Energy Whenever Research Articles

A Novel Thermally Integrated CO2-Carnot Battery (TI-PTES) utilizing Cold Thermal Storage

Abstract The growing integration of renewable energy sources in the energy grid presents intermittency and negative pricing challenges, necessitating large-scale energy storage solutions. Pumped Thermal Energy Storage (PTES) can address these issues by storing and delivering substantial energy whenever required. High-temperature heat pump development is crucial to deploying PTES for storing heat at sink temperatures that are well above the ambient temperature(>450°C) to ensure a reasonable round-trip efficiency(RTE). Currently, however, it is not a technological possibility for heat pumps to achieve these temperatures even with the support of freely available heat (200°C to 400°C) as source temperatures. This study explores a potential layout of the TI-PTES system that exploits commercially available equipment by storing heat below the ambient temperature while still being able to utilize the freely available heat source(Solar, Waste heat, biomass, etc.) to support the overall RTE. The charging phase employs a well-established CO2-refrigeration cycle to accumulate energy below the ambient temperature in cold thermal storage. While the discharging phase runs a trans-critical CO2 power cycle between the freely available heat source and the cold thermal storage. Overall, offering a practically implementable model for the PTES system with market-available components. The study investigates the design of this innovative system presenting the relevance of different operating and machine parameters as well as the contribution of freely available heat sources to the overall performance. Finally benchmarking the technology with other long-duration energy storages.

Model-Based Extreme Weather Data for Predicting the Performance of Buildings Entirely Conditioned by Ambient Energy

Abstract This study reports the development of extreme meteorological year (XMY) data for simulating buildings that are heated and cooled entirely by ambient energy in four climates varying in outdoor temperature and cloudiness. Electrification of conventional buildings is insufficient to meet climate goals since nearly half of U.S. electricity will still be produced from fossil fuels by 2050. Ambient-conditioned buildings depend on non-fossil sources such as the sun for heating and nighttime air or sky radiation for cooling. Such buildings are more susceptible to weather variability than conventional buildings, which simply use more auxiliary energy whenever weather conditions are challenging. On the other hand, ambient-conditioned buildings are more resilient to power outages so long as the design accounts for unusual weather during extreme years to consistently maintain indoor comfort. Ambient-conditioned buildings designed to remain comfortable with typical meteorological year (TMY2020) data produced up to over 1000 h per year of uncomfortable indoor temperature during the years (1998–2020) from which the TMY was derived. Parameters related to outdoor air temperature, sky temperature, and insolation were found to be unreliable for identifying the most challenging years. Rather, a whole-building model allowed the identification of the two most challenging years for heating and cooling, respectively. An XMY file concatenated from the most challenging summer and the most challenging winter provided a good match of indoor temperature predictions to those from the full individual years. This new XMY file facilitates the design of ambient-conditioned buildings for reliable indoor comfort.

Optimization and experimental validation of the air intake holes of the lithium-ion battery pack

Energy storage systems enable the storage of energy and provide access to carbon-neutral, environmentally friendly energy whenever or wherever it is needed. Lithium-ion batteries are currently the most preferred type among various battery technologies and are widely used in energy storage systems. Some of the features that make lithium-ion batteries advantageous include high energy density, long life, low maintenance requirements, and high operating voltage. The growing demand for energy throughout the day increases the need for batteries with high storage capacity. However, the increased capacity also leads to heating issues in lithium-ion batteries. The heating problem in lithium-ion batteries can result in nonhomogeneous temperature distribution, shortened lifespan, thermal runaway, increased internal resistance, and performance loss. Therefore, an effective thermal management system is essential for cooling lithium-ion batteries. This study aims to provide insight into the forced air cooling of prismatic 280 Ah LiFePo4 batteries, which have limited information in the literature and are more prone to overheating compared to lower-capacity batteries. In this study, five different battery pack case designs, each with different sizes and numbers of air intake holes, were determined and modelled using the SolidWorks program. Within the battery pack cases, 16 280 Ah lithium-ion batteries are placed, and an axial fan is used to cool these batteries. Initially, computational fluid dynamics analyses of the five different designs were performed in the SolidWorks Flow Simulation program. An experiment was then conducted on the design that provided the most efficient thermal management to validate the numerical results. The selected design, fulfilling the purpose of homogeneous temperature distribution and having the minimum temperature difference between batteries, was designated as Design 5. It exhibited a 62 % improvement in cooling performance with a 0.25 °C temperature difference, indicating successful temperature homogeneity between batteries. During a two-hour experiment with a 140 A discharge current, temperature measurements were taken from the surfaces of the batteries using thermocouples. Finally, the maximum error rate between experimental and numerical studies was determined to be 1.47 %, indicating successful validation of the numerical study. The air intake hole optimization, a novel design approach, prevents temperature distribution inhomogeneity caused by the distance of the batteries to the fan and offers an effective way to cool down high-capacity 280 Ah batteries.

Near Real-Time Load Forecasting of Power System Using Fuzzy Time Series, Artificial Neural Networks, and Wavelet Transform Models

Due to the increasing usage of electrical power, the size of electrical power system has increased manifold over the years. There is no inventory or buffer from generation to customer; therefore, to provide a reliable and quality electrical energy whenever demanded, power utility engineers require an adequate, efficient, and precise load forecast to meet continuously varying load demands. This article presents the design and analysis of demand forecasting over shorter interval for power system. The fuzzy time series (FTS), artificial neural network (ANN), and wavelet transform (WT) based forecasting is presented and analyzed in this article. The real-time data from Indian utility is collected for forecasting the demand and to check the effectiveness of FTS, ANN, and WT. The various error definitions are used to calculate the accuracy of the proposed techniques, and the application results verify the superiority of WT and ANN over FTS by showing reduced error value with greater accuracy. Additionally, it is watched that wavelet db3, level 3 is discovered to be the most accurate Daubechies wavelet-oriented technique for predicting the demand in comparison to other dbs, and it highly aligns in reducing the error between actual and predicted demand.

Optimal Control Strategy for PEM Hybrid Electric Vehicle using Matlab Simulink

The conventional fossil fuels are being replaced by alternate energy sources very fast. This is mainly due to the limited resources left in the Nature and the polluting characteristic of fossil fuel. Only thirty additional years are left for the supply of fossil fuels. The extreme climate change is largely attributed to automotive fossil fuel burning. The advent of pure Electric vehicles has resulted in reduction of harmful greenhouse gas emissions. It addresses the answer to the concerns of oil resource depletion, air pollution and climate changes. The benefit of using electric power in automotive sector is immense. However, the outcome of hybrid EVs can surpass pure EVs due to its capability of charging on the go, hence no extra charging time. In absence of any moving parts in a fuel cell, the maintenance and noise are also minimal. PEM fuel cell is a most eligible power source having reduced emissions and high efficiency characteristics. The efficiency of hybrid vehicle is a result of charging effectiveness. Control Strategy plays an important role in conservation and elevating energy whenever required. These are the energy power banks to optimize battery sizing and minimize losses. This paper explains a control strategy to enhance efficiency of FCHV system along with reduction of hydrogen consumption. This is achieved by maximizing fuel cell efficiency by balancing the power split between battery and fuel cell. The rule based strategy results in maximizing fuel cell system efficiency by sustaining the state of charge (SOC) of the battery. The SOC is aimed to be kept around a value which can address extremely low charge and high charge condition of the battery. At the same time, load on fuel cell is switched in a manner so as not to have a sudden ascent or descent of power, which helps in preventing the terminal deterioration in the fuel cell. Hence, PEMFC works as Range extender to the powertrain system and charges the battery while the vehicle is moving. The fuel cell efficiency and durability is maximized by balancing the power split between battery and fuel cell. The rule based strategy is applied in order to maximize fuel cell system efficiency and sustaining the state of charge (SOC) of the battery.

A Comprehensive Review of the Bidirectional Converter Topologies for the Vehicle-to-Grid System

Over the past decade, there has been a great interest in the changeover from cars powered by gasoline to electric vehicles, both within the automotive industry and among customers. The electric vehicle–grid (V2G) technology is a noteworthy innovation that enables the battery of an electric vehicle during idling conditions or parked can function as an energy source that can store or release energy whenever required. This results in energy exchange between the grid and EV batteries. This article reviews various bidirectional converter topologies used in the V2G system. Additionally, it can reduce the cost of charging for electric utilities, thus increasing profits for EV owners. Normally electric grid and the battery of an electric vehicle can be connected through power electronic converters, especially a bidirectional converter, which allows power to flow in both directions. The majority of research work is carried out over the converters for V2G applications and concerns utilizing two conversion stages, such as the AC-DC conversion stage used for correcting the power factor and the DC-DC conversion stage for matching the terminal voltage. Furthermore, a bidirectional conversion can be made for an active power transfer between grid–vehicle (G2V) and V2G effectively. This review explores and examines several topologies of bidirectional converters which make it possible for active power flow between the grid and the vehicle and vice versa. Moreover, different types of charging and discharging systems, such as integrated/non-integrated and on/off board, etc., which have been used for electric vehicle applications, are also discussed. A comparison study is carried out based on several other factors that have been suggested. The utilization of semiconductors in power converters and non-conventional resources in charging and discharging applications are the two improving technologies for electric vehicles.

Inter-continental Data Centre Power Load Balancing for Renewable Energy Maximisation

The ever increasing popularity of Cloud and similar services pushes the demand for data centres, which have a high power consumption. In an attempt to increase the sustainability of the power generation, data centres have been fed by microgrids which include renewable generation—so-called ‘green data centres’. However, the peak load of data centres often does not coincide with solar generation, because demand mostly peaks in the evening. Shifting power to data centres incurs transmission losses; shifting the data transmission has no such drawback. We demonstrate the effectivity of computational load shifting between data centres located in different time zones using a case study that balances demands between three data centres on three continents. This study contributes a method that exploits the opportunities provided by the varied timing of peak solar generation across the globe, transferring computation load to data centres that have sufficient renewable energy whenever possible. Our study shows that balancing computation loads between three green data centres on three continents can improve the use of renewables by up to 22%. Assuming the grid energy does not include renewables, this amounts to a 13% reduction in CO2 emissions.

Power Generation by Revolving Door

As the world move forward in various fields like research and development; conservation of energy is a major issue to be resolved. To meet load demand, renewable energy and some unconventional source of energy can provide the necessary amount of clean energy for atmosphere stabilization and scale down the consumption of fossil fuel. Due to shortage of power in the rural areas as well as developing cities saving of energy is a vital factor so we have to save the energy whenever as possible. In this paper, prospect and usefulness of “Power Generation by using Revolving Door” has been reviewed. The objectives of this paper is to designed fabricated of a miniature revolving door which can generate energy by amplifying the initial RPM of door shaft that harnesses human motion and change it as electricity.

RED WoLF hybrid storage system: Adaptation of algorithm and analysis of performance in residential dwellings

The manuscript proposes the innovative energy storage technology which will allow reducing the load from the grid during peak time consumption, as a result, less CO2 will be generated by electrical grid or renewable energy such as wind energy will not be wasted but rather stored in each household. We do not manage the household consumption, but we store the energy whenever it is “greenest“ and can be used in the future and at the same time avoid the usage of the grid during the peak time, thus there is no effect on the dweller lifestyle. Although the technologies used in the article are well known and are ready to use, such a unique combination was never proposed before. We combine photovoltaic arrays, storage heaters and batteries. The inclusion of storage heaters allows us not to use the battery to heat the dwelling and consequently dramatically reduce the battery size needed for the storage. The article also shows the success in avoiding peak times of such combination during numerical simulation test of the control algorithm. These results become exceptionally interesting since this algorithm will be later tested on various pilot sites across North Europe and thus innovate the energy sector.

Design and Development of 21700 Type Cells for Electric Vehicle Applications

The world’s transition to sustainable energy has been largely accelerated from the transportation field. Thanks to the increasingly wide deployment of charging station and government incentives, electric vehicles are seeing a fast growth in sales over years. Most of them are completely or partially powered by Li-ion batteries, which store and distribute the energy whenever is the needed for the operation of the vehicle. The battery pack consists of tens, hundreds, or thousands of individual cells, depending on the size (kWh) of the pack and cell as well as the form factor of the cell. As an EV start up, SF Motors is trying to produce the intelligent EV for everyone. One prominent feature of EV is their fast acceleration. A high power is delivered during fast acceleration, which requires the cell to be discharged at extreme high rates. Simultaneously, extensive heat is generated during fast acceleration, causing cell temperature increase and stimulating safety concerns. Here, we’re developing 21700-type cylindrical cells which can deliver extreme high power safely in a short time without compromising its high energy density. Each factor affecting cell rate capabilities like electrode materials, areal loadings, electrode architecture and electrolytes are individually investigated by various electrochemical techniques such as symmetric cells and three-electrode cells. By integrating state-of-art electrode materials, advanced cell design and processing, we’re able to build cells with high energy density, high power, and long cycling life while keeping a high standard for safety. The successful implementation of this extreme high power cell will enable advanced electric vehicles with long drive range (> 300 miles) and top performance driving experiences.

Design and Development of 21700 Type Cells for Electric Vehicle Applications

The world’s transition to sustainable energy has been largely accelerated from the transportation field. Thanks to the increasingly wide deployment of charging station and government incentives, electric vehicles are seeing a fast growth in sales over years. Most of them are completely or partially powered by Li-ion batteries, which store and distribute the energy whenever is the needed for the operation of the vehicle. The battery pack consists of tens, hundreds, or thousands of individual cells, depending on the size (kWh) of the pack and cell as well as the form factor of the cell. As an EV start up, SF Motors is trying to produce the intelligent EV for everyone. One prominent feature of EV is their fast acceleration. A high power is delivered during fast acceleration, which requires the cell to be discharged at extreme high rates. Simultaneously, extensive heat is generated during fast acceleration, causing cell temperature increase and stimulating safety concerns. Here, we’re developing 21700-type cylindrical cells which can deliver extreme high power safely in a short time without compromising its high energy density. Each factor affecting cell rate capabilities like electrode materials, areal loadings, electrode architecture and electrolytes are individually investigated by various electrochemical techniques such as symmetric cells and three-electrode cells. By integrating state-of-art electrode materials, advanced cell design and processing, we’re able to build cells with high energy density, high power, and long cycling life while keeping a high standard for safety. The successful implementation of this extreme high power cell will enable advanced electric vehicles with long drive range (> 300 miles) and top performance driving experiences.

Quadratic conservative scheme for relativistic Vlasov–Maxwell system

For more than half a century, most of the plasma scientists have encountered a violation of the conservation laws of charge, momentum, and energy whenever they have numerically solved the first-principle equations of kinetic plasmas, such as the relativistic Vlasov–Maxwell system. This fatal problem is brought by the fact that both the Vlasov and Maxwell equations are indirectly associated with the conservation laws by means of some mathematical manipulations. Here we propose a quadratic conservative scheme, which can strictly maintain the conservation laws by discretizing the relativistic Vlasov–Maxwell system. A discrete product rule and summation-by-parts are the key players in the construction of the quadratic conservative scheme. Numerical experiments of the relativistic two-stream instability and relativistic Weibel instability prove the validity of our computational theory, and the proposed strategy will open the doors to the first-principle studies of mesoscopic and macroscopic plasma physics.

Energy Management for Renewable Microgrid in Reducing Diesel Generators Usage With Multiple Types of Battery

Using solar photovoltaics (PV) to help a microgrid (MG) operator for cost reduction may not be a straightforward problem due to the intermittent nature of PV power generation and unpredictable load demands. One potential way to address this challenge is to use batteries that can store the surplus PV energy whenever possible and supply the energy back to the MG when needed. In this context, this paper proposes a battery energy management system (BEMS) for an MG, in which PVs and diesel generators (DGs) are the primary sources of electricity. The novelty of the proposed BEMS lies within the energy management of multiple types of batteries’ characteristics and the reduction of DGs’ operating hours simultaneously. Furthermore, the proposed BEMS also takes into account different characteristics of the batteries when controlling the charging and discharging decision to extend the battery lifetime. Real-world data of MG load and PV power generations are used to verify the effectiveness of the proposed BEMS. Through numerical simulation case studies, it is demonstrated that the proposed BEMS is capable of achieving the following: reduction in DGs’ operating hours, reduction in PV power fluctuations, and concurrent management of multiple batteries of different characteristics and extension of battery lifetime by controlling battery charge and discharge rate.

Charging performance of a CO2 semi-clathrate hydrate based PCM in a lab-scale cold storage system

Cold thermal energy storage aids in the efficient deployment of thermal energy whenever there is a mismatch between energy generation and energy use. In this study, a lab-scale demonstration of cold storage system was built to investigate the performance of CO2 semi-clathrate hydrate as a cold storage material in the charge of a realistic cold thermal storage. The experimental rig was basically a vessel equipped with an external loop and an ultrasonic crystallizer to boost the hydrate formation. The hydrate was formed from a salt solution composed of tetra-n-butyl ammonium bromide 20wt%, tetra-n-butyl ammonium fluoride 0.25wt% and sodium decyl sulfate 0.15wt%. At a constant pressure condition of 5.0bar, the hydrate formation was triggered by the heat transfer fluid at 7.5°C. The charged cooling capacity of two control strategies, namely ‘constant pressure’ and ‘constant mass’, were compared. The repeatability and stability of hydrate formation conditions were studied. It was indicated that CO2 semi-clathrate hydrate could serve in cold storage systems effectively. However, it was also found that under the experimental conditions, hydrate formation was hard to thoroughly complete due to the lack of sufficient driving force or heat/mass transfer.

Investigation on the Microfluidics in PEM Water Electrolyzers

A sustainable and robust electrochemical energy storage and/or a hybrid system to accommodate daily, even hourly changes of renewable resources becomes more critical. An advanced polymer electrolyte membrane water electrolyzer (PEMWE) has been shown to be effective energy storage medium by producing hydrogen/oxygen from water with electricity from renewable sources. When the renewable resources are available, hydrogen will be produced and stored, such that it can later provide a constant power supply with a PEM fuel cell, which is a reverse device of the electrolyzer. This entire portfolio will make renewable and hybrid energy systems effective to provide reliable and multiscale energy whenever needed. In proton exchange membrane water electrolyzers (PEMWEs), water is electrochemically splitting into oxygen and hydrogen. The oxygen generated at the anode side and the circled water flowing over the liquid/gas diffusion layer yield two-phase transport conditions in micro-channels and pores of LGDL, which significantly impact the performance. Due to limitations of the design of conventional PEMWEs and LGDLs, the in-situ phenomena of two-phase flow has few been explored in operating PEMWEs. In this research, an innovative design of a transparent PEMWE is developed coupled with the thin and well-tuned titanium LGDLs with straight pores. The high-speed and micro-scale visualization system (HMVS), and electrochemical impedance spectroscopy will be used for in-situ characterizations. Visualization results are used for better understanding the behavior of two-phase flow and its effects on the PEMWE performance. Patterns of gas-bubble formation, evolution, departure and transport are identified. The effects of property of materials, including LGDL pore sizes, channel dimensions, are also investigated.

Modeling and Simulation of Electro-Hydraulic Compound Regenerative Braking Control Strategy for Electric Vehicle

This paper mainly discusses the dynamic distribution of regenerative braking system and conventional friction braking system of EV.In order to meet the requirements of vehicle braking stability and recycle the braking energy whenever possible, the paper proposes a control strategy which based on ECE regulation and I curve.Then the proposed control strategy is embedded into the simulation software ADVISOR.The result shows that the control strategy of regenerative braking the paper presented is better than ADVISOR’s own on braking energy recovery, and is especially suitable for frequent braking city conditions.

Adaptive energy-efficient scheduling algorithm for parallel tasks on homogeneous clusters

Increasing attention has been directed towards the two key issues of performance and energy consumption for parallel applications in high performance clusters. The traditional energy-efficient scheduling algorithms mainly leverage a threshold to balance system performance and energy consumption. But the random threshold cannot flexibly adapt the system characters and application requirements, thus making the scheduling results instable. In this paper, we propose a novel two-phase Adaptive Energy-efficient Scheduling (AES), which combines the Dynamic Voltage Scaling (DVS) technique with the adaptive task duplication strategy. The AES algorithm justifies threshold automatically, thus improving the system flexibility. In the first phase, we propose an adaptive threshold-based task duplication strategy, which can obtain an optimal threshold. It then leverages the optimal threshold to balance schedule lengths and energy savings by selectively replicating predecessor of a task. Therefore, the proposed task duplication strategy can get the suboptimal task groups that not only meet the performance requirement but also optimize the energy efficiency. In the second phase, it schedules the groups on DVS-enabled processors to reduce processor energy whenever tasks have slack time due to task dependencies. To illustrate the effectiveness of AES, we compare it with the duplication-based algorithms and the DVS-based algorithms. Extensive experimental results using the real-world applications demonstrate that our algorithm can effectively save energy while maintaining a good performance.

Optimization of smart microgrid considering domestic flexible loads

The generated power is adjusted on the base of the predicted energy demand for near future, in the existing power systems. In other words, the generated energy follows load profile to meet the energy demand. There is no control over the loads except load shedding which may happen during the fault incidents or peak energy demand. Integration of renewable energy sources into the grid, has introduced further complexity in the above mentioned strategy of following the load curve. Main renewable energies like wind or solar power are not accurately predictable. The uncertain amount of the generated energy necessitate the increase in the generation and storage capacity of the energy by constructing bigger or more number of power plants and energy storage facilities. This will increase cost, pollution, and number of turning off/on of the power plants. Identification and appropriate control of flexible loads can be employed to balance energy generation and demand. In other words contrary to the traditional methods, the proposed method will enable the system to meet the demand not only by changing the generated energy but also by controlling the loads when necessary. Also utilizing flexible loads will significantly reduce energy loss of the storage equipments. Instead of storing energy to be used later, flexible load can consume that energy whenever is needed. In this paper, we consider smart microgrid consist of wind turbines, solar panels, fuel cells, electrolyzers, and smart appliance. In this study, we consider washing machines as flexible loads and we want to manage and control these loads to reduce sizes of generation units, buying and selling energy from distribution grid and total cost of smart microgrid. This study is performed for Ekbatan residential complex Tehran, Iran.

Amino acid coevolution induces an evolutionary Stokes shift

The process of amino acid replacement in proteins is context-dependent, with substitution rates influenced by local structure, functional role, and amino acids at other locations. Predicting how these differences affect replacement processes is difficult. To make such inference easier, it is often assumed that the acceptabilities of different amino acids at a position are constant. However, evolutionary interactions among residue positions will tend to invalidate this assumption. Here, we use simulations of purple acid phosphatase evolution to show that amino acid propensities at a position undergo predictable change after an amino acid replacement at that position. After a replacement, the new amino acid and similar amino acids tend to become gradually more acceptable over time at that position. In other words, proteins tend to equilibrate to the presence of an amino acid at a position through replacements at other positions. Such a shift is reminiscent of the spectroscopy effect known as the Stokes shift, where molecules receiving a quantum of energy and moving to a higher electronic state will adjust to the new state and emit a smaller quantum of energy whenever they shift back down to the original ground state. Predictions of changes in stability in real proteins show that mutation reversals become less favorable over time, and thus, broadly support our results. The observation of an evolutionary Stokes shift has profound implications for the study of protein evolution and the modeling of evolutionary processes.

Door based Power Generation System and Automatic Opening of Door

As the world is advance in various fields like research and development; conservation of energy is very important aspect. Due to shortage of electricity in the rural areas as well as developing cities saving of energy is an important factor so we have to save the energy whenever as possible. To conserve energy we have taken the step and introduce a new concept ‘ELECTRICITY GENERATION WITH THE HELP OF DOOR’. In this concept conversion of mechanical energy from opening a door into electrical energy for backup power supply is studied. The green energy solution makes use of an everyday occurrence to protect against intermitted power loss. The energy you expend by pushing a revolving door you can convert into electrical energy that is usable. For example at Hospitals, Banks, Post offices, Hotels or the use of door is frequent etc. Our aim is to convert small amounts of human energy into electricity by use of generator. The Revolution Door and Electrical component are of two prototype devices with mechanical/electrical systems that harnesses human motion and redistribute it as electricity. This source of power can be used at the offices, colleges or Hotels and most likely by the Hospitals door operating system. Also by accumulating this low intensity electricity in Batteries, it can be supplied to the Big villages or in towns where there is scarcity of electric supply.