With the development of the economy and society, energy problems have become a great concern. The heat pump-coupled thermal energy storage (TES) system is a potential form of building heating, which can improve the stability of the grid and promote the consumption of renewable energy. Phase change materials (PCMs) are widely used in the field of building heating, but there are still some problems such as unsatisfactory melting points, low thermal conductivity, phase separation, and supercooling, which limit the application of PCMs in heat pump heating systems. Therefore, it is very important to improve PCMs by a performance improvement method. This work first summarizes the classification, advantages and disadvantages of PCMs, and introduces the connection between PCMs and heat pumps. Then, a detailed summary of PCMs applied in heat pump heating systems is presented, and a comprehensive review of the performance improvement methods for PCMs, which include additives, encapsulation, and... [more]

The energy transition requires widespread electrification of the transport sector. To promote the penetration of electric vehicles (EVs), it is essential to understand consumers’ perceptions and behavior, particularly regarding the main determinants of EV purchase and the acceptance of electric mobility (EM). With this aim, we focused on an industrialized city in Portugal, addressing the differences between the effective ownership of an EV and the acceptability of EM and between the domestic sector (DS) and the business sector (BS) through questionnaires. Our results indicate that sociodemographic variables are the main determinants of the purchase of EVs and the acceptance of EM in the DS. Men and higher income individuals are more likely to own an EV. On the other hand, younger generations are more likely to have high EM acceptance. Individuals who already own an EV are the ones that have the desire and economic means to do so, regardless of any incentives. Still, widespread market p... [more]

The article presents energy, economic and environmental analyses of the possibilities of using alternative, high-efficiency sources of heat and energy for the multi-family residential building located in Wrocław, Poland, in the temperate climate zone characteristic of Central Europe. For conventional, alternative and hybrid heating systems based on renewable energy sources, comparative analyses of final energy demand, demand for non-renewable primary energy, CO2 emissions, investment costs and life cycle costs were carried out. The detailed comparative analyses of the research results led to the formulation of conclusions and recommendations which may serve as guidelines for designers of multi-family residential buildings and investors. The solutions of heating and hot water preparation systems recommended in the article will enable the design and construction of buildings with no negative impact on the environment. Taking into account the economic and environmental analyses, the optim... [more]

Partial upgrading of bitumen (PUB) improves the quality (increases the value) of crude oil from bituminous sands to the level where pipeline specifications are met without—or with reduced use of—costly diluent. By reducing the cost of transportation to downstream refineries, PUB can serve as a solution to market access challenges and takeaway capacity constraints for oil sand producers. However, despite significant government and private investments, proponents in the Canadian province of Alberta still face challenges in commercializing the technology. We used a capacity investment model to explore the expected effects of different policy support types on a firm’s decision to invest in a partial upgrading facility integrated with an existing oil sands extraction facility. We evaluated 10 potential policy interventions and their expected effects on investments in partial upgrading. We focused our analysis of these policy interventions on the revenues and costs of firms, risk sharing, an... [more]

Renewable resources for producing energy for self-consumption are growing, namely solar energy. This work focuses on the comparison of photovoltaic systems for energy production for self-consumption on a property in three different regions of Portugal using traditional and emerging technologies, without batteries’ implementation. According to Portuguese law, there is no stipulated value for selling surplus energy produced by a self consumption unit, to the public grid. In order to analyse the economic viability of the project, two scenarios are studied: the delivery, at zero cost of the surplus energy produced to the grid, and its sale. Furthermore, the same analysis is carried out considering partial shading on the photovoltaic generator. The results show that if there is no surplus production sale to the grid, the project becomes economically unviable for the four PV technologies. Otherwise, for the traditional technologies, the project is economically viable, presenting a payback ti... [more]

Extensive energy consumption has incurred global environmental problems such as climate change. Home appliances are highly used products and consume large amounts of energy. When widely applied, energy-efficient home appliances promote energy efficiency and reduce carbon emissions. Therefore, people’s intention to purchase these home appliances merits research attention. In this study, a comprehensive model was developed using the theories of planned behavior, perceived value, and environmental awareness. Data were collected through a questionnaire survey, to which 448 valid responses were returned, and analyzed using partial least squares. The results indicated that consumers’ intention to purchase energy-efficient home appliances was positively affected by their attitude toward purchasing the appliances. Such attitude was significantly and positively affected by functional value, price value, environmental value, and environmental awareness. However, consumers’ attitudes toward purch... [more]

This article deals with fault detection and the classification of incipient and intermittent open-transistor faults in grid-connected three-level T-type inverters. Normally, open-transistor detection algorithms are developed for permanent faults. Nevertheless, the difficulty to detect incipient and intermittent faults is much greater, and appropriate methods are required. This requirement is due to the fact that over time, its repetition may lead to permanent failures that may lead to irreversible degradation. Therefore, the early detection of these failures is very important to ensure the reliability of the system and avoid unscheduled stops. For diagnosing these incipient and intermittent faults, a novel method based on a Walsh transform combined with a multilayer perceptron (MLP)-based classifier is proposed in this paper. This non-classical approach of using the Walsh transform not only allows accurate detections but is also very fast. This last characteristic is very important in... [more]

Clathrate and semi-clathrate hydrates have recently been gaining major interest as hydrogen storage material. The benefits of hydrates, such as reversible formation and dissociation, their environmentally friendly nature, economical costs, and lower fire risk, make them one of the most promising hydrogen storage materials. One of the major challenges when storing hydrogen in hydrate crystals is the extreme pressure and temperature conditions required for the formation of hydrogen hydrates. Solving the problems of extreme pressure and temperature through the use of promoter molecules would make these materials a promising storage medium with high potential. Through the use of efficient, economical, and green promoter molecules, hydrogen hydrate can be used to store large amounts of hydrogen economically and safely. This review aims to present a comprehensive summary of the different hydrate promoters that have been tested specifically in terms of hydrogen storage. The hydrate promoters... [more]

According to data from the BP Statistical Review of World Energy 2020 [...]

The growth of renewable energy actively takes part in decarbonizing the fossil-fuel-based energy system. It reduces carbon emissions, carbon footprint, and greenhouse gas emissions and increases clean energy. The usage of renewable resources reduces and solves several problems, such as increasing temperature, carbon footprint, greenhouse gas emissions, and energy waste. Every sector contributes to increasing the above-mentioned factors in the environment. One of the main reasons for this biodegradation and climate change is energy resources. Using renewable energy instead of fossil fuel can solve the problem. This paper aims to find open research problems about the application of renewable energy and to initiate new innovative ideas regarding renewable energy. A detailed state of the art includes trends for renewable energy resources, their theoretical evolution, and practical implementations. Methodologies used for decision analysis in renewable energy are discussed in detail. The tim... [more]

Energy is the substance foundation of human society. Single−atom catalysts (SACs) have emerged as promising electrode materials in the energy field owing to their unique characteristics. It was demonstrated that the hydrogen evolution reaction (HER) performance of SACs relies on the metal−centric species and the corresponding local coordination engineering. Herein, the recent progress relating to asymmetric atomic catalysts for the HER is reviewed, including low coordination, heteroatomic coordination, and bimetallic coordination. In addition, the connection between the coordination structures and the presented electrocatalytic performance was discussed. The main challenges that need to be addressed for the asymmetric atomic catalysts in the HER are summarized. Finally, some insights into the development of high−quality asymmetric atomic catalysts are included.

Over the past few years, considerable research work has been performed on the graphene-based nano-dispersion for improvement of the thermal conductivity and thermal characteristics of base fluid. Graphene-based dispersion shows the good stability, better enhancement in thermal conductivity, and heat transport behavior compared to the other nano-dispersions drawing significant attention among researchers. This article carries out comprehensive reviews on the heat transport behavior of graphene-based nano-dispersion over the past ten years. Some researchers have carried out the investigations on the various methods adopted for the preparation of graphene-based nano-dispersion, techniques involved in making good dispersion including stability characterizations. There needs to be a better agreement in results reported by the various researchers, which paves the way for further potential research needs. Some researchers studied thermo-physical properties and heat transport behavior of graph... [more]

Chemical looping (CL) technology is a novel technology for the clean and efficient use of energy. Oxygen carriers (OCs) are the cornerstone of CL technology. The development of low−cost, high−performance OCs is crucial for the application of CL conversion. Hematite, one of the natural Fe−based OCs, has several advantages (e.g., low cost and environmental friendliness), but its low reactivity limits its application in CL. The performance of hematite can be effectively improved by modifying some of its active components. This study explored the improvement of hematite reactivity by adding alkaline (earth) metals (K, Na, and Ca) and transition metals (Ni, Cu, and Mn). The crystal phases of the OCs were characterized using X-ray diffraction (XRD), and the results revealed that the addition of metals significantly changed the phase of the original hematite. The active solid solution of K−Fe−O and Na−Fe−O species exhibited strong catalytic activity to facilitate lignite char conversion. The... [more]

The expanding role of renewable energy sources in the electricity market share implies the increasing role of hydropower and the exploitation of unharnessed hydraulic potential, in the scope of sustainability and net zero emissions. Hydro-turbine design practices are expected to expand beyond achieving high efficiency goals, to multi-objective criteria ranging from efficient reversible operation to fish-friendly concepts. The present review paper outlines fundamental characteristics of hydropower, summarizing its potential impact toward aquatic life. Estimates of lethality for each damage mechanism are discussed, such as barotrauma, blunt impact and shearing, along with relevant advances in experimental techniques. Furthermore, numerical techniques are discussed, ranging from simple particle tracking to fully coupled six-degree-of-freedom tracking, which can be used to investigate candidate designs and their fish-friendly performance, presenting their advantages and disadvantages. Subs... [more]

This article aims to provide a technique for identifying and categorizing interturn insulation problems in variable-speed motor drives by combining Salp Swarm Optimization (SSO) with Recurrent Neural Network (RNN). The goal of the proposed technique is to detect and classify Asynchronous Motor faults at their early stages, under both normal and abnormal operating conditions. The proposed technique uses a recurrent neural network in two phases to identify and label interturn insulation concerns, with the first phase being utilised to establish whether or not the motors are healthy. In the second step, it discovers and categorises potentially dangerous interturn errors. The SSO approach is used in the second phase of the recurrent neural network learning procedure, with the goal function of minimizing error in mind. The proposed CSSRN technique simplifies the system for detecting and categorizing the interturn insulation issue, resulting in increased system precision. In addition, the pr... [more]

The integration of distributed generation (DG) into a power distribution network allows the establishment of a microgrid (MG) system when the main grid experiences a malfunction or is undergoing maintenance. In this case, the power-generating capacity of distributed generators may be less than the load demand. This study presents a strategy for the effective utilization of deployed active and reactive power sources under power mismatch conditions in the islanded distribution networks. Initially, the DGs’ and capacitors’ optimal placement and capacity were identified using the Jaya algorithm (JA) with the aim to reduce power losses in the grid-connected mode. Later, the DG and capacitor combination’s optimal power factor was determined to withstand the islanded distribution network’s highest possible power demand in the event of a power mismatch. To assess the optimal value of the DG−capacitor pair’s operating power factor (pfsource) for the islanded operation, an analytical approach ha... [more]

The 5th generation (5G) cellular networks offer high speeds, low latency, and greater capacity, but they face greater penetration loss through buildings than 4G due to their higher frequency bands. To reduce this loss in energy-efficient buildings, a passive antenna system was developed and integrated into sandwich walls. However, the thermal effects of this system, which includes highly thermally conductive metals, require further study. In this research, three-dimensional heat transfer simulations were performed using COMSOL Multiphysics to determine the thermal transmittances (U-values) of 5G antenna walls. The results revealed that, using stainless steel as the connector material (current design), the U-value rose from 0.1496 (for the wall without antenna) to 0.156 W/m2K, leading to an additional heating loss per year of only 0.545 KWh/m2 in Helsinki. In contrast, with the previous design that used copper as the connector material, the U-value increased dramatically to 0.3 W/m2K, e... [more]

The photovoltaic panel has become the most promising alternative technology for energy demand. Solar trackers have been used to improve the efficiency of a photovoltaic panel to maximize the sun’s exposure. In high temperatures, however, the photovoltaic efficiency is significantly reduced. This study observes photovoltaic/thermoelectric generator performance driven by a dual-axis solar tracking system. A photovoltaic/thermoelectric generator panel was built and equipped with angle and radiation sensors. A microcontroller processes the sensor signal and drives the motor to follow the sun’s movement in two-axis directions. Thermocouples are mounted on the photovoltaic and thermoelectric generator surfaces to monitor the temperature. The result shows that the temperature of the photovoltaic/thermoelectric generator is lower than that of the photovoltaic one. However, a contradiction occurred in the output power. The efficiency of the combined photovoltaic/thermoelectric generator was 13.... [more]

Sustained increase in plastic use has placed a significant burden on waste disposal infrastructure. Pyrolysis is the process of decomposing high-molecular-weight compounds by heating waste plastics at 500−1000 °C without oxygen. This process considerably reduces greenhouse gas emissions and has a high alternative energy effect (0.57 TOE ton−1). After a separation process, the oil produced by pyrolysis (C5−C20) can yield naphtha oil (C6−C7). Subsequently, hydrogen can be produced through a reforming reaction of this naphtha oil. Here, we produced hydrogen from waste plastic pyrolysis oil over a Ni/Ce-Zr-Mg/Al2O3 catalyst using a steam reforming process. A model oil combining the major substances of C6 and C7 (hexane, hexene, heptane, heptene, and toluene) was formed. From the reaction products, the hydrogen yield was obtained based on analysis of H2, CO, and CO2 concentrations using gas chromatography. The effect of N2 and O2 addition on hydrogen yield was analyzed within a temperature... [more]

Distributed Power Generation and Energy Storage Systems (DPG-ESSs) are crucial to securing a local energy source. Both entities could enhance the operation of Smart Grids (SGs) by reducing Power Loss (PL), maintaining the voltage profile, and increasing Renewable Energy (RE) as a clean alternative to fossil fuel. However, determining the optimum size and location of different methodologies of DPG-ESS in the SG is essential to obtaining the most benefits and avoiding any negative impacts such as Quality of Power (QoP) and voltage fluctuation issues. This paper’s goal is to conduct comprehensive empirical studies and evaluate the best size and location for DPG-ESS in order to find out what problems it causes for SG modernization. Therefore, this paper presents explicit knowledge of decentralized power generation in SG based on integrating the DPG-ESS in terms of size and location with the help of Metaheuristic Optimization Algorithms (MOAs). This research also reviews rationalized cost-b... [more]

Prior to the year 2000, air conditioning was not common in many cities throughout the world. However, today, 20 years later, air conditioning is common. This circumstance has a negative impact on the climate. Additionally, the situation regarding energy usage as a result of this is alarming. For a healthy and pleasant livelihood, indoor temperature and air flow must be controlled. False partitions with insulating layers have been used to regulate the temperature inside rooms, but they are unable to regulate the variation in humidity caused by the exchange of water between interior and exterior walls. In this manuscript, we provide a sensory system that can automatically detect relative humidity and temperature. Temperature is sensed at each layer of the false partition using an LM35-based integrated circuit and humidity is detected by an FA−ZnO nano-composite layer through an indoor false partition owing to changes in the material’s resistance. Depending upon the change in resistance b... [more]

Herein, we have prepared tin oxide (SnO2) nanoparticles (NPs), through a co-precipitation method, using SnCl2·2H2O dissolved in distilled water (DW) as a precursor. Then, the prepared NPs were heat treated in a muffle furnace, as a function of temperature, under an open atmosphere. The prepared SnO2 NPs were then re-dispersed in DW, followed by spray casting on a glass substrate, for preparing SnO2 thin films. The average thickness of the fabricated SnO2 thin films was 2.76 µm. We demonstrated a very clear variation in the structural, compositional, and morphological features of the different films (in particular, variation of the density of oxygen vacancies), which altered their electrical and optical properties. Raising the calcination temperature of the SnO2 thin films, from 250 °C to 650 °C, led to a monotonic reduction in the crystallite size, from 10.4 nm to 6.7 nm, and a decrease in the O/Sn ratio, from 5.60 to 4.79. A 14.5% decrease in the O/Sn ratio resulted in a decrease in t... [more]

The energy crisis caused by global structural changes in the economic sphere is the cause accelerating the energy transition based on the concept of sustainable development. This study is to test the hypothesis about the incentive effect of tax expenditures on alternative energy and energy conservation. The objects of empirical research are the EU, OECD countries, OECD partner countries and Russia from 2018−2020. The tools of scientific research are based on methods of economic−statistical and comparative analysis and expert judgments. The concept of tax expenditures in terms of decarbonization is analyzed using a systematic approach. The integrated methodological approach shows the relationship between the tax policy and government strategies in achieving sustainable development goals to ensure the transition to rational energy consumption patterns and sustainable energy sources. The authors analyze incentives for the energy sector and alternative energy sources in the considered grou... [more]

This paper presents a comprehensive model predictive control (CMPC) method to control a three-phase four-legged inverter (TP4LI) for PV systems. The proposed TP4LI model aims to predictively model and control switching frequency and higher voltage/current switching to reduce losses. The CMPC model can be operated in four modes, namely standard MPC mode (Mode I), switching frequency reduction (SFR) mode (Mode II), high voltage/current switching loss reduction (SLR) mode (Mode III), and SFR plus SLR mode (Mode IV, a combination of Modes II and III). The proposed CMPC approach controls the TP4LI to (1) successfully track balanced and unbalanced reference currents with balanced or unbalanced loads; (2) reduce switching losses; and (3) keep the generated current total harmonic distortion (THD) within the industry’s recommended limits. The TP4LI model with the CMPC approach was verified and validated in the MATLAB/Simulink for a PV system. The simulation results show good tracking and perfor... [more]

The maintenance paradigm has evolved over the last few years and companies that want to remain competitive in the market need to provide condition-based maintenance (CBM). The diagnosis and prognosis of the health status of equipment, predictive maintenance (PdM), are fundamental strategies to perform informed maintenance, increasing the company’s profit. This article aims to present a diagnosis and prognosis methodology using a hidden Markov model (HMM) classifier to recognise the equipment status in real time and a deep neural network (DNN), specifically a gated recurrent unit (GRU), to determine this same status in a future of one week. The data collected by the sensors go through several phases, starting by cleaning them. After that, temporal windows are created in order to generate statistical features of the time domain to better understand the equipment’s behaviour. These features go through a normalisation to produce inputs for a feature extraction process, via a principal comp... [more]