• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.11
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• pp.923-930
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• 2002

Cooling characteristics of a parallel channel with protruding heat sources using convection and conduction heat transfer are studied numerically. A two-dimensional model has been developed for numerical prediction of transient, compressible, viscous, laminar flow, and conjugate heat transfer between parallel plates with uniform block heat sources. The finite volume method is used to solve the problem. The assembly consists of two channels formed by two covers and one printed circuit board which has three uniform heat source blocks. Six different cooling methods are considered to find out the most efficient cooling method in a given geometry and heat sources. The velocity and temperature fields of cooling medium, the temperature distribution along the block surface, and the maximum temperature in each block are obtained. The results are compared to examine the cooling characteristics of the different cooling methods.

• Product Safety
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• s.200
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• pp.72-75
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• 2010

자판기가 라면을 끓인다'는 사실은 더 이상 화젯거리가 아니다. 지난 2003년부터 선보인 끓인 라면자판기는 이미 세인의 많은 관심을 불러일으킨 바 있다. 아이디어 상품으로 시장성도 좋아 많은 업체들이 시장 가세를 진행하며, 시장은 뜨겁게 과열된 바 있다. 하지만 아쉽게도 이 열기는 오래 가지 못했다. 최고의 관심을 받은 아이디어 상품인 만큼 많은 업체들의 섣부른 개입으로 인해 조악한 제품이 판을 치고 특허분쟁으로까지 이어졌다. 그 과정에서 소비자 신뢰는 갈수록 떨어지게 되었고 끓인 라면자판기 시장은 급락하지 않을 수 없었다. (주)세원벤딩의 김철영 대표는 끓인 라면자판기 시장이 이렇게 된 것은 시장 가능성 자체의 문제가 아니라고 보고 있다. 문제는 업체들의 잘못된 시장계획을 진행한 결과이기 때문에 얼마든지 시장 부활을 이끌어 낼 수 있다고 보고 있는 것. 그래서 초심으로 돌아가 '최고의 제품', '최고의 마케팅'으로 다시 시장을 살려내겠다는 결의를 다지고 진행하고 있다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1021-1024
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• 2008

Near infrared heating as an alternative to the conventional heating techniques for thermography -NDT is tried in this paper. A concrete specimen containing a defect was heated by the near infrared ray and the thermography-NDT technique was applied. Using a dimensinless temperature, the defects were detected. It was found that the near infrared ray could efficiently heat up the concrete specimen compared to others conventional methods like lamps, heat flow, etc.

• Journal of Hydrogen and New Energy
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• v.29 no.5
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• pp.490-496
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• 2018

Recently, the power and refrigeration cogeneration based on Kalina cycle has attracted much attention for more efficient utilization of low-grade energy. This study presents a thermodynamic performance analysis of a cogeneration cycle of power and absorption refrigeration based on Kalina cycle. The cycle combines Kalina cycle (KCS-11) and absorption cycles by adding a condenser and an evaporator between turbine and absorber. The effects of ammonia mass fraction and separation pressure were investigated on the system performance of the system. Results showed that the energy utilization of the system could be greatly improved compared to the basic Kalina cycle.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.1
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• pp.56-64
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• 2004

A numerical study have been performed on a cavity with one heat source by the open ratio and tilt angle. The goal of this study is to get the information for designing a solar collector absorber. semi-conductor equipment and block heater and so on. The parameters for this study is the various open ratio. and tilt angle of the cavity and Rayleigh numbers The finite volume method with SIMPLE computational algorithm are used and calculated the heat transfer in the cavity. As a result, the heat trans(or was promoted by increase of Rayliegh numbers and open ratios But, the heat transfer was not promted at lower wall of cavity because the flow pattern are very small at lower space in the cavity(Or=0.1) As the Rayleigh number is increased the mean nusselt numbers are increased at inside wall.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1406-1411
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• 2004

A series of experiments was conducted to examine characteristics of a grooved flat-strip heat pipe having multiple heat sources. The inner grooves of the heat pipe have the aspect ratio of 1 to $2.5(0.42{\times}1.05$ mm) whose pitch was 0.6 mm. Four block heaters ($10{\times}20$ mm) were placed in the evaporator section at intervals of 20 mm and six different heating modes were tested. The maximum surface heat flux of 80 $W/cm^2$ was achieved while the operating temperature was kept below $100^{\circ}C$, In the nearest heating mode (from the condenser location), the heat pipe exhibited more stable temperature distribution than the far heating mode where the heaters is located furthest from the condenser.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.82-87
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• 2007

In the present study, the simulation on the annual performance evaluation of a renewable energy systems with fuel cell driven compound source hybrid heat pump systems is applied to the heating and cooling of large community building. The large community building has the economical advantage to apply heat pump cooling and heating systems the long period operation. If air and ground source hybrid heat pump systems are combined, COP of the system can be increased largely. Fuel cell driven compound source hybrid heat pump system can reduced the fuel cost as well as thermal storage tank sharply.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.12
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• pp.1255-1265
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• 2001

A numerical study has been conducted to characterize the transient flow in a utility gas turbine burning natural gas. The solution domain encompasses the supply gas pressure regulator to the combustor of the gas turbine that employs multi-nozzle fuel injectors. Some results produced for verification in the present study agree suite well with the experimental ones. It is found that the total gas flow may decrease noticeably during its combustion mode change, which would be the reason of momentary combustion upset, when a reference case of opening ratios of control valves in the system is applied. Several parameters are then varied in order to make the total gas flow stable over that period of time. Results of this study may be useful to understand the unsteady behavior of combustion system burning natural gas.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.4 no.1
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• pp.1-10
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• 1992

The purpose of this paper is to provide an efficient method of operating and designing HVAC systems for reasonable energy consumption in building. Accroding to the conditions of indoor temperature and humidity, and the methods of dividing and grouping the capacity of boiler and refrigerator, the amount of their annual energy consumptions is simulated by using an energy analysis program which is developed in this paper, and opatimal design methods of HVAC system are suggested as well.

• Solar Energy
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• v.18 no.4
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• pp.39-47
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• 1998

The natural convection heat transfer in a vertical plate with discrete heat sources was studied experimentally. The particular interest was the thermal interaction of the heat sources. In this study, the radiative and conductive heat transfer were considered as heat loss, Thus, the net convective heat transfer rate was presented as adiabatic temperature and thermal wake function. As a results, for non-uniform heating condition, heat input ratio(q1/q2) was most dominant parameter for the thermal wake function. The convective heat transfer rate is decreased with the increasing of channel ratio. For the range of $7.50{\times}10^5<Rac<8.66{\times}10^6$, a useful correlation was proposed as a function of channel Rayleigh number.