• 제목/요약/키워드: operation performance

검색결과 9,264건 처리시간 0.031초

트랙터의 기관속도 및 변속비의 최적제어에 관한 연구(II) -최적운전 제어 시스템의 성능- (Automatic Control of Engine Speed and Transmission Ratio for Efficient Tractor Operations(II) -Performance of Optimal System-)

  • 강성봉;류관희;오길근
    • Journal of Biosystems Engineering
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    • 제19권4호
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    • pp.291-300
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    • 1994
  • It is desired to operate tractor engines at or near maximum torque much of the time in field operation to increase fuel efficiency. To do this it is necessary to reduce engine speed and to shift gears to higher ratios as frequently as possible. Because of load variations in most drawbar work and inconvenience in gear shift, however, gear-type transmission are usually set in one ratio at unnecessarily high engine speeds, and engine-torque variations are used to compensate for changes in drawbar load. As a result, the most of time the tractor is not operated efficiently in terms of fuel consumption and work output. The objective of this study was to develop an automatic control system which is able to operate a tractor equipped with gear transmission under the optimal condition in terms of fuel efficiency with automatic governor setting and gear shift. An indoor experimental test set which can be used to simulate tractor operation, control engine speed and transmission ratio was developed in the previous paper. In this paper, the performance of the optimal operation system is reported. Through a series of tests, it was found that the automatic control system for optimal operation of tractors with gear transmission had a satisfactory performance.

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3차원 그래픽을 위한 Geometry 프로세서의 설계 (The Design of Geometry Processor for 3D Graphics)

  • 정철호;박우찬;김신덕;한탁돈
    • 한국정보처리학회논문지
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    • 제7권1호
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    • pp.252-265
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    • 2000
  • 본 논문에서는 3차원 그래픽의 처리 과정 중 부동 소수점 연산이 많은 소요되는 geometry 프로세싱 처리 방법과 계산량을 단계별로 분석하였다. 그리고, 그래픽 프로세싱의 수행 특성을 추출하여, 이에 맞는 기능 유닛을 설계하고, 데이터 처리 방안과 제안하는 geometry 프로세서의 구조를 설명한 다음, 성능을 분석하였다. 제안하는 geometry 프로세서는 부동 소수점 덧셈, 곱셈, 나눗셈 연산을 동시에 수행 가능하며, geometry 프로세싱 전 단계를 수행하는데 23.5%의 성능 향상이 있었다. 그리고, 나눗셈/제곱근 연산을 위해서 면적대 성능비가 우수한 SRT 나눗셈 연산기를 추가하여 곱셈 연산기를 이용하는 연산기보다 약 23%의 성능 향상을 이루었다.

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가정용 열병합 발전을 위한 스털링 엔진의 열원 온도 및 냉각수 유량에 따른 성능 실험 (Performance Measurements of A Stirling Engine for Household Micro Combined Heat and Power with Heat Source Temperatures and Cooling Flow Rates)

  • 심규호;김민기;이윤표;장선준
    • 한국유체기계학회 논문집
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    • 제18권1호
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    • pp.37-43
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    • 2015
  • A Beta-type Stirling engine is developed and tested on the operation stability and cycle performance. The flow rate for cooling water ranges from 300 to 1500 ml/min, while the temperature of heat source changes from 300 to $500^{\circ}C$. The internal pressure, working temperatures, and operation speed are measured and the engine performance is estimated from them. In the experiment, the rise in the temperature of heat source reduces internal pressure but increases operation speed, and overall, enhances the power output. The faster coolant flow rate contributes to the high temperature limit for stable operation, the cycle efficiency due to the alleviated thermal expansion of power piston, and the heat input to the engine, respectively. The experimental Stirling engine showed the maximum power output of 12.1 W and the cycle efficiency of 3.0 % when the cooling flow is 900 ml/min and the heat source temperature is $500^{\circ}C$.

점적 emitter 의 성능과 수리적 특성 (Performance and Hydraulic Characteristics of Drip Emitters)

  • 이남호
    • 한국농공학회지
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    • 제41권3호
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    • pp.33-40
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    • 1999
  • Variations in the discharge rates of drip emittes were examined to find the effects of operation pressure and the tube length and to evaluate performance of the emitters. Several point-source emitters were selected such as pressure compensated, anti-leak pressure compensated, turbulent flow regulated, flow regulated, ready-made dripper, and spaghetti. Combination of operation pressure and tube length were compared. The microirrigatioon system was operated at pressures of 0.5 , 1.0 , 1.5 and 2.0 bar. The discharge from emitters wer collected at every ten meters along the lateral tube and weighted. In order to evaluate the drip emitters performance coeffcient of discharge variation , statistical uniformity, and emission uniformity were calculated. No significant variation in discharge along drip tube resulted with all emitters. There is no trend of variatiiono of discharge rate from pressure compensated emitters with increase in operation pressures. But discharge rate from other types of emitters increased with increase in operation pressures. The nominal discharge of each emitter was secured at pressure of 1.0 bar, Evaluation using statiscal and emission uniformity coefficients indicated that most of the emitters excepts tubulent flow regulated emitter and ready-made dripper performed at excellent level.

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기존 건축물의 운영단계 에너지효율 개선을 위한 관리 및 제도화 방안 연구 (A Study on the Institutionalization of Energy Efficient Operation and Maintenance Program for Existing Buildings)

  • 조진균;이영재
    • 한국태양에너지학회 논문집
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    • 제40권3호
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    • pp.33-42
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    • 2020
  • Operational energy is the energy that is used during the occupancy stage of building life cycle. It is associated with relatively longer proportion of infrastructure's service life and can constitute 80-90% of the total energy. Assessing the energy use in buildings is essential since they are significant contributors to energy demand. In this regard, energy performance of buildings has become the focus of many regulations. This paper aimed to review the regulations about the energy performance of buildings during their operational stage in Korea. For energy efficient operation program for existing buildings, governments should implement policies and support voluntary programs that rely on collecting and managing building performance data and using this data to inform public and private-sector operation and maintenance strategies. Implementing these policies and programs requires tools and processes for collecting, curating, managing, analyzing, and publishing this data. Energy assessment tool, that is a data resource management tool that enables to assess energy use across the entire portfolio of buildings, is also required.

불응축가스 주입량에 따른 VCHP의 열제어 특성 (Analysis of Thermal Control Characteristics of VCHP by the Charging Mass of Non-Condensible Gas)

  • 서정세;박영식;정경택
    • 설비공학논문집
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    • 제17권12호
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    • pp.1139-1144
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    • 2005
  • This study has been performed to investigate the thermal performance of variable conductance heat pipe (VCHP) with meshed wick. The length of condenser portion in a VCHP is varied by the expansion of inert gas with the operation temperature, and the heat transport capacity is thus varied with the operating temperature. In this study, numerical evaluation of the VCHP is made for the thermal performance of VCHP, based on the diffusion model of inert gas. Water is used as a working fluid and nitrogen as a control inert gas in the copper tube. As a result, the thermal performance of VCHP has been compared with that of constant conductance heat pipe (CCHP) according to the variation of operation temperature. Maximum heat transport capacity of VCHP is mainly presented for operation temperature and the variation of operation temperature is also presented for heat transfer rate of VCHP.

A Takagi-Sugeno fuzzy power-distribution method for a prototypical advanced reactor considering pump degradation

  • Yuan, Yue;Coble, Jamie
    • Nuclear Engineering and Technology
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    • 제49권5호
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    • pp.905-913
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    • 2017
  • Advanced reactor designs often feature longer operating cycles between refueling and new concepts of operation beyond traditional baseload electricity production. Owing to this increased complexity, traditional proportional-integral control may not be sufficient across all potential operating regimes. The prototypical advanced reactor (PAR) design features two independent reactor modules, each connected to a single dedicated steam generator that feeds a common balance of plant for electricity generation and process heat applications. In the current research, the PAR is expected to operate in a load-following manner to produce electricity to meet grid demand over a 24-hour period. Over the operational lifetime of the PAR system, primary and intermediate sodium pumps are expected to degrade in performance. The independent operation of the two reactor modules in the PAR may allow the system to continue operating under degraded pump performance by shifting the power production between reactor modules in order to meet overall load demands. This paper proposes a Takagi-Sugeno (T-S) fuzzy logic-based power distribution system. Two T-S fuzzy power distribution controllers have been designed and tested. Simulation shows that the devised T-S fuzzy controllers provide improved performance over traditional controls during daily load-following operation under different levels of pump degradation.

상용 개질촉매의 중온 영역 운전 특성: Ru 촉매와 Ni 촉매 비교 (Mid-Temperature Operation Characteristics of Commercial Reforming Catalysts: Comparison of Ru-Based and Ni-Based Catalyst)

  • 김영상;이강훈;이동근;이영덕;안국영
    • 한국수소및신에너지학회논문집
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    • 제32권3호
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    • pp.149-155
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    • 2021
  • Most of the reformer experiments have been conducted only in high-temperature operation conditions above 700℃. However, to design high efficiency solid oxide fuel cell, it is necessary to test actual reaction performance in mid-temperature (550℃) operation areas. In order to study the operation characteristics and performance of commercial reforming catalysts, a reforming performance experiment was conducted on mid-temperature. The catalysts used in this study are Ni-based FCR-4 and Ru-based RuA, RuAL. Experiments were conducted with a Steam-to-carbon ratio of 2.0 to 3.0 under gas hourly space velocity (GHSV) 2,000 to 5,000 hr-1. As a result, RuA and RuAL catalysts showed similar gas composition to the equilibrium regardless of the reforming temperature. However, the FCR-4 catalyst showed a lower hydrogen yield compared to the equilibrium under high GHSV conditions.

통합운영학교의 운영 실태 및 성과에 관한 연구 - 문헌조사를 중심으로 - (A Study on the Actual Operation Condition and Performance of Integrated Operation School - Focused on literature research -)

  • 이지유;이종국
    • 교육녹색환경연구
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    • 제19권4호
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    • pp.50-59
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    • 2020
  • 통합운영학교는 1998년 8개교를 운영함으로써 국내에 도입되어 현재 106개교로 점차 늘고 있는 추세이다. 하지만 지난 20년 동안 통합운영학교을 주제로 한 연구에서 각자 다양한 문제점들이 지적되었으나 오늘날에도 이러한 지적사항들이 반영되지 않고 있다. 따라서 본 연구는 통합운영학교의 개념, 배경, 최근현황, 유형 등을 전반적으로 정리한 후, 문헌조사를 통하여 통합운영학교의 문제점을 교육과정의 측면, 교원관리의 측면, 학생관리의 측면, 교육시설 운영 및 관리의 측면, 법률 및 정책의 측면에서 종합적으로 정리하여 제시하고, 그 개선방안을 제안하는 것을 목적으로 하였다. 이를 통해 통합운영학교의 우려되었던 점과 실제 연구를 통해 나타난 결과를 비교할 수 있었으며, 이에 대한 개선방안을 정리하였다.

MEA 제조 방법에 따른 직접 메탄올 연료전지의 성능저하 현상 평가 (Effect of MEA fabrication on the performance degradation of DMFC)

  • 조윤환;조용훈;박현서;원호연;성영은
    • 신재생에너지
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    • 제3권1호
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    • pp.60-67
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    • 2007
  • Catalyst coated membrane [CCM] type and catalyst coated substrate [CCS] type of membrane electrode assembly [MEA] were manufactured and evaluated their performance. Degradation test were conducted to find the difference of long term stability in two types of MEA and the factor for performance degradation problem occurred. Performance degradation test of single cell in two different types of MEA were carried out when current density was $200mA/cm^{2}$. The degradation test had proceeded for 230 hours and performance degradation was checked by I-V curve and impedance measurement at regular intervals. Also, MEA before/after operation and changes of catalyst layer were characterized by SEM, TEM, and XRD. Maximum power density of CCM type was higher than that of CCS type. Meanwhile, an increase of particle size of catalyst and an increase of impedance resistance after long term operation were observed. In the case of using CCM type MEA, the performance was deteriorated 38% of initial performance. In the case of using CCS type MEA, the performance was deteriorated 43% of initial performance. In consideration of difference of initial performance, performance of CCM type is higher than that of CCS type but both types had similar problems during degradation test.

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