Compared with limestone-based wet flue gas desulfurization (WFGD), magnesia-based WFGD has many advantages, but it is not popular in China, due to the lack of good wastewater treatment schemes. This paper proposes the wastewater treatment scheme of selling magnesium sulfate concentrate, and makes thermal and economic analysis for different concentration systems in the scheme. Comparisons of different concentration systems for 300 MW power plant were made to determine which system is the best. The results show that the parallel-feed benchmark system is better than the forward-feed benchmark system, and the parallel-feed optimization system with the 7-process is better than other parallel-feed optimization systems. Analyses of the parallel-feed optimization system with 7-process were made in 300, 600, and 1000 MW power plants. The results show that the annual profit of concentration system for a 300, 600, and 1000 MW power plant is about 2.58 million, 5.35 million, and 7.89 million Chine... [more]

To help meet the global demand for energy and reduce the use of fossil fuels, alternatives such as the production of syngas from renewable biomass can be considered. This conversion of biomass to syngas is possible through a thermochemical gasification process. To design such gasification systems, model equations can be formulated and solved to predict the quantity and quality of the syngas produced with different operating conditions (temperature, the flow rate of an oxidizing agent, etc.) and with different types of biomass (wood, grass, seeds, food waste, etc.). For the comparison of multiple different types of biomass and optimization to find optimal conditions, simpler models are preferred which can be solved very quickly using modern desktop computers. In this study, a number of different stoichiometric thermodynamic models are compared to determine which are the most appropriate. To correct some of the errors associated with thermodynamic models, correction factors are utilized... [more]

In this paper, we present a new approach for the analysis of the dependence of construction costs on the geometric shape of a building. Instead of difficult or even impossible-to-establish uniform prices and costs, we propose a cost analysis concerning the amount of materials needed for construction. We show that the basic parameters are the base area of the building (plan), assumed in the study as the building area, and the area of the external walls of the building. The amount of consumption of most materials is proportional to the base area and the area of the external walls. The materials required for construction consume large amounts of energy during their manufacture. Therefore, shape optimization is not only economically significant for the investor but is also important in terms of the energy consumption, i.e., embodied energy. We propose a set of indicators to help a designer optimize the shape of the building at the initial design stage.

Generator maintenance scheduling presents many engineering issues that provide power system personnel with a variety of challenges, and one can hardly afford to neglect these engineering issues in the future. Additionally, there is vital need for further development of the repair planning task complexity in order to take into account the vast majority of power flow constraints. At present, the question still remains as to which approach is the simplest and most effective, as well as appropriate for further application in the power flow-oriented statement of the repair planning problem. This research compared directed search, differential evolution, and very fast simulated annealing methods based on a number of numerical calculations and made conclusions about their prospective utilization in terms of a more complicated mathematical formulation of the repair planning task. A comparison of results shows that the effectiveness of directed search methods should not be underestimated, and t... [more]

Hydrate-based CO2 capture from large emission sources is considered a promising process for greenhouse gas mitigation. The addition of nanoparticles may promote or inhibit the formation of hydrates. In this work, CO2 hydrate formation experiments were performed in a dual-cell high-pressure reactor. Non-modified, hydrophilic modified and hydrophobic modified aluminum oxide (Al2O3) nanoparticles at different concentrations were added to assess their promoting or inhibitory effects on CO2 hydrate formation. The equilibrium temperature and pressure, induction time, and total gas consumption during CO2 hydrate formation were measured. The results show that the presence of Al2O3 nanoparticles exerts little effect on the phase equilibrium of CO2 hydrates. Under the experimental conditions, the addition of all Al2O3 nanoparticles imposes an inhibitory effect on the final gas consumption except for the 0.01 wt% addition of hydrophilic modified Al2O3 nanoparticles. The induction time required fo... [more]

The implementation of a three-dimensional viscous inverse design used for an axial compressor is introduced in this paper. The derivation process of the inverse design algorithm is also described in detail. Moreover, an improved blade update method and a modified relaxation factor are included to enhance the inverse design algorithm. The inverse design is built on an in-house inverse design module coupled with commercial Computational Fluid Dynamic (CFD) software NUMECATM. In contrast to analysis design, the pressure loading and the normal thickness distribution along the blade surfaces are prescribed during the process of inverse design. The numerical methods used to solve the flow field are verified using the experimental data of the transonic fan rotor NASA Rotor 67. A recovery test for the Rotor 67 is carried out to validate the developed three-dimensional inverse design tool. To explore the potential application of the inverse design system, it is then used to improve the aerodyna... [more]

Despite the fact that some renewable energy (RE) technologies are already techno-economically viable, the high spatial dilution nature of their sources, together with aspects beyond the techno-economic ones (such as environmental, social, cultural, and other aspects), can become strong constraints and barriers when it comes to their integration into electric systems. Therefore, with the objective of determining whether studies on spatial energy planning (SEP) are addressing these issues, a systematic review has been carried out to address whether SEP studies are considering aspects beyond the techno-economic ones when integrating RE technologies and, if they are being considered, how they are addressed in their analyses and what criteria, factors, and indicators of the aspects that are employed. Apart from the revelation that the concept of SEP has been included within high-quality scientific literature for less than ten years, SEP seems to be an unexploited tool with the potential to... [more]

In this paper, we discuss a method for fabricating an ultrathin polymer substrate with one-dimensional nanograting patterns to improve the power conversion efficiency (PCE) of ultrathin polymer solar cells (PSCs) and suppress the dependence on the incident angle of light. Because the fabricating process of the ultrathin polymer substrate was carried out using a solution process, it can be manufactured in a large area, and the PCE of the patterned ultrathin substrate-based PSC is improved by 8.9% compared to the non-patterned device. In addition, triple-patterned ultrathin PSCs incorporating the same nanograting pattern as the substrate were fabricated in the electron transport (ZnO) layer and the photoactive layer (PBDTTT-OFT and PC71BM mixture (ratio-1: 1.5)) to achieve PCE of 10.26%. Thanks to the nanograting pattern introduced in the substrate, ZnO layer, and photoactive layer, it was possible to minimize the PCE change according to the incident angle of light. Moreover, we performe... [more]

This article presents a novel passive fluid borne noise source reduction strategy, based on tandem axial-piston unit indexing with the usage of symmetric lines. The strategy consists of setting the phase between the two synchronous units to accomplish destructive interference in targeted unit harmonics. A strategy capable of achieving destructive interference in all odd harmonics is investigated first analytically and then confirmed by a simulation study. Experiments on the proposed strategy confirmed its effectiveness at the first and third pump fundamental harmonics, and pressure ripple reduction was accomplished. The fluid borne noise source reduction in the first and third harmonic is verified to be propagated to pipe vibration and sound power. Regarding the first harmonic, pressure ripple was reduced by up to 18 dB; while for third harmonic, pressure ripple was reduced by up to 11 dB. In the experiment, however, noise cancellation is not achieved for the higher odd harmonics, as i... [more]

In central Italy, there are extensive European black pine (Pinus nigra Arn.) plantations which range from 30 to 60 years of age and where no thinning operations have been made. The main purpose of this study was to provide a comparative analysis of two cable yarder technologies (Maxwald, mobile pulley carriage and Savall, semi-automatic carriage), in terms of fuelwood production and cost, from the first thinning of a 33 year old plantation in slope areas of these plantations. The results showed that fuelwood production was cost-effective in both systems (Savall by 15.1 and Maxwald by 14.8 € m−3), although the productivity of the Savall system was higher than the Maxwald system (6.1 vs. 5.7 m3 h−1). The respect amounts of productivity have the potential to increase by 27% for the Savall yarder and 25% for the Maxwald yarder upon condition that the delay times are reduced to minimum level by proper training of workers, by a better organization, and planning of operations. The total effec... [more]

This paper identifies and characterizes the technical measures and policy instruments that can be used to promote energy efficiency and the use of renewable sources for domestic hot water (DHW). DHW presents a considerable potential for abatement of greenhouse gas emissions around the world. Measures were characterized in terms of level of transformation, impact and scope, among others. Policy instruments were characterized in terms of target groups, competences required for implementation, major challenges and nature of the instruments. A matrix showing the applicability of policy instruments per technical measure was derived, enabling policy makersto better choose articulated measures and policy instruments for their policy packs.

This paper presents a proposal for a historic building thermal diagnostics algorithm for the example of a historical townhouse located in Lviv, Ukraine. The authors proposed a testing and diagnostics procedure that should precede design and renovation work associated with improving the energy standard of the buildings under discussion. The procedure was presented using a case study of a selected historical building. The scope of the study included an assessment of the building’s technical condition, thermal vision diagnostics, wall moisture, and water absorption in the context of protection against rain. Sample thermal and hygrothermal calculations were performed for a sample architecture element. The calculations included simulations of partition envelope behaviour after planned thermal retrofitting had been carried out. Performing the presented thermal diagnostics methods in three interlinked blocks (A, B, and C) shall ensure the proper thermal retrofitting of historical buildings in... [more]

The electrolyte is one of the components that releases the most heat during the thermal runaway (TR) and combustion process of lithium-ion batteries (LIBs). Therefore, the thermal hazard of the electrolyte has a significant impact on the safety of LIBs. In this paper, the combustion characteristics of the electrolyte such as parameters of heat release rate (HRR), mass loss rate (MLR) and total heat release (THR) have been investigated and analyzed. In order to meet the current demand of plateau sections with low-pressure and low-oxygen areas on LIBs, an electrolyte with the most commonly used lithium salts, LiPF6, was chosen as the experimental sample. Due to the superior low-temperature performance, an electrolyte containing LiBF4 was also selected to be compared with the LiPF6 sample. Combustion experiments were conducted for electrolyte pool fire under various altitudes. According to the experimental results, both the average and peak values of MLR in the stable combustion stage of... [more]

Cold ironing refers to the usage of less polluting power supply sources to deliver electricity to the moored ship. Such a shore-to-ship system is used when the ship is at a port so the auxiliary combustion engines may be turned off. This paper presents the numerical simulation results of a medium voltage cold-ironing system with regard to the currents flowing between the ship’s hull and grounding busbar. The IT electrical inland system with a neutral grounding resistor, as commonly used in shore-to-ship systems, is investigated. Parasitic capacitances present between the phase-to-hull and phase-to-ground in real-world applications can vary from each other. The direct and alternating currents flowing across the hull, seawater and the pier structure are amongst the causes that can lead to premature reinforced concrete degradation. Chosen cases of phase-to-ground or hull unequal capacitances influencing AC stray currents were considered.

A NILM dataset is a valuable tool in the development of Non-Intrusive Load Monitoring techniques, as it provides a means of evaluation of novel techniques and algorithms, as well as for benchmarking. The figure of merit of a NILM dataset includes characteristics such as the sampling frequency of the voltage, current, or power, the availability of indications (ground-truth) of load events during recording, the variety and representativeness of the loads, and the variety of situations these loads are subject to. Considering such aspects, the proposed LIT-Dataset was designed, populated, evaluated, and made publicly available to support NILM development. Among the distinct features of the LIT-Dataset is the labeling of the load events at sample level resolution and with an accuracy and precision better than 5 ms. The availability of such precise timing information, which also includes the identification of the load and the sort of power event, is an essential requirement both for the eval... [more]

Besides the widely applied hydropower, wind farms and solar energy, biomass and municipal and industrial waste are increasingly becoming important sources of renewable energy. Nevertheless, fouling, slagging and corrosion associated with the combustion processes of these renewable sources are costly and threaten the long-term operation of power plants. During a high-temperature biomass combustion, alkali metals in the biomass fuel and the ash fusion behavior are the two major contributors to slagging. Ash deposits on superheater tubes that reduce thermal efficiency are often composed of complex combinations of sulfates and chlorides of Ca, Mg, Na, and K. However, thermodynamic databases involving all the sulfates and chlorides that would favor a better understanding and control of the problems in combustion processes related to fouling, slagging and corrosion are not complete. In the present work, thermodynamic properties including solubility limits of some phases and phase mixtures in... [more]

The accurate determination of methane adsorption isotherms in coals is crucial for both the evaluation of underground coalbed methane (CBM) reserves and design of development strategies for enhancing CBM recovery. However, the experimental measurement of high-pressure methane adsorption isotherms is extremely tedious and time-consuming. This paper proposed the use of an ensemble machine learning (ML) method, namely the gradient boosting decision tree (GBDT), in order to accurately estimate methane adsorption isotherms based on coal properties in the Qinshui basin, China. The GBDT method was trained to correlate the adsorption amount with coal properties (ash, fixed carbon, moisture, vitrinite, and vitrinite reflectance) and experimental conditions (pressure, equilibrium moisture, and temperature). The results show that the estimated adsorption amounts agree well with the experimental ones, which prove the accuracy and robustness of the GBDT method. A comparison of the GBDT with two com... [more]

The installation of smart meters at customer premises provides opportunities for the monitoring of distribution grids. This paper addresses the problem of improving the observability of low-voltage distribution grids using smart metering infrastructure. In particular, this paper deals with the application of state estimation algorithm using smart meter measurements for near-real-time monitoring of low-voltage distribution grids. This application is proposed to use a nonlinear weighted least squares method-based algorithm for estimating the node voltages from minimum number of smart meter measurements. This paper mainly deals with sensitivity analysis of the state estimation algorithm with respect to multiple uncertainties for, e.g., measurements errors, line parameter errors, and pseudo-measurements. Simulation studies are conducted to estimate the accuracy of the DSSE under various operating scenarios of a real-life low-voltage grid, and cost-effective ways to improve the accuracy of... [more]

It is widely known that hydroelectric power plants benefit from optimized operation schedules, since the latter prevent water and, therefore, monetary wastes, contributing to significant environmental and economic gains. The level of detail on the representation of such systems is related to how far ahead the planning horizon is extended. Aiming at the very short-term optimization of hydroelectric power plants, which usually requires the most detailed models, this paper addresses an undesired effect that, despite being already mentioned in the literature, has not been properly explored and explained yet. This effect is given by the indication of spillage by the optimizer, even when the reservoir does not reach its maximum capacity. Simulations implemented in Julia language using real power plant data expose this phenomenon. Possible ways to circumvent it are presented. Results showed that, in specific cases, spillage allows the achieving of more efficient operating points by reducing t... [more]

The aim of this work is to analyze and stabilize the power system when connecting an energy storage system (ESS) to replace the traditional power reserve of a power plant. Thus, it is necessary to validate and simulate the power facility protection system using a relay coordination approach. The input feasibility of the generator for the frequency regulation (FR) of the operational ESS is also validated through detailed analysis studies including power flow, short circuit and relay coordination analysis. The case scenarios for ESS installation are categorized based on its operation mode and location in the power system. These studies are carried out on the power system at the peak load condition specified for both grids. With the electrical transient analyzer program (ETAP), an analysis is performed to study the implementation of the ESS in a large, integrated power system to determine which location best fits the installation of ESS considering the load flow, short circuit and relay c... [more]

The optimal allocation and sizing of distributed generation (DG) resources are important in installing these resources, to improve the technical parameters of the network, including the power losses, voltage profile, and short-circuit level, as well as to increase economic factors. In this paper, a new multi-criteria algorithm and objective function are proposed for the optimal sizing and allocation of renewable and non-renewable DG resources simultaneously. The proposed algorithm is implemented on 63/20 kV substations at 20 kV levels. In the proposed objective function, all important technical and economic factors as well as important constraints, such as penetration level of DGs and budget constraint, are considered in a way that all factors are assigned to monetary values. Moreover, a new mathematical formulation is introduced for the allocation of renewable DG resources to reduce run-time optimization. The genetic algorithm (GA) is employed in the proposed algorithm to minimize the... [more]

The present study describes the isolation of the novel strain Candida intermedia CBS 141442 and investigates the potential of this microorganism for the conversion of lignocellulosic streams. Different C. intermedia clones were isolated during an adaptive laboratory evolution experiment under the selection pressure of lignocellulosic hydrolysate and in strong competition with industrial, xylose-fermenting Saccharomyces cerevisiae cells. Isolates showed different but stable colony and cell morphologies when growing in a solid agar medium (smooth, intermediate and complex morphology) and liquid medium (unicellular, aggregates and pseudohyphal morphology). Clones of the same morphology showed similar fermentation patterns, and the C. intermedia clone I5 (CBS 141442) was selected for further testing due to its superior capacity for xylose consumption (90% of the initial xylose concentration within 72 h) and the highest ethanol yields (0.25 ± 0.02 g ethanol/g sugars consumed). Compared to t... [more]

In this paper, we developed an effective method for purifying oil sludge using a sorbing electrochemical matrix and assessed the prospects of this method in comparison with conventional hydrocracking. We synthesized Ni-W supported hydrocracking catalysts with different morphology and studied their activity under various conditions, we compared the obtained catalysts with commercial catalyst SGK-5. We demonstrated that the introduction of a secondary mesoporous structure in the catalyst leads to an increase in the yield of light fractions to 52 wt.%. The possibility is demonstrated to obtain hydrocarbons from reservoir oil sludge, dispersed into an aqueous solution of detergent, by the method of low-temperature hydrogenation in sorbing electrochemical matrices. The obtained product was characterized by low viscosity, low content of transition metals (<320 ppm), and sulphur (<260 ppm).

The water distribution subsystem is the most failing subsystem included in the water supply system. One of the main consequences of water supply failures is the lack of water supply to consumers, which is always very onerous. The paper presents a method of determining the conditional probability that a break in the supply of water to consumers of a certain duration will be caused by a specific type of failure. The result of the work was to identify water supply network failures that result in the longest water supply suspension time. The method was presented on a real water supply system. In order to reduce the incidence of long-term interruptions in water supply, water supply companies should mainly continue replacing gray cast iron pipes with thermoplastic materials. Actions taken to increase the safety of drinking water supply meet the current standards for the safety of drinking water, developed by the World Health Organization and the European Union.

Automatic peer-to-peer energy trading can be defined as a Markov decision process and designed using deep reinforcement learning. We consider prosumer as an entity that consumes and produces electric energy with an energy storage system, and define the prosumer’s objective as maximizing the profit through participation in peer-to-peer energy trading, similar to that of the agents in stock trading. In this paper, we propose an automatic peer-to-peer energy trading model by adopting a deep Q-network-based automatic trading algorithm originally designed for stock trading. Unlike in stock trading, the assets held by a prosumer may change owing to factors such as the consumption and generation of energy by the prosumer in addition to the changes from trading activities. Therefore, we propose a new trading evaluation criterion that considers these factors by defining profit as the sum of the gains from four components: electricity bill, trading, electric energy stored in the energy storage s... [more]