• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.461-466
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• 2013

In this paper, main mechanism and measurement method of energy consumption for machine tools are investigated by experiment and simulation. To evaluate total energy consumption of the machine tools, standard test workpiece and measuring method and test procedures are suggested. And, improvement of energy consumption evaluation by the motion kinematics theory is used. In addition, to estimate energy consumption of machine tools in design process, mass distribution of the structure and 5 axis motions are investigated and simulated by numerical analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.287-293
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• 2003

This study examined the temperature-dependent regression model of energy consumption based on various measuring period. The methodology employed was to construct temperature-dependent linear regression model of daily energy consumption from one day to three months data-sets and to compare the annual heating energy consumption predicted by these models with actual annual heating energy consumption. Heating energy consumption from a building in Daejon was examined experimentally. From the results, predicted value based on one day experimental data can have error over 100%. But predicted value based on one week experimental data showed error over 30%. And predicted value based on over three months experimental data provides accurate prediction within 6% but it will be required very expensive.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.2
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• pp.8-17
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• 2012

The objective of this study is to perform an analysis of the heat(heating and cooling) and lighting energy consumption according to the window area ratio and the application of horizontal louver, which is external shading device installed for the purpose of energy savings in office buildings. For this, a building was chosen as a typical example, and the heat and lighting energy consumption was calculated by using the daylight and building energy analysis simulation. The results showed that the total energy consumption, when the lighting control was applied, was reduced by an average of 11.49[%] compared to when there was no lighting control. The smaller the glazing ratio is, the less the total energy consumption is. Also, the application of the horizontal louver increases the total energy consumption under the same condition of glazing ratio.

• KIEAE Journal
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• v.14 no.2
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• pp.11-19
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• 2014

Building energy consumption takes up almost 25% of the total energy consumption. Therefore, diversified ways, such as improving wall and window insulation, have been considered to reduce building energy consumption. Recently, green roof system has been explored as an effective alternative for dealing with reducing heating and cooling energy, thermal island effect and improving water quality. However, recent studies regarding a green roof system have only focused on building energy reduction without considering the applied usage, location, and story of the green roof system. Therefore, this study pays attention to the heating and cooling energy in relation to the applied usage, location, and story of a green roof system for investigating its impact on energy reduction. The result of simulations show that the reduction in heating energy consumption is higher when applied to Cherwon-gun province which has a continental climate condition, compared to the city of Busan that is distinguished by its warm climate. Cooling energy saving turns out to be higher when the green roof system is applied to Busan in comparison with Cherwon. As for the applied usage or function of the building, residential space acquires the highest heating and cooling energy saving effect rather than commerce, educational or office space because of HVAC's running time based on usage. When it comes to the story of the green roof, both heating and cooling energy saving become the highest when the green roof is applied to single-storied buildings. The reason is that single story building is affected by the ground largely. Generally, the variations of heating energy consumption are larger than the cooling energy consumption. The outcome of the simulations, when a green roof system is applied, indicates that the energy consumption reduction rate is dynamically responding to the applied usage, location, and story. Therefore, these factors should be counted closely for maximizing the reduction of energy consumption through green roof systems.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.7
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• pp.27-34
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• 2018

The energy consumption of apartment houses is affected by various factors. The criteria for assessing current energy usage are area, region and purpose. The purpose of this study is to obtain the reliability of the method of evaluating the existing energy consumption certificate and to derive usable evaluation factors according to the correlation of factors affecting energy consumption. The research process collects energy usage data for apartment houses in Daegu and calculates statistical results through correlation analysis and multiple regression analysis. As a result, it was found that the power energy is influenced by the yearly factor of physical characteristics, and the heat energy and total energy usage are influenced by the energy source which is energy characteristic factor.

• Journal of The Korea Institute of Healthcare Architecture
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• v.18 no.3
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• pp.29-39
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• 2012

Window and shading designs have a great influence on energy consumption and daylighting in buildings. As far as energy is concerned, small window area is advantageous. But it is not good to the patient healing in hospital. So it is important to find out the optimum window shape which is favorable for both energy consumption and patient healing. In this study, annual energy consumption and daylight illumination levels were analyzed according to the window shapes and shading devices for a multi-beded patient room in hospitals. The simulations were conducted for 19 different cases by COMFEN 4.0 computer simulation program. The results of this paper are as follows. First, window to wall area ratio and shading devices have great influences on annual energy consumption. But it is a problem in that they decrease significantly daylight level in bed room. Second, considering the same energy consumption, reducing the width of window rather than the hight of window is desirable for the secure of daylight level. Third, increase of the number of horizontal shade is not desirable in south face of the building for the energy consumption and daylight level. Fourth, sun shade is not necessary in north face of the building for the energy consumption and daylight level.

• KIEAE Journal
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• v.15 no.5
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• pp.89-94
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• 2015

Purpose: Various policies to reduce the energy consumption have been carried out to save Earth environment against global warming and environmental pollution in many countries. Energy consumption of buildings in Korea has reached 24% of total energy consumption, and energy consumption of apartment has been continuously increasing. Therefore, Korea government has executed building energy efficiency rating certification system to control energy consumption of buildings. Method: This study was conducted to evaluate the energy performance of apartment unit plans according to the increasement of front width of unit plans, and tried to present the basic data to design more energy conscious unit plans for apartments. For the study, three shapes of unit plans -the 2Bay, 3Bay and 4bay unit- were selected for imput models. They were simulated using ECO2 software to assess building energy efficiency rating certification in Korea. Result: According to the results, in cases that balcony windows were not installed, the primary energy consumption of the 3Bay and 4Bay units were less than 2Bay unit, respectively, 0.1% and 2,5%. The primary energy consumption of the 3Bay and 4Bay units, in cases that balcony windows were installed, was less than 2Bay unit, respectively, 1.7% and 3.2%.

• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.48-56
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• 2013

Energy consumption analysis of multi-family apartment is an important area of research for the design of energy-saving housing. In this study, we selected a universal type of Flat-type apartments and analyzed the heating energy consumption of variables such as U-value, G-value, infiltration rate, heating setpoint and boiler efficiency with EnergyPlus and eQUEST. With these results, we identify the characteristics of EnergyPlus and eQUEST and provided base data for the design of energy-saving housing. The results indicate that infiltration rate is the most important factors to consider. And eQUEST heating energy consumption is approximately 10% higher compared to the EnergyPlus under same condition.

• Journal of Communications and Networks
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• v.12 no.2
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• pp.103-113
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• 2010

In this paper, a tradeoff between the total energy consumption-per-bit and the end-to-end rate under spatial reuse in wireless multi-hop network is developed and analyzed. The end-to-end rate of the network is the number of information bits transmitted (end-to-end) per channel use by any node in the network that is forwarding the data. In order to increase the bandwidth efficiency, spatial reuse is considered whereby simultaneous relay transmissions are allowed provided there is a minimum separation between such transmitters. The total energy consumption-per-bit includes the energy transmitted and the energy consumed by the receiver to process (demodulate and decoder) the received signal. The total energy consumption-per-bit is normalized by the distance between a source-destination pair in order to be consistent with a direct (single-hop) communication network. Lower bounds on this energy-bandwidth tradeoff are analyzed using convex optimization methods. For a given location of relays, it is shown that the total energy consumption-per-bit is minimized by optimally selecting the end-to-end rate. It is also demonstrated that spatial reuse can improve the bandwidth efficiency for a given total energy consumption-per-bit. However, at the rate that minimizes the total energy consumption-per-bit, spatial reuse does not provide lower energy consumption-per-bit compared to the case without spatial reuse. This is because spatial reuse requires more receiver energy consumption at a given end-to-end rate. Such degraded energy efficiency can be compensated by varying the minimum separation of hops between simultaneous transmitters. In the case of equi-spaced relays, analytical results for the energy-bandwidth tradeoff are provided and it is shown that the minimum energy consumption-per-bit decreases linearly with the end-to-end distance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.5
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• pp.342-348
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• 2011

This study analyzes the current and after retrofit energy consumption of lighting and cooling system of a superstore in Seoul. Energy consumption data were measured and collected with a measurement system. Annual energy consumption was calculated using TRNSYS program. After replacing lighting and chiller with higher efficiencies, annual TOE consumption decreased from 1,066 before retrofit to 832 after retrofit, saving 234 TOE (22%) in total. Similarly, total annual $TCO_2$ consumption decreased from 2,214 to 1,721, reducing 493 $TCO_2$ (22%) during this pilot study.