• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2000.11a
• /
• pp.135-143
• /
• 2000

This parer is the among educational environment, lighting's role is more important since it improves the visual tasks, capability of work, and it help to build both balanced mind and body. Also, since students need spend most of their time inside rather than outside, students need appropriate illuminance everyday. If optimum illuminance and distribution of luminance is properties controlled, people can decrease the fatigue of eyes, and also, people can maximize their efficiency of work. This present studying class chose of two school measured illuminance using the computer simulation improved ratio of luminance and luminance by distribution of lighting improve the economy and energy saving.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1959-1961
• /
• 2002

Requirements for high-efficiency equipment for energy saving are rapidly increasing recently keeping pace with development of digital and semiconductor technology. Accordingly, there are many changes and development in ballast. Ballast currently in use are Magnetic ballast (Coiled Type) and Electronic ballast. Electronic ballast produces incredible energy saving effect, but falls short of confidence instead. In addition, use at higher frequency through switching device creates Electromagnetic Interference (EMI) and high frequency. EMI creates low quality of equipment, damage in facilities and low productivity by leading miss operation of equipment, and interferes with surrounding machines. In this analysis I am going to examine characteristics of EMI on the Electronic ballast of FLR32SS one type pursuant to annex 3 of Electric Goods Technology Standard, and counter technology.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.2
• /
• pp.406-417
• /
• 2014

This paper presents a numerical optimization method to improve the performance of the propeller with Turbo-Ring using real-coded genetic algorithm. In the presented method, Unimodal Normal Distribution Crossover (UNDX) and Minimal Generation Gap (MGG) model are used as crossover operator and generation-alternation model, respectively. Propeller characteristics are evaluated by a simple surface panel method "SQCM" in the optimization process. Blade sections of the original Turbo-Ring and propeller are replaced by the NACA66 a = 0.8 section. However, original chord, skew, rake and maximum blade thickness distributions in the radial direction are unchanged. Pitch and maximum camber distributions in the radial direction are selected as the design variables. Optimization is conducted to maximize the efficiency of the propeller with Turbo-Ring. The experimental result shows that the efficiency of the optimized propeller with Turbo-Ring is higher than that of the original propeller with Turbo-Ring.

• Journal of the Society of Naval Architects of Korea
• /
• v.57 no.6
• /
• pp.381-387
• /
• 2020

According to the increase of concern for environmental problems, the energy saving becomes an important issue because it is one of the most effective methods of decreasing CO2 which is major environmental problem. In the present study, the post device after propeller related with rudder has been focussed. Recently the full-spade twisted rudder has been frequently used not only to increase the efficiency but also to remove the cavitation risk on leading edge. In addition to that the rudder bulb is also applied to the rudder to increase the propulsion efficiency as well as to minimize the cavitation erosion risk around twisting part. The parametric study has been conducted for investigating the optimum configuration of twisting rudder with bulb by CFD. The present optimization has been applied to the KVLCC2 full-body ship. The verification of the computed results is also expected to be conducted by the comparison with experimental results in the near future.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.5
• /
• pp.351-357
• /
• 2023

In this study, we devised methods to enhance the efficiency of rotor sails which have been applied as one of the energy saving devices of ships. The idea of the study originated from the notion that installing protrusions or increasing the surface roughness on the smooth surface of the rotor sail could delay the separation of the incoming wind flow and consequently increase the lift force. Five cylinder models were considered and tested in an open-type wind tunnel at Chungnam National University. A smooth surface cylinder exhibits the highest lift-to-drag ratio at a specific Reynolds number, and as the Reynolds number increases this value decreases sharply. The variation in this typical Magnus force can be significantly improved by altering the surface shape and roughness of the rotor sail. It has been observed that increasing the surface roughness improves the lift characteristics, resulting in increased efficiency. Furthermore, it revealed that the reverse Magnus effect which may occur during actual operation in the low spin ratio region can be significantly enhanced.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.2
• /
• pp.344-351
• /
• 2010

In this paper, we developed a green home simulator using LabVIEW for house designers or users to assess energy saving costs in an easy and direct way. The LabVIEW simulator has a strong graphic user interface, which is intuitive to general users. Therefore, the developed simulator enables one to gather information on electric power consumed in its house and to calculate efficiency for installing green energy generators such as solar and wind power generators. As an actual application, we simulate and compare the efficiencies of installing green energy generators at various cities and seasons using the developed LabVIEW simulator. The simulation results confirm that energy saving effects of green energies are easy to calculate by the proposed green home simulator.

• Environmental and Resource Economics Review
• /
• v.20 no.1
• /
• pp.99-118
• /
• 2011

'Low Carbon, Green Growth' may be the achievable target in industry section, depending on whether less reliance on fossil-fuels use can bring higher productivity growth in the long run. This paper tests for the short-run and long-run effects of investment on energy-saving equipments on productivity growth in the Korean manufacturing industries. The investment in energy efficiency causes an increase in costs (measurement effect) in the short-run, but in the long-run likely improve energy intensity and reduce costs (positive real effect) despite the delay in new other investment for technical innovation (negative real effect). A 2SLS regression was attempted to deal with endogeneity of energy-saving investment. The productivity effects were tested for five manufacturing sub-industries showing relatively high energy intensity with annual time series data from 1982 through 2006. No productivity effects were accepted for all five sub-industries except Chemical products. Positive real effect was considered to be exceeded by negative real effect, resulting in decreased productivity growth for Chemical products.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.17 no.3
• /
• pp.205-211
• /
• 2014

Interests on energy saving devices (ESDs) have been increased with the concern of the energy efficiency design index (EEDI) developed by the international maritime organization (IMO). To study the influence of ESDs, KVLCC2 with energy saving pre-swirl stator (PSS) was selected. To validate the computations, computed nominal wake of the model scale ship was compared with the experimental data, and the numerical uncertainty assessment was done for the full scale ship computations. The PSS changed rotational flow, which was assistant to the propeller thrust for the model and full scale ships. Performances of the full scale ships were predicted by ITTC methods, and new prediction method was proposed.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2002.08a
• /
• pp.53-56
• /
• 2002

Samsung's newly developed high luminance efficiency 42" VGA plasma display panel is introduced. A new discharge cell structure, SDR (Segmented electrode in Delta color arrayed Rectangular subpixel) has been applied to a full size panel for the first time. In this paper, we describe how this new discharge cell structure for high efficiency is integrated to an energy saving plasma display with better picture quality.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.40 no.1
• /
• pp.91-116
• /
• 2015

This study aims to provide public sectors with eco-efficiency information. To implement the purposes of the study, environmental and economic variables of Eco-Efficiency were identified through decision tree model, then the relative Eco-Efficiencies of 243 public sectors were evaluated through input-oriented DEA (Data Envelopment Analysis) model. Specifically, the amount of public purchasing per a staff and the amount of energy use per a staff were considered as input factors. Sales per a staff was considered as output factor. The result shows that most of the public sectors (94.2%) were evaluated as "inefficient" taking into consideration of average value, 0.501 from market-based public corporations, 0.288 from local public corporations, 0.28 from quasi-market-based public corporations, 0.269 from fund-management-based quasi-governmental institutions, 0.09 from non-classified public institutions, and 0.078 from commissioned-service-based quasi-governmental institutions. Furthermore, it is possible to establish a plan for internal Eco-Efficiency improvement based on information of the reference set. In order to improve the Eco-Efficiency in the public sectors in the long term, environmental impacts of the overall public sectors' operations (e.g., energy saving, water saving, waste reduction, and purchasing of green products) needs to be properly proposed in consideration of BSC (Balanced Scorecard) indicators of public sectors.