Article
Construction & Building Technology
Lijie Wang, Jun Zhao, Zuhua Xu, Fei Zhao, Chunyue Song, Chao Yang, Zhijiang Shao
Summary: The use of heat storage capacity of a district heating network (DHN) can improve the volatility of the power grid, but solving the partial differential equations (PDEs) describing the thermodynamics and heat transfer behavior of DHN system leads to a high computational complexity problem. A data-driven model called Gaussian interpolated spatiotemporal Volterra model is proposed, which can fit the input-output characteristics of the DHN system without requiring the thermodynamic model and parameters of DHN. By adding heat storage capacity as new dispatch variables to the operation schedule of the integrated energy system, the optimization results demonstrate the superiority of wind power accommodation and effectively reduce the computational burden by avoiding the PDEs solving problem of DHN.
ENERGY AND BUILDINGS
(2023)
Article
Thermodynamics
Stanislav Chicherin, Aleksander Starikov, Andrey Zhuikov
Summary: The aim of this paper is to propose a method to make low temperature district heating (LTDH) more feasible by utilizing operational data. The total network cost, compared to traditional systems, increases by 28.4% using design data only. However, a new assessment shows that the cost to modernize the DH network is only 18.6 million EUR, with 12.9% savings. Operational data, including network and outdoor temperatures, flow rate, and pressure, leads to more accurate evaluation. Adjusting heat demands and supply/return temperatures closer to operational values brings positive effects, outweighing the negative impact of higher pressure drop.
Article
Energy & Fuels
Juliane Schmidt, Peter Stange
Summary: The software tool introduced in this study supports decision makers and network planners in finding the cost optimal design for district heating networks. It incorporates user defined cost data, geo-referenced input, and technical boundary conditions for optimization. The tool can consider various constraints like existing networks and obstacles, and typically leads to an unmeshed network structure to ensure uninterrupted service.
Article
Thermodynamics
Jaros law Mikielewicz, Dariusz Mikielewicz
Summary: The paper compares a traditional district heating system with conventional boilers to a low temperature DH system that incorporates CHP and the organic Rankine Cycle to produce both electricity and heat within the system. A developed analytical model is used to analyze the efficiency of the systems, although only simplified examples are provided in this paper.
Article
Energy & Fuels
Olaia Eguiarte, Antonio Garrido-Marijuan, Roberto Garay-Martinez, Margus Raud, Indrek Hagu
Summary: Recently, there has been a trend towards reducing temperatures in district heating networks to improve sustainability. However, there is still insufficient knowledge on how to successfully transition to a low temperature district heating system while maintaining operational levels. This paper presents the experience of gradually reducing temperatures in a district heating subnetwork in Tartu, Estonia from 2018 to 2021. Heat meter data was used extensively to assess the capacity of substations and network branches, leading to targeted improvements and interventions. The ongoing process has shown a 4.8% reduction in network heat loss through a temperature decrease of 7 degrees Celsius.
Article
Thermodynamics
Hjoerleifur G. Bergsteinsson, Phillip B. Vetter, Jan Kloppenborg Moller, Henrik Madsen
Summary: This paper proposes a method for estimating network temperatures using smart meter data, and using these temperatures to estimate network characteristics. Compared to traditional physical measurement methods at critical points, this method eliminates the need for actual physical critical points and allows for changing the location of critical points if needed. The proposed method utilizes a stochastic state-space model and maximum likelihood estimation, with the Kalman Filter used to evaluate the likelihood function.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
A. Khosravi, T. Laukkanen, V. Vuorinen, S. Syri
Summary: The city of Espoo, Finland is planning to develop Kera as a green suburb with high energy efficiency and low CO2 emissions. The study found that the heat pump scenario is an efficient and cost-effective way to retrieve waste heat from the data center and 5G smart poles.
Article
Construction & Building Technology
Ding Mao, Peng Wang, Yuchen Ju, Long Ni
Summary: This study proposes a model for evaluating the failure consequences of district heating networks and verifies its effectiveness. The failure consequences are most influenced by maintenance time, and reducing maintenance time can reduce property economic losses.
SUSTAINABLE CITIES AND SOCIETY
(2022)
Article
Engineering, Electrical & Electronic
Tian Lan, Kai Strunz
Summary: This paper discusses the importance of using thermal energy storage to maintain the supply temperature in a district heating system. It proposes a concept and implementation of droop control based on the power sharing relationship between the temperature of the district heating water and other thermal energy resources. The functionality of the control is demonstrated through application to a residential district heating network model using the simulation program PSCAD.
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
(2023)
Article
Thermodynamics
Stanislav Chicherin, Amjad Anvari-Moghaddam
Summary: This study investigates variations and peak values of actual heat demand profiles in a centralized district heating network. It reveals that there is almost no weather correlation during warm months with supply temperatures exceeding 60 degrees C, and that thermal inertia of buildings affects their behavior differently in terms of needed space heating. By using precise heat demand data to design thermal energy storage units or district heating plants, DH operators can reduce energy prices and save energy fees for end-users by implementing weighted moving average strategies and advanced control techniques.
Article
Construction & Building Technology
Ding Mao, Peng Wang, Yi-Ping Fang, Long Ni
Summary: This study analyzes the structure, function, operation, and failure characteristics of district heating networks (DHNs) and proposes vulnerability analysis methods. The effectiveness of these methods is validated through application to a DHN in a Chinese city. The study finds that the heat source connectivity efficiency loss rate effectively characterizes topological and functional vulnerability. It also reveals that controllable DHNs have higher functional vulnerability under large area failure scenarios.
SUSTAINABLE CITIES AND SOCIETY
(2024)
Article
Energy & Fuels
Ivan Postnikov
Summary: District-distributed heating systems integrate various energy technologies to achieve maximum heating efficiency to consumers. Prosumers play a key role in the distributed sector of these systems. This study focuses on determining the reliability parameters of system components to ensure the required level of reliability at the minimum cost, considering the redundancy of prosumers. The methodology includes the nodal probability of failure-free operation index, Markov random process, laws of heat transfer, and other methods. A case example is presented, results are analyzed, and future research directions are proposed.
Article
Thermodynamics
Martina Capone, Elisa Guelpa, Vittorio Verda
Summary: Reducing operating temperatures in district heating networks is crucial for integrating low exergy heat and achieving sustainability. This paper analyzes the potential temperature reduction in existing substations and develops a methodology to estimate the achievable temperature reduction. The results show that existing substations can shift their operation from 120°C to 104°C and achieve supply temperatures around 90°C with some improvements on the system.
Article
Energy & Fuels
Ivan Postnikov, Ekaterina Mednikova
Summary: This article examines the relevance of fuel supply reliability to heat sources in district heating systems. It proposes a methodical approach for assessing potential fuel shortages in the fuel supply system using statistical tests or the Monte Carlo method. An algorithm is developed to evaluate the reliability of the fuel supply system, accounting for various modeling conditions such as current fuel reserves and fuel interchangeability between heat sources. Computational experiments are conducted, and some results are presented. Conclusions and directions for further research are provided.
Article
Thermodynamics
Guoqiang Liu, Xuan Zhou, Junwei Yan, Gang Yan
Summary: This study proposed a temperature and time-sharing dynamic control approach for building space heating, integrating three energy-saving heating patterns to address the issue of poor indoor temperature control. Experimental results showed that the approach could save annual heat use by 14.6%-28.7% and yield considerable economic and environmental benefits.
Article
Engineering, Mechanical
R. Janulionis, G. Dundulis, A. Grybenas
Summary: The paper presents a numerical methodology for determining the elastic-plastic fracture toughness of steel P91, validated through experimental tests. Additionally, the study evaluates the impact of thermal ageing on the elastic-plastic fracture toughness of the steel, showing up to a 20% decrease in J(Q) values after ageing at 650 degrees C for approximately 10900 hours.
ENGINEERING FAILURE ANALYSIS
(2021)
Article
Nuclear Science & Technology
Andrius Slavickas, Raimondas Pabarcius, Aurimas Tonkunas, Sigitas Rimkevicius
Summary: Neutron transport simulations of RBMK-1500 fuel assembly were conducted using multigroup and continuous energy data libraries within the SCALE system, showing differences in the estimation of RBMK neutronic characteristics. The CE library based on ENDF/B-VII.1 data was identified as the best alternative for neutron transport simulations of the RBMK fuel assembly.
SCIENCE AND TECHNOLOGY OF NUCLEAR INSTALLATIONS
(2021)
Article
Materials Science, Multidisciplinary
Matthias Bruchhausen, Gintautas Dundulis, Alec McLennan, Sergio Arrieta, Tim Austin, Roman Cicero, Walter-John Chitty, Luc Doremus, Miroslava Ernestova, Albertas Grybenas, Caitlin Huotilainen, Jonathan Mann, Kevin Mottershead, Radek Novotny, Francisco Javier Perosanz, Norman Platts, Jean-Christophe le Roux, Philippe Spatig, Claudia Torre Celeizabal, Marius Twite, Marc Vankeerberghen
Summary: The European INCEFA-PLUS project investigated the fatigue life of austenitic steels and found that mean strain and hold time have minimal impact on fatigue life. An empirical model describing fatigue life was developed, and there were statistically significant interaction effects between surface roughness and the environment, as well as between surface roughness and strain range, though their practical relevance is small.
Article
Mechanics
Isaac Solomon, Evaldas Narvydas, Gintautas Dundulis
Summary: The mechanical properties and fatigue predictions of D16T aluminum alloy specimens were studied through experimental and numerical simulations, along with the demonstration of the influence of holes in engineering components.
Article
Green & Sustainable Science & Technology
Robertas Alzbutas, Mindaugas Vaisnoras, Inga Saruniene, Ricardas Krikstolaitis, Mindaugas Valincius, Egidijus Babilas, Juozas Augutis, Sigitas Rimkevicius, Tomas Iesmantas, Feliksas Anusauskas, Lauras Mataitis
Summary: Understanding the hazards and risks of an oil terminal is crucial for implementing safety measures, while also considering potential consequences and risk reduction strategies.
Article
Energy & Fuels
Linas Martisauskas, Juozas Augutis, Ricardas Krikstolaitis, Rolandas Urbonas, Inga Saruniene, Vytis Kopustinskas
Summary: This paper presents a framework for assessing the resilience of energy systems using quantitative indicators and demonstrates the future foresight capabilities and potential of selected resilience indicators through calculations for the Lithuanian energy system. The results reveal that a diverse electricity production mix and supply and production diversification in the prospective energy system are the most important factors impacting energy system resilience.
Article
Nuclear Science & Technology
Audrius Grazevicius, Marijus Seporaitis, Mindaugas Valincius, Algirdas Kaliatka
Summary: Most numerical investigations of thermal-hydraulic phenomena following the loss of residual heat removal capability during mid-loop operation of pressurized water reactors have been performed using simplifications that lack accuracy. A more detailed methodology is needed to accurately predict thermal-hydraulic accidents in nuclear power plants. Modelling results and experimental data confirm the existence of thermal stratification and natural convection.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2022)
Article
Nuclear Science & Technology
Valdas Ragaisis, Tadas Kaliatka, Povilas Poskas, Algirdas Kaliatka, Arturas Smaizys, Remigijus Janulionis, Ernestas Narkunas, Arunas Sirvydas, Egidijus Babilas, Sigitas Rimkevicius
Summary: This paper discusses the evaluation method for radiological consequences to the public in the event of a large aircraft crash at RBMK nuclear power plants during decommissioning and dismantling stages. The evaluation includes structural damage, fire propagation, spent nuclear fuel cooling capability, airborne radionuclide release, radionuclide dispersion, and public exposure. Widely used software and methods for specific tasks are also discussed.
PROGRESS IN NUCLEAR ENERGY
(2022)
Article
Nuclear Science & Technology
Andrius Slavickas, Tadas Kaliatka, Raimondas Pabarcius, Sigitas Rimkevicius
Summary: RBMK fuel assemblies differ from other LWR FA due to specific fuel rod arrangement, low enrichment, and the use of erbium burnable absorbers. Testing 10 different depletion simulation schemes helped to estimate the impact of possible SCALE code options and different nuclear data libraries on reactivity and spent fuel composition.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Remigijus Janulionis, Gintautas Dundulis
Summary: Residual stresses are often caused by heterogeneous deformations and can occur during manufacturing, repair, or due to operational loads. Understanding and considering these stresses is important in evaluating the structural integrity of low-toughness materials or in cases of fatigue and stress corrosion cracking. Numerical modeling and finite element analysis were used to calculate the stress intensity factors along the crack front of pre-strained stainless-steel specimens with residual stresses. The results showed a different distribution of stress intensity factors compared to specimens without residual stresses.
APPLIED SCIENCES-BASEL
(2023)
Article
Energy & Fuels
Shitong Fang, Houfan Du, Tao Yan, Keyu Chen, Zhiyuan Li, Xiaoqing Ma, Zhihui Lai, Shengxi Zhou
Summary: This paper proposes a new type of nonlinear VIV energy harvester (ANVEH) that compensates for the decrease in peak energy output at low wind speeds by introducing an auxiliary structure. Theoretical and experimental results show that ANVEH performs better than traditional nonlinear VIV energy harvesters under various system parameter variations.
Article
Energy & Fuels
Wei Jiang, Shuo Zhang, Teng Wang, Yufei Zhang, Aimin Sha, Jingjing Xiao, Dongdong Yuan
Summary: A standardized method was developed to evaluate the availability of solar energy resources in road areas, which combined the Analytic Hierarchy Process (AHP) and the Geographic Information System (GIS). By analyzing critical factors and using a multi-indicator evaluation method, the method accurately evaluated the utilization of solar energy resources and guided the optimal location selection for road photovoltaic (PV) projects. The results provided guidance for the application of road PV projects and site selection for route corridors worldwide, promoting the integration of transportation and energy.
Article
Energy & Fuels
Chang Liu, Jacob A. Wrubel, Elliot Padgett, Guido Bender
Summary: The study investigates the effects of coating defects on the performance of the anode porous transport layer (PTL) in water electrolyzers. The results show that an increasing fraction of uncoated regions on the PTL leads to decreased cell performance, with continuous uncoated regions having a more severe impact compared to multiple thin uncoated strips.
Article
Energy & Fuels
Marcos Tostado-Veliz, Xiaolong Jin, Rohit Bhakar, Francisco Jurado
Summary: In this paper, a coordinated charging price mechanism for clusters of parking lots is proposed. The research shows that enabling vehicle-to-grid characteristics can bring significant economic benefits for users and the cluster coordinator, and vehicle-to-grid impacts noticeably on the risk-averse character of the uncertainty-aware strategies. The developed pricing mechanism can reduce the cost for users, avoiding to directly translate the energy cost to charging points.
Article
Energy & Fuels
Duan Kang
Summary: Building an energy superpower is a key strategy for China and a long-term goal for other countries. This study proposes an evaluation system and index for measuring energy superpower, and finds that China has significantly improved its ranking over the past 21 years, surpassing other countries.
Article
Energy & Fuels
Fucheng Deng, Yifei Wang, Xiaosen Li, Gang Li, Yi Wang, Bin Huang
Summary: This study investigated the synergistic blockage mechanism of sand and hydrate in gravel filling layer and the evolution of permeability in the layer. Experimental models and modified permeability models were established to analyze the effects of sand particles and hydrate formation on permeability. The study provided valuable insights for the safe and efficient exploitation of hydrate reservoirs.
Article
Energy & Fuels
Hao Wang, Xiwen Chen, Natan Vital, Edward Duffy, Abolfazl Razi
Summary: This study proposes a HVAC energy optimization model based on deep reinforcement learning algorithm. It achieves 37% energy savings and ensures thermal comfort for open office buildings. The model has a low complexity, uses a few controllable factors, and has a short training time with good generalizability.
Article
Energy & Fuels
Moyue Cong, Yongzhuo Gao, Weidong Wang, Long He, Xiwang Mao, Yi Long, Wei Dong
Summary: This study introduces a multi-strategy ultra-wideband energy harvesting device that achieves high power output without the need for external power input. By utilizing asymmetry, stagger array, magnetic coupling, and nonlinearity strategies, the device maintains a stable output voltage and high power density output at non-resonant frequencies. Temperature and humidity monitoring are performed using Bluetooth sensors to adaptively assess the device.
Article
Energy & Fuels
Tianshu Dong, Xiudong Duan, Yuanyuan Huang, Danji Huang, Yingdong Luo, Ziyu Liu, Xiaomeng Ai, Jiakun Fang, Chaolong Song
Summary: Electrochemical water splitting is crucial for hydrogen production, and improving the hydrogen separation rate from the electrode is essential for enhancing water electrolyzer performance. However, issues such as air bubble adhesion to the electrode plate hinder the process. Therefore, a methodology to investigate the two-phase flow within the electrolyzer is in high demand. This study proposes using a microfluidic system as a simulator for the electrolyzer and optimizing the two-phase flow by manipulating the micro-structure of the flow.
Article
Energy & Fuels
Shuo Han, Yifan Yuan, Mengjiao He, Ziwen Zhao, Beibei Xu, Diyi Chen, Jakub Jurasz
Summary: Giving full play to the flexibility of hydropower and integrating more variable renewable energy is of great significance for accelerating the transformation of China's power energy system. This study proposes a novel day-ahead scheduling model that considers the flexibility limited by irregular vibration zones (VZs) and the probability of flexibility shortage in a hydropower-variable renewable energy hybrid generation system. The model is applied to a real hydropower station and effectively improves the flexibility supply capacity of hydropower, especially during heavy load demand in flood season.
Article
Energy & Fuels
Zhen Wang, Kangqi Fan, Shizhong Zhao, Shuxin Wu, Xuan Zhang, Kangjia Zhai, Zhiqi Li, Hua He
Summary: This study developed a high-performance rotary energy harvester (AI-REH) inspired by archery, which efficiently accumulates and releases ultralow-frequency vibration energy. By utilizing a magnetic coupling strategy and an accumulator spring, the AI-REH achieves significantly accelerated rotor speeds and enhanced electric outputs.
Article
Energy & Fuels
Yi Yang, Qianyi Xing, Kang Wang, Caihong Li, Jianzhou Wang, Xiaojia Huang
Summary: In this study, a novel hybrid Quantile Regression (QR) model is proposed for Probabilistic Load Forecasting (PLF). The model integrates causal dilated convolution, residual connection, and Bidirectional Long Short-Term Memory (BiLSTM) for multi-scale feature extraction. In addition, a Combined Probabilistic Load Forecasting System (CPLFS) is proposed to overcome the inherent flaws of relying on a single model. Simulation results show that the hybrid QR outperforms traditional models and CPLFS exceeds the best benchmarks in terms of prediction accuracy and stability.
Article
Energy & Fuels
Wen-Jiang Zou, Young-Bae Kim, Seunghun Jung
Summary: This paper proposes a dynamic prediction model for capacity fade in vanadium redox flow batteries (VRFBs). The model accurately predicts changes in electrolyte volume and capacity fade, enhancing the competitiveness of VRFBs in energy storage applications.
Article
Energy & Fuels
Yuechao Ma, Shengtie Wang, Guangchen Liu, Guizhen Tian, Jianwei Zhang, Ruiming Liu
Summary: This paper focuses on the balance of state of charge (SOC) among multiple battery energy storage units (MBESUs) and bus voltage balance in an islanded bipolar DC microgrid. A SOC automatic balancing strategy is proposed considering the energy flow relationship and utilizing the adaptive virtual resistance algorithm. The simulation results demonstrate the effectiveness of the proposed strategy in achieving SOC balancing and decreasing bus voltage unbalance.
Article
Energy & Fuels
Raad Z. Homod, Basil Sh. Munahi, Hayder Ibrahim Mohammed, Musatafa Abbas Abbood Albadr, Aissa Abderrahmane, Jasim M. Mahdi, Mohamed Bechir Ben Hamida, Bilal Naji Alhasnawi, A. S. Albahri, Hussein Togun, Umar F. Alqsair, Zaher Mundher Yaseen
Summary: In this study, the control problem of the multiple-boiler system (MBS) is formulated as a dynamic Markov decision process and a deep clustering reinforcement learning approach is applied to obtain the optimal control policy. The proposed strategy, based on bang-bang action, shows superior response and achieves more than 32% energy saving compared to conventional fixed parameter controllers under dynamic indoor/outdoor actual conditions.
