• Title/Summary/Keyword: 가정용에너지시스템

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Economic Assessment of the Battery Energy Storage System with Its Customer Type (수용가 형태에 따른 전지전력저장시스템의 경제성 평가)

  • 손학식;최준호;김재철
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.2
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    • pp.81-89
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    • 2002
  • The Battery Energy Storage System (BESS) has lots of advantages such as load leveling, quick response emergency power (spinning reserve), frequency and voltage control, improvement of reliability, and deferred generation and transmission construction. However, it is very critical that economic feasibility requires justification from the customer side of meter to promoting the dissemination of BESS in nation widely. In this paper, we proposed the economic assessment model of customer owned BESS which is complemented and improved the existing model. The proposed model is applied to the typical customer types, i.e. light industrial, commercial, and residential, which are taken from the statistical analysis on the load profile survey of Korea Electric Power COmpany (KEPCO). The economic viability performed for each customer load type to justifying their economic feasibility of BESS installation from the economic measures such as payback period, Net Present Worth (NPW), Rate Of Return (ROR). The results show that the BESS has economic benefits to the specific customer type, i.e. residential customer. Therefore, the government and the energy agency should be committing the support program, such as tax incentive, financial support, to disseminate the BESS nation widely. The results of this paper are useful to the customer investment decision-making and the national energy policy & strategy in Korea.

Performance of Ru-based Preferential Oxidation Catalyst and Natural Gas Fuel Processing System for 1 kW Class PEMFCs System (Ru계 촉매의 CO 선택적 산화 반응 및 1 kW급 천연가스 연료처리 시스템의 성능 연구)

  • Seo, Yu-Taek;Seo, Dong-Joo;Seo, Young-Seog;Roh, Hyun-Seog;Jeong, Jin-Hyeok;Yoon, Wang-Lai
    • Journal of Hydrogen and New Energy
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    • v.17 no.3
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    • pp.293-300
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    • 2006
  • KIER has been developing a Ru-based preferential oxidation catalysts and a novel fuel processing system to provide hydrogen rich gas to residential PEMFCs system. The catalytic activity of Ru-based catalysts was investigated at different Ru loading amount and different support structure. The obtained result indicated that 2 wt% loaded Ru-based catalyst supported on ${\alpha}-Al_2O_3$ showed high activity in low temperature range and suppressed the methanation reaction. The developed prototype fuel processor showed thermal efficiency of 78% as a HHV basis with methane conversion of 92%. CO concentration below 10 ppm in the produced gas is achieved with separate preferential oxidation unit under the condition of $[O_2]/[CO]=2.0$. The partial load operation have been carried out to test the performance of fuel processor from 40% to 80% load, showing stable methane conversion and CO concentration below 10 ppm. The durability test for the daily start-stop and 8 h operation procedure is under investigation and shows no deterioration of its performance after 50 start-stop cycles. In addition to the system design and development.

고 분산성 자성 나노유체의 열전도도 및 점성

  • Seo, Yong-Jae;Lee, Hyo-Suk;Jo, Guk;Gil, Dae-Seop;Jeong, Gyeong-U;Ju, Myeong-Eun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2010.05a
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    • pp.4.2-4.2
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    • 2010
  • 최근 열전달율을 획기적으로 향상시킬 수 있는 고 열전도성 나노유체가 주목을 받고 있다. 고 열전도성 나노유체는 액상보다 열전도도가 수백~수만 배 높은 고상의 금속 또는 비금속 나노입자를 물이나 오일 등에 미량 균일하게 분산시킴으로써 기존의 유체가 가지지 못한 높은 열전도율과 분산안정성을 갖는 기능성유체를 말한다. 고 열전도성 나노유체는 기존 냉각시스템에서 냉각유체만 교체할 경우에도 열전달 효율을 20% 이상 향상시킬 수 있는 저비용 고효율작동 유체이다. 이 나노유체는 발전설비, 공조설비, 에너지 산업, 석유화학, 화학공업, 제철산업, 가정용 냉난방설비, 자동차 등 산업 전 분야의 열교환시스템에 활용이 가능하다. 따라서 고 열전도성 나노유체는 종래 열효율의 한계를 돌파할 수 있는 에너지 이용 효율 향상 기술의 패러다임을 바꿀 혁신적인 신소재로 여겨지고 있다. 그러나 현재까지 개발된 나노유체는 초기 열전도 특성은 우수하나 장기간 분산안정성이 확보되지 않아 시간이 경과함에 따라 열전도도가 점점 감소하는 경향을 보인다. 또한 탄소나노튜브를 분산한 나노유체의 경우와 같이 유체의 점도가 크게 증가하여 실제 산업에 적용 시 커다란 동력손실을 초래할 수 있으며 열교환시스템에 파울링이 발생할 소지가 크다. 이러한 문제점을 해결하기 위해서는 나노유체에서 열전달이 일어나는 메커니즘이 규명되어야 하지만 아직 명확한 이론이나 가설이 정립되어 있지 않다. 이 논문에서는 나노유체가 높은 열전도율을 보이는 현상을 설명할 수 있는 몇 가지 이론을 살펴 보고 지금까지 개발된 안정성이 아주 높은 나노유체의 열전도 특성을 비교 분석하여 획기적인 열전도성 나노유체 개발 가능성을 살펴보고자 한다. 이를 위해 나노입자의 조성, 유체 내 농도 및 자기장 등이 나노유체의 열전도율에 미치는 영향을 연구하였다.

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Development of Intelligent Outlets for Real-Time Small Power Monitoring and Remote Control (실시간 소전력 감시 및 원격제어용 지능형 콘센트 개발)

  • Kyung-Jin Hong
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.2
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    • pp.169-174
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    • 2023
  • Currently, overall power usage is also increasing as power demand such as homes, offices, and factories increases. The increase in power use also raised interest in standby power as a change in awareness of energy saving appeared. Home and office devices are consuming power even in standby conditions. Accordingly, there is a growing need to reduce standby power, and it aims to have standby power of 1W or less. An intelligent outlet uses a near-field wireless network to connect to a home network and cut or reduce standby power of a lamp or appliance connected to an outlet. This research aims to develop a monitoring system and an intelligent outlet that can remotely monitor the amount of electricity used in a lighting lamp or a home appliance connected to an outlet using a short-range wireless network (Zigbee). Also, The intelligent outlet and monitoring system developed makes it possible for a user to easily cut off standby power by using a portable device. Intelligent outlets will not only reduce standby power but also be applicable to fire prevention systems. Devices that cut off standby power include intelligent outlets and standby power cutoff switches, so they will prevent short circuits and fires.

An Experimental Study on the Sensor Response at Hydrogen Leakage in a Residential Fuel Cell System (가정용 연료전지 시스템 내부 수소 누출 시 센서 응답 특성에 관한 연구)

  • Kim, Young-Doo;Shin, Dong-Hoon;Chung, Tae-Yong;Nam, Jin-Hyun;Kim, Young-Gyu;Lee, Jung-Woon
    • Journal of Hydrogen and New Energy
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    • v.20 no.5
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    • pp.378-383
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    • 2009
  • Hydrogen is the primary fuel in fuel cell systems. Because of high inflammation and explosion possibility of hydrogen, fuel cell systems require safety measures to prevent hydrogen hazard upon leakage. In this study, a model enclosure was made by referring to a commercial residential fuel cell system and hydrogen leakage experiments and computational simulations were conducted therein. Hydrogen was injected into the cavity through leakage holes located at the bottom while its flow rate was precisely controlled using MFC. The transient sensor signals from hydrogen sensors installed inside the enclosure were recorded and analyzed. The hydrogen sensor signals showed different delay times depending on their position relative to a leakage point, which indicated that hydrogen generally moves upward and accumulates at the upper region of a closed cavity. The inflammable regions with hydrogen concentration over 4% LEL were observed to locate near the leakage hole initially, and broaden towards the upper cavity region afterward. The simulation result showed that detection time at the hydrogen sensor was similar to the pattern of experimental results. However, the maximum concentration of hydrogen had a gap between experiment and simulation at detect point due to measurement errors and reaction rate.

Model-based Fault Detection Method for the Air Supply System of a Residential PEM Fuel Cell (가정용 고분자전해질 연료전지 공기공급시스템의 모델 기반 고장 검출 기술)

  • WON, JINYEON;KIM, MINJIN;LEE, WON-YONG;CHOI, YOON-YOUNG;HONG, JONG SUP;OH, HWANYEONG
    • Journal of Hydrogen and New Energy
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    • v.30 no.6
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    • pp.556-566
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    • 2019
  • Recently, as the supply of residential polymer electrolyte membrane fuel cells (PEMFCs) increases, the durability and lifetime of the PEMFC system are becoming important. The related studies have been mainly focused on the durability and lifetime of materials while the research on the durability and maintenance of the system level is insufficient. In this paper, a model-based fault detection method is developed considering an air supply system that is dominant to the system performance and efficiency. A commercial 1 kW residential fuel cell system is built, and experiments are conducted under various operation loads and states (normal, 6 faults). From the experimental data, nominal models and residuals are generated. With the residual pattern obtained from real-time data, the detection and classification of various faults can be possible. The technical importance of this paper is to minimize extra sensor installation by using the empirical model rather than a complex mathematical model, and to decrease the number of models by using the applicable model at three loads. Finally, the model-based fault detection method for the air supply system of a PEMFC is established and is expected to be applicable to other subsystems.

A Study on Electromagnetic Compatibility Performance Evaluation of Power Conditioning System for Residential Fuel Cell (가정용 연료전지 전력변환장치 전자파적합성 성능 평가 연구)

  • Choi, Young-Joo;Nam, Tae-Ho;Lee, Eun-Kyung;Lee, Duk-Gwon;Lee, Jung-Woon;Lee, Seung-Kuk;Moon, Jong-Sam
    • Journal of the Korean Institute of Gas
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    • v.21 no.6
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    • pp.23-29
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    • 2017
  • Solar and wind energy among the renewable energy produce irregular power because resource is difficult to control. When connected to grid have unstable. However, when the fuel cell system is connected to grid more stable because regular frequency and output power based on controllable hydrogen energy. To using fuel cell system in the household, it is important that the safety performance of power conditioning system(PCS) and it is important that evaluation method of electromagnetic compatibility(EMC). In this study, we consider that introduce power-frequency magnetic field immunity test before analyzed that compare with the EMC of the international standards and KGS AB 934 PC53. Also, we conduct that actual assessment and study on available the quantitative analysis as using complementary indicator.

A Study on Water Balance in Stationary Load Proton Exchange Membrane(PEM) Fuel Cell Power Generator (고정 부하를 갖는 PEM 연료전지 발전기에 있어서의 수분 평형에 관한 연구)

  • Bakhtiar, Agung;Oh, Hoo-Kyu;Yoon, Jung-In;Kim, Young-Bok;Choi, Kwang-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.31 no.4
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    • pp.128-135
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    • 2011
  • 일반적으로 PEM 연료전지에서는 수분 균형이 시스템의 효율에 결정적으로 영향을 미치기 때문에, 이에 대한 균형(balance)을 잡는 것이 매우 중요하다. 특히, 촉매 층에서 물이 넘치는 익수현상(flooding)이나 건조현상(drying)이 발생하게 되면 연료전지의 효율이 급격하게 저하하므로, 항상 수분의 균형이 잡히도록 시스템을 제어하는 것이 일반적이다. 이 때,수분의 익수현상이나 건조현상은 PEM 연료전지의 용량과 주위의 환경, 즉 온도와 습도에 많은 영향을 받게 된다. 금번 논문에서는 가정용 규모인 3kW급에서 10kW급까지의 PEM 연료전지를 설치하였을 때, 주위의 환경(온도와 습도)이 수분 이동에 어떠한 영향을 미치는 지를 시간에 따라서 시뮬레이션(simulation)한 결과를 보여주고 있다. 결과에서 유입공기의 온도가 $50^{\circ}C$ 이하일 경우, 고정부하가 5kW급 이하이면 대부분이 건조현상이 발생하였으나, 고정부하가 6kW급 이상이 되면 익수현상이 운전시간이 20분 이내에서 발생하였다. 또한 고정부하를 최고 10kW급까지 올린 경우, 유입공기의 온도가 $50^{\circ}C$까지는 익수현상이 발생하였으나 $60^{\circ}C$ 이상인 경우에는 거의 건조현상이 발생함을 알 수 있었다.

Scheduling Algorithms and Queueing Response Time Analysis of the UNIX Operating System (UNIX 운영체제에서의 스케줄링 법칙과 큐잉응답 시간 분석)

  • Im, Jong-Seol
    • The Transactions of the Korea Information Processing Society
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    • v.1 no.3
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    • pp.367-379
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    • 1994
  • This paper describes scheduling algorithms of the UNIX operating system and shows an analytical approach to approximate the average conditional response time for a process in the UNIX operating system. The average conditional response time is the average time between the submittal of a process requiring a certain amount of the CPU time and the completion of the process. The process scheduling algorithms in thr UNIX system are based on the priority service disciplines. That is, the behavior of a process is governed by the UNIX process schuduling algorithms that (ⅰ) the time-shared computer usage is obtained by allotting each request a quantum until it completes its required CPU time, (ⅱ) the nonpreemptive switching in system mode and the preemptive switching in user mode are applied to determine the quantum, (ⅲ) the first-come-first-serve discipline is applied within the same priority level, and (ⅳ) after completing an allotted quantum the process is placed at the end of either the runnable queue corresponding to its priority or the disk queue where it sleeps. These process scheduling algorithms create the round-robin effect in user mode. Using the round-robin effect and the preemptive switching, we approximate a process delay in user mode. Using the nonpreemptive switching, we approximate a process delay in system mode. We also consider a process delay due to the disk input and output operations. The average conditional response time is then obtained by approximating the total process delay. The results show an excellent response time for the processes requiring system time at the expense of the processes requiring user time.

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The Power System for Home Appliance Air-Conditioner using Partial Switching Power Factor Correction Module (부분 스위칭 PFC 모듈을 이용한 가정용 에어컨 전원장치)

  • Suh, Ki-Young;Mun, Sang-Pil
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.18 no.6
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    • pp.183-190
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    • 2004
  • This paper proposes a methodology to solve problems upon the circuit design applied to inductor load by applying a circuit to improve power factor with is partial switching PFC module to the power supply system for cooling/heating inverter air conditioner and by designing an input power section in compliance with IEC555-2 on the basis of better input power factor and minimized harmonic components of current. On the other hand, this paper suggested how to control the increase of output voltage along with tぉw current waves and partial switching PFC circuit as well, which can provide the output as twice as input voltage This study applied a method to control the compressors of air conditioner by means of increased the voltage applicable to compressor motor by lowering switching number conclusively, it could solve questions about efficiency, economics, electronic noise and so forth. and so that the reasonable voltage for running moor could be set up along with lower power consumption of air conditioner than estimated It was demonstrated that total sum of energy efficiency to operate system was increased to the extent of valid level. And all this merits and appropriateness was proved by computer simulation and experience.