A building, a central location of human activities, is equipped with many devices that consume a lot of electricity. Therefore, predicting the energy consumption of a building is essential because it helps the building management to make better energy management policies. Thus, predicting energy consumption of a building is very important, and this study proposes a forecasting framework for energy consumption of a building. The proposed framework combines a decomposition method with a forecasting algorithm. This study applies two decomposition algorithms, namely the empirical mode decomposition and wavelet transformation. Furthermore, it applies the long short term memory algorithm to predict energy consumption. This study applies the proposed framework to predict the energy consumption of 20 buildings. The buildings are located in different time zones and have different functionalities. The experiment results reveal that the best forecasting algorithm applies the long short term memor... [more]

The fabrication of bulk heterojunction organic solar cells (OSCs) is primarily based on a phase demixing during solution deposition. This spontaneous process is triggered when, as a result of a decrease in the solvent concentration, interactions between donor and acceptor molecules begin to dominate. Herein, we present that interdiffusion of the same molecules is possible when a bilayers of donors and acceptors are exposed to solvent vapor. Poly(3-hexyl thiophene) (P3HT), and poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole) (PCDTBT) were used as donors and two types of fullerene derivatives were used as acceptors: phenyl-C61-butyric acid methyl ester (PC60BM) and phenyl-C71-butyric acid methyl ester (PC70BM), Secondary ion mass spectrometry depth profiling revealed that the interpenetration of donors and acceptors induced by solvent vapor annealing was dependent on solvent vapor and component compatibility. Exposure to chloroform vapor resulte... [more]

In the present study, the laminar flow and heat transfer of water jet impingement enhanced with nano-encapsulated phase change material (NEPCM) slurry on a hot plate is analytically investigated for the first time. A similarity solution approach is applied to momentum and energy equations in order to determine the flow velocity and heat transfer fields. The effect of different physical parameters such as jet velocity, Reynolds number, jet inlet temperature, and the NEPCM concentration on the cooling performance of the impinging jet are investigated. The volume fraction of NEPCM particles plays an essential role in the flow and heat transfer fields. The results show that NEPCM slurry can significantly enhance the cooling performance of the system as it improves the latent heat storage capacity of the liquid jet. However, the maximum cooling performance of the system is achieved under an optimum NEPCM concentration (15%). A further increase in NEPCM volume fraction has an unfavorable eff... [more]

In this work, sodium aluminate alkaline solution was used to capture CO2 in a continuous bubble column scrubber and aluminum tri-hydrate (ATH) precipitates were produced. As the sodium carbonate could be recycled after the filtrated solution was crystallized by evaporation, a novel CO2 capture process was developed successfully. There were five experimental operation variables, including solution flow rate (A), concentration of the solution (B), gas flow rate (C), CO2 gas concentration (D), and liquid temperature (E), with four levels to each variable. The influence of each variable on absorption efficiency (EF), absorption rate (RA), absorption factor (φ), mass transfer coefficient (KGa), and precipitation rate (RP) in a steady state was explored in this study. The Taguchi experimental design was adopted, and 16 experiments were performed; as the optimum operating conditions found in Taguchi analysis required further verification, there were a total of 21 experiments in the end. Accor... [more]

How to improve the combustion efficiency and reduce harmful emissions has been a hot research topic in the engine field and related disciplines. Researchers have found that nano-additives to diesel-biodiesel fuel blends have achieved significant results. Many research results and both current and previous studies on nanoparticles have shown that nano-additives play an essential role in improving the performance of internal combustion engines and reducing the emission of harmful substances. This paper summarizes the recent research progress of nanoparticles as additives for diesel-biodiesel fuel blends. Firstly, the excellent properties of nanoparticles are described in detail, and the preparation methods are summarized and discussed. Secondly, the effects of several commonly used nanoparticles as diesel-biodiesel fuel blends on combustion performance and harmful substances emissions in terms of combustion thermal efficiency, brake specific fuel consumption, CO, UHC and NOx, are reviewe... [more]

The EN ISO 52016-1:2017 standard introduced a new methodology for the hourly calculation of energy needs that allows the study of the dynamic energy performance of buildings. In this study, a comparative analysis was carried out between two heat transfer models for opaque building elements: the one described in the new standard EN ISO 52016-1:2017 (Annex B) and that proposed by the Italian national annex (Annex A). The analysis, carried out on 1854 cases, showed better results for the heating period than for the cooling period, with a lower Root-Mean-Square Error and Coefficient of Variation of the Root-Mean-Square Error for the model proposed by the Italian National Annex. Increasing the performance of the building by decreasing the solar transmission coefficient of the glazed surfaces leads to a worse Root-Mean-Square Error of about 11%. In addition, a sensitivity analysis of the thermo-physical parameters of the opaque building components was carried out and an alternative method fo... [more]

Analysis of the sustainability implications of the geothermal industry has tended to take a high-level or systemic overview of national performance rather than deeper, stakeholder-focused investigations. This study seeks to begin to fill this gap in the literature, investigating the following research question: how do projects in the Icelandic geothermal energy sector create co-benefits with stakeholders and reflect the integration of sustainable energy development (SED)? The focus of the analysis is identifying the stakeholders, what the sustainability benefits co-created with stakeholders are, and when in the projects’ life-cycle do these occur. Based on eleven semi-structured interviews with project managers in Iceland’s geothermal industry, the study identifies an array of stakeholders in the sector, including national and municipal governments, public sector institutions, businesses, the public, employees, and landowners. The sustainability co-benefits of Iceland’s geothermal powe... [more]

In the wireless power transmission (WPT) to electric vehicles (EVs) in parking lots, there is a risk of abnormal heat generation due to the absorption of the magnetic field in metallic foreign objects. Accordingly, currently available products are equipped with a function that automatically halts power transmission when a metallic foreign object is detected. However, if possible, continuing power transmission while suppressing the magnetic field absorption may be an another solution. Therefore, this paper proposes a novel function which enables wireless power transmission with high efficiency while suppressing the magnetic field absorption of metallic foreign objects. In this study, it was assumed that a metallic foreign body was present in an arbitrary point in a two-dimensional plane and the power transmission was conducted by the phased array WPT. An algorithm using particle swarm optimization (PSO) to search for the optimal combination of the phase and amplitude of the coil input v... [more]

An engine must operate at an appropriate working temperature, the wear resistance of the engine parts must be increased, and frictional loss of energy must be reduced to increase performance and reduce exhaust pollution. This study determines the effect of cylinder temperature and different coatings for piston rings on engine characteristics. Ni-W alloy and Ni-W-BN(h) composite coatings are applied to the compression ring, and the dynamometer test is performed over 50 h using different operating parameters. The experimental data are analyzed by curve fitting for engine performance with cylinder temperature (Tsc) and the concentration of exhaust pollution particles. The experimental results show that a Ni-W alloy plating increases the wear resistance of piston rings. A Ni-W-BN(h) composite coating contains self-lubricating particles, which increases the wear resistance and lubricating properties. In terms of engine performance, Ni-W-BN(h) coated piston rings give the best brake mean eff... [more]

This article examines the acceptance of renewable energy in the adoption of the climate package, taking into account the GREEN consumer values among consumers in Poland. The research problem addressed in this paper relates to the measurement of consumer values in terms of the GREEN concept; specifically, consumer acceptance of the available offerings provided by real businesses. In addition, consumer needs are important in terms of ensuring the acceptance of renewable energy, which will create opportunities for its production in the context of the Fit 55 climate package. The study formulates some research questions and hypotheses to justify the concept with empirical data by applying statistical tests. The study is presented in several sections with a detailed presentation of secondary and primary data. The main outcome of the research is based on the primary data using a structured survey questionnaire administered in Poland and 557 collected samples. Nowadays, the responsibility also... [more]

This paper discusses the Reliability, Availability, Maintainability, and Safety (RAMS) of an electrical power supply system in a large European hospital. The primary approach is based on fuzzy logic and Petri nets, using the CPNTools software to simulate and determine the most important modules of the system according to the Automatic Transfer Switch. Fuzzy Inference System is used to analyze and assess the reliability value. The stochastic versus fuzzy approach is also used to evaluate the reliability contribution of each system module. This case study aims to identify and analyze possible system failures and propose new solutions to improve the system reliability of the power supply system. The dynamic modeling is based on block diagrams and Petri nets and is evaluated via Markov chains, including a stochastic approach linked to the previous analysis. This holistic approach adds value to this type of research question. A new electrical power supply system design is proposed to increa... [more]

This paper evaluates the energy performance of shallow ground source heat pumps using the state-of-art whole building energy simulation tool. In particular, the paper presents a systematic and easy to implement approach to model the energy performance of shallow and helical ground heat exchangers and assess their energy efficiency benefits to heat and cool buildings. The modeling approach is based on the implementation of G-functions, generated using a validated numerical model, in a state-of-art whole building energy simulation tool. Both the numerical model and the simulation tool are applied to assess the energy performance of various shallow geothermal systems designed to meet heating and cooling needs for detached single-family homes in California. Specifically, a series of sensitivity analyses is conducted to determine the energy performance of the shallow geothermal systems in 16 locations representing all California climate zones. It is found that the suitability and the effici... [more]

As fossil fuels continue to be extracted and used, issues such as environmental pollution and energy scarcity are surfacing. For the transportation industry, the best way to achieve the goal of “carbon neutrality” is to research efficient power systems and develop new alternative fuels. As the world’s largest product of chemicals, ammonia is a new renewable fuel with good combustion energy. It can be used as an alternative fuel to reduce carbon emissions because of its proven production process, low production and transportation costs, safe storage, the absence of carbon-containing compounds in its emissions, and its future recyclability. This paper firstly introduces the characteristics of ammonia fuel engine and its problems; then it summarizes the effects of various ammonia-blended fuels on the combustion and emission characteristics of the engine from the combustion problem of ammonia-blended engine; then the fuel storage of ammonia-blended hydrogen is discussed, the feasibility of... [more]

The current work investigates the feasibility of a novel Carbon Capture and Utilization (CCU) approach—also known as Underground Sun Conversion (USC) or geo-methanation. The overall objective of the current work is a comprehensive assessment on the technical, economic and legal aspects as well as greenhouse gas impacts to be concerned for establishing USC technology concept. This is achieved by applying multidisciplinary research approach combining process simulation, techno-economic and greenhouse gas assessment as well as legal analysis allows answering questions about technical, economic feasibility and greenhouse gas performance as well as on legal constraints related to large scale CCU using geo-methanation in depleted hydrocarbon reservoirs. CO2 from the industry and renewable H2 from the electrolyser are converted to geomethane in an underground gas storage and used in industry again to close the carbon cycle. Process simulation results showed the conversion rates vary due to op... [more]

Renewable Energy Communities have been recently introduced in European legislation to promote distributed generation from renewable energy sources. In fact, they allow to produce and consume energy from shared local power plants. Low temperature district heating and cooling networks with distributed heat pumps have demonstrated their capability to exploit renewable and waste heat sources in the urban environment. Therefore, they are considered a promising infrastructure to help decarbonize the building sector. As their main operating cost is the electricity purchased by the utility for heat pumps and circulation pumps, this work investigates whether a Renewable Energy Community could help mitigate such cost by sharing electricity produced by local photovoltaic (PV) systems. The research relies on computer simulations performed with both physical and statistical models for the evaluation of electrical load profiles at the district level. Results show that due to the different seasonalit... [more]

With the increase of photovoltaic penetration rate, the fluctuation of photovoltaic power generation affects the reliability of ship power grids. Marine PV grid-connected systems with high penetration rates should generally have a low voltage ride-through capability. In the present paper, a strategy in which super capacitors are applied for energy storage in a marine photovoltaic grid-connected system is proposed, and an inverter adopts independent decoupling control of active and reactive currents to improve the LVRT capability of photovoltaic grid-connected systems. In addition, a comprehensive control strategy is also designed to control the supercapacitor, to regulate the active power through the control method of the voltage outer loop and the current inner loop, in order to maintain the DC bus voltage stability. At the same time, the inverter can increase the reactive power output to support the grid voltage. The advantage of this system is in smoothing the power imbalance in a s... [more]

VANETs have gained much attention from both industry and academia because of their characteristics, such as dynamic topology. There are various applications of VANETs that are classified on the basis of safety, efficiency, commercial usage, and productive areas. This paper presents an IoT-based formal model for vehicle-life integration enabling RSUs with the help of different approaches. We have developed a model that uses vehicle scenarios in smart transportation systems so that quick data transmission is provided between the source and destination vehicles. Further, fog-based RSUs provide a wide range to communicate with hospitals and emergency vehicles to deal with emergency situations. All the appropriate entities are connected to ensure a consistent traffic flow for the arrival of an emergency vehicle in emergency places. The UML, graph theory, and VDM-SL formal technique are used to represent this system. To model the network and discover appropriate paths for V2V communication,... [more]

Clean heating has not been widely applied in rural Chinese areas. Considering the abundance of solar energy resources, harvesting solar energy for heating can be an effective solution to the problem of space heating in most rural areas. As the disperse building distribution in rural areas makes it difficult to implement centralized heating on a large scale, deploying centralized−decentralized hybrid solar heating system can achieve the best result from both the technical and economic perspectives. Taking a virtual village in Tibet as an example, this paper explores how to obtain optimal design of centralized−decentralized hybrid solar heating system based on building clustering. The results show that: (1) Compared with the fully centralized system and fully decentralized system, the centralized−decentralized hybrid solar heating system in the studied case could achieve a life cycle cost (LCC) saving of 4.8% and 2.3%, respectively; (2) The LCC of centralized−decentralized hybrid solar h... [more]

The purpose of this paper is to analyze the magnetic field distribution over a disc with magnets. This disk is part of an electromagnetic microgenerator that allows the generation of electricity as a result of changes in the magnetic field. The other part of the microgenerator is the structure of the coils. In the previous work of the authors, a complete microgenerator system was presented where the coils were made using thick-film and low-temperature co-fired ceramic (LTCC) technology. Several studies related to the influence of the shape and number of coils on the generated power were carried out, as well as the realization of complete electromagnetic microgenerators with voltage rectifying circuits. Until now, a disc with 28 neodymium magnets of size 10 × 3 × 1.5 mm3 was used for testing. In order to optimize the structure of the microgenerator with respect to the disc with magnets and thus increase the generated power, it was decided to perform appropriate tests to analyze the magn... [more]

Cavity width and height are two key geometric parameters of squealer tips, which could affect the control effect of squealer tips on tip leakage flow (TLF) of gas turbines. To explore the optimal values and the control mechanisms of cavity width and height, various cases with different cavity widths and heights are investigated by solving the steady Reynolds Averaged Navier−Stokes (RANS) equations. In this study, the range of cavity width is 9.2−15.1 τ, and that of cavity height is 1.0−3.5 τ. The results show that the optimal value of cavity height is 2.5−3.0 τ, and that of cavity width is about 10.0−10.5 τ. The small cavity width could restrain the breakdown of tip leakage vortex (TLV) and reduce the extra mixing loss. Both small cavity width and large cavity height could enhance the blocking effect on the TLF, reducing the corresponding mixing loss. However, both of them will inhibit the length of the scraping vortex (SV), which is bad for the control of loss. In addition, large cavi... [more]

An array of multimodal and multiscale images of fractured shale rock samples and analogs was collected with the aim of improving the numerical representation of fracture networks. 2D and 3D reconstructions of fractures and matrices span from 10−6 to 100 m. The origin of the fracture networks ranged from natural to thermal maturation to hydraulically induced maturation. Images were segmented to improve fracture identification. Then, the fractal dimension and length distribution of the fracture networks were calculated for each image dataset. The resulting network connectivity and scaling associations are discussed at length on the basis of scale, sample and order of magnitude. Fracture network origin plays an important role in the resulting fracture systems and their scaling. Rock analogs are also evaluated using these descriptive tools and are found to be faithful depictions of maturation-induced fracture networks.

This paper presents the comparison of combustion characteristics in a constant volume combustion chamber (CVCC) with alternative fuel biodiesel blends. To achieve this goal, a CVCC experimental was established, and the biodiesel was made from fish oil and was used as test fuel. The combustion process of diesel fuel (B0) and bio-diesel 10% (B10) will be investigated based on doing experiments with two conditions: air-fuel mixed before and after ignition timing. The influence of the oxygen concentration on the burning process is also being investigated. The results of the research show that the heat release rate of B0 is faster and higher than that of B10 in the case of air-fuel mixed before ignition timing. In the case of after ignition timing, these values are almost similar to B0 and B10.

Smart buildings provide opportunities for technological transformations in building environments to improve resource management, comfort, and efficiency of the systems present in these facilities. For this, Internet of Things (IoT) solutions contribute, with monitoring and remote control features, to automate these environments. However, these solutions can promote the disposal or replacement of outdated but still-needed legacy systems. Thus, a reference model that uses retrofit techniques to update pre-existing systems would be an alternative to enable smart building convergence. The lack of models that advocate this type of strategy provides an opportunity for the emergence of methods capable of filling this gap. Thus, this work presents a strategy for implementing monitoring, control, and communication resources to achieve smart building convergence in legacy building systems. This strategy consists of the use of retrofit techniques based on the adaptation of the SmartLVGrid metamod... [more]

This article examines the features of the heat supply organizations (HSO) anti-crisis management, which has become relevant due to the pandemic in the spring of 2020. It is noted that the spread of coronavirus and the related economic problems had a negative impact on the sustainable development indicators of both countries and organizations. HSO, which are rarely considered in modern publications, are positioned in the study as the most important part of the economy of any country, on which the future stabilization of the economic situation among heat consumers depends. This study made it possible to draw a conclusion about the strengthening of the HSO engineering systems technical state role in the anti-crisis management of these organizations. The study summarizes and presents the main characteristics of the heating networks technical condition and systematizes all types of diagnostics that are encountered in practice. The characteristics of HSO management choices of the technical s... [more]

This paper proposes a decentralized control structure and method for a multilevel single-phase power converter using space vector pulse width modulation (SVPWM). The focus of this paper is on the decentralized control structure for the power converter cells that will exchange information with neighboring cells in order to adjust the switching vector and switching time for each cell. In this study, the switching vectors and the corresponding switching times of each cell will be self-determined based on the phase angle of two neighboring cells. Normally, SVPWM applied to the multilevel power converters need complete information about the total cells and cell’s position to build a control algorithm. Meanwhile, a decentralized space vector pulse width modulation (DSVPWM) method is proposed that can be applied to power converters with any number of cells and can be considered as a multilevel SVPWM method. In addition, the decentralized multilevel single-phase power converter has high flexib... [more]