• Title/Summary/Keyword: energy saving control

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A Dynamic Server Power Mode Control for Saving Energy in a Server Cluster Environment (서버 클러스터 환경에서 에너지 절약을 위한 동적 서버 전원 모드 제어)

  • Kim, Ho-Yeon;Ham, Chi-Hwan;Kwak, Hu-Keun;Kwon, Hui-Ung;Kim, Young-Jong;Chung, Kyu-Sik
    • The KIPS Transactions:PartC
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    • v.19C no.2
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    • pp.135-144
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    • 2012
  • All the servers in a traditional server cluster environment are kept On. If the request load reaches to the maximum, we exploit its maximum possible performance, otherwise, we exploit only some portion of maximum possible performance so that the efficiency of server power consumption becomes low. We can improve the efficiency of power consumption by controlling power mode of servers according to load situation, that is, by making On only minimum number of servers needed to handle current load while making Off the remaining servers. In the existing power mode control method, they used a static policy to decide server power mode at a fixed time interval so that it cannot adapt well to the dynamically changing load situation. In order to improve the existing method, we propose a dynamic server power control algorithm. In the proposed method, we keep the history of server power consumption and, based on it, predict whether power consumption increases in the near future. Based on this prediction, we dynamically change the time interval to decide server power mode. We performed experiments with a cluster of 30 PCs. Experimental results show that our proposed method keeps the same performance while reducing 29% of power consumption compared to the existing method. In addition, our proposed method allows to increase the average CPU utilization by 66%.

A Study on the State feedback with Integral Control for a Variable Air Volume Unit (가변 풍량 유닛에 대한 적분기를 가진 상태 궤환 제어에 관한 연구)

  • 박세화
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.1 no.2
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    • pp.9-14
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    • 2000
  • State feedback with integral control for a variable air volume(VAV) unit which is recently taken notice of for the energy efficiency and saving in the building is studied to investigate the performance of the digital control methodology for the possible practical application. The digital controller which acquires the targat zone temperature and the air flow rate of the supplied air to the zone controls the opening of the damper in the VAV unit. Simulation results are performed for the conditions including reference changes and external thermal variations. In the simulation. simplified conditioned zone and the damper actuator modelling is considered. and relationships between controller gain Parameters and the system dynamics are investigated.

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Development of a Lighting Control Switch Using Power Line Communication Technology (전력선 통신기술을 이용한 조명제어 스위치의 개발)

  • Song Jae-yong;Moon Seung-bo;kil Gyung-suk;Lee Gyung-soo;Kim Chang-yul
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.4
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    • pp.792-797
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    • 2005
  • Lighting control switches based on the power line communication technology are developed and extended to incorporate dimming control to provide energy saving and appropriate illumination. The developed switch uses a general purpose microprocessor and associated electronics. Both the power line communication and the dimming function are implemented in one microprocessor, and it enables the low price commercialization. The frequency of the carrier was set at 250kHz considering the transmission data length and signal attenuation in power lines. Tests on prototypes in an low-voltage power lines have shown that the switches have a robust operation characteristics with the length of power lines and the variation of load capacities.

A Study on the Luminosity Control of Bulbs by Using PIC (PIC를 이용한 다수의 전구 밝기제어에 관한 연구)

  • Bae, Cherl-O;Park, Young-San
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.13 no.3
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    • pp.235-240
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    • 2007
  • Recently, energy saving buildings are interested in many parts and many types of thermal insulating materials have been developed. The temperature and brightness of inside and outside building are influenced by weather change and sun's brightness and location. The location of building considering the natural daylight is an important parameter to build a building. To modeling the natural daylight, we used 342 electric bulbs which mean artificial daylight. All these bulbs are installed on dome shape frame. Especially it is focused on the luminosity control of each bulb in this paper. The luminosity of bulbs is controlled by phase control using several PIC microprocessors and triacs.

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Design of the Driver of 7W Class LED Lamps as a Substitute for Incandescent Lamps (백열전구 대체용 7w급 LED 램프의 드라이버 설계)

  • Park, Young-San;Bae, Cherl-O
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.16 no.2
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    • pp.235-240
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    • 2010
  • In order to substitute incandescent lamps, a power supply device for 7W class LED lamps which are environmentally friendly and energy saving is designed LED lamps consist of a multitude of chip LED connected in parallel and series. 11ms it is necessary to supply LED lamps with DC voltage and current. However, when LED lamps are in use, they are connected directly to AC 220V. This is why we need to have AC/DC, DC/DC power converters including a control system of voltage and current. For this, a transformerless and simple LED lamp driver is designed 조ich can control the current and output voltage for LED string of LED lamp.

A Research on the $CO_2$ Peak Point Control According to Ventilation Rate During Sleeping (취침 시 환기횟수에 따른 $CO_2$ 피크치 제어에 관한 연구)

  • Kim, Se-Hwan;Kim, Dong-Gyu;Park, Jong-Il
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.1
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    • pp.49-54
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    • 2009
  • Ventilation requirement of apartment was mandated according to building equipment standards in 2006. When ventilation unit was considering for indoor air quality maintenance, we needed energy saving and efficiency ventilation control methods. This study carried out experiment of ventilation rate 0.7 adequacy. When we lived in apartment, we assumed that sleeping time was long stayed time in unconsciousness. Experiments carried out ventilation rate 0, 0.1, 0.4 and 0.7 in environment chamber from 22 o'clock to 06 o'clock, the concentration of $CO_2$, temperature and humidity rate measured. Analyzing the results, conclusions are as follows. 1) When we sleep in bedroom, ventilation rate 0.4 meet the requirements of domestic legal standards. Conform fan of similarity law, ventilation rate 0.4 reduced power cost about 80% than 0.7. 2) In generally sleeping time 8 hours, peak point control reduced running time of ventilation unit about 43% than normal control.

Development of LED Street Lighting Controller for Wind-Solar Hybrid Power System

  • Lee, Yong-Sik;Gim, Jae-Hyeon
    • Journal of Electrical Engineering and Technology
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    • v.9 no.5
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    • pp.1643-1653
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    • 2014
  • This paper presents the design and implementation of a wind-solar hybrid power system for LED street lighting and an isolated power system. The proposed system consists of photovoltaic modules, a wind generator, a storage system (battery), LED lighting, and the controller, which can manage the power and system operation. This controller has the functions of maximum power point tracking (MPPT) for the wind and solar power, effective charging/discharging for the storage system, LED dimming control for saving energy, and remote data logging for monitoring the performance and maintenance. The proposed system was analyzed in regard to the operation status of the hybrid input power and the battery voltage using a PSIM simulation. In addition, the characteristics of the proposed system's output were analyzed through experimental verification. A prototype was also developed which uses 300[W] of wind power, 200[W] of solar power, 60[W] LED lighting, and a 24[V]/80[Ah] battery. The control system principles and design scheme of the hardware and software are presented.

Development of Power Management System for Efficient Energy Usage of Small Generator (소형 발전기의 에너지 절약을 위한 전력관리 시스템 개발)

  • Jeon, Min-Ho;Oh, Chang-Hyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.12
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    • pp.2601-2606
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    • 2012
  • In this paper, an electricity management system, which saves energy by utilizing electricity consumption of load from an environment that uses at least two compact generators, is proposed and developed. A hardware is constructed by using TMS320C6713 DSP chip made by TI that is capable of high speed hardware floating point processing while serial communication is used for communication with a monitoring PC. Manual control is made possible from the monitoring PC and automatic on/off is enabled in the generator by using data collected by CT/PT sensor from the DSP mainboard. Test results confirm that the electricity management system proposed in this study functions without abnormality. The application of an algorithm that saves energy by using electricity consumption of load also allows for a longer supply of electricity compared to continuously using two compact generators.

Evaluation of Overall Heat Transfer Coefficient of Different Greenhouse Thermal Screens Using Building Energy Simulation (BES를 이용한 온실용 보온커튼의 관류열전달계수 산정)

  • Rasheed, Adnan;Lee, Jong Won;Lee, Hyun Woo
    • Journal of Bio-Environment Control
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    • v.27 no.4
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    • pp.294-301
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    • 2018
  • In winter, thermal screens are widely used to reduce heat loss from greenhouse to save energy. Unfortunately, not much data are available to the farmer to compare thermal screens while selecting the one that meets their specific requirements. Thus, there is a need to investigate the thermal performance of thermal screens. To address this issue, the Building Energy Simulation (BES) model of a hot box was used to calculate the overall heat transfer coefficient (U-value) of the thermal screens. To validate the model, computed and experimental U-values of single-and double-layered polyethylene (PE) material were compared. This validated model was used to predict the U-values of the selected thermal screens under defined weather conditions. We quantified the U-values of each selected material and significant changes in their U-values were noted in response to different weather conditions. Notably, the thermal properties of the tested screens were taken from the previous literature to calculate U-values using the BES model. The U-values of the thermal screens can help researchers and farmers evaluate their screens and make pre-design decisions that suit their investment capabilities.

A Study on Light-Shelf System using Location-Awareness Technology for Energy Saving in Residential Space (에너지 저감을 위한 주거공간 내 위치인식기술 적용 광선반 시스템 개발연구)

  • Gim, Sanghoon;Kim, Yongseong;Lee, Henagwoo;Seo, JangHoo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.6
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    • pp.275-286
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    • 2014
  • Light shelf is an efficient system that reduces the energy consumption by bringing the natural light down to the deep spaces inside of a building. However, the existing light shelves have limits in reducing energy usage, because the direction of the light flow is determined by the external environment such as the altitude of the sun and the azimuth. This current study presents a system that increases the efficiency of the light shelf by applying the Location-Awareness technology, in which the efficiency was verified through the performance evaluation. According to the examination of the technology for the Location-Awareness within residential space, 'Zigbee' type appears to be the most appropriate. The Location-Awareness technology operates the light shelf based on both the angle control axis and the light shelf angle control axis through the modularization of the reflector surface which is less affected by the external environment. The results of the performance evaluation showed that the movable light shelf that employs the Location-Awareness technology can reduce the energy consumption for lighting by 98.3% compared to the fixed light shelf and by 97.3% compared to the movable light shelf without Location-Awareness.