• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.12
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• pp.927-934
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• 2015

In this study, we numerically investigated the concentration characteristics of a linear Fresnel reflector system that can drive a solar thermal absorption refrigeration system to be installed in Saudi Arabia. Using an optical modeling program based on the Monte Carlo ray-tracing method, we simulated the concentrated solar flux, concentration efficiency, and concentrated solar energy on four representative days of the year - the vernal equinox, summer solstice, autumnal equinox, and winter solstice. Except the winter solstice, the concentrations were approximately steady from 9 AM to 15 PM, and the concentration efficiencies exceed 70%. Moreover, the maximum solar flux around the solar receiver center changes only within the range of $13.0{\sim}14.6kW/m^2$. When we investigated the effects of the receiver installation height, reflector width, and reflector gap, the optimal receiver installation height was found to be 5 m. A smaller reflector width had a greater concentration efficiency. However, the design of the reflector width should be based on the capacity of the refrigeration system because it dominantly affects the concentrated solar energy. The present study was an essential prerequisite for thermal analyses of the solar receiver. Thus, an optical-thermal integration study in the future will assist with the performance prediction and design of the entire system.

• Bulletin of the Korean Space Science Society
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• 2005.04a
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• pp.129-132
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• 2005

This paper describes BAUSAT-2 orbital thermal analysis and preliminary design of thermal control subsystem. To design thermal control subsystem of HAUSAT-2, we have considered active & passive thermal control method based on basic theory and themal equilibrium equation. Using this result, suitable thermal control method and material have been selected. We have designed thermal control subsystem based on analysis of HAUSAT-2's thermal environments on sun synchronous orbit with altitude 650km, inclination $98^{\circ}$ and thermal distribution and range expectation of each HAUSAT-2's surface. Thermal analysis consists of system level, box level and board level analysis. We have completed system level and box level analysis. Till now, board level analysis of main heat dissipation board in progress. Thermal control subsystem has designed according to thermal analysis result. This design is to maintain all of the HAUSAT-2 components within the allowable temperature limits. In future, STM

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.326-328
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• 2015

Function of the window of the building is an environment of the room through the entry of solar radiation. It is vulnerable to significant energy conservation off the thermal efficiency. Also this summer, cooling costs are weighted because of excessive solar radiation. In this paper, we develop a windows automatic control system to use the indoor environmental information, such as home temperature, humidity, light intensity, solar radiation. The system collects the indoor environment information using a variety of sensor, using the collected information, and controls the motor to the system to control the window.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.574-577
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• 2019

국내 에너지 생산량의 고갈과 더불어 태양열, 풍력 등이 지속적 가능한 신재생 대체 에너지로 떠오르는 것과 더불어 가정에서 직접 전력을 생산하는 전력생산시스템이 주목을 받고 있다. 이를 위한 정부의 정책으로 태양광 패널을 이용하여 전력을 생산하고 이를 이웃 간의 전력 거래를 할 수 있는 실증사업을 실시하였다. 본 논문에서는 이 실증 사업에서 보안성과 안정성을 높이고 빠른 거래가 가능한 블록체인 기반 P2P 전자거래 시스템을 설계하고, 이를 통해 신재생 에너지 거래 시스템 개발 기술의 기술 사업화 과정에서 발생할 수 있는 경제적 리스크를 최소화할 수 있는 기틀을 마련한다.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.492-504
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• 2005

본 신 재생에너지설비 시공 및 설치확인 기준 연구는 신재생에너지 시스템의 효율적인 보급과 사후관리 비용 절감 및 성능향상으로 인한 에너지 생산을 효과적으로 할 수 있게 될 뿐 만 아니라 보급확대를 위해서는 필수적으로 있어야 할 기준이다. 현재 보급사업으로 추진되고 있는 5개 에너지원에 대한 설비 시공 및 설치확인 기준을 작성하여 보급사업의 지침서 역할을 하도록 하였다. - 태양열 시스템 시공 및 설치확인 기준 개발 - 지열이용 시스템 시공 및 설치확인 기준 개발 - 태양광발전 시스템 시공 및 설치확인 기준 개발 - 풍력발전 시스템 시공 및 설치확인 기준 개발 - 소수력발전 시스템 시공 및 설치확인 기준 개발

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.4
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• pp.331-341
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• 2013

In a solar domestic hot water (SDHW) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (TST) as hot water. In this study, a computational fluid dynamics (CFD) model was developed to predict the solar thermal energy storage in a hybrid-type TST equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a TST, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the TST. The developed model was validated by the good agreement between the CFD results and the experimental results performed with the hybrid-type TST in SDHW settings.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.70-70
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• 2011

국내의 많은 연구를 통해 신재생에너지의 사전 경제성 평가를 위한 모델들은 다수 개발된 바 있지만, 기본적인 연산 프로세스와 연산방식만 지원되고 있을 뿐, 연산결과에 크게 영향을 미치는 신재생에너지의 각 요소 데이터가 제공되지 못하고 있다. 이에 대하여 본 연구에서는 한국에너지기술연구원에서 개발된 신재생에너지 자원지도 데이터를 근간으로 하여 경제성 평가의 기본이 되는 정보를 데이터베이스로 구성함과 동시에 GIS(Geographical Information System)을 활용하여 해당 영역에서 직접 대상위치를 선정하고, 인자값의 설정에 따라 사전 적정성 평가를 지원하는 연산 프로세스를 개발하고자 하였다. 웹 도구를 활용하여 사용자의 접근을 용이하게 하며, 설비데이터의 입력이 가능하게 구성하여 지속적으로 업데이트가 가능한 시스템의 제작을 그 목표로 한다.

• Journal of the Korean Solar Energy Society
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• v.32 no.5
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• pp.41-51
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• 2012

Heliostat field is the most important subsystem in the tower type solar thermal power plant since its optical performance affects the total system efficiency most significantly while the construction cost of it is the major part of total construction cost in such a power plant. Thus a well designed heliostat field to maximize the optical efficiency as well as to minimize the land usage is very important. This work presents methodology, procedures and result of heliostat filed design for 200kW solar thermal power plant built recently in Daegu, Korea. A $2{\times}2(m)$ rectangular shaped receiver located at 43(m) high and tilted $28^{\circ}$ toward heliostat field, 450 of heliostats of which the reflective surface is formed by 4 of $1{\times}1(m)$ flat plate mirror facet, and the land area having about $140{\times}120(m)$ size are used to form the heliostat field. A procedure to deploy 450 heliostats in radial staggered nonblocking formation is developed. Also the procedures to compute the cosine effect, intercept ratio, blocking and shading ratio in the field are developed. Finally the heliostat filed is designed by finding the optimal radial distance and azimuthal spacing in radial staggered nonblocking formation such that the designed heliostat field optical efficiency could be maximized. The designed heliostat field has 77% of annual average optical efficiency, which is obtained by annually averaging the optical efficiencies computed between the time of where sun elevation angle becomes $10^{\circ}$ after sunrise and the time of where sun elevation angle becomes $10^{\circ}$ before sunset in each day.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.107-116
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• 2005

As a unique payload of Komsat-2, MSC, comprising EOS(Electro-Optical Sub-system), PMU(Payload Management Unit) and PDTS(Payload Data Transmission Sub-system), is supposed to take pictures of one panchromatic and 4 multi-spectral image between wavelength 450mm~900mm, and is being under final Satellite I&T. It will perform the earth remote sensing with applications such as acquisition of high resolution images, surveillance of large scale disasters and its countermeasure, survey of natural resources, etc.. Under the hostile influence of the extreme space environmental conditions due to deep space and direct solar flux, the thermal design is especially of major importance in designing a payload. There are tight temperature range restrictions for electro-optical elements while on the other hand there are low power consumption requirements due to the limited energy source on the spacecraft. This paper describes details of thermal control system for MSC.

• Solar Energy
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• v.19 no.4
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• pp.45-53
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• 1999

This report Introduces a total heat exchanger in a solar air-conditioning system using Lithium Chloride(LiCl) solution. The hot and humid outside air is cooled and dehumidified by LiCl solution that is sprayed on the packed layer of the total heat exchanger. LiCl solution once diluted is concentrated again in a regenerator using solar energy. Three types as the packed materials were used in this experiment and the dehumidification performance was evaluated by the value of $k_xa(kg/h{\cdot}m^3{\cdot}{\Delta}x)$, overall mass transfer coefficient based on a humidity ratio potential difference, the influence of inlet LiCl solution flow rate, air flow rate, packed layer height on $k_xa$ was investigated. It was found that air flow rate, LiCl solution flow rate, packed layer height for all types had a great influnce on the value of $k_xa$.