• International Journal of Air-Conditioning and Refrigeration
• /
• v.6
• /
• pp.1-13
• /
• 1998

The basic heat transfer process that occurs in a building can best be illustrated by an electrical circuit network. Present paper reports the dynamic simulation of annual energy consumption in an office building by the thermal resistance capacitance network method. Unsteady thermal behaviors and annual energy consumption in an office building were examined in detail by solving the simultaneous circuit equations of thermal network. The results are used to evaluate the accuracy of the modified BIN method for the energy consumption analysis of a large building. Present thermal resistance-capacitance method predicts annual energy consumption of an office building with the same accuracy as that of response factor method. However, the modified BIN method gives 15% lower annual heating load and 25% lower cooling load than those from the present method. Equipment annual energy consumptions for fan, boiler and chiller in the HVAC system are also calculated for various control systems as CAV, VAV, FCU+VAV and FCU+CAV. FCU+CAV system appears to consume minimum annual energy among them.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2008.10a
• /
• pp.53-56
• /
• 2008

The full of potential method is generally used for measuring the earthing-resistance. This method needs two auxiliary electrodes and it is required that two auxiliary electrodes are placed at enough distances from the earthing electrode, e.g. building foundation. However, in urban area there is not enough space for taking measurement. So, it is very difficult to measure the earth resistance precisely. However, there is the 4- potential method when it stand on the theory of the full of potential method. It is the purpose of this paper to basic study on correction method of measured earthing resistance by 4-potential method.

• Journal of Ship and Ocean Technology
• /
• v.1 no.2
• /
• pp.1-10
• /
• 1997

The prediction of the total resistance of a ship is generally based on considering it to be a simple sum of the viscous resistance and the wave resistance. An experimental approach for predicting full-size ship resistance on this basis is practical but obviously has the deficiency that a model has to be built for each prototype of interest and the resulting tank tests are time consuming. On the other hand, purely theoretical calculations of the wave resistance, using, for example, the Michell theory, require relatively little computer time and give an excellent portrayal of the overall variation of the vessel resistance as a function of forward speed. Unfortunately, there are sufficient differences between this theory and the measured results to make this method impractical for design purposes. The proposal examined here is to use a data bank of experimental resistance results to modify the theoretical predictions. It is demonstrated that the technique will produce remarkably accurate resistance predictions and can take into account the effects of the water depth, any restriction of canal or river width, as well as the prismatic coefficient, and other geometric parameters.

• International Journal of High-Rise Buildings
• /
• v.2 no.1
• /
• pp.23-30
• /
• 2013

This paper explains the Japanese present situations relevant to the fire resistance performance. Performance-based fire provisions was introduced in 1998 for the first time when the Building Standard Law was amended. However, performance-based fire resistance design had been used since long before the official introduction of performance-based provisions. A Comprehensive Technology Development Project of Ministry of Construction from 1982 to 1986 established a technical basis for performance-based fire safety engineering in Japan. A system of calculation methods for fire resistance verification was prescribed in the Ministry Notification in 2000 utilizing the results of this project as a background. This method, referred to as the Fire Resistance Verification Method (FRVM), is the standard method to verify the fire resistance performance of principal building parts such as columns, beams, and walls of steel, concrete, or wood structured buildings. For tall buildings, however, more advanced method for performance verification is often necessary because new building materials or structural systems are often used for these buildings. An example project of tall building owned by a major newspaper company is presented in this paper. Advanced thermal deformation analysis is executed to secure the fire resistance of the building.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.20 no.6
• /
• pp.491-497
• /
• 2015

This study proposes a new control method for a resistance spot welding inverter to improve weld quality. The proposed method is based on the dynamic resistance characteristics of steel sheets to be welded. A point in the second peak value of the dynamic resistance occurs during one shot of the welding current flow. A constant voltage control is applied from zero to the peak point, and a constant current control is adopted from the peak point to the end of the shot. The mixed mode control of the constant voltage and current guarantees high weld quality. Experiments are conducted with a 5 kA power supply and 0.5 mm steel sheets to compare quality. Experimental results show that weld quality is improved more than 10 times that of the conventional control method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.9 no.1
• /
• pp.1-13
• /
• 1997

This paper reports the dynamic analysis of energy consumption for an office building by heat resistance-capacitance method. If a building is divided into several wall components and the wall components is replaced by one thermal capacitance and several thermal resistances, the building becomes an electric circuit. By solving the simultaneous equations of the circuit, the dynamic heat transfer characteristics and the energy consumption rate of the building were predicted. Accuracy of modified BIN method was evaluated by the present resistance-capacitance method. The result shows that modified BIN method overpredicts the heating load of the office building 15%. Annual energy consumptions of equipments(fan, boiler, chiller) for various ventilating control system(CAV, VAV, FCU+VAV, FCU+CAV) were compared. FCU+CAV shows the minimum annual energy consumption.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2000.11a
• /
• pp.77-81
• /
• 2000

The purpose of this paper is to describe a new measuring method of ground resistance for the grounding system in energized power equipment and substations. It is very difficult to measure the accurate ground resistance in energized power equipment and substations because of the noise conducted from all external connections to the grounding system and harmonics components caused by unbalanced loads and overloads. The ground resistance that is measured with existing methods includes not only the effect of desired signals but also noise components for the measurement period in grounding system. The measured value of ground resistance can entirely be different from actual value. In this paper, to eliminate 60[Hz] power system interference and harmonic components the low-pass filter method was used in the measurement of ground resistance.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2008.05a
• /
• pp.73-77
• /
• 2008

In this study, we would like to study on the application of roof exposure waterproofing method of joint stability through shiplap rubberized asphalt color sheet to complement problem of fracture, exfoliation and water leakage by existing roof exposure sheet waterproofing material joint weakness. Accordingly, examined basis performance and stability for joint that shiplap rubberized asphalt color sheet through test of that tensile strength, bonding strength, water permeability after bonding, peel resistance after bonding, lengthen resistance after bonding and hang resistance after bonding. The results of this study, waterproofing method to using shiplap rubberized asphalt color sheet is judged to solved fracture, exfoliation and water leakage problems happened in joint by problem was joint of exposure sheet by minimizing gap of joint being integration by shiplap.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2001.05a
• /
• pp.202-207
• /
• 2001

The added resistance of a ship advancing in waves can be split into the resistance due to the radiation wave and the resistance due to the diffraction wave. In this study, the former has been calculated by a method based on Maruo's formula. The latter must be calculated by other methods. Ship motion is calculated by the usual strip method. The amplitude of two dimensional far-field waves is calculated using the improved Green integral equation. The present numerical method can be used for the estimation of the added resistance due to the radiation wave since the present numerical result is much smaller than other existing numerical results considered to be overestimated.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.431-438
• /
• 2003

The domestic design method for the shaft resistance of drilled shafts into a bedrock Is based on the empirical method, where the uniaxial compressive strength of rock specimen is utilized for calculation of the shaft resistance. This method has uncertainties in prediction of capacity of drilled shafts and result in uneconomic engineering design. Recently a new improved design method was suggested, which reflects important factors that affect the strength of pile sockets. Socket roughness is one of significant factors influencing the shaft resistance of drilled shaft socketed into rock In this paper roughness information for the shaft resistance design of socket pile was suggested on the basis of statistical analysis of data measured from wall surface In the bore holes of drilled shafts.