Electric Source Research Articles

Influence of supply temperature and booster technology on the energetic performance and levelized cost of heat of a district heating network with central heat pump

The development of new low-temperature district heating networks in existing urban areas can accelerate the replacement of fossil-fuel-based heating systems by collective heating using electricity or renewable heat sources. Buildings can either be connected to the network in their current, non-refurbished state for rapid deployment or be refurbished before connection to achieve maximum energy efficiency. To assess the difference between these two strategies, this paper examines eight low-temperature district heating concepts with central heat pump, comparing their energy use and levelized cost of heat. The study includes four scenarios for each strategy, considering supply temperatures ranging from 10 °C to 75 °C. Heat pumps or electric heaters are used as booster technology when the network supply temperature is too low for space heating or domestic hot water purposes. The use of booster heat pumps shows the highest seasonal coefficient of performance for both refurbished (4.61) and non-refurbished buildings (3.43). However, booster technologies result in the highest levelized cost of heat, driven mainly by the high investment cost of the network and booster units. Lowest levelized cost of heat of 213 €/MWhth is obtained for non-refurbished buildings at 75 °C and 297 €/MWhth for refurbished buildings at 55 °C without boosters.

Energy and Environmental Aspects of the Sustainability of Clothing Production

The textile and clothing industries are very often lumped together when it comes to the environmental aspect such that the negative connotation of the textile industry from an environmental aspect is automatically transferred to the clothing industry. However, the two industries should be considered separately, particularly with regard to the machinery used and energy consumption in the production process. The energy consumption of electricity, compressed air, vacuum, steam, and other energy sources in the clothing industry is low compared to other related industries. Furthermore, no carcinogenic and allergenic waste is generated during the production of clothing, which has a low carbon footprint, i.e., it practically does not pollute the air, soil, and water. The waste produced during cutting is clean and unused and is immediately recycled. All of this contributes to the sustainability of the clothing industry from the energy and environmental aspects. This article describes the cutting and joining techniques used in the manufacture of clothing, from the energy and environmental aspects as well as aspects of the weaves, the necessary machine elements and mechanisms, and the energy used in all joining techniques, from which the above claims and facts can be seen.

Impacts of Solar Home Systems in Rural Areas: A Case Study in Bangladesh

Access to electricity is important for development in general, but access at low costs is a vital tool of economic and social development, especially for those locations that lie very far from the grid. The present study investigates the impacts of solar home systems in a rural area of Bangladesh, focusing on the ways in which the adoption of SHS transforms household livelihoods. It has improved the lives of the community members through an affordable and reliable source of electricity that allowed enhanced lighting and security, increased educational opportunities, empowerment of women, reduced reliance on harmful energy sources, increased economic productivity, environmental sustainability, human relationships and well-being. These studies emphatically underscore the fact that the biggest challenge remains affordability: in most instances, SHS is accessed through family savings or loans from NGOs. In spite of these barriers, SHS has conventionally been portrayed as an empowering tool that enhances the quality of life and aids in fulfilling the goals of sustainable development in rural areas. The paper concludes by relating conventional energy sources with a comparison, emphasizing broader benefits and possible long-term potentials for SHS in tackling energy poverty within rural Bangladesh.

Production and recycling of blast furnace slag: A life cycle assessment approach in India

AbstractThis article investigated the cradle‐to‐gate environmental impact of granulated blast furnace slag (GBFS) produced in the steel industry and replacement of blast furnace (BF) slag (50%) in place of clinker in Portland slag cement using GaBi software (Indian extension database). In case of GBFS production, maximum burden on the environment is due to BF slag production and the amount of electricity consumed (161 MJ/ton) during the granulation process. The influence of electricity sources on GBFS production was studied via scenario analysis. For investigation, solar and thermal electricity mixes were considered in 50:50 and 75:25 ratios. For the 75:25 ratios, the abiotic depletion potential (fossil), acidification, eutrophication, global warming, and human toxicity potential show a decreasing trend of approximately 45%, 49%, 48%, 46%, and 41%, respectively. The scenario analysis of BF slag transportation (from 100 to 750 km) demonstrates a negative impact due to fuel. The results quantitatively confirm that the addition of GBFS can lower the overall impact for construction and steel industries.

An Analysis of a Complete Aircraft Electrical Power System Simulation Based on a Constant Speed Constant Frequency Configuration

Recent developments in aircraft electrical technology, such as the design and production of more electric aircraft (MEA) and major steps in the development of all-electric aircraft (AEA), have had a significant impact on aircraft’ electrical power systems (EPSs). However, the EPSs of the latest aircraft produced by the main players in the market, Airbus with the Neo series and Boeing with the NG and MAX series are still completely traditional and based on the constant speed constant frequency (CSCF) configuration. For alternating current ones, the EPS is composed of the following: prime movers, namely the aircraft turbofan engine (TE); the electrical power source, i.e., the integrated drive generator (IDG); the command and control system, the generator control unit (GCU); the transmission and the system distribution system; the protection system, i.e., the CBs (circuit breakers); and the electrical loads. This paper presents the analysis of this system using the Simscape package from Simulink v 8.7, a MATLAB v 9.0 program, which is actually the development of some systems designed in two previous personal papers. For the first time in the literature, a complete MATLAB modelled EPS system was presented, i.e., the aircraft turbofan engine model, driven by the constant speed drive system (CSD) (model presented in the first reference as a standalone type and with different parameters), linked to the synchronous generator (SG) (model presented in second reference for lower power and rotational speed) in the so-called integrated drive generator (IDG) and electrical loads.

Sustainable operation of large scale heat pumps in cogeneration dominated district heating networks

Large scale heat pumps (LSHP) have seen a rapid proliferation in recent years, with projects and initiatives aimed at integrating electrically driven LSHP into existing district heating networks (DHN). The financial advantages have driven most LSHP installations to be powered by electricity generated by on-site cogeneration (CHP), given CHP’s dominant role in DHN. This LSHP + CHP combination poses the question, to what extent ecological improvements, measured as a reduction in specific CO2 emissions through LSHP operation can be achieved, contingent on the source of electricity and heat source employed. In this paper, the LSHP + CHP combination was generally analysed under usage of exergy analysis and a 2nd law derived method is presented. This method allows to evaluate the magnitude of CO2 reduction through LSHP operation across all common heat sources in 1st to 4th generation DHNs in conjunction with CHP. Results show, that in LSHP + CHP combination, heat from LSHP using either of the 2 heat sources ambient air or surfaced water, inevitably comes with higher specific CO2 emissions over the CHP heat. Only when using a sufficiently hot and emissions-free heat source, the LSHP heat from a LSHP + CHP combination can yield to an annual best case of half the CO2 emissions of the CHP. Importantly, the choice of power source has a far more significant impact, as LSHP powered by electricity from renewable energy sources achieve more than an eight-fold reduction in emissions compared to the LSHP + CHP combination. Therefore, power consumption with sufficiently low specific CO2 emissions out of external source is imperative to fully realize the ecological benefit of LSHP in DHN, underlining that the successful heat transition through LSHP relies heavily on the transformation of the electricity supply.Graphical

The Problem of Power Variations in Wind Turbines Operating under Variable Wind Speeds over Time and the Need for Wind Energy Storage Systems

One of the most important and efficient sources of green electricity is catching air currents through wind turbine technology. Wind power plants are located in areas where the energy potential of the wind is high but it varies. The time variation of the wind generates fluctuations in the power produced by the wind farms that is injected into the grid. This elevates, depending on the intensity, problems of network stability and the need for balancing energy, thus raising both technical and cost issues. The present paper analyzes the behavior of a wind turbine (WT) over time in varying wind speed conditions, highlighting that without automation algorithms, a WT is far from the operation at the maximum power point (MPP). However, even when it is brought to operate at MPP, there are still significant variations in the power injected into the network. These power variations can be compensated if the wind system has energy storage facilities for the captured wind. All of these assumptions are analyzed using improved mathematical models and processed in simulations, with experimental data used as input from a wind turbine with an installed power of 2.5 [MW] in operation on the Romanian Black Sea coastal area. Consequently, the paper demonstrates that during an operation in the optimal area, from an energy perspective, the wind turbine’s maximum power point requires a storage system for the captured wind energy.

Fuel cells – converting ethanol chemical energy into electricity

The growing demand for stable energy sources related to today's armed conflicts and increasingly frequent natural disasters related to the ongoing climate change has increased interest in alternative sources of electricity. This research aimed to compare different concentrations/types of ethanol in the process of converting chemical energy into electric current using fuel cells. It was found that fuel cells can be used as an emergency energy source. The highest efficiency was obtained with the use of low concentrations of alcohol, between 5 and 10 %. The highest cell power was obtained using denatured alcohol (168.9 mW).

Time-dependent Aharonov-Bohm type topological effects on dipoles

Exploring the time-dependent characteristics of AB-type effects holds significant importance in contemporary physics and its practical applications. Here, we delve into the investigation of time-dependent topological effects emerging in AB-type experimental setups. We first analyse the topological effects on magnetic dipoles moving in closed trajectories around the time-varying magnetic field source solenoid, then on electrical dipoles around a time-varying electric field source in 2+1 dimensions without any approximation. Last, we discuss the characteristics of the topological effects by considering the identity and dualities between phases from an integrated perspective.

Off-grid PV/biomass/DG/battery hybrid renewable energy as a source of electricity for a farm facility

Reliable, cost-effective energy systems are pivotal for sustainable development in the agricultural sector. Using the energy balance analysis of the Hybrid Optimization Model for Electric Renewable (HOMER), this study presents a techno-economic assessment of a hybrid renewable energy system for a farm facility. The energy system components considered in the analysis include solar photovoltaics, wind turbines, diesel generators, biomass, and battery storage. The results shows that ten feasible energy systems can technically power the typical farm facility, with a PV-Biomass-DG battery being the best in terms of the total net present cost. The PV-Biomass-DG-battery systems consist of 561.023 kW of PV, 88 kW of diesel generator, 10 kW of biomass, 81 kW of converter, and 584 batteries operated in a load-following mode. When the cost of energy (COE) of EA1 0.206325 $/kWh is compared to EA7 0.407681 $/kWh, a difference of $0.201356 will be saved for every kWh. Also, a comparison of the operating cost of EA1, $65,713.23 and the operating cost of EA7 $212,027.4 showed a margin of $146,314.17 being saved. Energy systems EA3 and EA4 had the lowest carbon dioxide production levels of 15.8 kg annually, respectively. The simple payback period metrics increased from EA1 to EA6 between 2.97 years to 6.99 years. The result of the study shows that adopting a low-carbon energy transition is technically and economically viable for the agricultural sector, especially in developing countries.

Impacts of Plug-in Electric Vehicles and Renewable Energy Source on Unit Commitment Problem using Cat Mouse Based Optimization A lgorithm

Objectives: The main objective of this paper is to solve the Cost Based Unit Commitment (CBIC) problem considering Renewable Energy Sources (RES) and Plug-in Electric vehicles (PEVs). The proposed problem minimizes the total operating of the interconnected system. Methods: A novel and recently developed successful optimization tool of Cat and Mouse Based Optimizer (CMBO) is proposed for optimal solution of Cost Based UC problem. The proposed CMBO approach is having two groups such as Cat group and Mice group for searching the global optimal solution with less computational time. It contains two phases like Cat’s movement towards Mice and Mice escape to a safe place is effectively updating the new position of Cat and Mice to easily reaching the best solutions. The control parameter of CMBO is number of agents is 50, number of variables is 10 and maximum number of iteration is 500. MATLAB 14.0 platform is utilized for the projected problem. Findings: The method tested on standard IEEE-39 bus system (10 generators and 24 hour) with an equivalent PEV and Wind farm. The CMBO approach minimize the total operating cost with various test cases. The outcomes such as UC schedule, Real power output of thermal, wind and PEV units, fuel cost, startup cost and total operating cost of the interconnected system are numerically and graphically reported. The total operating cost is 4.11 % minimized when compared with base case approach and 0.73 % reduced than the other existing method viz. Parallel UCs-RP method. Novelty: The CMBO is recently developed powerful optimizer and parameter free algorithm, so easily reaches the global optimal solutions. The obtained simulated results are compared with other mathematical and intelligent computational approaches for proving the efficiency and performance of the proposed CNBO technique. Keywords: Unit Commitment, Plug­in Electric Vehicles, Renewable Energy Sources, Cost minimization, Cat and Mouse Based Optimizer

Natural gas as a generating source in the diversification of the Brazilian electric matrix

Energy consumption grows annually, requiring an increase in the production and distribution standards of available energy sources. One of the main energy consumptions is linked to the electricity sector, which is globally dependent on fossil fuels such as oil and coal. In Brazil, more than 60% of electricity consumption comes from hydroelectric plants, and the lack of variability in generating sources generates instability and energy insecurity in the country. In this sense, it is necessary to evaluate an alternative source of electricity that can work together with hydroelectric plants and guarantee the stability of generation. Natural gas presents itself as an alternative, as it is a safe source and less aggressive to the environment when compared to other non-renewable sources. Through data collection and bibliographic research on proven reserves, processing capacity, and distribution of natural gas, this work analyzed the Brazilian potential for the use of natural gas and the biggest gaps in the sector. The results showed that, despite the great potential in proven natural gas reserves, Brazil is stagnant in its processing and distribution capacity. In addition, there are challenges related to high rates and taxes on the use of natural gas.

Doubly special relativity as a nonlocal quantum field theory

In this work, we explore the quantum theories of the free massive scalar, the massive fermionic, and the electromagnetic fields in a doubly special relativity scenario. This construction is based on a geometrical interpretation of the kinematics of this kind of theory. In order to describe the modified actions, we find that a higher (indeed infinite) derivative field theory is needed, from which the deformed kinematics can be read. From our construction, we are able to restrict the possible models of doubly special relativity to those that preserve linear Lorentz invariance. We quantize the theories and also obtain a deformed version of the Maxwell equations. We analyze the electromagnetic vector potential for both an electric pointlike source and magnetic dipole. We observe that the electric and magnetic fields do not diverge at the origin for some models described with an anti–de Sitter momentum space, but they do for a de Sitter space in both problems. Published by the American Physical Society 2024

Self‐Potential Tomography Preconditioned by Particle Swarm Optimization—Application to Monitoring Hyporheic Exchange in a Bedrock River

AbstractA self‐potential (SP) data‐inversion algorithm was developed and tested on an analytical model of electrical‐potential profile data attributed to single and multiple polarized electrical sources. The developed algorithm was then validated by an application to SP‐monitoring field data measured on the floodplain of East Fork Poplar Creek, Oak Ridge, Tennessee, to image electrical sources in areas conducive to preferential flow into the flood plain from the bedrock‐lined riverbed. The algorithm combined stochastic source‐localization by particle‐swarm‐optimization (PSO) of electrical sources characterized by simplified geometries with source tomography by regularized weighted least‐squares minimization of a quadratic objective function. Prior information was incorporated by preconditioning the tomography algorithm by PSO results. Variable percentages of random noise were added to analytical‐model data to evaluate the algorithm performance. Results indicated that true parameters of single‐source models were inverted and approximated with small residual error, whereas inversion of analytical‐model data representing multiple electrical sources accurately approximated the locations of the sources but miscalculated some parameters because of the non‐uniqueness of the inverse‐model solution. Source tomography applied to analytical model data during testing produced a spatially continuous parameter field that identified the locations of point‐scale synthetic dipole sources of electrical current flow with varying degrees of accuracy depending on the prior information incorporated into the tomography. When applied to SP‐monitoring field data, the algorithm imaged electrical sources within a known fault that intersects the bedrock riverbed and flood plain of East Fork Poplar Creek and depicted dynamic electrical conditions attributed to hyporheic exchange.

Awareness of Campus Building Users to Achieve Energy Efficiency in Facing the Implementation of Green Buildings (Case Study: Politeknik Negeri Pontianak Integrated Lecture Building)

Abstract Building users’ awareness is a very crucial factor in efforts to achieve efficient energy use in buildings, especially in the green building concept. However, research that examines the awareness of building users specifically in the campus environment is still very rarely conducted, especially in Indonesia. This research, which uses a case study at Politeknik Negeri Pontianak integrated lecture building, investigates the criteria for awareness of building users and their behavior in using energy in the building. This research tries to identify social parameters in achieving building energy efficiency using a quantitative approach. The series of statistical tools used includes ranking of average values. The results of this research show that the focus of improvement can be done by increasing awareness of several things, namely recognizing the problem of decreasing electrical resources, dividing resource use in order to reduce electricity consumption, and understanding efforts and making preparations in the face of reduced electrical energy sources.

Development of Small Modular Reactor iPWR Dynamics Simulator

Abstract In the energy transition era, nuclear power serves as a significant source of electricity with low emissions, contributing to approximately 10% of the world’s total electricity production. The advanced and distinct features of iPWR-type SMR in the field of nuclear power generation contribute to a greater safety margin. This opens up possibilities for extending the utilization of secure, environmentally friendly, and dependable nuclear energy across various energy sectors. Moreover, the public need to understand the technical performance of the iPWR. To improve understanding of iPWR’s technical performance, a simulator is developed. The simulator is developed to provide a comprehensive study of nuclear reactor transient behavior, to serve as an educational tool for students, and to demonstrate the safety features during accident scenarios. This article introduces a simulator that combines modules of neutronics, reactor thermal-hydraulics, and the NSSS. The simulator uses the design parameters of iPWR with a power capacity of 160 MWt that relies on natural convection. The proposed simulator was developed using LabVIEW software to perform the reactor dynamics calculations. Furthermore, hardware devices for controlling the simulator can be integrated to simulate the control room of an NPP. The calculation was based on the standard lumped parameter point kinetics and thermal-hydraulic equations. To simplify the process and reduce computational cost, several assumptions are incorporated into the equations, including one-group thermal neutron and constant gain thermal power. The simulator development yields preliminary data for reactor calculations, the graphical user interface (GUI) of the simulator, and the Virtual Instruments (VIs) comprising the reactor model. The reactor model comprises multiple components, each represented as a subVI within the LabVIEW environment. This simulator serves as an effective educational and dissemination tool for increasing public acceptance of NPP by providing insights into the behavior of the reactor and facilitating a better understanding of its operation, safety features, and potential benefits.

ANALIZA PRELIMINARĂ DE VALORIFICARE A SISTEMELOR FOTOVOLTAICE INTEGRATE ÎN CLĂDIRI LA ÎNTREPRINDERILE TERMOENERGETICE

The research carried out in this paper focuses on the study of the integration of photovoltaic panels into buildings, a solution known as BIPV (Building Integrated Photovoltaics), which represents a new form of solar energy use: these are building materials, but these also facilitate the generation of solar electricity on additional surfaces and allow an optimisation of the overall operation as a main source of electricity and can also be seamlessly integrated into the building envelope and its components. In the paper, the opportunities for development of building-integrated photovoltaic systems at thermal power enterprises were analysed, using concrete data of the JSC "CET-Nord" in the Republic of Moldova as an example for further research, as well as determining the potential photovoltaic capacity of administrative and production buildings of the enterprise. This will help to improve the understanding of the impact of BIPV systems on the energy transition of cities and on the notion of near-zero energy cities in Europe, by identifying possible future approaches to BIPV that can be used by energy specialists as well as architects and urban planners to assess how much of the energy used by buildings could be provided by BIPV systems when implemented as building envelope materials across the entire building envelope.

Global Wind-Power Generation Capacity in the Context of Climate Change

Establishing power systems with a high share of renewable energy sources is a pivotal step toward achieving a globally sustainable transition to green and low-carbon energy. This study focuses on low-output wind power that affects the generation capacity of power systems with a high share of renewable energy sources. Utilizing the Coupled Model Intercomparison Project Phase 6 datasets, a predictive model for low-output wind power was employed to investigate regional trends worldwide. The frequency and duration of low-output wind-power events exhibited increasing trends globally, particularly in East Asia and South America, but not in North America. By 2060, the annual total days with low-output wind power in East Asia and South America could rise to 13 and 5 d, and the maximum continuous duration of low-output wind power could reach 5 and 2 d, respectively. As wind power becomes a primary electricity source, such low output could lead to shortages in energy supply within the power system, triggering large-scale power outages. This issue calls for critical attention when establishing power systems with a high share of renewable energy sources. The conclusions provide a basis for analyzing power supply risks and configuring flexible power sources for scenarios with a high share of renewable energy.

Analysis of the Influence of Electricity Generation Mix on CO2 Emissions from Electric Vehicles in Europe

The rise in population mobility, with the dominant modal share of passenger vehicles, is particularly concerning due to its negative impact on the environment. Environmental issues caused by internal combustion engine (ICE) vehicles are increasing, as evidenced by the fact that road transport is responsible for 22% of total CO2 emissions. In this context, although electric cars do not emit harmful substances directly, power plants that generate electricity from various sources contribute significantly to these emissions. To determine the impact of electric vehicles on the environment, this study conducted a comparative analysis of gCO2/km emissions depending on the type of vehicle engine (petrol, diesel, and electric) across different European countries, based on their electricity sources. For more representative results, the comparison was made using the same make and model of car-Volkswagen e-Golf (electric car) and Golf 7 with diesel and petrol ICE engines. The results indicate that in Serbia, electric vehicles emit slightly less CO2 compared to diesel and petrol vehicles of similar characteristics. However, the difference is very small compared to diesel engines, amounting to only 3 gCO2/km.

Optimal Control Strategy for Power Management Control of an Independent Photovoltaic, Wind Turbine, Battery System with Diesel Generator

The need for a greater supply of energy from sustainable sources is growing because of increasing energy prices, concerns about nuclear power, climate change, and power grid disruptions. This research offers a method for the balance of power management of a combination of multi-source DC and AC supplier systems that enables sources of clean energy based on an independent grid to function economically and with the highest levels of system predictability and stability possible. The DC microgrid's hybrid generation source consists of a diesel power source, wind, photovoltaic (PV) power, and a battery bank. The energy system can fulfill the load demand for electricity at any moment by connecting various renewable sources. It can function both off and on the grid. The microgrid may occasionally not be able to provide sufficient electricity, while every green energy source's electricity contribution is based on how its supply varies and how much power is needed to meet demand. As a result, a diesel generator is required as additional backup power, particularly while operating off-grid. This paper designs and implements an MPPT technique for a PV system based on the GWO algorithm. By creating PWM pulses in response to variations in the PV panel voltage, this method modifies the converter's duty cycle, while wind turbines using MPPT based on P&O, to get the most out of hybrid energy sources that are renewable while simultaneously enhancing the quality of power. The priority sources of electricity for the grid are photovoltaics and wind power. Based on the results of simulations and experiments, the proposed control method for DC, which uses the MPPT approach, can dynamically switch between all of the system's various modes of operation, independent of the battery's condition or environment, ensuring safe operation and constant bus voltage. An analysis was conducted on the suggested system's performance. It has been noted that compared to the conventional approaches, the suggested GWO-based MPPT methodology is quicker and produces fewer MPP oscillations. It offers a more effective reaction to quickly shifting atmospheric conditions. Results of simulation for the recommended control scheme with MATLAB/Simulink.