• 제어로봇시스템학회논문지
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• 제3권2호
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• pp.197-203
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• 1997

In this paper, we present a GP-PID(Generalized Predictive PID) controller which has the same structure as a generalized predictive control with steady-state weighting. The proposed controller can perform better than the conventional PID controller because it includes intrinsic delay-time compensator. The PID tuning parameters and delay-time compensator are calculated by equating the two degree of freedom PID to a linear form of GPC. The proposed controller is combined with a supervisor for safe start and self-tuning. GP-PID controller has been tested for various numerical models and an experimental stirred tank heater. As a result, it was observed that the proposed controller shows a satisfactory performance for variable delay as well as stochastic disturbance.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.660-664
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• 2001

Ringbom Stirling engine which is a kind of low temperature difference model Stirling engine is manufactured and its characteristics are measured at some temperature differences. Pressure, displacer position and rotation speed are measured. Displacer position and rotation speed are detected by photo-sensor. The hot side of Ringbom Stirling engine is warmed by electric heater. The cold side of Ringbom Stirling engine is cooled by the air. This result may be useful for further design and manufacture of Ringbom Stirling engine. Also, it would be used as an educational material for mechanical engineering students.

• 대한기계학회논문집
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• 제18권3호
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• pp.690-700
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• 1994

The effects of thermal stratification on the flow of a stratified fluid past a circular cylinder were examined in a wind tunnel. In order to produce strong thermal stratifications, a compact heat exchanger type variable electric heater is employed. Linear temperature gradient of up to $250^{\circ}C/m$ can be well sustained. The velocity and temperature profiles in the cylinder wake with a strong thermal gradient of $200^{\circ}C/m$ were measured and the smoke wire flow visualization method was used to investigate the wake characteristics. It is found that the temperature field effects as an active contaminant, so that the mean velocity and temperature profiles can not sustain their symmetricity about the wake centerline when such a strong thermal gradient is superimposed. It is evident that the turbulent mixing in the upper half section is stronger than that of the lower half of the wake in a stably stratified flow.

• 설비공학논문집
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• 제23권5호
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• pp.327-333
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• 2011

In the present work, a new freeze protection method has been proposed for a natural circulation system of solar water heater. Though electrothermal wire is popularly used for the purpose, there are freezing troubles by wire cut-off and shortage of excessive electric power consumption. In the experimental device, hot water in storage tank was used to heat the outlet pipe from the tank if the pipe surface temperature falls lower than a set point. The cold water pipe to the storage tank was installed to directly contact the hot water pipe surface temperature rose by transferred heat.

• 융복합기술연구소 논문집
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• 제2권2호
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• pp.40-48
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• 2012

A small domestic desiccant dehumidifier is modelled using effectiveness models for a desiccant wheel and a wet-air condenser. The desiccant wheel and condenser models are used to compose a system model in the form of a set of simultaneous linear algebraic equations, which is solved by Gauss method. The system model is used to simulate the behaviour of a dehumidifier with a 1kW electric air heater. It is found that the maximu COP is about 0.5 and dehumidification capacity is 18kg/day when the ratio of dehumidification area is 0.7. The optimum wheel thickness and face velocity are found 100mm and 1.5m/s, respectively.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2006년도 춘계 종합학술대회 논문집
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• pp.470-474
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• 2006

헤어드라이어의 경우 소비자들이 상품에 대한 충분한 지식을 갖고 구매를 하게 되므로 특별히 판매원의 의견과 서비스를 받지 않고 직접 선택하는 경향이 높아 상품의 포장과 라벨링이 매우 중요한 요소로 지적되고 있다. 본 개발에서는 기존의 금속 열선에서 벗어나 "세라믹 히터"를 이용하여 원적외선의 방사 및 고효율의 열량을 낼 수 있는 방법과 가전제품에서 가장 전자파가 발생되는 헤어드라이기에 전자파 차폐 기술을 적용하여 고성능 및 다기능성의 요구에 부합하고자 한다.

• 한국연소학회지
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• 제15권3호
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• pp.40-47
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• 2010

Calorific value of mixed gas, like liquefied natural gas (LNG), is strongly depends on its compositions which are affected by the mining place and producing time. The variation in calorific value have an direct influence on the combustion characteristics and performances of boiler, burner, vehicle, power plants etc. Thus, developing experimental method to measure exact calorific value is becoming an issue in the related industrial fields. Flame calorimeter is developed to get calorific value at the dynamic equilibrium state using electric substitution method. Refrigerant-11 carries heat from combustor and/or heater to the Peltier elements which pumped it out to the cooling water. It is found out that error in the measured calorific value of methane is 2.86% compared with the theoretical one. Developed design technique and the experimental data will be applied to design the national standard gas calorific value measuring apparatus.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.250-253
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• 1989

As the necessity of increasing the midnight base load is extensively increased, electric power companies have to increase the demand of midnight electrical power by lowering the electrical charge rate at midnight. One of the most widely used midnight equipments is the heat Storage type's electrical boiler. A Single chip microprocessor controller for the heat-storage type's electrical boiler is developed. This controller call reduce the undesirable peak load at the begining of midnight (i.e.11 P.M.) time band by using backward load control method. Futhermore, this controller enables reservation of heat storge and the effective heating control the field test has been done by use the boiler for 66$m^2$ with the heater of 21KW quality.

• 센서학회지
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• 제29권4호
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• pp.227-231
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• 2020

Silver nanowire random networks are promising candidates for replacing indium tin oxide (ITO) as transparent and conductive electrodes. They can also be used as transparent heating films with self-cleaning and defogging properties. By virtue of the Joule heating effect, silver nanowire random networks can be heated when voltage bias is applied; however, they are unsuitable for long-term use. In this work, we study the Joule heating of silver nanowire random networks embedded in polymers. Silver nanowire random networks embedded in polymers exhibit breakdown under the application of electric current. Their surface morphological changes indicate that nanoparticle formation may be the main cause of this electrical breakdown. Numerical analyses are used to investigate the temperatures of the silver nanowire and substrate.

• 한국초전도ㆍ저온공학회논문지
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• 제14권2호
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• pp.32-35
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• 2012

The objective of the present work is to develop a precise instrument for measuring the thermal property of insulating material over a temperature range from 30 K to near room temperature by utilizing a cryocooler. The instrument consists of two thermal links, a test sample, heat sink, heat source and vacuum vessel. The cold head of the cryocooler as a heat sink is thermally anchored to the thermal link and used to bring the apparatus to a desired temperature in a vacuum chamber. An electric heater as a heat source is placed in the middle of test sample for generating uniform heat flux. The entire apparatus is covered by thermal shields and wrapped in multi-layer insulation to minimize thermal radiation in a vacuum chamber. For a supplied heat flux the temperature distribution in the insulating material is measured in steady and transient state. The thermal conductivity of insulating material is measured from temperature difference for a given heat flux. In addition, the specific heat of insulating material is obtained by solving one-dimensional heat diffusion equation.