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Optimum cutting speed of block-cutting machines in natural stones for energy saving 被引量:3
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作者 N.Bilim 《Journal of Central South University》 SCIE EI CAS 2012年第5期1234-1239,共6页
Energy consumption of block-cutting machines represents a major cost item in the processing of travertines and other natural stones. Therefore, determining the optimum sawing conditions for a particular stone is of ma... Energy consumption of block-cutting machines represents a major cost item in the processing of travertines and other natural stones. Therefore, determining the optimum sawing conditions for a particular stone is of major importance in the natural stone-processing industry. An experimental study was carried out utilizing a fully instrumented block-cutter to investigate the sawing performances of five different types of travertine blocks during cutting with a circular diamond saw. The sawing tests were performed in the down-cutting mode. Performance measurements were determined by measuring the cutting speed and energy consumption. Then, specific energy was determined. The one main cutting parameter, cutting speed, was varied in the investigation of optimum cutting performance. Furthermore, some physico-mechanical properties of file travertine blocks were determined in the laboratory. As a result, it is found that the energy consumption (specific energy) of block cutting machines is highly affected by cutting speed. It is determined that specific energy value usually decreases when cutting speed increases. When the cutting speed is higher than the determined value, the diamond saw can become stuck in the travertine block; this situation can be a problem for the block-cutting machine. As a result, the optimum cutting speed obtained for the travertine mines examined is approximately 1.5-2.0 m/min. 展开更多
关键词 cutting speed TRAVERTINE block cutting machine specific energy natural stone energy saving
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Energy saving analysis of segment positioning in shield tunneling machine considering assembling path optimization 被引量:4
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作者 施虎 龚国芳 +1 位作者 杨华勇 梅雪松 《Journal of Central South University》 SCIE EI CAS 2014年第12期4526-4536,共11页
A motion parameter optimization method based on the objective of minimizing the total energy consumption in segment positioning was proposed for segment erector of shield tunneling machine. The segment positioning pro... A motion parameter optimization method based on the objective of minimizing the total energy consumption in segment positioning was proposed for segment erector of shield tunneling machine. The segment positioning process was decomposed into rotation, lifting and sliding actions in deriving the energy calculation model of segment erection. The work of gravity was taken into account in the mathematical modeling of energy consumed by each actuator. In order to investigate the relationship between the work done by the actuator and the path moved along by the segment, the upward and downward directions as well as the operating quadrant of the segment erector were defined. Piecewise nonlinear function of energy was presented, of which the result is determined by closely coupled components as working parameters and some intermediate variables. Finally, the effectiveness of the optimization method was proved by conducting a case study with a segment erector for the tunnel with a diameter of 3 m and drawing comparisons between different assembling paths. The results show that the energy required by assembling a ring of segments along the optimized moving path can be reduced up to 5%. The method proposed in this work definitely provides an effective energy saving solution for shield tunneling machine. 展开更多
关键词 energy saving segment erector work of gravity path optimization shield tunneling machine
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Numerical simulation of thermal process and energy saving of lime furnace 被引量:1
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作者 易正明 周孑民 陈红荣 《Journal of Central South University of Technology》 2005年第3期295-299,共5页
Based on the principle of thermal balance and material balance of lime furnace, the reaction and heat transfer process mathematical-physical model and the on-line monitoring model of the decomposition rate of limeston... Based on the principle of thermal balance and material balance of lime furnace, the reaction and heat transfer process mathematical-physical model and the on-line monitoring model of the decomposition rate of limestone were set up. With this model, numerical simulation is used to analyze the effects of operational parameters on the process of lime calcining and to optimize it. By using visual basic program to communicate and program, the centralized management and automatic control of the lime furnace are realized. The software is put into practical production, which makes the lime furnace operate steadily and efficiently, and causes the increase in output and decrease in energy consumption. 展开更多
关键词 lime furnace thermal balance material balance numerical simulation energy saving
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Dynamics of electromagnetic slip coupling for hydraulic power steering application and its energy-saving characteristics 被引量:2
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作者 唐斌 江浩斌 +2 位作者 徐哲 耿国庆 徐兴 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第5期1994-2000,共7页
To improve high-speed road feel and enhance energetic efficiency of hydraulic power steering(HPS) system in heavy-duty vehicles, an electromagnetic slip coupling(ESC) was applied to the steering system, which regulate... To improve high-speed road feel and enhance energetic efficiency of hydraulic power steering(HPS) system in heavy-duty vehicles, an electromagnetic slip coupling(ESC) was applied to the steering system, which regulated discharge flow of steering pump to realize variable assist characteristic as well as uniquely transfer on-demand power from engine to steering pump. The model of ESC was established and the dynamic characteristics of ESC were presented by the way of simulation and experiment. Upon the layout of the assist characteristics, output torque of ESC was derived. Based on the ESC model, the output torque characteristics of ESC were simulated under steering situation and straight driving situation, respectively. The consistency of simulated ESC output torque and the one deduced from assist characteristics verifies the correctness of the ESC dynamic model. To illustrate energy saving characteristics of ESC-HPS, energy consumption comparison of ESC-HPS and conventional HPS was carried out qualitatively and quantitatively. It follows that the energy consumption of ESC-HPS decreases by 50% compared with that of HPS. 展开更多
关键词 heavy-duty vehicle hydraulic power steering system electromagnetic slip coupling DYNAMICS energy saving
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Utilization of Livestock's Dejection as Biogas Origin in Building New Countryside in Heilongjiang Province--Developing Utilization of Biogas and Promoting Energy-saving and Emission Reduction
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作者 SHEN Xueqing CUI Lijuan ZHOU Dongxing 《Journal of Northeast Agricultural University(English Edition)》 CAS 2011年第1期91-96,共6页
With the startup and execution of new socialistic countryside construction in Heilongjiang Province,the transition from castoff to resource is strengthened in the countryside,aiming at neat appearance of the countrysi... With the startup and execution of new socialistic countryside construction in Heilongjiang Province,the transition from castoff to resource is strengthened in the countryside,aiming at neat appearance of the countryside,clean production and saving energy.People produce biogas and provide the countryside with new energy by means of turning livestock's dejection into resources,composting of the plant and animal's leavings in the courtyard and even in the factory.It is helpful for the countryside to conserve the energy and reduce emission of the waste.And it also plays an important role in protecting the eco-environment,beautifying homestead and developing the ecological agriculture and so on.The liquid and solid residue in the biogas production can be reused as fertilizer for crops or food for animals after pretreatment,which is propitious to accelerate the development of the circular economy in Heilongjiang Province. 展开更多
关键词 new socialistic countryside construction composting of livestock's dejection energy saving and emission reduction
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Coupled simulation of BES-CFD and performance assessment of energy recovery ventilation system for office model 被引量:6
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作者 Yunqing FAN T.Hayashi K.Ito 《Journal of Central South University》 SCIE EI CAS 2012年第3期633-638,共6页
Thermal comfort and indoor air quality as well as the energy efficiency have been recognized as essential parts of sustainable building assessment. This work aims to analyze the energy conservation of the heat recover... Thermal comfort and indoor air quality as well as the energy efficiency have been recognized as essential parts of sustainable building assessment. This work aims to analyze the energy conservation of the heat recovery ventilator and to investigate the effect of the air supply arrangement. Three types of mixing ventilation are chosen for the analysis of coupling ANSYS/FLUENT (a computational fluid dynamics (CFD) program) with TRNSYS (a building energy simulation (BES) software). The adoption of mutual complementary boundary conditions for CFD and BES provides more accurate and complete information of indoor air distribution and thermal performance in buildings. A typical office-space situated in a middle storey is chosen for the analysis. The office-space is equipped with air-conditioners on the ceiling. A heat recovery ventilation system directly supplies flesh air to the office space. Its thermal performance and indoor air distribution predicted by the coupled method are compared under three types of ventilation system. When the supply and return openings for ventilation are arranged on the ceiling, there is no critical difference between the predictions of the coupled method and BES on the energy consumption of HVAC because PID control is adopted for the supply air temperature of the occupied zone. On the other hand, approximately 21% discrepancy for the heat recovery estimation in the maximum between the simulated results of coupled method and BES-only can be obviously found in the floor air supply ventilation case. The discrepancy emphasizes the necessity of coupling CFD with BES when vertical air temperature gradient exists. Our future target is to estimate the optimum design of heat recovery ventilation system to control CO2 concentration by adjusting flow rate of flesh air. 展开更多
关键词 building energy simulation computational fluid dynamics (CFD) FLUENT TRNSYS energy saving
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Energy performance assessment on central air-conditioning system of commercial building: A case study in China
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作者 周璇 练斯甄 +1 位作者 闫军威 康英姿 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第8期3168-3179,共12页
Energy performance assessment on central air-conditioning system is essential to optimize operating, reduce operating costs, improve indoor environmental quality, and determine whether the retrofitting of the equipmen... Energy performance assessment on central air-conditioning system is essential to optimize operating, reduce operating costs, improve indoor environmental quality, and determine whether the retrofitting of the equipment is necessary. But it is difficult to evaluate it reasonably and comprehensively due to its complexity. A "holistic" approach was discussed to evaluate the energy performance of central air-conditioning system for an extra-large commercial building in a subtropical city. All procedures were described in detail, including field investigation method, field measurement instruments, data processing and data analyzing. The main factors affecting energy consumption of air-conditioning system were analyzed and the annual cooling-energy use intensity of this building was calculated and also compared with other shopping malls and other types of buildings in Guangzhou. And COP(coefficient of performance) of chiller, water transfer factor of chilled water system and cooling water system were taken into consideration. At last, the thermal comfort and indoor air quality issues were addressed. The results show that the chilled water pumps are over-sized and the indoor environmental quality should be improved. The purpose of this work is to provide reference for energy performance assessment method for air-conditioning system. 展开更多
关键词 energy performance assessment thermal comfort indoor air quality central air-conditioning system energy saving
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Energy optimization of representative barrier algorithms
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作者 陈娟 董勇 《Journal of Central South University》 SCIE EI CAS 2012年第10期2823-2831,共9页
Too high energy consumption is widely recognized to be a critical problem in large-scale parallel computing systems.The LogP-based energy-saving model and the frequency scaling method were proposed to reduce energy co... Too high energy consumption is widely recognized to be a critical problem in large-scale parallel computing systems.The LogP-based energy-saving model and the frequency scaling method were proposed to reduce energy consumption analytically and systematically for other two representative barrier algorithms:tournament barrier and central counter barrier.Furthermore,energy optimization methods of these two barrier algorithms were implemented on parallel computing platform.The experimental results validate the effectiveness of the energy optimization methods.67.12% and 70.95% energy savings are obtained respectively for tournament barrier and central counter barrier on platforms with 2048 processes with 1.55%?8.80% performance loss.Furthermore,LogP-based energy-saving analytical model for these two barrier algorithms is highly accurate as the predicted energy savings are within 9.67% of the results obtained by simulation. 展开更多
关键词 energy saving tournament barrier central counter barrier LOGP Open MPI
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Field study of seasonal thermal comfort and adaptive behavior for occupants in residential buildings of Xi’an,China 被引量:3
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作者 WEI Na ZHENG Wu-xing +3 位作者 ZHANG Nan ZHAO Sheng-kai ZHAI Yong-chao YANG Liu 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第7期2403-2414,共12页
The study aims to investigate the thermal comfort requirements in residential buildings and to establish an adaptive thermal comfort model in the cold zone of China.A year-long field study was conducted in residential... The study aims to investigate the thermal comfort requirements in residential buildings and to establish an adaptive thermal comfort model in the cold zone of China.A year-long field study was conducted in residential buildings in Xi’an,China.A total of 2069 valid questionnaires,along with indoor environmental parameters were obtained.The results indicated occupants’thermal comfort requirements varied with seasons.The neutral temperatures were 17.9,26.1(highest),25.2,and 17.4℃(lowest),and preferred temperatures were 23.2,25.6(highest),24.8,and 22.4℃(lowest),respectively for spring,summer,autumn,and winter.The neutral temperature and preferred temperature in autumn are close to the neutral temperature in summer,while the neutral temperature and preferred temperature in spring are close to that in winter.Besides,the 80%and 90%acceptable temperature ranges,adaptive thermal comfort models,and thermal comfort zones for each season were established.Human’s adaptability is related to his/her thermal experience of the current season and the previous season.Therefore,compared with the traditional year-round adaptive thermal comfort model,seasonal models can better reflect seasonal variations of human adaptation.This study provides fundamental knowledge of the thermal comfort demand for people in this region. 展开更多
关键词 thermal comfort seasonal variation adaptive thermal comfort model energy saving residential buildings
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Assessment of green roof performance for sustainable buildings under winter weather conditions 被引量:2
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作者 J.Srebric 《Journal of Central South University》 SCIE EI CAS 2012年第3期639-644,共6页
A green roof is a specialized roof system that supports vegetation growth on rooftops.This technology is rapidly gaining popularity as a sustainable design option for buildings.In order to contribute to an understandi... A green roof is a specialized roof system that supports vegetation growth on rooftops.This technology is rapidly gaining popularity as a sustainable design option for buildings.In order to contribute to an understanding of green roof in regions with cold winters and snow,an on-site experimental investigation was present with a focus on the assessment of green roof performance during the winter.This field experiment took place on a six small buildings during the winter of 2010-2011.The work monitored three buildings with green roofs,two buildings with reference roofs and one building with a bare soil coverage for the roof.These six buildings were identically constructed and instrumented with sensor networks to provide heat flux data through the roofs.The 15 min averaged data were statistically analyzed for a week under the two separate periods,first without a snow cover and second with a snow cover.The results show that the roof type is a significant factor in affecting the thermal performance of these buildings.Most importantly,green roofs reduce heat flow through the roof and thus reduce the heating energy demand during the winter.However,the energy savings for buildings with the green roofs are reduced under snow conditions because the snow diminishes thermal resistance of the roof and increases the heat transfer process through the roofs. 展开更多
关键词 green roof energy savings building envelop sustainable buildings
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Server load prediction algorithm based on CM-MC for cloud systems 被引量:2
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作者 XU Xiaolong ZHANG Qitong +1 位作者 MOU Yiqi LU Xinyuan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第5期1069-1078,共10页
Accurate prediction of server load is important to cloud systems for improving the resource utilization, reducing the energy consumption and guaranteeing the quality of service(QoS).This paper analyzes the features of... Accurate prediction of server load is important to cloud systems for improving the resource utilization, reducing the energy consumption and guaranteeing the quality of service(QoS).This paper analyzes the features of cloud server load and the advantages and disadvantages of typical server load prediction algorithms, integrates the cloud model(CM) and the Markov chain(MC) together to realize a new CM-MC algorithm, and then proposes a new server load prediction algorithm based on CM-MC for cloud systems. The algorithm utilizes the historical data sample training method of the cloud model, and utilizes the Markov prediction theory to obtain the membership degree vector, based on which the weighted sum of the predicted values is used for the cloud model. The experiments show that the proposed prediction algorithm has higher prediction accuracy than other typical server load prediction algorithms, especially if the data has significant volatility. The proposed server load prediction algorithm based on CM-MC is suitable for cloud systems, and can help to reduce the energy consumption of cloud data centers. 展开更多
关键词 cloud computing load prediction cloud model Markov chain energy saving
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