• Title/Summary/Keyword: energy space

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Analysis of energy and daylight performance of adjustable shading devices in region with hot summer and cold winter

  • Freewan, Ahmed A.;Shqra, Lina W.
    • Advances in Energy Research
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    • v.5 no.4
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    • pp.289-304
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    • 2017
  • Large glazed surfaces and windows become common features in modern buildings. The spread of these features was influenced by the dependence of designers on mechanical and artificial systems to provide occupants with thermal and visual comfort. Countries with hot summer and cold winter conditions, like Jordan, require maximum shading from solar radiation in summer, and maximum exposure in winter to reduce cooling and heating loads respectively. The current research aims at designing optimized double-positioned external shading device systems that help to reduce energy consumption in buildings and provide thermal and visual comfort during both hot and cold seasons. Using energy plus, a whole building energy simulation program, and radiance, Lighting Simulation Tool, with DesignBuilder interface, a series of computer simulations for energy consumption and daylighting performance were conducted for offices with south, east, or west windows. The research was based on comparison to determine the best fit characteristics for two positions of adjustable horizontal louvers on south facade or vertical fins on east and west facades for summer and winter conditions. The adjustable shading systems can be applied for new or retrofitted office or housing buildings. The optimized shading devices for summer and winter positions helped to reduce the net annual energy consumption compared to a base case space with no shading device or with curtains and compared to fix shading devices.

Multi-scale Driving of Turbulence and Astrophysical Implications

  • Yoo, Hyunju;Cho, Jungyeon
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.61.1-61.1
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    • 2013
  • Turbulence is a common phenomenon in astrophysical fluids such as the interstellar medium (ISM) and the intracluster medium (ICM). In turbulence studies it is customary to assume that fluid powered by an energy injection on a single scale. However, in astrophysical fluids, there can be many different driving mechanisms that act on different scales simultaneously. In this work, we assume multiple energy injection scale (2${\surd}$12 and 15

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Experimental Study of Cooling Energy Saving Verification Using Blinds and Phase Change Material(PCM) (창호 블라인드와 상변화물질 적용에 의한 냉방 에너지 사용량 절감효과에 대한 검토 연구)

  • Song, Young-Hak;Kim, Ki-Tae;Koo, Bo-Kyung;Lee, Keon-Ho
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.1
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    • pp.26-31
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    • 2014
  • This study looks into changing building energy use by application of phase change material (PCM). PCM does not need extra energy for operation and is used for reducing building energy use and, CO2 output by displaying semi-permanent effects after installation. It also is able to avoid the maximum electric power time-zone by inducing a time lag phenomenon of cooling and heating loads with high thermal capacity using latent heat. To verify the efficiency of blinds and PCM, tests about the PCM operation mechanism using air conditioning machinery and nocturnal panel cooling were done. In the test results of the case using PCM installation, a $45^{\circ}$ blind angle with machinery air conditioning and nocturnal panel cooling at the same time shows a 22 percent energy saving effect against general space. The test results of each case were compared and analyzed based on the blind and window opening settings. Finally, the energy reduction of existing buildings using PCM application was reviewed based on the final measurement results.

An Evaluation for Predicting the Far Wake of Tidal Turbines

  • Yang, C.J.;Hoang, A.D.
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2012.06a
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    • pp.155-156
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    • 2012
  • In the modern age, as man's demand of energy is continuously grew, tidal becomes one of the sustainable energy sources that have been investigating thoroughly recently. Tidal turbine has proved high potential as a future power-generating device. To effectively capture tidal energy on site, a group of tidal turbines should be used and positioned in some formation with proper size and space so that energy can be absorbed from multiple point. Thus, the turbines together with the flow filed becomes a huge domain, a tidal farm. So, it becomes more convenient if a whole turbine farm is simulated by means of actuator discs since the time and cost for analysis can be reduced. This paper aims to evaluate the operating performance (power efficiency and energy restoration rate), mutual influence (for different longitudinal and lateral spaces), the influence of velocity profiles, turbulence intensity and the far wake characteristic of tidal turbines operating in farm formation. The results of this study help contributing to the present development of tidal turbine as the future potential energy conversion machinery.

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A Study on Design Tendencies in Office Buildings of Public Institutions after Reinforcement of the Building Energy Performance Criteria in Korea (건물에너지성능기준 강화 이후 국내공공기관 업무용 건축물의 디자인경향)

  • Lee, Ah-Young
    • KIEAE Journal
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    • v.11 no.6
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    • pp.139-149
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    • 2011
  • This study focuses on design tendencies in office buildings of public institutions after tightening up Korea's building energy performance criteria. Important office design criteria and recommendations pay attention to the issues such as building orientation, greening buildings, building form, space and envelop by intensifying building energy performance related laws, government guidelines and evaluation systems. The design tendencies explored in this research are as follows. Office buildings mainly face south and have various types of indoor and roof green spaces not for ecological reasons but for the rest. Building depth becomes thinner and atria are inserted into office buildings to improve daylighting and natural ventilation. Building cores are located on north or west and east sides acting as buffer spaces to reduce heat loss and to block solar radiation. Office building envelop design includes various creative ideas to control or utilize solar energy as like three dimensional or double structured skin and window size variation to cope with the intensity of solar radiation. Further, solar energy generation systems are integrated with building component such as roofs, sun screens and windows. This study demonstrates that government's reinforcement of the building energy performance criteria drives the change in design methods and approach.

Determining Appropriate Capacity on Installing Photovoltaic System at Deteriorated Educational Facilities

  • Lhee, Sang Choon;Choi, Young Joon;Choi, Yool
    • KIEAE Journal
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    • v.14 no.3
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    • pp.23-29
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    • 2014
  • With high acknowledgements of environmental conservation and energy saving, many architectural technologies using renewable energy have been recently applied at buildings which take about 20% of total energy consumption. Among renewable energy sources, the photovoltaic is considered as the most highly potential one due to advantages of infiniteness and cleanliness. Also, projects to install renewable energy systems have been continuously performed at deteriorated educational facilities as energy efficient remodeling projects or green school projects by the Korean government. This paper proposes appropriate capacities by school level on installing photovoltaic systems at deteriorated school buildings, based on the balance of annual electricity power demand and supply between buildings and systems. Using the Visual DOE program and Merit program, the appropriate installment capacity of photovoltaic system turned out be 40kWp at elementary school building and 60kWp at middle and high ones. In addition, annual energy use proved to be reduced by 20.2% at elementary school, 26.9% at middle school, and 21.0% at high school by installing photovoltaic systems with the appropriate capacities.

A Study on the Dynamic Performance of a Solar Absorption Cooling System (태양열 흡수식 냉방 시스템의 동특성 연구)

  • Baek, N.C.;Lee, J.K.;Yang, Y.S.;Jeong, S.
    • Solar Energy
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    • v.18 no.3
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    • pp.81-87
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    • 1998
  • Solar energy has been experiencing renewed interest because of the recent economical crisis in Korea. Absorption cooling is one of the promising solar energy utilization technologies. In this study the dynamic performance of a solar driven absorption cooling machine(SDACM) was numerically investigated. The simulated machine is a commercially available water/LiBr single effect absorption chillers driven by hot water from solar collectors. The present study has been directed to investigate the dynamic behavior of a solar cooling system including an absorption chiller, solar collector, a hot water storage tank, fan coil units, and the air-conditioned space. The operation of the system was simulated for 9 hours in varying operation conditions. The variation of temperature and concentration in the system components, and that of heat transfer rates in the system were obtained. It was also found that the room temperature was maintained near the desired value by controlling the mass flow rate of hot water.

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Electric Lighting Energy Saving Through the Use of A Fresnel Lens Based Fiber-optic Solar Lighting System: Simulation and Measurements (광화이버 및 Fresnel lens 적용 집광식 자연채광 시스템의 이용을 통한 조명에너지의 절감: 시뮬레이션 및 실측 비교)

  • Jeong, Haejun;Kim, Wonsik;Kim, Yeongmin;Han, Hyun Joo;Chun, Wongee
    • Journal of the Korean Solar Energy Society
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    • v.37 no.3
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    • pp.1-12
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    • 2017
  • This paper deals with the effectiveness of a fiber optic solar lighting system that uses a Fresnel lens mounted on a two-axis solar tracker. A series of comparative analyses were made concerning its performance as compared to fluorescent lighting by using a simulation model based on ECOTECT and RADIANCE as well as referring to actual data. ECOTECT was used to model the test room (space) while RADIANCE was used for its indoor lighting conditions (environment). It was found that the average indoor light levels of fluorescent lighting fully satisfy the KS standard (KS A 3011, general office, class [G]: 300-400-600 lux) whereas those of the solar lighting with light diffusers depends on the occlusion factor of roller shades installed on the south window.

Two-dimensional Numerical Simulation of a Pulsed Heat Source High Temperature Inert Gas Plasma MHD Electrical Power Generator

  • Matsumoto, Masaharu;Murakami, Tomoyuki;Okuno, Yoshihiro
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.589-596
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    • 2008
  • Performance of a pulsed heat source high temperature inert gas plasma MHD electrical power generator, which can be one of the candidates of space-based laser-to-electrical power converter, is examined by a time dependent two dimensional numerical simulation. In the present MHD generator, the inert gas is assumed to be ideally heated to about $10^4K$ pulsed-likely within short time(${\sim}1{\mu}s$) in a stagnant energy input volume, and the energy of high temperature inert gas is converted to the electricity with the medium of pure inert gas plasma without seeding. The numerical simulation results show that an enthalpy extraction ratio(=electrical output energy/pulsed heat energy) of several tens of % can be achieved, which is the same level as the conventional seeded non-equilibrium plasma MHD generator. Although there still exist many phenomena to be clarified and many problems to be overcome in order to realize the system, the pulsed heat source high temperature inert gas MHD generator is surely worth examining in more detail.

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A case study for installing of Energy Metering Systems in an Office Building (사무소 건물의 에너지 미터링 시스템 구축에 관한 사례연구)

  • Han, Hye-Sim;Lee, Na-Eun;Lee, Jin-Sook;Jeong, Hak-Geun;Jang, Cheol-Yong
    • KIEAE Journal
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    • v.13 no.5
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    • pp.51-57
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    • 2013
  • Energy saving starts by knowing how much energy is being consumed. A building factor is easier than any other things in energy saving. Since, especially, it is closely connected with user's space-use-patterns and manager's utility-operation-style. An energy metering system lets building users know about energy consumption pattern in buildings and measure energy in real time. Development and materialization of metering systems need more careful plans, so that they depend on a demand of individual facilities and available infrastructures they used to use. But, so far, there is no guidelines how to install metering systems. This paper suggested how to install meters and researched a method for how to analyze by using metered data. For that, Green Building in KIER is used as a test bed. As the results, nevertheless the smallest number of meters is basically one for the whole building energy measuring, it is too limited in analysis. So we needed to add the sort of fuel and utility types and found that it depends on all cases. For this reasons, a guideline should be created in order to install meters as soon as possible. It would be suggest a way to save more energy in building factor.