1,908 research outputs found
Dataset to support thesis "Hybrid and dual chemistry battery for energy storage application"
No full textThis data set contains the experimental data of the hybrid battery systems analysed in the "Hybrid and Dual Chemistry Battery for Energy Storage Applications" thesis.
The data set contains the following:
- Data_Cycles_2024.zip is the cycle data of a hybrid battery demonstrator.
- Experimental_data.zip is the experimental data for the individual Li-ion and lead-acid batteries.
- The files Hybrid_Data_24V_-_1LA_1LI_Strings.zip, Hybrid_Data_24V_-_1LA_2LI_Strings.zip, Hybrid_Data_24V_-_2LA_1LI_Strings.zip, Hybrid_Data_24V_-_3LA_1LI_Strings.zip, and Hybrid_Data_48V.zip contain the experimental lab data of the hybrid battery system for different string and voltage configurations.
- Modelling_Data.zip is the modelling data of the hybrid system.
The data formats are CSV and MATLAB (.mat). </span
Hybrid and Dual Chemistry Battery for Energy Storage Applications
No full textEnergy storage is predicted to play an increasing role in a renewable energy future. There is a wide range of storage technologies available, with different technical characteristics, to assist the renewable transition. Hybrid options are also possible to improve the technical and economic performance of storage systems. The technology proposed in this work is the directly connected hybrid lead-acid and Li-ion battery storage system, which makes use of Li-ion's high-performance characteristics and the low-cost, lower specifications of lead-acid cells. The work presented in this thesis answers the following key questions, which also summarise the novelty of this research:•What are the hybrid characteristics of directly coupled, hybrid Li-ion (NMC) and lead-acid (VRLA) systems?•Can the instantaneous hybrid behaviour be modelled using equivalent circuits?•How do hybrid battery systems perform over time in real-world applications? •What storage applications are best suited for hybrid lead-acid and Li-ion systems, and what are the associated techno-economic parameters? To answer these questions, I have built and tested hybrid systems, developed battery models, and monitored the first commercial hybrid lead-acid and Li-ion system installed in the UK. The lab analysis, done for five domestic-size hybrid systems of 24V and 48V, provides details about the system efficiency and energy flows in a hybrid configuration. The round-trip efficiency drops from a maximum of around 94-95% in the first charge/discharge stages, when only Li-ion strings are active, to 82-90%, depending on the lead-acid strings' depth of discharge. The most important parameters in the round-trip efficiency function are the kWh capacity ratio between the two chemistries, the energy available and the charge/discharge current. The energy transfer between the strings, caused by the transient currents, is negligible when only Li-ion is active, and increases with the lead-acid depth of discharge.A hybrid equivalent circuit battery model was built to predict the experimental results. The model approximates the dynamic effects of energy transferred between the strings with an accuracy of 90%, except when the lead-acid strings are discharged to 10-30% depth of discharge. The overall efficiency, the total energy discharged, and the Li-ion energy available for independent cycling can be predicted with above 90% accuracy. The demonstrator project data shows that the hybrid system is stable over time, the average operating round-trip efficiency in real-world applications is 90%, and the lead-acid degradation in hybrid configurations is around 1.3% per year. The energy transfer between the strings, due to different dynamic time constants of the two chemistries, depends on the charge stopping points, and to a lesser extent, on the discharge interruption depth of discharge. For the analysed system, the average Li-ion to lead-acid energy transfer during the charging process is 13 kWh, 5.5% of the total charged energy. The average lead-acid to Li-ion energy transfer during discharge is 5.2 kWh, 2.47% of the total discharged energy. The final techno-economic analysis shows that the hybrid battery system can be used for renewable storage applications, dedicated to serving residential, commercial, industrial, and off-grid EV charging load profiles, but it is not suitable for front-of-the-meter applications, which operate in frequency response or balancing markets. The cost-saving potential for using hybrid Li-ion and lead–acid systems varies with the load profile, storage operational strategy, and renewable overgeneration design choices. The total system cost reduction can be up to 26.1% when compared with full Li-ion solutions. However, for the cost-optimised energy solutions, the CAPEX reduction using hybrid storage is between 1.4% and 12.7%, depending on the percentage cost of storage as a share of the total energy system. The minimum cost ratio between Li-ion and lead-acid, beyond which the hybrid storage system is no longer justified, is between 1.1 and 1.5
Binding fullerenol C60(OH)24 to dsDNA
No full textMariana Pinteala, Andrei Dascalu, Cezar UngurenasuPetru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica, Iasi, RomaniaAbstract: The first C60(OH)24-DNA complex and its fluorescence enhancement is reported. The enhanced fluorescence intensity of fullerenol C60(OH)24 is in proportion to the concentration of DNA in the range of 1 &times; 10-9 to 8 &times; 10-5 molL-1 and the detection limit was 1.3 ng mL-1. Fullerenol C60(OH)24 binds significantly to the phosphate backbone of native dsDNA and to base-pairs within the major groove of sodium salt of dsDNA.Keywords: nanomedicine, fullerenol, DNA complexation, fluorescent prob
Experimental investigations into a hybrid energy storage system using directly connected lead-acid and Li-ion batteries
No full textThis paper presents experimental investigations into a hybrid energy storage system comprising directly parallel connected lead-acid and lithium batteries. This is achieved by the charge and discharge cycling of five hybrid battery configurations at rates of 0.2–1C, with a 10–50% depth of discharge (DoD) at 24 V and one at 48 V. The resulting data include the overall round-trip efficiency, transient currents, energy transfers between the strings, and the amount of energy discharged by each string across all systems. The general observation is that the round-trip efficiency drops from a maximum of around 94–95% in the first stages of the charge/discharge process, when only the Li-ion strings are active, to around 82–90% when the lead-acid strings reach a DoD of up to 50%. The most important parameters in the round-trip efficiency function are the ratio between the Li-ion and lead-acid energy available and the charge/discharge current. The energy transfer between the strings, caused by the transient currents,
Performance of a hybrid battery energy storage system
No full textThe use of energy storage systems is inevitable in a power grid dominated by renewable generators. This paper presents a performance overview of a 100 kW/270 kWh, grid-connected, hybrid battery energy storage system. The hybrid system uses two types of battery chemistries, li-ion and lead–acid connected directly at the DC bus — without power electronic converters. After a brief introduction and a short technical description of the project, the paper presents a three year, 2019 to 2021, operational data set. The battery data is later split into individual charge/discharge cycles and analyzed in terms of power and strings current sharing, energy, round-trip efficiency and energy transfer between the strings. The analysis shows that the average round-tripenergy efficiency of the system is 90% and depends on the depth of discharge. The energy transfer between the strings can happen during charge or discharge and the average values are 5.5% (during charge) and 2.47% (during discharge) of the total discharged energy. Minimum capacity loss was recorded for the lead–acid cells and practically no capacity degradation for the li-ion cells
Multi-Agent Reinforcement Learning using Centralized Critics in Collaborative Environments
No full textAgents trained through single-agent reinforcement learning methods such as self-play can provide a good level of performance in multi-agent settings and even in fully cooperative environments. However, most of the time, training multiple agents together using single-agent self-play yields poor results as each agent tries to learn how to perform their task while their teammates are also learning. Thus, training models to reach an optimal behaviour in such situations becomes a challenging, if not impossible issue to overcome. One possible solution to deal with this problem is to facilitate a centralized training process in which the policies of all agents are evaluated by a centralized critic that has access to the observations and actions of all the agents in the environment. By using this approach, the environment becomes stationary and the agents learn in a similar way to using a single-agent algorithm in settings where only one agent needs to be trained. In this paper, we test whether by using a multi-agent reinforcement learning algorithm with centralized critics, as opposed to single-agent ones, we would obtain an agent that generalizes better to new partners in a collaborative environment such as Overcooked, where coordination is critical for good performance. The results display a similar performance between the two algorithms when evaluated through self-play and slightly better or worse results when paired with the human model, representing a mediocre agent, depending on the map. Thus, the multi-agent, centralized critics algorithm used in this study did not train agents that generalize better to new partners. However, the training metrics clearly indicate that the centralized critics method makes the agents learn and converge twice as fast as its single-agent version.https://github.com/andrei-07/rp-overcooked-centralized-critics Link to GitHub repositoryCSE3000 Research ProjectComputer Science and Engineerin
Andrei Tarkovsky:
No full textThe author studies the originality of the film language of Andrei Tarkovsky, one of the great filmmakers of the twentieth century. For this purpose he considers the symbolic, poetic, technical and mystical elements of Tarkovsky’s seven films. Beyond the standard critics, he builds an unitary language for the interpretation of a work reputedly tight.El autor estudia la originalidad del lenguaje cinematográfico de Andrei Tarkovsky, uno de los grandes directores de cine del siglo XX. Para este propósito considera los aspectos simbólicos, poéticos, técnicos y místicos de sus siete películas. Desecha el formato de ficha crítica y construye un lenguaje unitario para la interpretación de una obra reputada como hermética
A techno-economic analysis of a hybrid energy storage system for EV off-grid charging
No full textThis paper presents the techno-economic advantages of a DC coupled li-ion and lead-acid hybrid energy storage systems used for EV off-grid charging using visitors arriving at Marwell Zoo car park as a case study. The analysis shows that the hybrid storage systems can reduce the overall system costs by using li-ion batteries for frequent cycling linked with lead-acid for longer, less aggressive cycles. On-site over generation of 600 % of the total load give sthe lowest total system cost. For the optimized overgeneration, hybrid storage system can further reduce the cost of the EV off grid charging system by up to 10 % when compared with a li-ion only energy store
The 3D Smith Chart and its practical applications
No full textMueller, A.; Dascalu, DC.; Soto Pacheco, P.; Boria Esbert, VE. (2012). The 3D Smith Chart and its practical applications. Microwave journal. 55(7):64-72. https://riunet.upv.es/handle/10251/52766S647255
História e Documentário no Cinema de Andrei Tarkóvski
No full textIn the article, the author discuses the Cinematic history and documentary of Andrei Tarkóvski
- …
