Street lighting should realise normative illuminance levels throughout the roadway. The determination of the illuminance level of a road requires the use of a measurement technique based on classic point measurements at a specific grid of measurement points. Classical stationary measurements using the method indicated in the prescriptive requirements are time-consuming and labor-intensive. The authors of the article have presented a concept of a measurement system that could be used to partially automate road lighting measurements and increase their universality. The proposed measurement system uses the simultaneous measurement of illuminance values from lux meters located on the roof of the vehicle. The measurement is carried out while the vehicle is driving on a lit road, and the illuminance values are localized using a global GPS satellite location system equipped with RTK corrections. The use of GPS RTK localization data corrections allowed the measurement results to be unambiguous... [more]

The modular multilevel converter (MMC) has become a very promising technology for long-distance and large-capacity transmission of offshore wind power. However, both sides of the AC transmission line at the sending end are controllable electronic power devices, resulting in difficulty in fault identification and inapplicability of traditional differential protection schemes. In order to solve this problem, a wave-similarity-based protection scheme is proposed for AC transmission line faults. Firstly, the symmetrical and asymmetrical fault current characteristics of the double-fed induction generator (DFIG) and MMC are studied, indicating that the fault current characteristics are obviously different from the synchronous units. Secondly, the wave-similarity-based protection scheme is proposed based on the different wave forms of the fault currents of the MMC and DFIG. When the similarity coefficient is less than the margin coefficient, there is a fault in this phase. Moreover, the propo... [more]

Lithium batteries in the electric vehicles (EVs) reveal that the operating temperature and temperature uniformity within the battery pack significantly affect its performance. An efficient thermal management system is urgently needed to protect the battery module within suitable temperature range. In this study, the composite silica gel (CSG), coupled with cross-structure mini-channel cold plate (MCP) as the cooling system, has been proposed and applied in a battery module, which can provide a reliable method of controlling battery temperature with low energy consumption. The experimental and simulation results reveal that a composite silica gel-based liquid system can control the temperature below 45 °C and maintain the temperature difference within 2 °C at a 3C discharge rate. Besides, the CSG, coupled with the structure of reciprocal chiasma channels for the battery module, presents an optimum temperature-controlling performance among various cooling structures during the charge and... [more]

Power system simulations with long-term data typically have large time steps, varying from one second to a few minutes. However, for PV inverter semiconductors in grid-connected applications, the minimum thermal stress cycle occurs over the fundamental grid frequency (50 or 60 Hz). This requires the time step of the fatigue simulation to be approximately 100 μs. This small time step requires long computation times to process yearly power production profiles. In this paper, we propose a fast fatigue simulation for inverter semiconductors using the quasi-static time-series simulation concept. The proposed simulation calculates the steady state of the semiconductor junction temperature using a fast Fourier transform. The small thermal cycling during a switching period and even over the fundamental waveform is disregarded to further accelerate the simulation speed. The resulting time step of the fatigue simulation is 15 min, which is consistent with the solar dataset. The error of the prop... [more]

A commercial three-layer particleboard served as model furniture for testing pretreatment with the oyster mushroom (Pleurotus ostreatus (Jacq.) P. Kumm.) over 9-, 12-, 16-, and 20-week periods based on the effects of reducing the enzymatic resistance of component cellulose. The effects of pretreatment were assessed based on Fourier-transform infrared spectroscopy (FTIR) of the treated particleboards, wherein indexes (peaks and peak ratios) connected with parameters influencing enzymatic cellulose hydrolysis were analysed. The data were analysed in two ways: the measurement of peak heights in both primary spectra and deconvoluted spectra. The peak heights for the determination of the total crystallinity index (TCI) were measured according to narrow and broad baselines. Time and how indexes are calculated were found to be the main factors significantly influencing the values of indexes of pretreatment in most cases. Until week 9, P. ostreatus pretreatment seems to be advantageous for bio... [more]

Global warming is one of the major problems in the developing world, and one of the major causes of global warming is the generation of carbon dioxide (CO2) because of the burning of fossil fuels. Burning fossil fuels to meet the energy demand of households and industries is unavoidable. The current commercial and experimental techniques used for capturing and storing CO2 have serious operational and environmental constraints. The amine-based absorption technique for CO2 capture has a low absorption and desorption ratio, and the volatile and corrosive nature of the solvent further complicates the situation. To overcome all of these problems, researchers have used ionic liquids (ILs) and deep eutectic solvents (DESs) as a replacement for commercial amine-based solvents. ILs and deep eutectic solvents are tunable solvents that have a very low vapor pressure, thus making them an ideal medium for CO2 capture. Moreover, most ionic liquids and deep eutectic solvents have low toxicity and can... [more]

The simultaneous firing characteristics of woodchips and spent mushroom substrates (SMS) were studied in a stoker-type industrial boiler. The type of spent substrate intended for combustion consisted of oyster mushrooms. SMS from mushroom farms generally have a high water content. Dryers are therefore used for combustion. The moisture content of SMS was reduced to achieve low moisture to combust sufficiently at about 20%. First, the basic characteristics of the boiler were confirmed by conducting a woodchip combustion test under various operating loads of 30, 50, 70, and 100%. Thereafter, a simultaneous combustion test of woodchips and SMS was performed. During the experiment, exhaust gas concentrations in the boiler combustion chamber were measured, such as the temperature of oxygen (O2), carbon monoxide (CO), and nitrogen oxides (NOx). In addition, industrial and basic analyses were performed on woodchips and SMS. The main differences in the fuel analysis results between woodchips an... [more]

Renewable energy supply is essential for carbon neutrality; however, technologies aiming to optimally utilize renewable energy sources remain insufficient. Seasonal variability in renewable energy is a key issue, which many studies have attempted to overcome through operating systems and energy storage. Currently, hydrogen is the only technology that can solve this seasonal storage problem. In this study, the amount of hydrogen required to circumvent the seasonal variability in renewable energy supply in Korea was quantified. Spatiotemporal analysis was conducted using renewable energy resource maps and power loads. It was predicted that 50% of the total power demand in the future will be met using solar and wind power, and a scenario was established based on the solar-to-wind ratio. It was found that the required hydrogen production differed by approximately four-times, depending on the scenarios, highlighting the importance of supplying renewable energy at an appropriate ratio. Spati... [more]

A monopile is the most conventional structure foundation for offshore wind turbines (OWTs) in the world. However, the Korean offshore wind industry has mostly been using the jacket type of foundation. The main reason for the current situation in Korea is that most of the marine soil consists of weak layers of sand and clay. Thus, the monopile foundation depth has to be deep enough to satisfy the intended serviceability design requirement of the monopile and the rotation limit at the seabed; a conventional monopile design concept alone might be insufficient in Korean offshore conditions, or otherwise could be very expensive, e.g., resulting in a rock socket installation at the tip of the monopile. The main objective of this paper is to introduce a novel hybrid monopile that is composed of a monopile and a supplemental support with three buckets, followed by assessing the lateral resistance of the hybrid system through physical experiments and finite element (FE) simulations. Namely, 1/6... [more]

Unconventional oil and gas formations are abundant, have become an increasingly important part of the global energy supply, and are attracting increasing attention from the industry. Predicting key reservoir properties plays a significant role in both geological science and subsurface engineering workflows. With the advent of horizontal well drilling and multiple-stage hydraulic fracturing, the Montney Shale formation is one of the most promising and productive shale plays in Canada. However, very few academic papers discuss its in situ stress, reservoir pressure, and permeability, which are essential for the development of the Montney Shale. The objective of this study is to analyze the geo-stress, the pore pressure, and several key reservoir properties by using diagnostic fracture injection test (DFIT) data from the Montney Shale. One horizontal well from the Wapiti field has been analyzed with a set of DFIT data, and its results show that the general pressure and Gdp/dG responses fr... [more]

Precise motion control remains one of the most important problems in modern technology. It is especially difficult in the case of two-mass systems with flexible coupling if only the motor position and velocity are measured. We propose a new methodology of control system design in this situation. The concept is founded on a robust observer design, based on a linear matrix inequality (LMI) solution. The observer cooperates with the original nonlinear controller. The presented approach allows us to solve the position tracking problem for a two-mass drive, with unknown parameters, in the presence of disturbances (for instance, nonlinear friction-like torques) acting on both ends of the flexible shaft. Under this set of assumptions, the problem was never solved previously. The closed-loop system stability is investigated, and the uniform ultimate boundedness of state estimation errors and tracking errors is proven using Lyapunov techniques. Numerical properties of the design procedure and c... [more]

This paper presents an experimental study on a single tank thermal energy storage (TES) system integrated with a cooking unit. The tank had a capacity of 45 L of oil. The cooking chamber was embedded in the storage tank, thereby eliminating the use of pumps and connecting pipes between the cooking unit and the storage unit. The system was designed to make good physical contact, circumferential and basally, with the cooking pot, to improve the rate of heat transfer. Experimental tests were performed with oil only and oil−rock pebbles as sensible heat storage materials. The charging unit was connected to the TES unit in such a way that it allowed circulation of oil between them during charging, using the thermosiphon principle. An electric heater rated at 800 W 240 V was inserted into the charging unit to charge the system. The thermal performance of the TES systems was evaluated in terms of the charging temperature, heat retention capacity, energy stored and cooking efficiency, and the... [more]

Aiming at the problem of maximum power point tracking (MPPT) of photovoltaic arrays in photovoltaic power generation systems, a particle swarm optimization (PSO) MPPT method combined with adaptive linear active disturbance rejection control (A-LADRC) algorithm was proposed and designed. In this method, PSO is used to track the maximum power point (MPP), and then the A-LADRC controller was used to track the reference voltage. The controller enhances the anti-interference ability against various external disturbances in the MPPT process and accelerates the response speed of the system. Compared with the perturbation observation method (P&O), traditional PSO and LADRC, the proposed method has good tracking performance and an anti-interference ability under various external disturbances.

The Common Agricultural Policy defines the framework directions for the structural changes of the agri-food sector until 2030. The main reason for the actions is a fundamental change in the European Union’s approach to environmental protection issues and the dynamically changing conditions on the market for energy and agricultural raw materials. The European Green Deal, the key element of which is the “Farm to Fork” strategy, is the expression of the announced changes. The assumption of the documents is the long-term restructuring and modernization of the EU economy, which will be characterized, among others, by a closed cycle, low greenhouse gas emissions, and food and energy security. The challenges and the current situation in the markets of energy carriers are of significance in the activities of the food industry, which shows a high demand for energy. The aim of the article is to assess the level of consumption and energy efficiency of food industry enterprises in Poland, to ident... [more]

Photovoltaic system condition monitoring can be performed via single-diode model fitting to measured current−voltage curves. Model parameters can reveal cell aging and degradation. Conventional parameter identification methods require the measurement of entire current−voltage curves, causing interruptions in energy production. Instead, partial curves measured near the maximum power point offer a promising option for online condition monitoring. Unfortunately, measurement data reduction affects fitting and diagnosis accuracy. Thus, the optimal selection of maximum power point neighbourhoods used for fitting requires a systematic analysis of the effect of data selection on the fitted parameters. To date, only one published article has addressed this issue with a small number of measured curves using symmetrically chosen neighbourhoods with respect to the maximum power. Moreover, no study has determined single-diode fit quality to partial curves constructed via other principles, e.g., as... [more]

This paper proposes a denoising method of vibration signal based on improved multiresolution singular value decomposition (IMRSVD) and effective component selection. A new construction method of trajectory matrix is used, which can enhance the oscillating component of the original signal. Next, based on the improved trajectory matrix, singular value decomposition (SVD), which plays the role of pre-decomposition, is used to obtain multiple one-dimensional components, and the further decomposition of that is achieved by multiresolution singular value decomposition (MRSVD). Finally, the effective components selection of a series of decomposed signal components is achieved based on the proposed feature evaluation index (FEI). The denoising experiments are carried out using the simulation signal and the vibration signal of planetary gear, respectively. The experimental results show that the proposed method performs better than the traditional SVD denoising method, and the weak fault feature... [more]

Global warming is mainly caused by carbon emissions. Currently, fewer countries are concentrating on reducing carbon emissions. The primary strategy utilized by numerous countries to achieve carbon emissions reduction is the carbon tax policy. With this in mind, a sustainable two-warehouse inventory model was taken carbon tax into account for a controllable carbon emissions rate by investing in green technology initiatives under uncertain emission and cost parameters. The globe is currently experiencing an eco-friendly period. Many individuals are interested in purchasing natural or herbal items since they are made from natural sources and do not affect the environment. The demand for products made with herbal or natural ingredients is considered eco-friendly demand. This study examines a two-warehouse inventory model of deteriorating commodities with price and marketing-dependent eco-friendly demand. The inventory system is presented to handle the inventory in the depository with last... [more]

The high share of PV energy requires greater system flexibility to address the increased demand/supply imbalance induced by the inherent intermittency and variability of the solar resource. In this work, we have developed a methodology to evaluate the margins for imbalance reduction and flexibility that can be achieved by advanced solar/wind forecasting and by strengthening the national transmission grid connecting the Italian market areas. To this end, for the forecasting of the day-ahead supply that should be provided by dispatchable generators, we developed three advanced load/PV/wind forecasting methodologies based on a chain or on the optimal mix of different forecasting techniques. We showed that, compared to the baseline forecast, there is a large margin for the imbalance/flexibility reduction: 60.3% for the imbalance and 47.5% for the flexibility requirement. In contrast, the TSO forecast leaves only a small margin to reduce the imbalance of the system through more accurate for... [more]

Real-time monitoring of the battery thermal status is important to ensure the effectiveness of battery thermal management system (BTMS), which can effectively avoid thermal runaway. In the study of BTMS, driver behavior is one of the factors affecting the performance of the battery thermal status, and it is often neglected in battery temperature studies. Therefore, it is necessary to predict the dynamic heat generation of the battery in actual driving cycles. In this work, a thermal equivalent circuit model (TECM) and an artificial neural network (ANN) thermal model based on the driving data, which can predict the thermal behavior of the battery in real-world driving cycles, are proposed and established by MATLAB/Simulink tool. Driving behaviors analysis of different drivers are simulated by PI control as input, and battery temperature is used as output response. The results show that aggressive driving behavior leads to an increase in battery temperature of nearly 1.2 K per second, an... [more]

One of the main energy sources utilized to produce power is coal. Due to the lack of combustion enhancement, the main issue with coal-based power plants is that they produce significant amount of pollutants. The major problem of slagging formation within the boiler; it sticks to the water tube walls, superheater, and reheater. Slagging might decrease the heat transferred from the combustion area to the water or steam inside the tubes, increasing the amount of coal and extra air. The abrupt fall of slag on the tube surface into the water-filled seal-trough at the bottom of the furnace might occasionally cause boiler explosions. In order to maximize heat transmission to the water and steam tubes by reducing or eliminating slag formation on the tube surface, the work presented here proposes an appropriate computational fluid dynamics (CFD) technique with a genetic algorithm (GA) integrated with conventional supercritical power plant operation. Coal usage and surplus air demand are both de... [more]

Using hydrogen energy as an alternative renewable source of fuel is no longer an unrealized dream, it now has real-world application. The influence of nanomaterials on various aspects of hydrogen energy, such as hydrogen production, storage, and safety, is considerable. In this review, we present a brief overview of the nanomaterials that have been used as photocatalysts during hydrogen production. The use of nanomaterials and nanomaterial composites for hydrogen storage is also reviewed. The specific use of graphene and its associated nanocomposites, as well as the milestones reached through its application are elaborated. The need to widen the applicability of graphene and its allied forms for hydrogen energy applications is stressed in the future perspectives. Hydrogen energy is our future hope as an alternative renewable fuel, and graphene has the potential to become the future of hydrogen energy generation.

A milk-processing plant was drafted as a distinctive staple industry amid the diverse field of industries. Dairy products such as yogurt, cheese, milk powder, etc., consume a huge amount of water not only for product processing, but also for sanitary purposes and for washing dairy-based industrial gear. Henceforth, the wastewater released after the above-mentioned operations comprises a greater concentration of nutrients, chemical oxygen demand, biochemical oxygen demand, total suspended solids, and organic and inorganic contents that can pose severe ecological issues if not managed effectively. The well-known processes such as coagulation−flocculation, membrane technologies, electrocoagulation, and other biological processes such as use of a sequencing batch reactor, upflow sludge anaerobic blanket reactor, etc., that are exploited for the treatment of dairy effluent are extremely energy-exhaustive and acquire huge costs in terms of fabrication and maintenance. In addition, these proc... [more]

This review deals with the simulation and optimization of the dry- and wet-torrefaction processes of lignocellulosic biomass. The torrefaction pretreatment regards the production of enhanced biofuels and other materials. Dry torrefaction is a mild pyrolytic treatment method under an oxidative or non-oxidative atmosphere and can improve lignocellulosic biomass solid residue heating properties by reducing its oxygen content. Wet torrefaction usually uses pure water in an autoclave and is also known as hydrothermal carbonization, hydrothermal torrefaction, hot water extraction, autohydrolysis, hydrothermolysis, hot compressed water treatment, water hydrolysis, aqueous fractionation, aqueous liquefaction or solvolysis/aquasolv, or pressure cooking. In the case of treatment with acid aquatic solutions, wet torrefaction is called acid-catalyzed wet torrefaction. Wet torrefaction produces fermentable monosaccharides and oligosaccharides as well as solid residue with enhanced higher heating va... [more]

Helical tube steam generators are often used in nuclear power plants because of their compact structure and high heat transfer efficiency. The impact of the internal fluid causes the vibration of the tube bundle, which leads to the failure of the integrity of the safety structure. Aiming at flow-induced vibration (FIV) of helical tube arrays, a finite element model of the helical tube was established to consider the constraint of the support structure. The computational fluid dynamics (CFD)/computational structural dynamics (CSD) coupling calculation method based on the superposition of three modes was used to study the FIV characteristics of helical tube arrays at different flow velocities. The influence of adjacent helical tubes’ vibration on the vibration of the target tube was also investigated. The results show that when FIV occurs in the helical tube, with the increase of inlet velocity, the axial amplitude will be greater than the radial at the same velocity. When some tubes vib... [more]

The extensive use of renewable energy sources (RESs) in energy sectors plays a vital role in meeting the present energy demand. The widespread utilization of allocated resources leads to multiple usages of converters for synchronization with the power grid, introducing poor power quality. The integration of distributed energy resources produces uncertainties which are reflected in the distribution system. The major power quality problems such as voltage sag/swell, voltage unbalancing, poor power factor, harmonics distortion (THD), and power transients appear during the transition of micro-grids (MGs). In this research, a single micro-grid is designed with PVs, wind generators, and fuel cells as distributed energy resources (DERs). A nonlinear auto regressive exogenous input neural network (NARX-NN) controller has been investigated in this micro-grid in order to maintain the above power quality issues within the specific standard range (IEEE/IEC standards). The performance of the NARX-N... [more]