provided for reference. Taking the quality of transmission as the main metric, and the overall cost of the network as the ancillary measurement, we compare the schemes obtained by the proposed framework against the baseline scheme obtained by a traditional periodic design strategy. Simulations are conducted on a topology of the Tencent DCI network. Under the condition that all schemes ensure that the minimum general signal-to-noise ratio (GSNR) remains above the given GSNR threshold, the schemes designed by our framework can achieve overall cost savings up to 25.73%.

Membrane-free electrodeionization using graphene composite electrode to purify copper-containing wastewater.

Membrane-free electrodeionization (MFEDI) technology involves in situ electric regeneration of ion exchange resin, and is used to efficiently purify copper-containing wastewater, so that both the wastewater and copper may be reused. The electrode is the core functional component of a MFEDI system. Electrode-selection greatly influences the electric regeneration efficiency, water recovery and energy consumption of MFEDI processes. In this study, a graphene composite electrode was developed to improve MFEDI-system performance. A graphene composite electrode and conventional platinum-plated titanium electrode were both characterized by scanning electron microscopy (SEM) and electrochemical testing. Furthermore, the treatment and electrical regeneration properties of MFEDI systems with these two electrodes were investigated. The specific surface area of the electrode increased after graphene loading, while the oxygen evolution potential decreased. Wastewater treatment experiments demonstrated that MFEDI systems with graphene composite electrodes effectively removed copper from wastewater. The study also highlighted that the electroregeneration efficiency of the MFEDI system was improved by loading with graphene; the average copper concentration in the regeneration solution increased by 1.4 times to 50.4 mg/L, while the energy consumption decreased from 1.55 to 1.48 kWh/m3, and the water recovery rate increased from 85 to 90%.

Amphoteric blend ion exchange resin with medium-strength alkalinity for high-purity water production in membrane-free electrodeionization

In our previous works, membrane-free electrodeionization (MFEDI), an original deionization technique to produce high-purity water, was invented. However, traditional ion exchange resins, the heart of MFEDI, cannot simultaneously achieve effective adsorption, easy electrical regeneration, and good conductivity. Previously, an amphoteric resin, quaternary ammonium- sulfonic acid resin (QA-SAR), that behaved as medium-strength acid resin, was proposed and applied to produce high-purity water with regeneration performance superior to that of traditional resins. Although the regeneration performance of QA-SAR was better than that of traditional resins, the ion-exchange capacity and conductivity were poor, which further resulted in poor effluent and high regeneration voltage. In view of this, a novel amphoteric resin containing more anionic groups than cationic groups and behaving as medium-strength basic resin, sulfonic acid-quaternary ammonium resin (SA-QAR), was proposed herein. It exhibited better regeneration performance and purification performance than traditional resins and QA-SAR. Under the same conditions, the effluent quality of the MFEDI system filled with SA-QAR remained stable and lower than 0.1 μS/cm, with energy consumption of approximately 0.32 kWh/m3 water, whereas the effluent quality of the system filled with 550A and the system filled with QA-SAR deteriorated quickly, with energy consumption of approximately 0.36 and 0.43 kWh/m3 water, respectively.

Analysis of Wastewater Treatment Technology Based on Bipolar Membrane Electrodialysis

Metal wastewater and saline wastewater are two major problems in the field of wastewater treatment. At present, common treatment methods include ion exchange, electrodialysis and reverse osmosis. The ion exchange method often uses chemical reagents to achieve regeneration, which is likely to cause secondary pollution after treatment. Electrodeionization technology can continuously operate to treat wastewater, and does not require the use of acid-base reagents to achieve resin regeneration, but the structure is complex and requires higher pretreatment. Bipolar membrane electro-regenerative ion exchange is a new technology that has been practically applied in water supply treatment by a certain enterprise. A considerable degree of ion exchange capacity, after reaching the exchange capacity, the bipolar membrane is used for water dissociation to achieve electrical regeneration of the membrane. On the basis of investigating the desalination and regeneration of groundwater (well water) by this technology, this paper studies its removal effect on simulated food processing salty wastewater, Cu2+ and Fe2+ containing simulated electroplating rinsing wastewater. Influence of operating conditions such as influent flow on the treatment effect.

Green hydrogen potentials from surplus hydro energy in Nepal

This paper studies the potentials of green hydrogen production from hydropower energy and its application in electricity regeneration and replacement of petroleum products from the transportation sector in Nepal. The potential surplus hydroelectric energy, and hydrogen production potential from the surplus energy considering different scenarios, is forecasted for the study period (2022–2030). The results showed that hydrogen production potential ranges from 63,072 tons to 3,153,360 tons with the utilization of surplus energy at 20% and 100% respectively, in 2030. The economic analysis of hydrogen from hydropower projects that electricity is valued based on per kg of hydrogen when the surplus electricity is provided at feasible lower price values compared to the US $1.17. This study concludes that hydrogen production from spilled hydro energy and its use in the transportation sector and independent electricity generation is a niche opportunity to lead the country towards sustainable energy solutions and an economy running on hydrogen.

Synthesis and characterization of an amphoteric resin for use in membrane-free electrodeionization

• A novel amphoteric resin was prepared and characterized. • It has better purification property than weak acid resin. • It is much easier to be electrically regenerated than strong acid resin. • It can replace conventional resins in MFEDI to produce high-purity water. Previously, we invented and investigated membrane-free electrodeionization (MFEDI), a novel deionization technique that uses ion exchange resins as the critical material, for the production of high-purity water. However, the functional materials used in MFEDI are common resins that cannot simultaneously achieve effective adsorption, easy electrical regeneration, and good conductivity. For instance, strong acid resin, a cation exchange resin commonly used in MFEDI, cannot be easily electrically regenerated; weak acid resin can be easily regenerated, but has poor conductivity and adsorption properties. There are currently no available resins that can meet all of the requirements of conductivity, adsorption and regeneration properties. In this study, a novel amphoteric resin was prepared and characterised. This amphoteric resin contained much more cationic functional groups than anionic functional groups, behaving as a medium-strength acid resin due to the introduction of anionic functional groups. The prepared amphoteric resin exhibited better purification property than weak acid resin, and could be electrically regenerated more easily than strong acid resin. When the amphoteric resin was coupled with strong base resin and the conductivity of the purified water was kept below 0.10 µs/cm, the water recovery and energy consumption were 74.60% and 0.84 kWh/m 3 water, respectively. By contrast, the energy consumption and water recovery were 40.74% and 2.65 kWh/m 3 water for strong acid resin, and 64.44% and 1.53 kWh/m 3 water for weak acid resin under similar conditions. Clearly, the developed amphoteric resin significantly improves the MFEDI properties.

Simulation of Stand-to-Sit Biomechanics for Robotic Exoskeletons and Prostheses With Energy Regeneration

Previous studies of robotic exoskeletons and prostheses with regenerative actuators have focused on level-ground walking. Here we analyzed the lower-limb joint mechanical power during stand-to-sit movements using inverse dynamics to estimate the biomechanical energy available for electrical regeneration. Nine subjects performed 20 sitting and standing movements while lower-limb kinematics and ground reaction forces were measured. Subject-specific body segment parameters were estimated using parameter identification. Joint mechanical power was calculated from joint torques and rotational velocities and numerically integrated over time to estimate the joint biomechanical energy. The hip absorbed the largest peak negative mechanical power (1.8 ± 0.5 W/kg), followed by the knee (0.8 ± 0.3 W/kg) and ankle (0.2 ± 0.1 W/kg). Negative mechanical work on the hip, knee, and ankle joints per stand-to-sit movement were 0.35 ± 0.06 J/kg, 0.15 ± 0.08 J/kg, and 0.02 ± 0.01 J/kg, respectively. Assuming known regenerative actuator efficiencies (i.e., maximum 63%), robotic exoskeletons and prostheses could regenerate ~26 Joules of electrical energy while sitting down, compared to ~19 Joules per walking stride. Given that these regeneration performance calculations are based on healthy young adults, future research should include seniors and/or rehabilitation patients to better estimate the biomechanical energy available for electrical regeneration.

Low energy consumption electrically regenerated ion-exchange for water desalination.

A new regeneration method of ion exchange resin named Adjacent Bed Electrically Regenerated Ion-exchange (ABERI) was proposed to eliminate the environmental impact of traditional chemical regeneration and improve the economy of replacing chemical regeneration with electrical regeneration. The desalting operation of ABERI was the same as the conventional mixed bed. When the resins were exhausted, anion and cation resins were separated and then packed in a dedicated regenerator adjacently. The resins were regenerated by the H+ and OH- ions produced from a pair of electrodes installed on both sides of the resin bed. By optimizing the regeneration time, current, and feed water flow rate, the energy consumption of ABERI was 0.38 kWh/m3 water; that is, 54% of that of another electrical regeneration technology, membrane-free electrodeionization (MFEDI). Compared with MFEDI, the quality and quantity of purified water produced after regeneration were improved. In ABERI, the average conductivity and the volume (times of bed volumes) of the purified water are 0.9 μS/cm and 109; that is, 75 and 133% of that of MFEDI, respectively. The preliminary economic analysis showed that ABERI offers the potential to regenerate ion exchange resin in an eco-friendly and cost-effective manner.

Low‐voltage and ion‐free‐reverse‐migration electrically regenerated mixed‐bed ion exchange for MEG desalination

AbstractAn improved electrical regeneration method of ion exchange was proposed to enhance the feasibility of applying ion exchange for mono‐ethylene glycol (MEG) desalination and simplify the existing MEG regeneration process in deepwater gas fields. Compared with the latest electrical regeneration process named membrane‐free electrodeionization (MFEDI), this method required lower voltage, did not consume high purity water, and eliminated ion backward migration in principle. These improvements were achieved by changing the electric field direction and the flow direction from parallel in MFEDI to perpendicular during ion exchange regeneration step. In this work, a pair of commercial ruthenium oxide‐coated titanium electrodes was installed on both sides of the cuboid experimental setup. The mixed resins consisting of strong‐base and weak‐acid resins were filled between the electrodes. In water flow and direct current electric field, the resins were regenerated successfully. The feasibility of efficient regeneration with high conductivity feed water (3–200 μS/cm) was verified. After regeneration of the resin bed for 1 h at a voltage lower than 73 V, 33.83% of NaCl in 5.16 bed volume (BV) simulated rich MEG liquid was removed. After 15 cycles of repeated operation, the performance of the resins remained stable. These results provide the possibility to reclaim MEG in deepwater gas fields through a simpler method.

Exploring the possibilities to increase the autonomy of an electric vehicle

The paper identifies the possible energy sources that an electric vehicle can use during its operation to increase energy autonomy. The identified sources are modeled and simulated, and the results are interpreted in terms of viability. The paper presents the constructive principles of a power regeneration system consumed by an electric vehicle during operation to increase its autonomy. It also identifies the possible energy sources that an electric vehicle can use during its operation. The concepts of electricity regeneration are modeled and simulated, and the results are interpreted in terms of viability.

Low temperature, medium temperature and high temperature performance of the continuous regenerative diesel particulate filter assisted by electric regeneration

A model is established to investigate low temperature (<300 °C), medium temperature (300–550 °C) and high temperature (>550 °C) performance of the continuous regenerative diesel particulate filter (CR-DPF) assisted by electric regeneration regarding to balance point temperature, regeneration speed and outlet temperature respectively and relevant influencing factors. Results show that inlet PM concentration and inlet flow rate are positively correlated to balance point temperature and vice versa for initial soot loading and intake NOX concentration. Increasing intake NOX concentration and flow rate increase rapid continuous regeneration speed. At low and medium temperatures, rapid thermal response tends to increase passive regeneration speed and the trend is more with decreasing wall thickness and channel density. In the high temperature range, outlet temperature increases and temperature gradients presented in the early stage of regeneration become steeper with decreasing channel density and wall thickness. However, “L/D” has limited impact on low, medium and high temperature performance.

Electrically regenerated ion-exchange technology for desalination of low-salinity water sources

A promising approach to increasing freshwater availability is the effective desalination of widely available and abundant low-salinity water sources. Here we report a new approach to desalinate low-salinity water sources using inexpensive ion exchange resins (IER) which are commonly used for water softening and require regular chemical regeneration. We incorporate IER into a functional composite material that enables electrical regeneration of IER, eliminating the need for regular use of corrosive chemicals. These proof-of-concept results demonstrate reliable regeneration of IER-composite electrodes using a lab-scale prototype device. With further characterization and development, this new approach offers a path to sustainable use of conventional IER for desalination of low-salinity water sources.

Membrane-free electrodeionization using phosphonic acid resin for nickel containing wastewater purification

Membrane-free elctrodeionization (MFEDI) is a technology in which ion exchange resins can be electrically regenerated in situ. It allows the purification of nickel containing wastewater, as well as the production of concentrated nickel solution, which could be recycled. However, proper choice of packed ion exchange resins is crucial to MFEDI. In this study, emphasis was placed on improving the performance of MFEDI by the introduction of phosphonic acid resin. Much of this information was obtained by analyzing the characteristic of phosphonic acid resin, the stack configuration of packed ion exchange resin and the mechanism of electrical regeneration. The layered hybrid resin bed filled with both phosphonic acid resin and weak acid resin was found to be the most effective stack configuration for the adjustment of concentrate pH. The purification study demonstrated that, pure water with conductivity below 0.3 μS/cm was produced. The electrical regeneration study showed that, the average concentrate nickel concentration was over 95 mg/L, the concentrate pH was around 7.4, thus precipitation of nickel hydroxide was prevented. Moreover, in comparison to previous study, in which MFEDI was packed with hybrid strong acid and weak base resin and hybrid weak acid and strong base resin, the water recovery ratio was increased from 88.0% to 89.5%, the energy consumption was decreased from 5.6 to 4.1 kWh/m3 wastewater. The regeneration mechanism study revealed that, more than 72% of resin regeneration was attributed to the water splitting, and less than 28% of resin regeneration was contributed by the water electrolysis.

Experimental study on liquid desiccant regeneration by photovoltaic electrodialysis

Abstract Liquid desiccant regeneration is an important part of liquid desiccant air conditioning system and consumes the majority of the system’s power. Conventional methods for liquid desiccant regeneration use thermal energy to regenerate the liquid desiccant. One of the biggest problems for thermal regeneration is that the liquid desiccant should be cooled down before dehumidification. Furthermore, the efficiency for liquid desiccant regeneration drops under high temperature and humidity climates. In comparison, electrical regeneration, such as electrodialysis (ED), may solve the problems above. No phase change is involved in this process. In addition, low electrical energy is required and photovoltaic power is capable of proving the necessary energy. In this paper, the performance of liquid desiccant regeneration by photovoltaic electrodialysis (PV-ED) was experimentally investigated by considering two important factors, including the initial desiccant concentration and current intensity. The results showed that the initial desiccant concentration and current intensity had big impact on the performance of the system. Lower desiccant concentration and higher current intensity contributed to the current efficiency and solute transport, respectively. In addition, the energy consumption per unit solute migration increased with the increase of both current intensity and desiccant concentration. The results also indicated that the PV-ED regenerator performed better when the initial desiccant concentration was low and current intensity was high.

Research of Electric Power Regeneration using Automotive cooling Fan as Wind TurbineInvestigation of causes and Improvement Method for efficiency decrease of wind turbine mounted on actual vehicle

Research of Electric Power Regeneration using Automotive cooling Fan as Wind TurbineInvestigation of causes and Improvement Method for efficiency decrease of wind turbine mounted on actual vehicle

Comparative Analysis of Erbium Doped Fiber Amplifier (EDFA) and Raman Optical Amplifier (ROA) in Nonlinear-CWDM System

The massive demands for high-rate application drove the telecommunication service to use large bandwidth capacity. The Coarse Wavelength Division Multiplexing (CWDM), a common use in Metro-WDM, can be a solution to provide large bandwidth in optical communications. In a communications system, there are attenuation and nonlinear effect decreasing the system performance. In order to overcome the limitation imposed by electrical regeneration to maintain system performance, a means of optical amplification was sought. In this paper presents the comparison of two competing technologies emerged: Erbium Doped Fiber Amplifier (EDFA) and Raman Optical Amplifier (ROA) to overcome the attenuation in the nonlinear system. We designed the CWDM system using 8 channels with 20 nm channel spacing and 60 km length. The result was conducted by varying the CW Laser power using -8, -6, -4, -2, 0, 2, 4, and 6 dBm. Based on the result of the research, raman amplification can maintain the BER and the Q-factor of the CWDM system better than EDFA. In addition, the received power in raman amplification larger than that received in EDFA. In conclusion,a CWDM system using ROA amplifier has better performance for the system than using EDFA amplifier.

Carbon membranes for oxygen enriched air – Part I: Synthesis, performance and preventive regeneration

Abstract Chemisorption of oxygen on the active sites of carbon layers limits the use of carbon membranes in air separation application. A novel online electrical regeneration method was applied to prevent the active sites on carbon surface to be reacting with O2 while the membrane was in operation. This method reduced the aging effect and the membrane showed relative stable performance with only 20% loss in O2 permeability and 28% increase in O2/N2 selectivity, over the period of 135 days using various feeds containing H2S, n-Hexane and CO2-CH4 gas. The carbon membranes reported here were produced at the pilot-scale facility by the carbonization of regenerated cellulose under optimized conditions to achieve good air separation properties. The permeation properties of the membranes were tested by single gas separation experiments at 5 bar feed pressure (50 mbar permeate) and temperature range 20–68 °C. It was observed that O2 permeability is increasing exponentially with increase in operating temperature without significant loss in the O2/N2 selectivity. The O2 permeability of 10 Barrer (1 Barrer = 2.736E − 09 m3(STP)m/m2 bar h) with O2/N2 selectivity of 19 was achieved at 68 °C. Thermal (80 °C), chemical (propylene) and online-electrical (10 V DC) regeneration approaches were studied to lessen the aging effect on carbon membranes.