• Journal of Institute of Control, Robotics and Systems
• /
• v.9 no.3
• /
• pp.236-241
• /
• 2003

This paper addresses the optimal design of dividing wall distillation column which is rapidly applied in a variety of chemical processes over recent several years because of its high energy saving efficiency. A general dividing wall column model which can cope with the heat transfer through the dividing wall is developed using rigorous computer simulation. Based on the simulation model, the effects of the internal recycle flow distribution around the dividing wall and the heat transfer across the dividing wall on overall system performance are investigated. An improved column design method is suggested to utilize the heat transfer through the wall. The suggested method is compared with the existing method via simulation study in which the proposed design shows improved energy saving result.

• Journal of Energy Engineering
• /
• v.24 no.2
• /
• pp.174-178
• /
• 2015

We have surveyed on technical method of wireless power transfer and have also surveyed on applications of the wireless charging for mobiles and of the wireless charging for electrical vehicle and electrical equipments. In this study, we have described about wireless power transfer and have analyzed and checked wireless power transfer prospects of applications and practical development.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.9
• /
• pp.845-852
• /
• 2001

The phenomena of energy separation in vortex tubes was investigated experimentally to see the effects of the conductivity of a tube and convective heat transfer on the outer surface of a tube. The experiment was carried out with different conductivity (pyrex, stainless steel and copper) of a tube and three kinds of convective heat transfer modes (adiabatic condition, natural convection (air) and forced convection (water) on the outer surface of a tube. the results were obtained that hot exit fluid temperature was highly affected by a change of conductivity of a tube when the outer surface was cooled by the forced convection of water. However, the cold exit temperature was little affected by heat transfer modes on the outer surface in vortex tubes.

• Journal of the Korean housing association
• /
• v.15 no.3
• /
• pp.93-99
• /
• 2004

This study was conducted to estimate the solar energy, as an alternative energy evaluating an effect of solar radiation on indoor space of residential building. The basic data of solar radiation which is useful for architectural design was suggested using theoretical and experimental analysis. Accordingly, this study was carried out measuring the solar energy using Explicit Method. These results were compared with the results using steady state heat transfer method. The results of this study are summarized as follows; Based on the results using Explicit Method and steady state heat transfer on the indoor space of building, it was shown that an analysis on heat transfer using Explicit Method is more sensitive to the outdoor environmental changes. The results using Explicit Method to analysis and evaluate the solar radiation should be used for residential building design.

• Journal of Energy Engineering
• /
• v.24 no.2
• /
• pp.103-109
• /
• 2015

A heat recovery steam generator consists of inlet expansion duct and heat transfer tube bank modules. For the enhancement of heat transfer in the tube bank modules, the flow should be uniform before the 1st heat transfer tube bank module. The present study has been carried out to analyze the flow characteristics in the inlet expansion duct of a heat recovery steam generator by using numerical flow analysis. The aim of the present study is to establish the proper heat transfer mechanism in the heat transfer tube bank modules by the comparison of the heat transfer models, the case with the constant heat loss per unit volume and the case with heat loss by using inner and outer convective heat transfer coefficient of heat transfer tube. From the present research, it could be seen that the heat transfer mechanism with using inner and outer convective heat transfer coefficient derives more proper temperature distribution results and the acceptance criteria of the temperature distribution within ${\pm}10^{\circ}C$ before SCR is satisfied with using this heat transfer mechanism.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.5
• /
• pp.751-754
• /
• 2006

• Bulletin of the Korean Chemical Society
• /
• v.28 no.10
• /
• pp.1639-1640
• /
• 2007

• Solar Energy
• /
• v.9 no.3
• /
• pp.55-63
• /
• 1989

In this paper, the fluidization characteristics of the magnesia fluidized bed and the heat transfer characteristics with the specimen (SM55C) plunged in the bed have been investigated. To characterize the fluidization, the minimum fluidizing velocities and the relation ships between bed voidage and fluidization rate and obtained. To characterize heat transfer, the experiments for finding heating time transfer effect have been carried out by varying the magnesia particles sizes. optimum heating condition in the magnesia fluidized bed is obtained.

• Solar Energy
• /
• v.19 no.2
• /
• pp.45-56
• /
• 1999

The performance of vertical and horizontal tubes with extended surface of rectangular and triangular cross section was investigated theoretically for boiling heat transfer. A simple method for numerical program assuming one-dimensional heat flow was used to predict the performance of these extended surface tubes. The object of this study was to predict the effects of the height, thickness, numbers and, clearance of the extended surface on boiling heat transfer. The results showed that extended surfaces are quite effective as compared to plane surfaces especially near the bum-out point and to promote heat flux in boiling heat transfer.

• Water Engineering Research
• /
• v.5 no.4
• /
• pp.195-206
• /
• 2004

This paper deals with oxygen transfer by air entrainment and energy dissipations by flow characteristics at the stepped drop structure. Nappe flow occurred at low flow rates and for relatively large step height. Dominant flow features included an air pocket, a free-falling nappe impact and a subsequent hydraulic jump on the downstream step. Most energy was dissipated by nappe impact and in the downstream hydraulic jump. Skimming flow occurred at larger flow rates with formation of recirculating vortices between the main flow and the step comers. Oxygen transfer was found to be proportional to the flow velocity, the flow discharge, and the Froude number. It was more related to the flow discharge than to the Froude number. Energy dissipations in both cases of nappe flow and skimming flow were proportional to the step height and were inversely proportional to the overflow depth, and were not proportional to the step slope. The stepped drop structure was found to be efficient for water treatment associated with substantial air entrainment and for energy dissipation.