Calculation Of Energy Consumption Research Articles

The Analysis of Objectively Measured Weekly Physical Activity of Adolescent Boys

Research background and hypothesis. The objective methods for measuring PA are used more and more widely in various research studies all over the world. To our best knowledge, this pilot study is the first attempt in Lithuania to objectively assess physical activity of adolescents with an ambition to develop a more accurate methodology in assessing physical activity. Research aim of this study was to analyze the objectively measured weekly physical activity results of adolescent boys.Research methods. The PA of schoolboys was measured using Tri-axis ActiTrainer Activity Monitors. Boys were asked to wear the monitors for the whole week. The level of the intensity of PA was determined by calculating energy consumption in METs. Based on the frequency of vigorous and moderate PA per week, the participants of this study were devided into PA groups. Research results. All of the schoolboys experienced LPA on each of the assessed days. MPA on each day was experienced by 59.6 % of the boys. No participants achieved VPA on a daily basis. The frequency of MPA and VPA experienced most often was 5–7 and 1–3 days per week, respectively. The total PA measured during the week was largely comprised by LPA, i. e. 79.8%; MPA and VPA were 18.8 and 1.4%, respectively.Discussion and conclusion. Boys who achieve VPA, have a greater total PA during the week than those boys who do not experience VPA. If boys achieve VPA on more than 2 days during the week, even if it is just for 10 min, there is a significant increase in the total amount of weekly PA as well as a decrease in their body mass index (BMI). Boys’ who do not experience MPA at least for 6 days/week, the total amount of weekly PA decreases.Keywords: PA frequency, PA intensity, PA volume.

Train speed profile optimization with on-board energy storage devices: A dynamic programming based approach

Abstract Aimed to increase usage of regenerative energy and stabilize voltage variation of traction supply grid, an energy-saving model with on-board energy storage devices is proposed by jointly optimizing the running time and recommended speed profile of trains over the whole urban rail transit line. Regenerative energy, generated by the braking train, is considered to store into its individual on-board energy storage devices and provided for the follow-up traction operations. Some parameters, including the comfort criterion and increased train mass due to the installation of energy storage devices, are all taken into account in the energy consumption calculation. In the optimization process, the total running time is only required to be adjusted in a predetermined range to guarantee transportation capacity and meet passenger travel demands. A dynamic programming based heuristic is designed with operational experiences and a series of numerical experiments are implemented to demonstrate the effectiveness, corresponding to Beijing metro Yizhuang line.

Comparative analysis between different methods for calculating on-board ship's emissions and energy consumption based on operational data

With the aim of more reliably measuring ships' fuel consumption and emissions several different estimation methods have been put forward and are in use but there is ongoing debate still on the best way to measure maritime emissions. Fuel and emissions monitoring are already a common practice in the shipping industry. But there are currently neither harmonised guidelines nor legal requirements that clearly define the method and the rules to follow to monitor on-board fuel consumption for each situation during navigation.In this context, this article describes and compares four existing methods (EPA, IMO, Jalkanen and MAN) for calculating energy consumption and emissions, and presents a more realistic method, based on a case study. The purpose is to examine the differences between all of these methods, in order to propose the most suitable method of obtaining the data needed for better energy management, and a method that can be applied to any type of ship. The case study was carried out on Ro-Pax ships, comparing these four different methods through the application of a bottom-up integrated system approach. The study describes in detail and applies the most complete methodology for calculating energy consumption and emissions during cruising, operating in a Speed Reduction Zone (SRZ), manoeuvring and berthing.Application of the new improved method proposed in this paper could be the first step in implementing operational measures for detecting both abnormal high emissions and abnormal fuel consumption. The application of this method does not, in itself, reduce fuel use or improve efficiency, but it should be the necessary first step to establish uniform operational measures that will improve the management of energy on board ship and monitor accurately the performance of the fleet.

АНАЛИЗ ЭНЕРГОТРАТ ХОККЕИСТОВ НА ЭТАПАХ ГОДИЧНОГО ЦИКЛА

The object of this study was the energy demands of athletes in different periods of the annual cycle. The aim of the study was to determine the daily energy consumption of athletes (on the example of the hockey team), taking into account individual activity in different periods of the annual cycle, with the ultimate goal to identify the failure of averaged calculations carried out previously for athletes. In the article the technique of calculation energy expenses athletes using the clock readings of heart rate monitors. This technique is quite easy to use and in combination with the traditional method of calculation allows to simplify and specify the calculation of energy consumption at each stage of the annual training mesocycle. As a result of the survey, the main activities of the subjects with timing in each specific period of year cycle were identified, as well as hockey players provided data of their watches-heart rate monitors, at times of physical exertion of a certain intensity. In the study, we have used somatometry (measurement of height and weight), the obtained results were processed by methods of mathematical statistics. Further, according to the formulas, the values of the daily basic exchange and the value of the basic exchange per hour were determined. On the basis of calculations and data provided, the values of energy expenditure of hockey players in each stage of the annual cycle were calculated. The analysis of the obtained data revealed a significant difference in the readings of energy consumption in the competitive, training and recovery periods, which confirms the failure of the averaged calculations conducted earlier. This technique allows to individualize the calculations of this kind, and the accounting of the results, in turn, will create the possibility of adequate replenishment of energy consumption with the help of food ration.

THE STUDY OF ENERGY CONSUMPTION IN THE DIMENSION STONE CUTTING PROCESS

In the dimension stone industry, predicting the energy consumption in rock cutting process and examining its relationship with machining parameters are among the most important steps to achieve the optimum conditions in terms of energy consumption. A laboratory scale cutting machine with changing machining parameters was made and its energy consumption was evaluated through the statistical analysis. Tests were carried on seven carbonate rock samples under different operating conditions at different depths of cut, feed rates and peripheral speeds. Finally, an energy consumption model was obtained through statistical studies using SPSS software. The t and F tests were used to validate the model and to control each of the independent variables. To see the prediction capability of the derived model, the scatter diagram of the observed and estimated values was plotted. The results showed that the points are very close to the 1:1 diagonal straight line. It concluded that the developed model has a high degree of accuracy with a high correlation between the predicted and the observed values. Due to its high accuracy, the proposed model can be used in the calculation of energy consumption under various operating parameters.

Research on model calibration method for energy consumption evaluation of cluster motor system

In practical engineering, the conventional energy consumption calculation method of the motor system is facing many problems, such as difficulty in data acquisition, deviation of model parameters and so on. In order to ensure and improve the accuracy and evaluation ability of the energy consumption model, a calibration method based on parameter identification theory is proposed in this paper. Using the Levenberg-Marquardt algorithm, the rated efficiency, rated variable loss and constant loss parameters of the single and cluster motor systems are identified, and the correction model for the calculation of motor energy consumption is established. Taking a typical three machine cluster motor system as an example, a real physical experiment platform is built to obtain real running data. The example shows that the energy consumption model correction method proposed in this paper has strong engineering practicability, which provides an effective technical means for energy consumption assessment and energy saving transformation of motor energy system.

Calculation of Efficiency Maps Using a Scalable Saturated Model of Synchronous Permanent Magnet Machines

This paper proposes the novel scalable saturated model of synchronous permanent magnet machines, which combines ultrafast scaling laws with a saturated flux-linkage and loss model. The scalable model is used for the fast and accurate calculation of efficiency/loss maps and can also be used for drive cycle analysis including the calculation of energy consumption. It is verified by comparison with an existing state-of-the-art efficiency map and drive cycle analysis software. Additionally, an experimental verification of a saturated flux-linkage and loss model is presented. The additional possible usage of the scalable model is to find the optimal size of a scaled machine in order to meet the drive cycle performance and requirements of a traction motor.

Cost optimum calculation of energy efficiency measures in the Czech Republic

The EU Member States have adopted the Energy Performance of Buildings Directive (EPBD II) in their legislation. This directive introduces new procedures for evaluating the setting of energy performance requirements for buildings, including the so-called cost optimum requirements.The cost optimum is calculated using a comparative methodology framework developed in accordance with the Directive and shall be submitted every four years (EPBD II, 2010). The paper introduces the national cost optimum calculation completed in June 2017 in the Czech Republic.The main goal of this paper is to present selected results of the unique national cost optimum calculation model, including the methodology applied. The main method consists of primary data collection used to determine the cost for a full range of energy efficiency measures and the calculation of primary energy consumption in the selected types of buildings.Due to decreasing energy prices in recent years and the lower price for EE measures and renewables, no significant movement of the cost-optimal measures was observed.This article primarily creates the basis for calculating the cost optimum at the national level. The data can also be used to compare cost-related measures between particular EU Member States.

Thermodynamics of Ion Separation by Electrosorption.

We present a simple, top-down approach for the calculation of minimum energy consumption of electrosorptive ion separation using variational form of the (Gibbs) free energy. We focus and expand on the case of electrostatic capacitive deionization (CDI). The theoretical framework is independent of details of the double-layer charge distribution and is applicable to any thermodynamically consistent model, such as the Gouy-Chapman-Stern and modified Donnan models. We demonstrate that, under certain assumptions, the minimum required electric work energy is indeed equivalent to the free energy of separation. Using the theory, we define the thermodynamic efficiency of CDI. We show that the thermodynamic efficiency of current experimental CDI systems is currently very low, around 1% for most existing systems. We applied this knowledge and constructed and operated a CDI cell to show that judicious selection of the materials, geometry, and process parameters can lead to a 9% thermodynamic efficiency and 4.6 kT per removed ion energy cost. This relatively high thermodynamic efficiency is, to our knowledge, by far the highest thermodynamic efficiency ever demonstrated for traditional CDI. We hypothesize that efficiency can be further improved by further reduction of CDI cell series resistances and optimization of operational parameters.

Electric vehicle routing problem with recharging stations for minimizing energy consumption

Due to growing environmental concerns about greenhouse gas (GHG) emissions, people are more incline to use electric vehicles in various distribution services. Because of the limited battery capacity, electric vehicles are required to visit recharging stations en-route. Therefore, the routing schemes of conventional vehicles may not be suitable as the routing schemes of electric vehicles. In this paper, the Electric Vehicle Routing Problem (EVRP) is introduced, and the corresponding mathematical model is formulated. The EVRP seeks to minimize the energy consumption of electric vehicles. The comprehensive calculation of energy consumption used by electric vehicles is provided in the EVRP model. An ant colony (AC) algorithm based meta-heuristics is proposed as the solution method of the EVRP. The effectiveness of the proposed algorithms is evaluated through extensive numerical experiments on the newly generated instances. We also illustrate the benefits of using an energy consumption-minimizing objective function rather than a distance-minimizing objective function for routing electric vehicles.

Study on Energy Consumption Optimization Method Based on Machine Tool in Intelligent Manufacturing Unit

Manufacturing consumes a lot of energy in the process of turning resources into products or services. The manufacturing process of mechanical products is an important energy consuming manufacturing resource. In response to global warming, improve the sustainable development of the manufacturing and machining of parts for mechanical products manufacturing process is optimized for energy conservation, energy consumption of machine tool bearing gland belongs to typical industrial components. Machining manufacturing process optimization method of energy consumption, this paper studies the machine tool equipment resource modelling and quantitative evaluation on taste, quantitative calculation of energy consumption, mechanical processing and manufacturing process for low carbon manufacturing process planning and production scheduling. Through the application cases of automatic line of bearing gland of machine tool.

Modelling household spatial energy intensity consumption patterns for building envelopes, heating systems and temperature controls in cities

This paper explore the benefits of a bottom-up spatially enabled engineering building-based energy framework in identifying neighbourhoods, and community’s building aggregated areas with spatial patterns. We argue that an area-based approach allows more houses to be targeted in places where local area characteristics show inefficient elements, and may therefore potentially capture a greater number of households per unit of cost, compared to the existing self-referral methods. We propose a spatial method to show the extent of building envelopes, heating systems and temperature controls. Heating controls, which are not recorded in the United Kingdom Homes Energy Efficiency Database (HEED), but we believe would be considered good practice to maintain balanced temperatures around the house, and also potentially reduce the complexity in modelling the thermal zones. Additionally, heating controls are seen as compulsory in new building regulations, an eligible measure in Green Deal and Energy Company Obligations, and in the United Kingdom Department of Energy and Climate Change (DECC) heat strategy. This paper has taught us that the emerging picture surrounding local energy modelling and that, for example, singularities such as group heating and district heating (decentralised energy supply) have a great impact on final energy consumption calculations.

EFFICIENCY ANALYSIS OF THE REFRIGERATION SYSTEM IN FRATELLO TRADE AD BANJA LUKA

The aim of this paper is to show the importance of choosing a refrigerant in cooling plants, and to provide an insight into how this choice influences the system in terms of its efficiency and cost-effectiveness. The analysis of the influence of a refrigerant on the system’s efficiency and cost-effectiveness was done on an example of a refrigerator storing frozen fish in Fratello Trade AD, Banja Luka. Using the parameters of this system, this study examines whether the plant would be more efficient and economical if anotherrefrigerant was chosen. The existing refrigerant used by this plant is R-404A. Segments that are examined in terms of efficiency and economy include the performance coefficient of the plant and the annual consumption of electricity, that is, their respective costs. The performance coefficient of the plant gives an insight about the correspondence between kW of input electricity and kW of cooling power generated in the system. The higher this coefficient, the more efficient the system is. The calculation of annual energy consumption helps to determine which refrigerantis most cost-effective. The paper shows the analysis based on the choice of the refrigerant.

Bromide Ions Specific Removal and Recovery by Electrochemical Desalination.

Removal and recovery of bromide ions by electro-oxidation and electro-reduction are presented using hybrid physical adsorption and capacitive deionization cells, which contain activated carbon cloth electrodes. This is a proof of concept research with results, which indicate that when comparing the removal and recovery quantities of bromide and chloride ions (starting with the same initial concentration of 0.05 M for both salts), the desalination capacity of the bromide ions is larger by almost 2 orders of magnitude than that of the chloride ions; thus, we obtained specific desalination of bromide ions from a solution containing chloride ions. Removal and recovery of 3.5 mmol of bromide ions were achieved by a working electrode with 1 g of activated carbon cloth, and the calculated energy consumption for the removal and recovery of 1 g of bromide ions was about 2.24 kJ/g.

Objectively Measured Weekly Physical Activity among Adolescent Boys and its Relation to Health-Related Physical Fitness

Research background and hypothesis. The objective methods of measuring physical activity (PA) are used more and more widely in various types of research. However, in Lithuania there is a lack of such studies with adolescents. Thus, we conducted a pilot study to objectively measure boys’ PA and to develop a more accurate PA assessment methodology in Lithuania. The purpose of this study was to analyse the objectively measured adolescent boys’ weekly physical activity and its relation to their body composition and physical fitness.Research methods. The participants of this study were 104 healthy adolescent boys. Physical activity of schoolboys was measured using actigraphs (Tri-axis ActiTrainer Activity Monitors). The level of the intensity of physical activity was determined by calculating energy consumption in MET’s. Low PA (LPA) equals up to 3 MET’s, moderate PA (MPA) – 3–6 MET’s, and vigorous PA (VPA) – 8 or more METs. Based on the frequency of VPA and MPA per week, the participants of this study were divided into physical activity groups. For health-related physical fitness assessment the following tests were used: body composition (using TANITA Body Analyser, TBF-300); flexibility (sit and reach test, Eurofitas, 2002), power (vertical jump was measured using a jump parameter gauge (SBM-1), muscular strength and endurance (modified push-up test (Suni et al., 1994)). Research results. All of the schoolboys demonstrated LPA on each day of the assessment. MPA on each day was experienced by 59.6% of the boys. No participants achieved VPA . The most frequent MPA and VPA were observed 5–7 and 1–3 days per week, respectively. Results of body composition indicated that boys experiencing VPA had lower body fat mass compared to those who experienced only MPA and LPA (p < 0.05). Analysis of physical fitness results indicated that boys who experienced VPA were better muscular in strength and endurance test (p < 0.05), but results of high jump and sit and reach test were not significantly different. Discussion and conclusion. Boys who experienced VPA at least for 3 days/week demonstrated better muscular strength and endurance results and had lower body fat content (%) (p < 0.05). For boys who did not experience MPA at least for 6 days/week, the total amount of weekly physical activity decreased and they could not produce better results in strength and endurance test (p < 0.05). Better results of boys’ muscular strength and endurance were significantly related to their body lower BMI (r = 0.279; p < 0.05) and fat mass (r = 0.387; p < 0.01). Objectively Measured Weekly Physical Activity among Adolescent Boys and its Relation to Health-Related Physical FitnessKeywords: physical activity, MET’s, actigraphs.

Hierarchical Clustering-Task Scheduling Policy in Cluster-Based Wireless Sensor Networks

Organizing sensor nodes into a clustered architecture is an effective method for load balancing and prolonging the network lifetime. However, a serious drawback of the clustering approach is the imposed energy overhead caused by the “global” clustering operations in every round of the global round-based policy (GRBP). To mitigate this problem, this paper proposes a hierarchical clustering-task scheduling policy (HCSP), which triggers node-driven clustering as opposed to GRBP's time-driven clustering. Based on HCSP, each cluster is reconfigured only once at each local super round. Therefore, the cluster reconfiguration frequency varies on-demand and may differ from one cluster to another throughout the network lifetime. However, in order to refresh the entire network structure, global clustering is performed at the end of every global hyper round. Accordingly, HCSP aims to achieve a more flexible, energy-efficient, and scalable clustering-task scheduling than that of GRBP. This policy mitigates the clustering overhead, which is the worst disadvantage of clustering approaches. Energy consumption calculations and extensive simulations show the effectiveness of HCSP in saving energy and in prolonging the network lifetime.

An input–output model for energy accounting and analysis of industrial production processes: a case study of an integrated steel plant

To promote sustainability, it has become increasingly vital to properly account material and energy flows in industrial production processes. Therefore, a generic process-level input–output (IO) model was developed to provide an integrated energy (material) accounting and analysis approach for industrial production processes. By extending the existing process-level IO models, the production, usage, export and loss of by-products were explicitly considered in the proposed IO model. Moreover, the by-products allocation procedures were incorporated into the proposed IO model to reflect individual contributions of products to energy consumption. Finally, the proposed model enabled calculating embodied energy of main products and total energy consumption under hierarchical accounting scope. Plant managers, energy management consultants, governmental officials and academic researchers could use this input–output model to account material and energy flows, thus calculating energy consumption indicators of a production process with their specific system boundary requirements. The accounting results could be further used for energy labeling, identifying bottlenecks of production activities, evaluating industrial symbiosis effects, improving materials and energy utilization efficiency, etc. The model could also be used as a planning tool to determine the effect that a particular change of technology and supply chains may have on the industrial production processes. The proposed model was tested and applied in a real integrated steel mill, which also provided the reference results for related researches. At last, some concepts, computational issues and limitations of the proposed model were discussed.

A model for the effective thermal conductivity of moist porous building materials based on fractal theory

An accurate estimation of building material thermal conductivity is crucial for the modeling of heat transfer processes and the calculation of building energy consumption. The effect of moisture content on the thermal conductivity of the material is usually neglected in most currently used calculation methods. These methods cannot represent the interior multi-phase heat transfer process. In this paper, the coexisting solid-liquid-gas thermal conductivity physical model was proposed. Taking into account the pore structure characteristics of building materials, a coexisting tri-phase thermal conductivity calculation model based on capillary structure was established using fractal theory. The quantitative influence relationship of the parameters, such as porosity, pore diameter distribution, moisture content and fractal structure, on the thermal conductivity of moist porous materials was analyzed. The results provide a theoretical basis for the thermal conductivity correction of moist building materials.

Estimation and uncertainty analysis of energy consumption and CO 2 emission of asphalt pavement maintenance

Abstract Substantial energy consumption and CO2 emission are generated in asphalt pavement maintenance and their quantifications based on individual case are highly contingent on the input data qualities and model parameters, exhibiting high uncertainties. This study established energy consumption and CO2 emission uncertainty assessment statistical methodology to deal with the issue. Two sources of uncertainty, the data quality one and the model parameter one, were identified. The former was captured by converting the input data to probability density function (PDF) using Beta distribution following the definitions of data quality pedigree matrix; the latter was assessed by defining uncertainty factor (UF) to determine the distribution form and parameter. Environmental data of 18 field asphalt pavement maintenance projects were collected, including hot mix asphalt (both base and SBS modified asphalts), hot in-plant recycling (15% reclaimed asphalt pavement), cold in-place recycling and cold in-plant recycling asphalt maintenance plans, covering pavement material production, transportation, mixture preparation and construction phases. The PDFs and statistical parameters (mean, standard deviation and percentiles etc.) were obtained via Monte Carlo simulation for these maintenance measures. This study further developed environmental burden comparative parameter to construct the 95% confidence intervals for the comparisons of different maintenance measures. The methodology proposed in this study captured the uncertainty of energy consumption and CO2 emission calculation results of maintenance activity and allow researchers to evaluate the results in a statistical view.

Metro timetable optimisation for minimising carbon emission and passenger time: a bi‐objective integer programming approach

Timetable optimisation in metro systems is typically a multi-objective decision problem involving both social and passengers’ benefits. Based on the train operation and passenger demand data, this study develops a bi-objective timetable optimisation model to reduce both passenger time and carbon emission of train operation. Firstly, the cooperative scheduling rule of multiple trains within the same electricity supply section is analysed. The tractive energy consumption and utilisation of regenerative braking energy are calculated with a set of kinematical equations. The carbon emission is formulated according to the calculations of energy consumption. Meanwhile, a passenger time calculation function is established by analysing the real-world passenger demand data. Secondly, a bi-objective integer programming model with dwell time control is formulated, and a linearly weighted compromise algorithm and a heuristic algorithm are designed to find the optimal solution. Finally, a numerical example is presented based on the passenger and operation data from the Beijing Metro Yizhuang Line. The results show that the best found timetable can achieve a good performance on both carbon emission and passenger time in comparison with the currently used timetable.