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White-Model Predictive Control for Balancing Energy Savings and Thermal Comfort
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Computational Model of Shell and Finned Tube Latent Thermal Energy Storage Developed as a New TRNSYS Type
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An Overview of Promising Alternative Fuels for Road, Rail, Air, and Inland Waterway Transport in Germany
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Deriving Current Cost Requirements from Future Targets: Case Studies for Emerging Offshore Renewable Energy Technologies
Journal Description
Energies
Energies
is a peer-reviewed, open access journal of related scientific research, technology development, engineering, and the studies in policy and management and is published semimonthly online by MDPI. The European Biomass Industry Association (EUBIA), Association of European Renewable Energy Research Centres (EUREC), Institute for Chemical Processing of Coal (IChPW), International Society for Porous Media (InterPore), CYTED and others are affiliated with Energies and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Ei Compendex, RePEc, Inspec, CAPlus / SciFinder, and other databases.
- Journal Rank: CiteScore - Q1 (Control and Optimization)
- Rapid Publication: manuscripts are peer-reviewed and a first decision provided to authors approximately 16.2 days after submission; acceptance to publication is undertaken in 3.4 days (median values for papers published in this journal in the first half of 2022).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Sections: published in 41 topical sections.
- Testimonials: See what our editors and authors say about Energies.
- Companion journals for Energies include: Fuels, Gases, Nanoenergy Advances and Solar.
Impact Factor:
3.252 (2021)
;
5-Year Impact Factor:
3.333 (2021)
Latest Articles
Application of Alternating Current Stress Measurement Method in the Stress Detection of Long-Distance Oil Pipelines
Energies 2022, 15(14), 4965; https://doi.org/10.3390/en15144965 - 06 Jul 2022
Abstract
With the development of pipeline networks, many safety accidents were caused by pipeline stress concentration; it is of great significance to accurately monitor the pipeline stress state for maintaining pipeline safety. In this paper, based on alternating current stress measurement (ACSM) methods, a
[...] Read more.
With the development of pipeline networks, many safety accidents were caused by pipeline stress concentration; it is of great significance to accurately monitor the pipeline stress state for maintaining pipeline safety. In this paper, based on alternating current stress measurement (ACSM) methods, a 3D simulation model of a pipeline electromagnetic field was established by ANSYS software. The distribution law of the pipeline magnetic field and eddy current field were analyzed, and the influence of size and structure parameters of the coil inside the probe were studied. The internal stress detection system of the pipeline was designed, and the static tensile stress measurement experiment was carried out. Simulation and test results showed that the excitation coil with a larger diameter-to-height ratio had a higher measurement sensitivity. The sensitivity of the probe decreased monotonically with the increase of the difference between inner diameter and outer diameter of the detection coil. It increased monotonically with the increase of the equivalent radius of the detection coil. The best measurement results were obtained when the detection coil was located at the center of the two legs of the U-magnetic core. The results showed that the system could identify the pipeline stress concentration area effectively after detection engineering.
Full article
(This article belongs to the Special Issue Detection and Diagnosis in Oil and Gas Pipelines)
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Open AccessReview
Recent Progress on Hydrogen Storage and Production Using Chemical Hydrogen Carriers
Energies 2022, 15(14), 4964; https://doi.org/10.3390/en15144964 - 06 Jul 2022
Abstract
Depleting fossil fuel resources and anthropogenic climate changes are the reasons for the intensive development of new, sustainable technologies based on renewable energy sources. One of the most promising strategies is the utilization of hydrogen as an energy vector. However, the limiting issue
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Depleting fossil fuel resources and anthropogenic climate changes are the reasons for the intensive development of new, sustainable technologies based on renewable energy sources. One of the most promising strategies is the utilization of hydrogen as an energy vector. However, the limiting issue for large-scale commercialization of hydrogen technologies is a safe, efficient, and economical method of gas storage. In industrial practice, hydrogen compression and liquefaction are currently applied; however, due to the required high pressure (30–70 MPa) and low temperature (−253 °C), both these methods are intensively energy consuming. Chemical hydrogen storage is a promising alternative as it offers safe storage of hydrogen-rich compounds under ambient conditions. Although many compounds serving as hydrogen carriers are considered, some of them do not have realistic perspectives for large-scale commercialization. In this review, the three most technologically advanced hydrogen carriers—dimethyl ether, methanol, and dibenzyltoluene—are discussed and compared. Their potential for industrial application in relation to the energy storage, transport, and mobility sectors is analyzed, taking into account technological and environmental aspects.
Full article
Open AccessArticle
Optimization of Magnetic Gear Patterns Based on Taguchi Method Combined with Genetic Algorithm
Energies 2022, 15(14), 4963; https://doi.org/10.3390/en15144963 - 06 Jul 2022
Abstract
Magnetic gears (MGs) have gained increasing attention due to their sound performance in high torque density and low friction loss. Aiming to maximize the torque density, topology design has been a popular issue in recent years. However, studies on the optimization comparisons of
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Magnetic gears (MGs) have gained increasing attention due to their sound performance in high torque density and low friction loss. Aiming to maximize the torque density, topology design has been a popular issue in recent years. However, studies on the optimization comparisons of a general MG topology pattern are very limited. This paper proposes a Taguchi-method-based optimization method for a general MG topology pattern, which can cover most of the common types of radially magnetized concentric-surface-mounted MGs (RMCSM-MGs). The Taguchi method is introduced to evaluate the influence of each parameter in MGs. Moreover, the parameter value range is re-examined based on the sensitivity analysis results. The genetic algorithm (GA) method is adopted to optimize the topology pattern in the study.
Full article
(This article belongs to the Special Issue Future Smart Grids with High Integrations of New Technologies)
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Inductive Power Transfer for Electric Vehicle Charging Applications: A Comprehensive Review
Energies 2022, 15(14), 4962; https://doi.org/10.3390/en15144962 - 06 Jul 2022
Abstract
Nowadays, Wireless Power Transfer (WPT) technology is receiving more attention in the automotive sector, introducing a safe, flexible and promising alternative to the standard battery chargers. Considering these advantages, charging electric vehicle (EV) batteries using the WPT method can be an important alternative
[...] Read more.
Nowadays, Wireless Power Transfer (WPT) technology is receiving more attention in the automotive sector, introducing a safe, flexible and promising alternative to the standard battery chargers. Considering these advantages, charging electric vehicle (EV) batteries using the WPT method can be an important alternative to plug-in charging systems. This paper focuses on the Inductive Power Transfer (IPT) method, which is based on the magnetic coupling of coils exchanging power from a stationary primary unit to a secondary system onboard the EV. A comprehensive review has been performed on the history of the evolution, working principles and phenomena, design considerations, control methods and health issues of IPT systems, especially those based on EV charging. In particular, the coil design, operating frequency selection, efficiency values and the preferred compensation topologies in the literature have been discussed. The published guidelines and reports that have studied the effects of WPT systems on human health are also given. In addition, suggested methods in the literature for protection from exposure are discussed. The control section gives the common charging control techniques and focuses on the constant current-constant voltage (CC-CV) approach, which is usually used for EV battery chargers.
Full article
(This article belongs to the Special Issue Electric Vehicle Charging Technologies and Trends)
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Improved Adaptive Time Step Method for Natural Gas Pipeline Transient Simulation
Energies 2022, 15(14), 4961; https://doi.org/10.3390/en15144961 - 06 Jul 2022
Abstract
As the natural gas pipeline network becomes larger and more complicated, a stricter requirement of computation efficiency for the large and complicated network transient simulation should be proposed. The adaptive time step method has been widely used in the transient simulation of natural
[...] Read more.
As the natural gas pipeline network becomes larger and more complicated, a stricter requirement of computation efficiency for the large and complicated network transient simulation should be proposed. The adaptive time step method has been widely used in the transient simulation of natural gas pipeline networks as a significant way to improve computation efficiency. However, the trial calculation process, which is the most time-consuming process in time step adjustment, was used to adjust the time step in these methods, reducing the efficiency of time step adjustment. In order to reduce the number of trial calculations, and improve the calculation efficiency, an improved adaptive time step method is proposed, which proposes the concept of energy number and judges the energy number of the boundary conditions after judging whether the variation of the pipeline state is tolerable. A comparison between the adaptive time step method and the improved adaptive time step method in the restart process of natural gas pipelines and an actual operation of the XB section in China shows the accuracy, effect, and efficiency of the improved adaptive time step method. The results show that with the same accuracy, 27% fewer trial calculation processes and 24.95% fewer time levels are needed in the improved time step method.
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(This article belongs to the Topic Digitalization for Energy Systems)
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Bidding a Battery on Electricity Markets and Minimizing Battery Aging Costs: A Reinforcement Learning Approach
Energies 2022, 15(14), 4960; https://doi.org/10.3390/en15144960 - 06 Jul 2022
Abstract
Battery storage is emerging as a key component of intelligent green electricitiy systems. The battery is monetized through market participation, which usually involves bidding. Bidding is a multi-objective optimization problem, involving targets such as maximizing market compensation and minimizing penalties for failing to
[...] Read more.
Battery storage is emerging as a key component of intelligent green electricitiy systems. The battery is monetized through market participation, which usually involves bidding. Bidding is a multi-objective optimization problem, involving targets such as maximizing market compensation and minimizing penalties for failing to provide the service and costs for battery aging. In this article, battery participation is investigated on primary frequency reserve markets. Reinforcement learning is applied for the optimization. In previous research, only simplified formulations of battery aging have been used in the reinforcement learning formulation, so it is unclear how the optimizer would perform with a real battery. In this article, a physics-based battery aging model is used to assess the aging. The contribution of this article is a methodology involving a realistic battery simulation to assess the performance of the trained RL agent with respect to battery aging in order to inform the selection of the weighting of the aging term in the RL reward formula. The RL agent performs day-ahead bidding on the Finnish Frequency Containment Reserves for Normal Operation market, with the objective of maximizing market compensation, minimizing market penalties and minimizing aging costs.
Full article
(This article belongs to the Special Issue Management of Intelligent Distributed Energy Resources)
Open AccessArticle
Assessment of the Technological Sustainability of the Tri-Generation Model in the Era of Climate Change: A Case Study of Terminal Complexes
by
Energies 2022, 15(14), 4959; https://doi.org/10.3390/en15144959 - 06 Jul 2022
Abstract
In this study, the operating conditions of the tri-generation model in actual field situations for terminal complex buildings were investigated. The operational characteristics of the installed tri-generation system (TGS), and performance in terms of relative primary energy savings (RPES), were evaluated to confirm
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In this study, the operating conditions of the tri-generation model in actual field situations for terminal complex buildings were investigated. The operational characteristics of the installed tri-generation system (TGS), and performance in terms of relative primary energy savings (RPES), were evaluated to confirm its market competitiveness against separate heat and power (SHP). As a result of the analysis, the technological superiority of the TGS model compared to the SHP method was much lower than theoretical expectation, which was 17.9% in the best case and close to 0 in the worst case. The importance of the TGS’s operational strategy to achieve annual operational economics was emphasized based on the analysis of the TGS’s actual daily operational data. The sustainability of the TGS model in the era of climate change was also evaluated through RPES sensitivity analysis according to the level of renewable power generation in the power sector, which is rapidly increasing in response to climate change.
Full article
(This article belongs to the Special Issue Technology and Strategy for Sustainable Energy Systems)
Open AccessArticle
Prediction of the Absolute Methane Emission Rate for Longwall Caving Extraction Based on Rock Mass Modelling—A Case Study
Energies 2022, 15(14), 4958; https://doi.org/10.3390/en15144958 - 06 Jul 2022
Abstract
This article presents a methodology for predicting the absolute methane emission rate for longwall caving extraction based on the determination of destressing zones generated by longwall mining operations, by means of numerical modelling. This methodology was applied for the conditions of the K-2
[...] Read more.
This article presents a methodology for predicting the absolute methane emission rate for longwall caving extraction based on the determination of destressing zones generated by longwall mining operations, by means of numerical modelling. This methodology was applied for the conditions of the K-2 longwall panel in the KWK Pniówek mine. The finite difference method code FLAC2D was employed as an element of the methodology to determine the destressing zones. All results including the numerical modelling results, empirical results and the measured (in situ) results were gathered in the comparative analysis. As the final results, the accuracy and reliability of the proposed methodology were evaluated.
Full article
(This article belongs to the Special Issue Coal Mining)
Open AccessArticle
Using Spatial Data Science in Energy-Related Modeling of Terraforming the Martian Atmosphere
Energies 2022, 15(14), 4957; https://doi.org/10.3390/en15144957 - 06 Jul 2022
Abstract
This paper proposes a methodology for numerical modeling of terraforming Mars’ atmosphere using high-energy asteroid impact and greenhouse gas production processes. The developed simulation model uses a spatial data science approach to analyze the Global Climate Model of Mars and cellular automata to
[...] Read more.
This paper proposes a methodology for numerical modeling of terraforming Mars’ atmosphere using high-energy asteroid impact and greenhouse gas production processes. The developed simulation model uses a spatial data science approach to analyze the Global Climate Model of Mars and cellular automata to model the changes in Mars’ atmospheric parameters. The developed model allows estimating the energy required to raise the planet’s temperature by sixty degrees using different variations of the terraforming process. Using a data science approach for spatial big data analysis has enabled successful numerical simulations of global and local atmospheric changes on Mars and an analysis of the energy potential required for this process.
Full article
(This article belongs to the Special Issue Energy and Artificial Intelligence)
Open AccessArticle
A Cogging Torque Minimization Procedure for Interior Permanent Magnet Synchronous Motors Based on a Progressive Modification of the Rotor Lamination Geometry
Energies 2022, 15(14), 4956; https://doi.org/10.3390/en15144956 - 06 Jul 2022
Abstract
This article describes a simple cogging torque minimization procedure for interior permanent magnet synchronous machines (IPMSMs), consisting of a progressive modification of the rotor lamination geometry. This procedure can be generalized for the main topologies of PMSM, independently of the number of stator
[...] Read more.
This article describes a simple cogging torque minimization procedure for interior permanent magnet synchronous machines (IPMSMs), consisting of a progressive modification of the rotor lamination geometry. This procedure can be generalized for the main topologies of PMSM, independently of the number of stator slots or the location of the permanent magnets. For this purpose, a basic IPMSM structure is analyzed by means of the FEM (finite element method) approach, and then, several other IPMSM geometries, obtained by adequately modifying the rotor lamination geometry of the basic IPMSM model without changing its stator configuration, are proposed and discussed. The trends of the cogging torque generated by each model are computed and compared. From this comparison, it is demonstrated that, by simply acting on the shape of the rotor lamination and by choosing the optimized pattern, the cogging torque components can be theoretically canceled.
Full article
(This article belongs to the Special Issue Analysis and Design of Electric Machine)
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Long-Term Evaluation of Comfort, Indoor Air Quality and Energy Performance in Buildings: The Case of the KTH Live-In Lab Testbeds
Energies 2022, 15(14), 4955; https://doi.org/10.3390/en15144955 - 06 Jul 2022
Abstract
Digitalization offers new, unprecedented possibilities to increase the energy efficiency and improve the indoor conditions in buildings in a cost-efficient way. Smart buildings are seen by many stakeholders as the way forward. Smart buildings feature advanced monitoring and control systems that allow a
[...] Read more.
Digitalization offers new, unprecedented possibilities to increase the energy efficiency and improve the indoor conditions in buildings in a cost-efficient way. Smart buildings are seen by many stakeholders as the way forward. Smart buildings feature advanced monitoring and control systems that allow a better control of the buildings’ indoor spaces, but it is becoming evident that the massive amount of data produced in smart buildings is rarely used. This work presents a long-term evaluation of a smart building testbed for one year; the building features state-of-the-art monitoring capability and local energy generation (PV). The analysis shows room for improving energy efficiency and indoor comfort due to non-optimal control settings; for instance, average indoor temperatures in all winter months were above 24 °C. The analysis of electricity and domestic hot water use has shown a relevant spread in average use, with single users consuming approximately four times more than the average users. The combination of CO2 and temperature sensor was sufficient to pinpoint the anomalous operation of windows in wintertime, which has an impact on energy use for space heating. Although the quantification of the impact of users on the overall energy performance of the building was beyond the scope of this paper, this study showcases that modern commercial monitoring systems for buildings have the potential to identify anomalies. The evidence collected in the paper suggests that this data could be used to promote energy-efficient behaviors among building occupants and shows that cost-effective actions could be carried out if data generated by the monitoring and control systems were used more extensively.
Full article
(This article belongs to the Special Issue Energy Efficiency and Optimization Strategies in Buildings for a Sustainable Future)
Open AccessArticle
Exploring Natural Fermented Foods as a Source for New Efficient Thermotolerant Yeasts for the Production of Second-Generation Bioethanol
Energies 2022, 15(14), 4954; https://doi.org/10.3390/en15144954 - 06 Jul 2022
Abstract
Considering the cost-effectiveness of bioethanol production at high temperatures, there is an enduring need to find new thermotolerant ethanologenic yeasts. In this study, a total of eighteen thermotolerant yeasts were isolated from various natural fermented products in Morocco. Ethanol production using 50 g/L
[...] Read more.
Considering the cost-effectiveness of bioethanol production at high temperatures, there is an enduring need to find new thermotolerant ethanologenic yeasts. In this study, a total of eighteen thermotolerant yeasts were isolated from various natural fermented products in Morocco. Ethanol production using 50 g/L glucose or 50 g/L xylose as the sole carbon source revealed potential yeasts with high productivities and volumetric ethanol productivities at high temperatures. Based on molecular identification, the selected thermotolerant fermentative isolates were affiliated with Pichia kudriavzevii, Kluyveromyces marxianus, and Kluyveromyces sp. During the simultaneous saccharification and fermentation of lignocellulosic biomass at a high temperature (42 °C), the designated yeast P. kudriavzevii YSR7 produced an ethanol concentration of 22.36 g/L, 18.2 g/L and 6.34 g/L from 100 g/L barley straw (BS), chickpea straw (CS), and olive tree pruning (OTP), respectively. It also exhibited multi-stress tolerance, such as ethanol, acetic acid, and osmotic tolerance. Therefore, the yeast P. kudriavzevii YSR7 showed promising attributes for biorefinery-scale ethanol production in the future.
Full article
(This article belongs to the Special Issue Advances in Bioconversion of Lignocellulose to Fuels, Chemicals, and Biomaterials)
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The 50th Anniversary of The Limits to Growth: Does It Have Relevance for Today’s Energy Issues?
Energies 2022, 15(14), 4953; https://doi.org/10.3390/en15144953 - 06 Jul 2022
Abstract
The Limits to Growth was a remarkable, and remarkably influential, model, book and concept published 50 years ago this year. Its importance is that it used, for essentially the first time, a quantitative systems approach and a computer model to question the dominant
[...] Read more.
The Limits to Growth was a remarkable, and remarkably influential, model, book and concept published 50 years ago this year. Its importance is that it used, for essentially the first time, a quantitative systems approach and a computer model to question the dominant paradigm for most of society: growth. Initially, many events, and especially the oil crisis of the 1970s, seemed to support the idea that the limits were close. Many economists argued quite the opposite, and the later relaxation of the oil crisis (and decline in gasoline prices) seemed to support the economists’ position. Many argued that the model had failed, but a careful examination of model behavior vs. global and many national data sets assessed by a number of researchers suggests that the model’s predictions (even if they had not been meant for such a specific task) were still remarkably accurate to date. While the massive changes predicted by the model have not yet come to pass globally, they are clearly occurring for many individual nations. Additionally, global patterns of climate change, fuel and mineral depletion, environmental degradation and population growth are quite as predicted by the original model. Whether or not the world as a whole continues to follow the general patterns of the model may be mostly a function of what happens with energy and whether humans can accept constraints on their propensity to keep growing.
Full article
(This article belongs to the Special Issue Rethinking Energy: Earth System Science Approaches 2021)
Open AccessReview
Key Points and Current Studies on Seepage Theories of Marine Natural Gas Hydrate-Bearing Sediments: A Narrative Review
Energies 2022, 15(14), 4952; https://doi.org/10.3390/en15144952 - 06 Jul 2022
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The internal fluid flow capacity of hydrate-bearing sediment (HBS) is one of the important factors affecting the efficiency of natural gas exploitation. This paper focuses on seepage studies on gas hydrates with the following contents: scope of theories’ application, normalized permeability (K
[...] Read more.
The internal fluid flow capacity of hydrate-bearing sediment (HBS) is one of the important factors affecting the efficiency of natural gas exploitation. This paper focuses on seepage studies on gas hydrates with the following contents: scope of theories’ application, normalized permeability (Kt) models, extension combined with new technology, and development. No review has elucidated the prediction of original permeability (K0) of sediments without hydrates. Moreover, there are few studies on seepage theories with new technologies, such as Computed Tomography (CT), Nuclear Magnetic Resonance (NMR), Magnetic Resonance Imaging (MRI), and resistivity. However, this review summarizes the prospects, evolution, and application of HBS seepage theories from the perspectives of experiments, numerical simulation, and microscopic visualization. Finally, we discuss the current limitations and directions of the seepage theories of HBS.
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Real-Time Detection of Karstification Hazards While Drilling in Carbonates
Energies 2022, 15(14), 4951; https://doi.org/10.3390/en15144951 - 06 Jul 2022
Abstract
The nature of carbonate deposition can cause the development of unique geological features such as cavities and vugs called karsts. Encountering karsts while drilling can lead to serious consequences. To improve drilling safety in intervals of karstification, it is important to detect karsts
[...] Read more.
The nature of carbonate deposition can cause the development of unique geological features such as cavities and vugs called karsts. Encountering karsts while drilling can lead to serious consequences. To improve drilling safety in intervals of karstification, it is important to detect karsts as early as possible. The use of state-of-the-art geophysical methods cannot guarantee early or even real-time detection of karsts or karstification zones. In this paper we demonstrate, based on an analysis of 20 wells drilled in karstified carbonates in the Barents Sea, that a karst that is dangerous for drilling is often surrounded by one or more other karstification objects, thus forming a karstification zone. These zones can be detected in real time through certain patterns in drillstring mechanics and mud flow measurements. They can serve as indicators of intervals with a high likelihood of encountering karsts. The identified patterns corresponding to various karstification objects are summarized in a table and can be used by drilling engineers. Apart from that, these patterns can also be utilized for training machine learning algorithms for the automatic detection of karstification zones.
Full article
(This article belongs to the Special Issue Deep Oil and Gas Drilling and Production Technology)
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Forecast of Energy Consumption and Carbon Emissions in China’s Building Sector to 2060
Energies 2022, 15(14), 4950; https://doi.org/10.3390/en15144950 - 06 Jul 2022
Abstract
The goal of reaching the peak of carbon in the construction industry is urgent. However, the research on the feasibility of realizing this goal and the implementation of relevant policies in China is relatively superficial. In view of the historical data of energy
[...] Read more.
The goal of reaching the peak of carbon in the construction industry is urgent. However, the research on the feasibility of realizing this goal and the implementation of relevant policies in China is relatively superficial. In view of the historical data of energy consumption and building CO2 emission from 1995 to 2019, this paper establishes a BP neural network model for predicting building CO2 emissions. Moreover, the influencing factors, such as population, GDP, and total construction output, are introduced as the parameters in the model. Through the scenario analysis method explores the practical path to accomplish the peak of building CO2 emissions. When using traditional prediction methods to predict building carbon emissions, the long prediction cycle will increase the possibility of significant errors. Therefore, this paper constructs the calculation model of building carbon emission and forecasts the future carbon emission value through the BP neural network to avoid the error caused by the nonlinear relationship between influencing factors and predicted value. It will effectively predict the feasibility of the carbon peak and the carbon-neutral target set by government, and provide a useful predictive tool for adjusting the new energy structure and formulating related emission reduction policies.
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(This article belongs to the Special Issue Optimization and Innovation of Energy Efficient Buildings and Smart Cities)
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Open AccessReview
Novel Trends in Proton Exchange Membrane Fuel Cells
by
, , , , , , and
Energies 2022, 15(14), 4949; https://doi.org/10.3390/en15144949 - 06 Jul 2022
Abstract
Fuel cells (FCs) have received huge attention for development from lab and pilot scales to full commercial scale. This is mainly due to their inherent advantage of direct conversion of chemical energy to electrical energy as a high-quality energy supply and, hence, higher
[...] Read more.
Fuel cells (FCs) have received huge attention for development from lab and pilot scales to full commercial scale. This is mainly due to their inherent advantage of direct conversion of chemical energy to electrical energy as a high-quality energy supply and, hence, higher conversion efficiency. Additionally, FCs have been produced at a wide range of capacities with high flexibility due to modularity characteristics. Using the right materials and efficient manufacturing processes is directly proportional to the total production cost. This work explored the different components of proton exchange membrane fuel cells (PEMFCs) and their manufacturing processes. The challenges associated with these manufacturing processes were critically analyzed, and possible mitigation strategies were proposed. The PEMFC is a relatively new and developing technology so there is a need for a thorough analysis to comprehend the current state of fuel cell operational characteristics and discover new areas for development. It is hoped that the view discussed in this paper will be a means for improved fuel cell development.
Full article
(This article belongs to the Special Issue Renewable Energy and Energy Storage Systems)
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Open AccessFeature PaperReview
Assessing Lifestyle Transformations and Their Systemic Effects in Energy-System and Integrated Assessment Models: A Review of Current Methods and Data
Energies 2022, 15(14), 4948; https://doi.org/10.3390/en15144948 - 06 Jul 2022
Abstract
Achieving the ambitious climate targets required to limit global warming to 1.5 °C requires a deep transformation of the supply-and-demand side of energy–environmental–economic systems. Recent articles have shown that environmentally sustainable consumer behaviors driven by lifestyle changes can significantly contribute to climate-change mitigation
[...] Read more.
Achieving the ambitious climate targets required to limit global warming to 1.5 °C requires a deep transformation of the supply-and-demand side of energy–environmental–economic systems. Recent articles have shown that environmentally sustainable consumer behaviors driven by lifestyle changes can significantly contribute to climate-change mitigation and sustainable development goals. However, lifestyle changes are not adequately captured by scenarios developed with integrated assessment and energy-system models (IAMs/ESMs), which provide limited policy insights. This article conducts a systematic review of the IAM and ESM literature to identify the most important lifestyle changes in current mitigation pathways for the residential and transport sectors, review the employed state-of-the-art modeling approaches and scenario assumptions, and propose improvements to existing methodological frameworks. The review finds that mode shifts towards public transport and active transport modes, shared mobility, and eco-driving have the greatest impact in the transport sector, while actions that reduce space and water-heating requirements and the circular economy are the most effective practices in households. Common modeling approaches lack sophistication as they omit (1) the dynamics and costs of demand-side transitions, (2) the heterogenous responses of different consumer groups, and (3) the structural effects of lifestyles on the macro-economy. New approaches employing innovative methodologies combined with big data collected from users offer new avenues to overcome these challenges and improve the modeling of lifestyle changes in large-scale models.
Full article
(This article belongs to the Special Issue Feature Papers in Energy, Environment and Well-Being)
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Open AccessArticle
Experimental Study on Renewable Porous Carbon Dioxide Adsorbent Materials for Space Shuttles
Energies 2022, 15(14), 4947; https://doi.org/10.3390/en15144947 - 06 Jul 2022
Abstract
Porous adsorbent material is promising to be used to regeneratively remove CO2 from space shuttles. In this work, the amount and isosteric heat of CO2 adsorption in solid amine are experimentally studied at pressures ranging from 0 to 6 bar and
[...] Read more.
Porous adsorbent material is promising to be used to regeneratively remove CO2 from space shuttles. In this work, the amount and isosteric heat of CO2 adsorption in solid amine are experimentally studied at pressures ranging from 0 to 6 bar and temperatures ranging from 20 °C to 60 °C. The amount and isosteric heat of water adsorption in the solid amine is tested at different humidities (relative humidity 30–80%). The effective thermal conductivity of the solid amine at different atmospheres (air, N2, CO2 and water), pressures and temperatures is also investigated. The results show that the best temperature for CO2 adsorption in the solid amine is 45 °C under dry conditions. The amount of water adsorption increases with enhanced humidity, while the isosteric heat of water adsorption remains a constant value. The effective thermal conductivity of the solid amine increases with an increase in pressure. The adsorbed phase (CO2 and water) in the solid amine makes a contribution to improving the effective thermal conductivity of solid amine particles. The above findings can help design a better adsorption system in space.
Full article
(This article belongs to the Special Issue Advances in Heat and Mass Transfer and Reaction in Porous Media)
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Open AccessArticle
Exergetic Effects of Cooled Cooling Air Technology on the Turbofan Engine during a Typical Mission
Energies 2022, 15(14), 4946; https://doi.org/10.3390/en15144946 - 06 Jul 2022
Abstract
The cooled cooling air technology (CCA technology) shows expected performance in solving the growing thermal challenge for advanced aero engines by reducing the temperature of cooling air. The effect of CCA technology on the overall propelling performance with or without adjusting cycle parameters
[...] Read more.
The cooled cooling air technology (CCA technology) shows expected performance in solving the growing thermal challenge for advanced aero engines by reducing the temperature of cooling air. The effect of CCA technology on the overall propelling performance with or without adjusting cycle parameters is controversial. Based on this, both the energy and exergy methods have been adopted to elaborate the specific mechanisms of the above energy utilization discrepancy. As a result, the scheme of CCA technology without optimizing cycle parameters has lower propelling work and efficiency with the total exergy destruction increasing 0.5~2%. Oppositely, as for the scheme of CCA with meliorated cycle parameters, the propelling efficiency improved by around 2~4% with total exergy destruction reduced by 1~3.5%. By analyzing the distribution of exergy destruction, the avoidable and unavoidable exergy destruction caused by the combustion chamber, compressors, and turbines accounts for the largest proportion, which indicates that more attention needs to be paid in the future. During the whole flight mission, the percentage of exergy destruction is much higher in supersonic, subsonic cruise, combat, and escape conditions. In conclusion, the improvement of cycle parameters to reduce the exergy destruction should be considered when introducing CCA technology.
Full article
(This article belongs to the Section E3: Exergy)

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Topics
Topic in
Energies, Materials, Applied Sciences, Batteries, Nanoenergy Advances
Applications of Nanomaterials in Energy Systems
Topic Editors: Eleftheria C. Pyrgioti, Ioannis F. Gonos, Diaa-Eldin A. MansourDeadline: 31 July 2022
Topic in
Clean Technol., Energies, Resources
Advances in Clean Energies
Topic Editors: Yongliang Xie, Shimao WangDeadline: 1 September 2022
Topic in
Batteries, Electricity, Electronics, Energies, Nanoenergy Advances
Safety of Lithium-ion Batteries
Topic Editors: Binghe Liu, Lubing Wang, Yuqi Huang, Yongjun PanDeadline: 30 September 2022
Topic in
Energies, Electronics, Processes, Electricity, Solar
Energy Storage and Conversion Systems
Topic Editors: Alon Kuperman, Alessandro LampasiDeadline: 15 October 2022

Conferences
Special Issues
Special Issue in
Energies
Wave Energy Converters and Fault Tolerant Control
Guest Editor: Mário José Gonçalves Cavaco MendesDeadline: 15 July 2022
Special Issue in
Energies
Wide Band Gap Devices in Energy Storage Systems
Guest Editors: Gianluca Gatto, Milad MoradpourDeadline: 20 July 2022
Special Issue in
Energies
Low Carbon and Resilient Planning, Design, and Construction of the Built Environment: Mitigation and Adaptation Achievements and Future Directions
Guest Editors: Robert J. Ries, Yuan ChangDeadline: 31 July 2022
Special Issue in
Energies
Economic Analysis and Policies for the Environment, Natural Resources and Energy
Guest Editor: George HalkosDeadline: 15 August 2022
Topical Collections
Topical Collection in
Energies
Featured Papers in Electrical Power and Energy System
Collection Editors: Nicu Bizon, Mihai Oproescu, Philippe Poure, Rocío Pérez de Prado, Abdessattar Abdelkefi
Topical Collection in
Energies
Artificial Intelligence and Smart Energy
Collection Editors: Wei-Hsin Chen, Núria Agell, Zhiyong Liu, Ying-Yi Hong
Topical Collection in
Energies
Conference Papers Collection in Energy and Environment
Collection Editors: Hossein Hamidi, Yingfa Lu
Topical Collection in
Energies
Review Papers in Solar Energy and Photovoltaic Systems
Collection Editors: Ricardo Vasquez Padilla, Adalgisa Sinicropi, Eun-Chel Cho, Maria Laura Parisi