Significant Increase In Energy Efficiency Research Articles

Evaluation of innovative drying approaches in celery drying considering product quality and drying energy efficiency

Herein celery was dried with a tray dryer, taking into account the physical and chemical changes of the final product and its drying energy efficiency. In order to obtain the maximum energy efficiency, drying experiments were carried out with 3 different drying approaches: drying at a constant temperature, intermittent drying, and controlled temperature drying based on moisture ratio. A significant increase in energy efficiency was observed in the experiments performed at both intermittent drying and controlled temperature drying based on moisture ratio. Higher energy efficiency was obtained by drying at a higher constant temperature, but this in effect caused a degradation in both the chemical and physical properties of celery. Quality attributes of dried celery in intermittent drying were improved but the energy efficiency attained under these conditions was not as anticipated. However, controlled temperature drying based on moisture ratio had significantly higher energy efficiency as well as higher quality of the final product. Therefore, an innovative approach of controlled temperature drying based on moisture ratio stands out as the most effective technique in this study.

Optimisation of the Technological Parameters of the Ecological Milk Cooling Plant

The aim of this paper is to optimize the technological parameters of the ecological milk cooling plant with the application of natural cold, which ensures a significant increase in energy efficiency at collection points in the Republic of Moldova. The proposed plant captures the natural cold and stores it in the insulated cold accumulator without the use of freons, which is then used for cooling milk. In order to achieve the goal, the mathematical model of the intermediate refrigerant cooling process using renewable energy was developed in the paper. Based on the requirements imposed on the technological process as well as the developed mathematical model, it was determined that for cooling the intermediate refrigerant from the initial temperature of +140C to +40C, at the ambient temperature of +20C, 34.25 times more equivalent volume of air is required.

An incentive-based dynamic energy efficient spectrum allocation for cognitive radio networks

Cognitive radio is a successful technique for utilizing the unused and under-used spectrum, and dynamic spectrum access is one of the major facilitators in making this happen. When a secondary user (an unlicensed user) interferes with the licensed user, the idea of using unused or under-utilized spectrum offers a challenge. Therefore, effective spectrum sensing is necessary to ensure the primary user’s protection and the successful transmission of data by the secondary user. An Optimal Incentive algorithm is suggested to meet this need. It effectively uses the available idle channel based on the joint optimization of sensing time and transmission time without interfering with the primary user. The proposed work also contributes to a significant increase in energy efficiency with minimal interference. Simulation results show an increase in efficiency when compared with the algorithms, namely, exhaustive search and sub-optimal algorithms.

Development and implementation of direct electric cure of plain weave CFRP composites for aerospace

Curing aerospace composites is time-consuming with high energy requirements, particularly when using methods such as autoclaves, ovens and heated presses. This study investigates direct electric cure (DEC), which uses the Joule effect to directly heat carbon fibre composites to their cure temperature. Its benefits include a significant increase in energy efficiency, control over the cure temperature and low void content compared to oven curing. Samples were manufactured with vacuum-assisted resin transfer moulding (VARTM) and prepreg, as well as curing a two-meter-long leading-edge component, to demonstrate and evaluate the curing method at scale. The average void content for VARTM DEC samples was lower by 0.82 % compared to the oven-cured panel, however, the average degree of cure (DoC) decreased by 6.25 %. Normalised energy consumption for the cure was significantly reduced for all DEC cures, with VARTM cures using 99 % less energy than oven-cured components.

Nanoparticle-enabled increase of energy efficiency during laser metal additive manufacturing

The low energy efficiency of the laser metal additive manufacturing (AM) process is a potential sustainability concern for large-scale industrial production. Explicit investigation of the energy efficiency for laser melting requires the direct characterization of melt pool dimension and vapor depression, which is very difficult due to the opaque nature of the molten metal. Here we report the direct observation and quantification of effects of the TiC nanoparticles on the vapor depression and melt pool formation during laser powder bed fusion (LPBF) of Al6061 by in-situ high-speed high-energy x-ray imaging. Based on the quantification results, we calculated the laser melting energy efficiency (defined here as the ratio of the energy needed to melt the material to the energy delivered by the laser beam) with and without TiC nanoparticles during LPBF of Al6061. The results show that adding TiC nanoparticles into Al6061 leads to a significant increase of laser melting energy efficiency (114% increase on average, 521% increase under 312 W laser power, 0.4 m/s scan speed). Systematic property measurement, simulation, and x-ray imaging studies enable us, for the first time, to identify that three mechanisms work together to enhance the laser melting energy efficiency: (1) adding TiC nanoparticles increases the absorptivity; (2) adding TiC nanoparticles decreases the thermal conductivity, and (3) adding TiC nanoparticles enables the initiation of vapor depression and multiple reflection at lower laser power (i.e., lowers the laser power threshold for keyholing). The method and mechanisms of using TiC nanoparticles to increase the laser melting energy efficiency during LPBF of Al6061 we reported here may guide the development of feedstock materials for more energy efficient laser metal AM. • Quantified nanoparticle-enabled energy efficiency improvement. • Achieved significant increase of energy efficiency by nanoparticles. • Identified mechanisms of nanoparticle-enabled energy efficiency improvement. • Revealed effects of nanoparticles on vapor depression and melt pool evolution.

CONDENSATION THERMOELECTRIC DRYER AS THE BEST WAY OF DRYING FRUIT RAW MATERIALS

Drying of raw fruits and vegetables is both a thermophysical and technological process, in which the processes of heat and mass transfer are connected in one whole. When drying the prepared raw materials, the structural – mechanical, physico – chemical and other properties of the dried raw materials change. The choice of method and optimal mode of the drying process, the calculation of the design of the dryer and all ancillary equipment, is determined by the properties of the dried material, as well as the technology of its production. As in most processes, the naturalness of dried products and the ecological purity of the technological process come to the fore. Criteria of quality and efficiency of the process are combined into one task – to increase the efficiency of the drying process and the creation of non-energy-intensive heat technologies and equipment for their implementation. This article looks at a comparison of different drying chambers in their structure and principle of operation, which should play a major role in the energy efficiency of the entire drying process. The energy efficiency of the drying process of fruit and vegetable raw materials is achieved by improving the technological equipment and installing energy efficient controls, but we should not forget about the environmental friendliness of the process and the rational use of mechanical and thermal energy in the system. One of the most common processes is convective drying in a chamber or tunnel dryer. Significant increase in energy efficiency of the drying process is possible with the implementation of deep recovery of thermal energy using steam compression or thermoelectric heat pumps. After carrying out a series of laboratory and research works to compare different convection drying systems with thermoelectric heat pump, a diagram reflecting the heat consumption per 1 kg of evaporated moisture for each system was built.

Global Value Chain: The Effects of Trade Mechanism on Energy Efficiency using Simultaneous Equation: Evidence from Asian Countries within Belt and Road

Long-term economic development is thought to necessitate the use of energy. To sustain steady economic growth, economies have increased their dependence on energy sources, tightened restrictions, and put pressure on energy supplies. Our paper employed simultaneous equations with GMM and SBM model to examine the impact of trade mechanism on energy efficiency of Asian countries within the Belt and Road Countries. We find significant increase in energy efficiency. After controlling the heterogeneous effects, the magnitude impact of the coefficient was noticeably which approves that the heterogeneity of countries and years influence the empirical findings of the model. Further, we find and validates that trade in the GVC mechanism helps to promote energy efficiency. Energy efficiency could be greatly promoted by emphasizing its significance in the age of GVC. Several policy recommendations support the findings

Порівняльний аналіз існуючих методів підвищення показників енергозабезпечення будівль

У статті розглядаються найбільш розповсюджені та актуальні способи енергозбереження та оптимізації енергоспоживання в сучасних будівлях. Приведений опис аспектів системи енергозабезпечення пасивного будинку. Описані основні технічні рішення щодо підвищення енергоефективності окремих будівель з автономізацією систем його енергозабезпечення. Наведено короткий опис експлуатаційних можливостей комбінованої системи теплопостачання на основі використання теплонасосних технологій. Але такий підхід не дозволяє досягтизначного підвищення енергоефективності систем,проведеннятермомодернізації, тільки за рахунок нарощування ізоляційного шару часто непризводить до плануємого зменшення рівня енерговитрат.Тому розглянутий напрямок енергозбереження, який пов'язаний з підвищенням показників термічного опору будівель і одночасним використанням для їх енергозабезпечення енергії альтернативних джерел.В даному випадку підвищення ефективності системи енергозабезпечення та кліматизації досягається завдяки використанню енергії сонячного випромінювання, тепла грунту і повітря (в тому числі вентиляційного). При цьому враховувується специфіка процесів енергообміну, акумулювання теплової енергії.Такий підхід лежить в основі методу контролю температури будівлі з використанням кривої нагріву, яка не вимагає моделі процесу, а задача оптимізації вирішується тільки на рівні однієї ланки, а не всієї системи. Цей недолік усувається завдяки автоматичному контролю вентиляції, водопостачання, побутової техніки (система «Розумний будинок»). Для вирішення задач оптимізації доцільно використовувати комплексний підхід -це управління опаленням в поєднанні з контролем роботи вентиляційної системи і системи водопостачання. Це дозволяє реалізувати повноцінну підтримку певного клімату в будинку, з урахуванням вологості повітря і показниками температури в різних приміщення, пори року тощо, але потребує побудови певної математичної моделі. Даний огляд підтверджує актуальність подальшої роботи в напрямку вирішення задачі оптимізації з питань енергоспоживання та енерговитрат в сучасних будівлях.

ADDITIONAL HEAT LOSSES AT THE JUNCTIONS OF THE WINDOW FRAMES AND ENCLOSING STRUCTURES

The current state of housing and communal services, which have been built by the end of the 90s, requires complete modernization and a significant increase of energy efficiency. Global trends in energy efficiency of buildings are aimed at changing energy consumption to almost zero level (nZEB). Most of the measures aimed at achieving nZEB refer to measures of improvement the thermophysical properties of enclosures. With the improvement of the thermophysical properties of the enclosures, the influence of the thermally conductive inclusions that occur at the junctions of the window structures / reinforced concrete slab of the ceiling to the outer wall, etc., increases significantly.The paper contains 2D-models built in the THERM – a software for studying temperature fields at the junctions of linear heat-conducting inclusions. We have simulated heat-conducting fields for two variants of external walls with improved thermophysical properties of enclosures that conform to modern requirements for thermal protection. The calculation was made for the climatic conditions of Kyiv.It is established that for the same thickness of the outer wall, the replacement of the bearing layer of the silicate bricks structure with a aerocrete blocks improves the resistance to heat transfer by 2 times. From the point of view of influence of linear heat-conducting inclusions in places of adjunction of a window frame to an external wall is observed the opposite effect, when there is a bigger influence in a wall made of the aerocrete blocks. Taking into account linear and point heat-conducting inclusions leads to a deterioration of the resistance to heat transfer of the outer wall made of silicate bricks by 20%, and of the aerocrete blocks - by 33%. Consideration of heat-conducting inclusions even for a construction without difficult constructive decisions of protections leads to increase in heat losses.

Induction motor rotor bars type effects towards energy efficiency, economic and environment

<span lang="EN-MY">Nowadays, the rotating motor is the most demoralized machine for the global Motor industry. Comfort of practice, start-up, small, weightiness, Increased efficiency, low maintenance and inexpensive for each power rating that generally meets the necessary features for industries. Efficient improvements are inspected with copper for the rotor bars slot. Usually, the copper loss in the induction motor Rotor division contributes to the loss of energy. The research work was planned a new rotor design, by improved rotor bars type slot, size and design. These tasks were inspected using two approaches, in particular, MotorSolve (IM) and calculations in theory. One set of simulation has shown a significant increase in energy efficiency for a new rotor frame design. Calculations in theory are used MATLAB. As a result, these new designs have improved energy efficiency by 77% as compared to its 74% existing design. The results proved to be using MATLAB. For energy, cost savings and emission reduction (ER), new design rotor frame has been saved 154KWH/year, utility bill RM 60.20/Year and 0.113 CO<sub>2 </sub>tons/years intended for individually motor. Finally, the estimated cost aimed at 100,000 pieces of new rotor bars pattern induction motor and indicates this price was kept almost RM6 million.</span>

Energy Efficiency Optimization in Full-Duplex User-Aided Cooperative SWIPT NOMA Systems

A novel cooperative non-orthogonal multiple access (NOMA) strategy is proposed, where a full-duplex cell-center user acts as a friendly relay to help a cell-edge user. An advanced energy harvesting technology based on simultaneous wireless information and power transfer (SWIPT) is used at the cell-center user to harvest energy used at the cooperative stage. We propose a joint design to optimize the power splitting (PS) ratio and the beamforming vectors. The proposed design aims to maximize energy efficiency (EE) of the system while guaranteeing the minimum required target rate of the cell-edge user and the successful decoding rate at the cell-center user. To make the problem tractable, we use Dinkelbachs method to address the fractional functions and the semidefinite relaxation (SDR) technique to deal with the rank constraint. Then, an iterative algorithm based on successive convex approximation (SCA) is proposed to finally solve the reformulated problem. In order to rich the application of the proposed power allocation algorithm, we extend the proposed strategy to an imperfect channel state information (CSI) mode. ${S}$ -Procedure is introduced to approximate the channel uncertainties. Numerical results reveal that our proposed iterative algorithms have a good convergence rate. In addition, the proposed strategy offers a significant increase in energy efficiency compared to the existing strategies, especially at the low power region.

Построение туннельных осесимметричных сверхзвуковых воздухозаборников

Актуальность работы. Эффективность преобразования химической энергии топлива в механическое движение сверхзвукового летательного аппарата определяется потерями механической энергии на сопротивление летательного аппарата и потерями полного давления при торможении потока в воздухозаборнике воздушно-реактивного двигателя. Поэтому при прочих равных условиях более энергоэффективным будет тот летательный аппарат, у которого эти потери меньше. Существенное повышение энергоэффективности ожидается от применения осесимметричных изоэнтропических туннельных воздухозаборников. В рамках модели невязкого течения предлагается численная методика построения указанных воздухозаборников с профилированным центральным телом и цилиндрической обечайкой. Цель работы. В настоящее время отсутствуют способы профилирования осесимметричных изоэнтропических туннельных воздухозаборников, не имеющих элементов, выступающих за цилиндрический корпус летательного аппарата. Поэтому целью исследования является разработка методики построения таких воздухозаборников. Методы исследования. Используется численная реализация метода характеристик при условии изоэнтропичности течения. Предлагаемая методика состоит из двух задач. В первой задаче от угловой точки строится контур центрального тела с заданной ординатой точки фокусировки характеристик. Во второй задаче производится построение оставшейся части контура до другой угловой точки, при этом используется обращенное течение в кольцевом сопле с цилиндрической обечайкой. Одновременно с решением второй задачи определяется положение обечайки. Центральное тело может содержать на краях по угловой точке. При использовании промежуточной линии тока центральное тело будет гладким. Результаты. Создана методика для расчета семейства контуров осесимметричных туннельных сверхзвуковых воздухозаборников, геометрические характеристики которых однозначно описываются исходными данными.

A nano-photonic filter for near infrared radiative heater

Infrared (IR) radiative heating is a highly desirable method for heating as compared to convective heating due to the unprecedented control of radiative energy transfer, leading to a significant increase in energy efficiency. The greatest challenge however with IR radiative heating is its low penetration depth due to the strong IR absorption by the water content in the substance to be heated. Near IR (NIR) heating can circumvent this problem as it has greater penetration depths. The proposed nano-photonic design for NIR filter (or effective selective emitter) has transmissivity of more than 70% in NIR and less than 15% in both visible and IR wavelengths as opposed to currently available IR heaters, which have high emissivity across all wavelengths. This NIR filter can be applied to any radiative heating source to transform it into a NIR radiative heater. We demonstrate this with a simple prototype by applying it in front of tungsten-based incandescent lamp where significant reduction in white glow (glare) was observed. Potential application of this NIR filter would be in heating in both building and industrial sectors where the ability to provide localized heating could lead to significant energy savings. In addition, NIR selective emitters can be applied for power generation by supplying thermophotovoltaics (TPV) with photons at the right wavelengths, which will increase the efficiency of TPV.

Energy Efficient Selected Mapping Schemes Based on Antenna Grouping for Industrial Massive MIMO-OFDM Antenna Systems

Energy efficient massive multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) antenna systems have received a great deal of attention for use in industrial network applications due to the possibility of reducing operation costs and carbon footprint. One of the difficulties in realizing high energy efficiency (EE) massive MIMO-OFDM antenna systems is the high peak-to-average power ratio (PAPR) of the signal, which seriously limits the efficiency of power amplifiers (PA). Selected mapping (SLM) is a powerful PAPR reduction scheme for OFDM related systems, however, there is implicit consensus that SLM could not be applied to massive MIMO-OFDM antenna systems due to its high computational complexity and side information (SI) burden. In this paper, we propose an SLM-based PAPR reduction scheme that can be applied to massive MIMO-OFDM antenna systems based on antenna grouping. Using the antenna grouping based suboptimal scheme, we show that an SLM-based PAPR reduction scheme can be successfully applied to massive MIMO-OFDM antenna systems with significant increase of EE. The proposed scheme has very high flexibility with various adjustable parameters, so one can easily choose the settings they desire between performance-complexity tradeoff. Numerical analysis shows that the propose scheme can increase EE by $18.69\%$ compared with the conventional system.

Information and regulatory provision for the Estimation of renewable energy sources in Ukraine

The global development of energy should be based exclusively on the concept of sustainable development. It means renewable energy with significant increase in energy efficiency, creating conditions for universal access to high-quality electrical and thermal energy. Renewable energy advantages are inexhaustibility of natural resources, low risk level for human health, minimization of negative impact on environment. The article analyses information and regulatory provision of the estimation of renewable energy sources towards justifying of theoretical and methodological bases for statistical estimation of renewables and developing scientific and practical recommendations for the implementation. National and international regulation are the basis for methodological, regulatory and informational provision for statistical estimation of renewable energy sources in Ukraine. The international legal framework is presented by directives and agreements: Directive 2006/32/EC, Directive 2009/28/EC, Treaty establishing the Energy Community, Regulation No. 1099/2008 of the European Parliament and of the Council, Energy Statistics Manual. Gradual harmonization of Ukrainian legislation according to the European and international regulatory system is being performed with respect to the Ukrainian Constitution. The main documents on the national level are: Law of Ukraine «On electricity», Law «On alternative energy sources», Law «On alternative fuels», The Law of Ukraine «On combined heat and power (cogeneration) and waste power utilization», Law of Ukraine «On energy saving» etc. The normative legal framework of renewable energy regulation in Ukraine is presented by extensive regulatory system. Further research on information and regulatory provision of renewable energy sources will address the «green» tariffs and new forms of financial support for development of renewable energy sources.

Thermodynamic Analysis of Power Generation Cycles With High-Temperature Gas-Cooled Nuclear Reactor and Additional Coolant Heating Up to 1600 °C

Nuclear energy is one of the possibilities ensuring energy security, environmental protection, and high energy efficiency. Among many newest solutions, special attention is paid to the medium size high-temperature gas-cooled reactors (HTGR) with wide possible applications in electric energy production and district heating systems. Actual progress can be observed in the literature and especially in new projects. The maximum outlet temperature of helium as the reactor cooling gas is about 1000 °C which results in the relatively low energy efficiency of the cycle not greater than 40–45% in comparison to 55–60% of modern conventional power plants fueled by natural gas or coal. A significant increase of energy efficiency of HTGR cycles can be achieved with the increase of helium temperature from the nuclear reactor using additional coolant heating even up to 1600 °C in heat exchanger/gas burner located before gas turbine. In this paper, new solution with additional coolant heating is presented. Thermodynamic analysis of the proposed solution with a comparison to the classical HTGR cycle will be presented showing a significant increase of energy efficiency up to about 66%.

Energy efficiency of the machine-tractor unit in transient modes

The study of transient modes of operation of the machine-tractor unit (MTU) in order to improve energy efficiency and energy saving is a very important task. The process of starting and accelerating of MTU is the heaviest mode of operation, which is characterized by considerable dynamic loads and which has a significant influence on the most important indicators: productivity, fuel efficiency, as well as slipping of propulsors, abrasion of the soil and tires, loading and lifetime of the elements of the transmission of tractors. One of the effective methods for reducing dynamic loading is the introduction of elastic-damping links in the drive of propulsors of tractors. The study of impact of elastic-damping drive of traction wheels on the parameters of the MTU operation during the acceleration period were carried out in a complex way: theoretically, on the six mass dynamic equivalent model developed by us, which adequately reflects the actual overclocking processes, and experimentally, in the field conditions on full-scale samples. Methods of software mathematical modeling and developed methods of experimental research were used. The complex of the conducted researches has established: due to the decrease in dynamic loads the improvement of all operational parameters of the MTA has been obtained, including: reduction in the slippage of propellers, tire wear and abrasion, a significant increase in energy efficiency: specific fuel consumption in the process of starting and accelerating of MTU with an elastically damping drive on stubble in gears from the third to the sixth decreases by an average of 40% compared to a rigid serial drive. Due to the smoothing of the peaks of the hook load (by 38%) and the torque (by 36%) with the elastic elements, a more smooth and at the same time more intensive acceleration of the unit is obtained (acceleration time is shortened due to the fact that the slippage is reduced and crankshaft speed is reduced in lesser degree).

Utilization of waste heat from rotary kiln for burning clinker in the cement plant

Cement subsector next to the glass industry is counted among one of the most energy-intensive industries, which absorbs approx. 12-15% of the total energy consumed by the industry. In the paper various methods of energy consumption reduction of in the cement industry are discussed. Cement production carries a very large emissions of greenhouse gases, where CO2 emissions on a global scale with the industry than approx. 5%. Great opportunity in CO2 emissions reduction in addition to the recovery of waste heat is also alternative fuels co-firing in cement kilns [1], [2]. In the cement sector interest in fitting-usable waste energy is growing in order to achieve high rates of savings and hence the financial benefits, as well as the environment ones [3]. In the process of cement production is lost irretrievably lot of energy and reduction of these losses on a global scale gives a visible saving of consumed fuel. The aim of this study is to investigate the possibility of waste heat use in Rudniki Cement Plant near to Czestochowa. After analyzing of all waste heat sources will be analyzed the heat emitted by radiation from the surface of the rotary kiln at the relevant facility. On the basis of thermal-flow calculations the most favorable radiative heat exchanger will be designed. The calculations based on available measurements provided by the cement plant, a thermal power of the heat exchanger, the heat exchange surface, the geometry of the heat exchanger, and other important parameters will be established. In addition the preliminary calculations of hydraulic losses and set directions for further work will be carried out. Direct benefits observed with the introduction of the broader heat recovery technology, is a significant increase in energy efficiency of the industrial process, which is reflected in the reduction of energy consumption and costs. Indirectly it leads to a reduction of pollution and energy consumption.

Improving the ultra-low-power performance of IEEE 802.15.6 by adaptive synchronisation

In ultra-low data rate wireless sensor networks (WSNs) waking up just to listen to a beacon every superframe can be a major waste of energy. This study introduces MedMAC, a medium access protocol for ultra-low data rate WSNs that achieves significant energy efficiency through a novel synchronisation mechanism. The new draft IEEE 802.15.6 standard for body area networks includes a sub-class of applications such as medical implantable devices and long-term micro miniature sensors with ultra-low power requirements. It will be desirable for these devices to have 10 years or more of operation between battery changes, or to have average current requirements matched to energy harvesting technology. Simulation results are presented to show that the MedMAC allows nodes to maintain synchronisation to the network while sleeping through many beacons with a significant increase in energy efficiency during periods of particularly low data transfer. Results from a comparative analysis of MedMAC and IEEE 802.15.6 MAC show that MedMAC has superior efficiency with energy savings of between 25 and 87% for the presented scenarios.

DETERMINATION OF THE INFLUENCE OF UNCERTAIN MODEL PARAMETERS IN PRESSURIZED GASIFICATION OF BLACK LIQUOR USING A FACTORIAL DESIGN

ABSTRACT Introduction of pressurized gasification of black liquor in the pulping industry has the potential to give a significant increase in energy efficiency. However, uncertainties about the reliability and robustness of the technology are preventing large-scale market introduction. One important step toward a greater trust in the process reliability is the development of a better understanding of the sensitivity of the process to parameter variations. A computational fluid dynamics model for pressurized gasification of black liquor in an entrained-flow gasifier is presented and used for investigation of the effects of uncertainties in the specific heat capacity of black liquor, the radiation absorption coefficient, and the volatile devolatilization rate using factorial design methodology. It is found that all main factor effects, but none of the interaction effects, influence the considered responses: char conversion, maximum temperature, and outlet temperature. However, the main effects are found to be relatively small and the uncertainties in the examined model parameters would not invalidate the results from a design optimization with the presented model.