Electric night storage heater was introduced and disseminated for power grid balancing and efficient management of power generation facility. But fuel cost for heating has been increased rapidly while the cost of electricity increased slightly. This abnormal rate system caused peak load in winter at last. To solve this problem, application of an air source heat pump was suggested. In the study, the effect of replacing night heater by heat pump and the economics were analysed. In addition the expectation of prospect of heat pump penetration was simulated based on surveyed and investigated data. As a result, fund supporting as well as institutional backing was needed for effective propagation and return of investment.

The night time electric cost is cheaper due to electric supply and demand policy in Korea from 1985. Currently about 900,000 customers are using night time electric heating boilers and this causes shift of peak demand time to night in winter and increase of deficit spending. To solve this problem, replacing night time electric heating boiler by air-source heat pump using night time electricity has been proposed. An air-source heat pump can provide efficient heating equipment especially in a warm climate. For estimating the night time electric heat pump COP(Coefficient of Performance), Korean Standard KS C 9306:2010 and European Standard EN-14511:2004 is available. SCOP(Seasonal COP) using European weather bin data is also calculated. SCOP is not available yet but European Committee for Standardization will establish a standard in the near future. The evaluation result show that the replacing night time electric heating boiler by heat pump can be possible.

In order to find better performance of heat sink, in this research, different cases were analysed by changing number of slots and shape of fins. Round shape fins which have wide surface showed 24% better heat transfer rate than vertical fins. There were not big discrepancies between 1 slot and 2 slots fins. Consequently, for better performance of heat sink, developments for widening surface and better material for high heat transfer rate are needed.

선박에 사용되는 TEMA 열교환기 전열관의 확관 공정에서 발생되는 탄소성 응력과 변형량의 거동을 유한요소법으로 해석하였다. 열교환기의 관판 구명의 홈 깊이와 롤러 익스팬더의 작용압력을 변화시켜 해석한 결과, 전열관의 관판 구멍의 홈 깊이가 커지면 탄소성 압축응력은 감소하였고, 롤러 익스팬더 압력이 높을수록 관판 구멍의 홈 모서리 부분의 탄소성 응력이 증가되었다.

프로테오믹스 기법을 이용하여 벼 고온 스트레스 관련 단백질을 분리 동정하기 위하여 에서 고온처리한 벼의 줄기로부터 단백질을 분리하였다. 분리한 단백질로부터 Rubisco 단백질을 제거하기 위해 15% PEG fractionation을 실시한 후 상등액 분획의 단백질을 이차원전기 영동한 후, CBB 염색을 통해 차별적 발현을 보이는 단백질을 분석하였다. 총 46개의 단백질 spot이 발현양에 변화를 보였으며, 그 중 24개의 단백질이 고온 스트레스에 의해

To analyze and verify the effect of replacing thermal storage heater by a cascade cycle heat pump using midnight electricity was installed and tested at a customer's house in Wonju, Korea. The electric night storage heater is consist of 30kW electric heater and 2,700 liters of thermal storage water tank to supply hot water for warming house floor. The power for electric heater was cut off and hot water was only generated by cascade cycle heat pump. Current thermal storage water tank was not eliminated and electric heater wiring was modified. Some operation logic of the heat pump was also modified for proper operation. The required capacity of the heat pump and hot water temperature for given warming condition were estimated. The estimated capacity of heat pump was about 19kW and estimated hot water temperature for proper heating was at least 75℃.

In this study, the heat flow of the plant scale aluminum extrusion process was investigated to establish optimum continuous heat treatment conditions. During the extrusion of 6061 aluminum alloy, processing parameters such as the extrusion pressure, speed and temperature histories of billets were logged as a function of time. The surface temperature of the billets increased at constant ram speed, while it decreased with decreases of the ram speed. In order to maintain the billet temperature within a solutionizing temperature range prior to the succeeding water quenching step, the ram speed or the temperature of the blower should be controlled. The temperature histories of the billets during the extrusion and hot air blowing processes were successfully simulated by using the velocity boundary model in ANSYS CFX. The methodology to design an optimum process by using a commercial simulation program is described in this study on the basis of the metallurgical validation results of the microstructural observation of the extrudates. The developed model allowed the advantages of taking into account the motion of the extrudate coupled with the temperature change based on empirical data. Calculations were made for the extrudate passing through the isothermal chamber maintained at appropriate temperature. It was confirmed that the continuous heat treatment system is beneficial to the productivity enhancement of the commercial aluminum extrusion industry.

In this study, the economic efficiency of ground source heat pump systems were analyzed by comparing with the performance of a conventional system which applied to an air-conditioner for cooling and a boiler for heating. The economic assessment was carried out by the method of life cycle cost and payback period. As a result, the operation cost of the ground source heat pump system was reduced by 18% for cooling and 50% for heating throughout the year. The ratio of life operation cost to life cycle cost increased with the increase of the system capacity. In addition, the payback period was analyzed less than 5 years when the capacity of the ground source heat pump system was more than 10 RT.

The Heavy Water Reactor(HWR) Heat Transport(HT) system transient analysis for the design of major nuclear equipment during normal and abnormal operating conditions was performed. The compliance with requirements of AECB Regulatory Document R-77 for CANDU reactor was estimated in CANDU-9 nuclear reactor. The analysis results showed that for each postulated accident the peak pressure values in the reactor headers are within the acceptance criteria given in ASME code requirements and the fuel overheating is prevented. The analysis results showed that the flow reversal through the fuel channel occurred but didn't result in any damage on the fuel bundle.

This study aims to evaluate the heat transfer characteristics and energy consumption in the wet and dry ondol systems. Conditions of the continued heating mode set the room temperature at 20℃ and hot water supply temperature at 60℃ and 70℃ for 3 days. The scheduled heating mode operates heating at 6～9am (room temperature at 20℃), suspends heating at 9～18pm (leaving mode), and runs heating at 1 8～24am (room temperature at 20℃) and 24～6am (room temperature at 17℃) for 2 days. The results from the continued heating mode in the dry/wet ondol systems confirmed that the dry and wet systems had the same average indoor temperature (18.9℃) and similar energy consumption. In addition, the results from the scheduled heating mode in the dry/wet ondol systems confirmed that the dry ondol system had lower energy consumption than the wet ondol system. Therefore, the scheduled heating mode in the dry ondol system is expected to reduce energy consumption.

전해제련 공정은 악티늄족 원소를 동시에 회수하는 공정으로써, Pyroprocessing의 핵확산 저항성을 보장 하는 중요한 공정이다. 공학규모의 전해제련 장치를 설계하기 위한 기본 도구를 개발하기 위해서 실험실 규 모의 장치에 대한 열전달 해석을 수행하였다. 열전달 해석을 수치 해석적으로 계산하기 위해 ANSYS CXF 상 용 코드를 사용하였다. 열전달 해석 결과, 가열부의 길이가 수직으로 용융염의 높이보다 약 3배 이상이 되었 을 때, 용융염의 온도를 일정하게 유지할 수 있었으며, 냉각부의 길이는 그 영향이 미비하였다. 전해조 덮개아래의 아르곤 가스의 온도는 냉각 판의 개수에 따라 감소하였으며, 5개 이상 설치 할 경우 250 ℃ 이하로 유 지할 수 있음을 보였다. 이러한 계산 결과는 실제 실험 장치에서 측정된 장치 내부 온도 분포와 경향성이 일 치하는 것을 볼 수 있었다. 본 연구에서 해석된 전해제련 장치의 열 분포 특성은 공학규모 장치의 설계를 위 해 중요한 자료로 사용 될 수 있을 것이다.

The performance of a heat pump using river water as a heat source was compared with that of a conventional air-conditioner for cooling and a boiler system for heating. The heat pump system using river water considered the 1-stage cycle for cooling and the 2-stage cycle for heating. The COPs of the river water source heat pump were 0.5-1.1 higher than those of the conventional system in the cooling season. The LCC of the river water source heat pump system was lower 13.5% and 32.4% than that of the conventional system Ⅰand Ⅱ. In addition, when the initial cost ratios of the river water source heat pump system to the conventional system Ⅰand Ⅱ were less then 1.2 and 1.4, respectively, An acceptable payback was found to be less than 5 years.

본 연구는 계면경계에서 특이성을 갖는 이종재료 열전달문제를 효율적으로 해석할 수 있는 이동최소제곱 유한차분법을 제시한다 이동최소제곱 유한차분법은 격자망(grid)없이 절점만으로 이동최소제곱법을 이용하여 Taylor 다항식을 구성하고 차분식을 만들어 미분방정식을 직접 푼다. 초평면함수 개념에 근거한 쐐기함수를 이동최소제곱 센스(sense)로 근사식에 매입하여 쐐기거동과 미분 점프에 따른 계면경계 특성을 효과적으로 묘사하고 고속으로 미분을 근사하는 이동최소제곱 유한차분법의 강점을 발휘하도록 했다. 서로 다른 열전달계수를 갖는 이종재료 열전도문제 해석을 통해 이동최소제곱 유한차분법이 계면경계문제에서도 뛰어난 계산효율성과 해의 정확성을 확보할 수 있음을 보였다.

강바닥판 포장에 사용될 수 있는 특수아스팔트 중의 하나인 구스아스팔트는 의 고온 상태에서 시공되기 때문에 강바닥판에 예상하지 못한 열응력 및 열변형을 발생시킬 수 있다. 따라서 구스아스팔트의 타설 중에 강바닥판에 미치는 열영향을 시공조건을 고려하여 사전에 평가하고 그 영향의 최소화를 위해서는 열전달 및 열응력 수치해석을 실시하여야 하지만 구조해석에서 주로 사용되는 평판/보요소의 특성상 3차원 구조해석 모델에서 구현하기가 매우 어렵다. 본 연구에서는 강바닥판 교량의 열영향해석을 위하여 일반적인 구조해석모델에 직접 적용할 수 있는 등가열원(EHS) 산정방법을 제안하였다. 강바닥판 교량의 구스아스팔트에 의한 열영향을 정확히 평가하기 위하여 (1) 기존의 실험결과를 이용하여 열전달해석에 필요한 물리량을 검증하고, (2) 정밀해석을 통해 3차원 교량모델에 적합한 등가열원을 산정하였으며, (3) 이를 해석모델에 적용하여 산정한 등가열원에 의한 수치해석방법의 타당성을 검증하였다. 본 연구에서 제안된 등가열원은 실제 강교량의 3차원 열전달 및 열응력 해석에 즉각 활용될 수 있으며, 등가열원산정기법은 용접잔류응력해석, 교량의 화재 해석 등 열영향을 받는 다른 공학적 해석에 응용될 수 있을 것으로 기대된다.