The transcritical CO2 (T-CO2) power cycle using low temperature waste heat is a promising technique for energy saving and environmental protection. However, according to the literature, there is no commercialized unit in service yet. This study provides developers a reference to shorten the design phase of the T-CO2 cycle commercialization process. A sensitivity analysis of the system performance, i.e., thermal efficiency and net power output, regarding the isentropic efficiencies of pump (ηp) and expander (ηe) and the heat source temperature (Th,in) has been carried out using MATLAB and NIST REFPROP database. Simple and recuperative configurations are investigated based on their own optimal working pressures. The results show that the enhancement of ηe has a greater influence on improving the system performance, but the improvement will diminish as ηp, ηe, and Th,in increase. Although better system performance can be achieved with higher ηp, ηe, and Th,in, the cost of the system equip... [more]

The technological installations’ characteristics are possible to improve by equipping fans with a frequency-controlled electric drive. However, it can lead to an electromagnetic compatibility problem in the electrical supply system. This problem becomes worse if a large number of fans are included in the technological installation and the electric drives are powered from a substation connected to a limited power source. As an example, in this article we investigate the power supply system of a gas cooling unit with variable-frequency electric drives for fans. The electric drives’ operating mode dependences characterizing the non-sinusoidal voltages and currents of the power source are obtained with the help of simulation modeling in the MATLAB environment with the Simulink expansion package. The typical substation circuit usage for the power supply of a group of fans with a frequency-controlled drive does not meet the requirements of IEEE Standard 519-2014. We can solve the problem of... [more]

In the plan of the European Green Deal, the European Union assumed that by 2050 Europe will become the first climate-neutral continent in the world. This will be supported by alternative (renewable) energy sources (RESs), also termed green energy (GE). Their use should have long-term environmental benefits. To do this, it is necessary to skillfully select RES products. Therefore, the purpose is to develop a method for selecting devices that convert to GE, including not only qualitative criteria, but also environmental criteria and their price. The method is based on customer requirements and expert knowledge. The general concept of the method allows for the assessment of selected qualitative and environmental criteria of products and determining the price of purchase of these products. In a hybrid way, the following techniques were used: SMARTER method, brainstorming (BM), MAP method (alternative-punctual Czechowski’ method), ACJ method (price−qualitative analysis). Based on the result... [more]

This research developed an effective environmental temperature control system for homes and buildings. The study used a photovoltaic panel (PV) and developed a solar installation with thermosiphon circulation, which has a flat solar collector and heat-insulating translucent glass with double glazing with reduced pressure. The coolant is made of thin-walled corrugated stainless pipe. The heat from the solar flux heats the liquid removed from the collector, and cold water from the siphon enters its place. There is a constant circulation of heat, which increases heat transfer efficiency by eliminating additional partitions between the panel and thermal insulation. We have also developed a solar system control controller, which includes an electronic unit with six sensors. The six sensors are controlled by the STM32 programmable Logistics Integrated circuit (FPGA), designed to monitor the entire solar system, and the drives include power relays. The performance of the photovoltaic panel an... [more]

A method for evaluating the dominant seepage channel (DSC) water flooding in a layered sandstone reservoir is proposed and applied in an oilfield based on the water-cut derivative. The water-cut derivative curve of the reservoir with DSC shows double peaks. Therefore, based on the analysis of geology and production characteristics, the evaluation method of DSC is established. The evaluation index is proposed to quantitatively characterize the development degree of DSC and determine its distribution in a water-flooding reservoir. The test data validate that the proposed method can not only accurately determine the DSC and quantitatively evaluate its development degree, but also show its dynamic change. This method will be a powerful guide for water controlling and oil stabilizing in the adjustment stage of sandstone reservoirs.

Systems for determining the position of objects inside buildings have a wide range of applications, such as the surveillance of people’s movements in hospitals, and of goods or mobile robots in warehouse spaces or production halls. Hence, there is a need for the development of methods that could be applied for those purposes. This paper presents the results of research on an experimental system for localizing people being evacuated from a building. The proposed solution was designed as a part of the building evacuation management system. The method used for finding location belongs to the class of proximity-type methods and is based on Received Signal Strength Indicator (RSSI) information of Bluetooth Low-Energy (BLE) devices. The devices used to build the system (BLE receivers) and the evacuee’s wristband (BLE transmitters) are low-budget electronic modules. The paper presents preliminary research and the process of selecting data processing methods, as well as the results of tests of... [more]

A comprehensive assessment was conducted for the electricity dispatch in the Mexican National Interconnected System for the 2017−2021 period, as well as the projected period of 2022−2030, with special attention on emissions and the transition to clean energy. The reported official generation data for the 2017−2021 period were compared to the results of both one- and multi-node dispatch modeling. The officially reported generation mix was found to be sub-optimal in terms of costs and emissions. A small part of the differences can be traced back to transmission constraints. Some of the remaining discrepancies can be explained by out-of-merit order dispatch favoring fossil fuel power plants. While transmission constraints were not critical for the 2017−2021 period, an increasing unbalance between regions with cost-effective generation (exporting regions) and importing regions was found, calling for inter-region transmission corridor reinforcements in the near future. The 2022−2030 emissio... [more]

As the populations of cities grow, it is obvious that they need more and more resources. Energy is currently one of the most desirable resources due to the economic and energy crisis, but it needs to be used in a sustainable manner. There are cities that achieve smart city (SC) status that provide smart policies towards sustainable development. The aim of the present paper is to determine whether citizen engagement in SC can contribute to reduced energy consumption in the current economic crisis. The paper presents an original survey intended to collect primary data and a study conducted based exclusively on qualitative methods. The results concern a broad and multifaceted review of literature concerning SCs, as well as citizens’ engagement and their role in SC development. The study allows understanding of the economic phenomena taking place in SCs and filling the gaps regarding the behavior of SC citizens. It shows that SCs create smart citizens that feel responsible for the environm... [more]

Polymeric insulators have lightweight, excellent hydrophobicity and convenient transportation and installation. They are widely used in the external insulation for distribution and transmission lines. However, due to the long-term effects of pollution, ultraviolet radiation, discharge, temperature, humidity, altitude and other natural and complex environmental and service factors, the silicone rubber and other materials of polymeric insulators gradually age and lose their hydrophobicity and electrical insulation characteristics. The operability is significantly reduced, which seriously affects the safety and reliability of the power system. Hence, there is a need for assessing and evaluating the long-term aging and degradation of polymeric insulators under various operating conditions and environments. In this review, the various aging and characterization techniques of the polymeric insulators and their aging performance under the action of multiple factors are discussed. To enhance t... [more]

Pollution of water by plastic contaminants has received increasing attention, owing to its negative effects on ecosystems. Small plastic particles propagate in water and can travel long distances from the source of pollution. In order to research the settling motion of particles in water flow, a small-scale experiment was conducted, whereby spherical plastic particles of varying diameters were released in an open-channel flow. Three approaches were investigated to numerically simulate the motion of particles. The numerical simulation results were compared and validated with experimental data. The presented methods allow for deeper insight into particle motion in fluid flow and could be extended to a larger scale to predict the propagation of mesoplastics in natural environments.

This paper reports on a review on combined heat and power (CHP). A historical examination points out that combined heat and power was primarily used for hot heat valorizing (CHHP). The technological aspects evolved with this configuration first in industrial size. More recently, configuration with cold heat and power production (CCHP) appeared. Then, the immediate extension of this configuration led to trigeneration configuration, providing three useful effects: power and hot and cold heat. We suggest in the paper that progress regarding this last approach remains to be achieved towards the extension of trigeneration to polygeneration, whatever the form of energy and substance (water uses, for example). More generally, we consider that the goal, regarding the energy uses, is the integration of all needs in the design stage of the whole system (design optimization). Then, the evolution of the system in time should be considered, this being the purpose of control command of the optimized... [more]

This paper proposes a new peer-to-peer (P2P) energy trading method between energy sellers and consumers in a community based on multi-agent reinforcement learning (MARL). Each user of the community is treated as a smart agent who can choose the amount and the price of the electric energy to sell/buy. There are two aspects we need to examine: the profits for the individual user and the utility for the community. For a single user, we consider that they want to realise both a comfortable living environment to enhance happiness and satisfaction by adjusting usage loads and certain economic benefits by selling the surplus electric energy. Taking the whole community into account, we care about the balance between energy sellers and consumers so that the surplus electric energy can be locally absorbed and consumed within the community. To this end, MARL is applied to solve the problem, where the decision making of each user in the community not only focuses on their own interests but also ta... [more]

In order to realistically fulfil global and national climate protection targets, all potential measures have to be made use of to a maximum extent. Because it is readily available, biomass energy has been playing a key practical role for decades, supported by the traditional assumption of its carbon neutrality: under sustainable conditions, carbon dioxide emitted during combustion is held to be equal to its absorption during plant growth. In order to clarify conditions of carbon (C) neutrality, it is therefore necessary to model the annual natural C cycle on the entire planet and to include changes caused by a variety of growth strategies for biomass fuels. The “Combined Energy and Biosphere Model” CEBM calculates the cycle of plant growth, decay, biomass fuel production and its combustion on 2433 grid elements worldwide. CEBM results suggest that over many decades, the C pools of litter and especially soil organic carbon (i.e., humus layer) deplete considerably as a consequence of the... [more]

A large number of workers are entering the rapidly growing solar photovoltaic industry. The emerging occupational safety and health risks faced by the workers have rarely been measured and aptly addressed. Moreover, there is a lack of cross-cultural studies on solar photovoltaic workers engaged across different countries. This study was planned to measure the occupational safety and health risks, socio-demographic parameters, study the cross-cultural aspects and develop design concepts for risk mitigation. Field studies were conducted in solar installations in Saudi Arabia and India. Socio-demographic data and risk perception scores for eighteen different occupational safety and health risks were obtained from the workers (n = 135). In addition, discomfort glare was also measured. Design concepts were developed following the hierarchy of controls matrix and the bow-tie analysis method using the prevention through design approach. Heat stress, electrocution, solar radiation, and fire/el... [more]

Since the electronic power conditioner (EPC) is a crucial part applied of a Space Travelling-wave Tube Amplifier (STWTA), the reliability issue must be considered. Of all the failure modes of an EPC, the insulation failure of an EPC in thermal and moist environments is the most serious, and needs special attention. By investigating the influence of contamination, humidity, and temperature on surface insulation resistance (SIR) and surface discharge, we focused on the determination of the insulation failure boundary in an EPC. Considering real working conditions, we used the typical circuit applied in the EPC as the test object. The insulation deterioration phenomenon under different thermal and moisture stress was studied. The results show that: (1) SIR of the samples did not change with contamination levels when the relative humidity (RH) was below 70%. When RH was higher than 75%, the SIR began to vary with temperature and ionic contaminant concentration. (2) Even if the samples were... [more]

The paper is concerned with predicting energy consumption in the production and product usage stages and searching for possible changes in product design to reduce energy consumption. The prediction of energy consumption uses parametric models based on regression analysis and artificial neural networks. In turn, simulations related to the identification of improvement opportunities for reducing energy consumption are performed using a constraint programming technique. The results indicate that the use of artificial neural networks improves the quality of an estimation model. Moreover, constraint programming enables the identification of all possible solutions to a constraint satisfaction problem, if there are any. These solutions support R&D specialists in identifying possibilities for reducing energy consumption through changes in product specifications. The proposed approach is dedicated to products related to high-cost energy use, which can be manufactured, for example, by companies... [more]

One of the ways to minimize anthropogenic emissions from coal combustion is to replace conventional schemes used for the introduction of coal dust into the furnaces of power plants through the injection of water-containing fuels. In this research, the three most promising schemes for fuel combustion were implemented: (i) the simultaneous introduction of coal particles and water droplets into the combustion chamber; (ii) steam injection into the fuel particle combustion zone; and (iii) the introduction of coal−water slurries into the furnace. Three methods of supplying water to the combustion zone were evaluated using the multi-criteria decision-making technique. Experimental research was conducted to record a range of process characteristics: the time of the gas-phase and heterogeneous ignition, the time of complete combustion, minimum ignition temperatures, maximum combustion temperatures, the completeness of the fuel burnout and the concentrations of the main gaseous emissions. It ha... [more]

Clean electricity is generated by the anaerobic digestion of biomass waste. The environmental impacts of various biomass waste feedstocks vary, while co-digestion has been reported to improve anaerobic digestion performance. A consequential life-cycle assessment (LCA) and techno-economic analysis (TEA) are carried out for cow manure waste management for a cow farm. Three scenarios are considered in this study: (S1) mono-digestion of cow manure, (S2) co-digestion of cow manure and maize silage, and (S3) co-digestion of cow manure with cow feed waste, sewage sludge, and returned dairy products. The LCA aims to quantify the environmental impact of each MWh of electricity generated, assuming the plant is located in Malaysia, using OpenLCA software. The TEA economic parameters are quantified and compared between the three scenarios. Net present value (NPV), Internal Return Rate (IRR), and Return of Investment (ROI) are examined. Among the three scenarios, S2 with maize cultivation has a hig... [more]

Achieving sustainable development goals depends on governance effectiveness within the penetration of digital technologies in all spheres and levels. Furthermore, the energy sector is a crucial inhibitor of sustainable development that depends on the efficacy of digital public services. In this case, the paper aims at analyzing the impact of e-governance on achieving sustainable development goals, particularly on affordable and clean energy. The object of research is EU countries in the period 2013−2019. The data are compiled from the databases of Eurostat, the World Data Bank, and the Sustainable Development Report. The study applies the following methods: the taxonomy method to measure the e-governance index, the fixed effect, the random effect, and a pooled OLS regression model to check the impact of e-governance on affordable and clean energy. The results outlined the leaders (Estonia, Denmark, Finland, Sweden, Latvia, and Malta) and the outsiders (Romania, Croatia, Greece, Bulgari... [more]

In the literature on the subject, it is argued that tax policy is one of the tools stimulating the transition toward sustainable economies. Public authorities can use two functions for this purpose: fiscal and non-fiscal functions. High emission rates and the rising rapid atmospheric changes that come with them are serious threats to the climate and sustainable development. Reducing greenhouse gas emissions is one of the goals towards which the world strives (including the EU), so as to keep a balance between people’s expectations, economic aspects, and the needs of the environment. Therefore, it is necessary to explain whether, along with other factors, environmental policy and its component “green taxes” can act as a factor in limiting greenhouse gas emissions. The purpose of this article is to seek an answer to the question of whether “green taxes” as an instrument of tax policy are a significant factor influencing climate change by contributing to reducing greenhouse gas emissions.... [more]

In the petroleum industry, naphtha cracking centers (NCC), which produce ethylene, propylene, propane, and mixed-C4, are known to consume a large amount of energy and release a significant amount of carbon dioxide (CO2). This necessitates economic and environmental assessments with the aim of achieving a reduction in energy use in order to ensure efficiency in terms of cost and environmental impact. Herein, a heat exchanger network (HEN) is considered with the aim of determining its optimal operating strategy. In addition, the trade-off between reduction in utility costs (i.e., profit) and the installation cost of the heat exchanger (i.e., loss) is evaluated in terms of economic efficiency. Finally, an environmental impact assessment is performed with respect to the source of fuel consumed for steam generation. The HEN’s energy consumption in the three configurations analyzed herein was found to be reduced by 3%, 6%, and 8%. When considering variations in the fuel used for steam genera... [more]

Sugarcane leaves and trash burning during harvesting, and vinasse management, are major challenges of the Thai sugarcane industry. Identification of the appropriate valorization pathways for both the biomass waste streams using the sugarcane biorefinery concept is necessary. This study aims to assess the environmental sustainability of five CE models, including (1) sugarcane trash for electricity, (2) sugarcane trash to biochar, (3) sugarcane trash as a soil conditioner, (4) vinasse as a bio-fertilizer, and (5) vinasse for power generation. Life cycle assessment has been conducted using the ReCiPE midpoint impact assessment method. The results revealed that all waste utilization scenarios can help reduce the environmental impacts compared to the base case. The utilization of sugarcane leaves and trash for electricity generation brings about the lowest environmental impacts due to the environmental credits from the substitution of Thai grid electricity. The utilization of sugarcane leav... [more]

The use of solar thermal systems (STSs) has recently reached a significant edge. The increasing research on developing an alternative power supply for limiting fossil fuel usage and climate change are the driving forces of STSs. The current work explores the recent progress in STSs’ applications, including PV/T or “photovoltaic/thermal” systems, zero-energy buildings, greenhouse solar thermal applications, solar thermal for pumping water, solar thermal refrigerators, solar chimneys, water desalination, and solar collectors, along with the benefits and challenges of these applications. Then, the potential contribution of STSs in achieving the various SDGs or “Sustainable development goals”, including barriers and research gaps, are elaborated. In brief, STSs significantly contribute to the seventeen SDGs’ achievement directly and indirectly. Recent developments in the engineering applications of STSs are strongly based on the materials of construction, as well as their design, process o... [more]

The growing level of modern environmental problems and the need to ensure energy security creates new challenges for the development of the energy sector. Nowadays, countries must balance their international competitiveness and progress in achievement the Sustainable Development Goals. This provides a necessity for the development of alternative energy technologies. Modern trends in the development of alternative energy indicate a gradual increase in the relevance of biofuel production. At the same time, the development of clean energy technologies needs significant investments, and their commercial implementation is a long process. Moreover, energy industry transformations require significant changes in the functioning of complementary spheres. That makes necessary the use of additional incentives for the development of the bioenergy sector. Thus, an assessment of the impact of environmental taxes on biofuel production and consumption becomes crucial. This research is aimed at the ide... [more]

Long-lived minor actinides (MAs) are one of the primary contributors to the long-term radiological hazards of nuclear waste, and the buildup of MAs is hampering the development of nuclear power. The transmutation of MAs in reactors is regarded as a potential way to replace direct disposal to reduce the impact of MA on the environment and improve the utilization of fuel. Due to its superior features, such as outstanding neutron economy, no fuel assembly fabrication, high neutron flux, and especially online refueling and reprocessing, the molten chloride salt fast reactor (MCFR) is regarded as one of the potential reactors for MA incineration. In this work, MA transmutation capability and 233U breeding performance for an optimized MCFR have been evaluated in different scenarios. The results show that the MA transmutation capability and 233U breeding performance with online transuranic elements (TRU) and 232Th feeding scenario are improved significantly compared with the case in online 23... [more]