• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.567-570
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• 2009

The present study conducted comparative evaluation of wet dry floor heating systems using geothermal heat pump. Circulation hot water from geothermal heat pump which is $10{\sim}15^{\circ}C$ lower than that from boiler was used. In order to access indoor temperature ($25^{\circ}C$) it took 74 minutes for dry type and 247 minutes for wet type. Average floor temperature was $23.89^{\circ}C$ for wet type and $32.66^{\circ}C$ for dry type. Energy saving rate gradually increased by 66% after 138 minutes. In the results, for floor heating system using low temperature circulation water, wet type was not enough to meet stable and comfortable radiant floor heating due to low floor temperature and access time to indoor set temperature. While dry type was practicable for stable floor heating due to fast rise of indoor set temperature and comfortable floor temperature.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.393-399
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• 2008

A Study has been conducted on the characteristics of temperature variation depending on passenger number that is measured in Bundang Line(From Sunleng To Bojong). As a basic study, the air quality of passenger room for the electric rail car is evaluated. Although ISO7730 recommends that the height of measuring points for the heat environment is to set at 0.1m, 0.6m, 1.1m and 1.7m respectively, temperature are measured at two points at 1.1m and 1.7m because of the difficulty to measure temperature of 0.1m height in rush hour. We compared the results of temperature variations between two stations in rush hour(07:56-08:41). In general, the capacity of a passenger car is designed for 160 persons, but over 280 persons often board on electric rail in rush hour. The temperature of room is adjusted from $22^{\circ}C$ to $24^{\circ}C$, but it is measured from $26^{\circ}C$ to $28^{\circ}C$ on average. Therefore, it shows that there are difference between the set temperature and measured one. This article suggests the ways of the time adjusting and air-conditioning to satisfy customer's demand and the guide line to design the optimum capacity of air-conditioner of the new electric rail car which will be introduced in the near future.

• 전기전자학회논문지
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• 제27권1호
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• pp.25-29
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• 2023

폴리실라잔 고체 전해질 층과 은(Ag) 활성 전극의 공정이 멤리스터의 전기적 특성에 미치는 영향을 살펴보았다. 더 높은 온도에서 어닐링된 고체 전해질을 갖는 멤리스터가 더 낮은 온도에서 어닐링된 고체 전해질을 갖는 소자보다 더 높은 set voltage 및 더 나은 메모리 유지 특성을 보였다. 어닐링 온도 증가에 따른 set voltage의 증가 및 메모리 유지 특성의 향상은 각각 고체 전해질 층 내부의 빈 공간의 감소 및 균일도 증가 때문인 것으로 사료된다. 고체 전해질 층을 비교적 높은 온도에서 어닐링 할지라도, 폴리실라잔 용액의 농도가 지나치게 높은 경우에는 멤리스터의 저저항상태가 유지되지 못했다. 마지막으로, 용액공정으로 형성한 Ag 활성 전극을 갖는 멤리스터는 진공공정으로 형성한 Ag 활성 전극을 갖는 소자와 달리 WORM 특성을 갖는 것으로 나타났다. 이러한 WROM 특성은 용액공정 Ag 활성 전극에 존재하는 형태적 결함 때문인 것으로 사료된다.

• 한국태양에너지학회 논문집
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• 제27권1호
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• pp.47-54
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• 2007

Interests on renewable energy are increased due to oil price and environmental problems aroused from the fossil energy usage. In this study, performances of a solar assisted hybrid heat pump system are analyzed by experimental method. The developed system could runs at two types of operating mode. When the storage temperature is higher than the set temperature, the stored hot water in storage tank is supplied to the load directly. On the other hand, when the storage temperature lower than the set temperature, the water inside of the storage tank is used as heat source of the heat pump. In this study, the system control temperature for the alternation of the operating mode is set to $40^{\circ}C$ of the storage tank outlet. As results, it is founded that the COP of the developed heat pump system shows between 3.0 and 3.5. It is resonable performance for the heating system with a renewable energy as secondary heat source. The solar collect used in this study could supplies heat to the storage tank at over 400 W/m2 solar intensity. If the irradiation is lower than the 400 W/m2, the circulation pump stored and it could not supply heat to the storage tank. It is found that the difference temperature between the outlet of the storage tank and collector is $3^{\circ}C$. Even though, the extended study should be conducted to get a optimum performance of the developed system with various operating condition and control strategies.

• Korean Chemical Engineering Research
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• 제59권1호
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• pp.77-84
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• 2021

Plug flow reactor (PFR) 내의 과열점(hot spot) 온도를 조절하는 것은 생성물의 수득률 및 순도, 안전성 측면에서 중요하다. 본 연구에서는 더 현실에 가깝게 모델링 하기 위하여 PFR 내부의 냉각액 온도를 상태변수로 설정하고 방사 방향의 열 및 물질전달을 고려하였다. 모델은 반응물의 농도 및 온도와 냉각액의 온도 총 3개의 상태변수로 이루어져 있으며, 등온 냉각액의 유량을 조작변수로 가진다. 본 연구에서는 방사 방향의 열 및 물질전달을 고려한 제어식이 그렇지 않은 제어식보다 과열점의 온도를 set point 부근으로 더 효과적으로 유지한다는 것을 보였다. 본 연구에서 제안한 제어식은 냉각액의 온도가 반응물 온도의 약 0.7배 부근일 때 St가 1.3 이상이고 Ac/A가 2.0 이하인 조건에서 강건성을 유지하였다. 이 조건에서 반응기로 유입되는 반응물의 온도가 5% 범위에서 바뀔 때 본 연구에서 제안된 제안식을 이용하면 과열점의 온도를 set point의 1% 이내로 유지할 수 있다.

• 멤브레인
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• 제10권4호
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• pp.220-229
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• 2000

본 연구는 한외여과 중공사형 모듈과 역삼투 나권형 모듈로 구성된 모듈 set 1∼7을 이용하여 모듈 set에 따른 순수 및 2차 처리수의 투과 flux를 고찰하고, 적용압력과 온도변화에 의한 한외여과 막과 역삼투 막의 분리 특성을 고찰하였다. 탁도와 SS는 한외여과 막에서 효율적으로 제거되며 COD, T-N, TDS 등은 역삼투 막에서 우수한 제거효율을 나타내었다. 적용압력과 온도의 증가에 따른 투과 flux는 선형적으로 증가하는 경향을 보였다. 이로부터 한외여과 및 역삼투 막은 정유공장 방류수의 고도처리 및 재활용을 위해 적합한 것으로 나타났다.

• 수산해양기술연구
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• 제22권3호
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• pp.1-7
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• 1986

This is a basic study of further investigating the effect of oceanographic conditons, such as bottom profile, currents, and temperature, to the fish migrating course around the set-net. The survey was held at Dojang Po, southern part of Geoje Island, from July to October in 1985. There was a sea valley of which depth was 20 to 40 meters around the set-net. Near the bottom of that sea valley, there was different current pattern to the upper layer. In the sea calm condition of July and October, the vertical profiles of current and water temperature were simple. But in rough condition of September, they were complicated because of wind tuburance.

• 한국의류학회지
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• 제20권4호
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• pp.565-572
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• 1996

The purpose of this study was to measure partial heat resistance of Hanbok when it worn. Since Hanbok varies from season to season, four different set of Hanboks (R, SN, p and S) were tested. Also Durumagi (D) which is worn over Hanbok (5) to keep warm from winter cold was tested as well. The thermal manikin was used in this experiment. The room temperature, air velocity and the relative humidity was set at $20\pm0.5^{\circ}C$, 0.15 m/sec and $50\pm$5% respectively. The mean skin temperature of the manikin was set at $33\pm0.5^{\circ}C$. The results were as follows: 1. The order from the least total heat resistance to the most was SN, R, p, 5 and D. 2. Upper arms had the highest heat resistance among the 13 parts. The next was abdomen thighs, buttock, legs, forearms and chest, back, and head, the order from the most to the least.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.51-55
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• 1995

An adaptive unified predictive control (UPC) algorithm is applied to a batch polymerization reactor for poly(methyl methancrylate) (PMMA) and the effects of controller parameters are investigated. Computational studies are performed for a batch polymerization system model developed in this study. A transfer function in parametric form is estimated by recursive least squares (RLS) method, and the UPC algorithm is implemented to control the reactor temperature on the basis of this transfer function. The adaptive unified predictive controller shows a better performance than the PID controller for tracking set point changes, especially in the latter part of reaction course when gel effect becomes significant. Various performance can be acquired by selecting adequate values for parameters of the adaptive unified predictive controller; in other words, the optimal set of parameters exists for a given set of reaction conditions and control objective.

• 설비공학논문집
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• 제18권4호
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• pp.287-296
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• 2006

In this paper, optimal control strategy of the air-conditioning system with slab thermal storage was investigated based on the optimal control theory. An optimal heat output to the plenum chamber and the air-conditioned room was determined based on two kinds of criterion functions. The first one requires small deviation in room air temperature from a set-point value and low energy consumption. It is shown that the optimized control is to store heat through the whole storage time and to increase storage rate gradually with time. As the second case, a criterion that both a deviation of operative temperature from a set-point temperature and the energy consumption should be minimized was adopted. The room air temperature was a little high and the cooling load during storage time was reduced, compared with the results when a criterion function considering only the room air temperature is used.