• 설비공학논문집
• /
• 제3권4호
• /
• pp.276-285
• /
• 1991

The transient heat transfer characteristics in the radiant heating panel were predicted by numerical analysis. Thermal behaviors of panel, such as temperature distributions in panel and convective and radiative heat fluxes in panel surface with respect to time were obtained. Heating hours per day, rate of energy supplied and maximum temperature differences at panel surface were also compared for several important parameters. The performance and thermal comfort of heating panel were studied and compared for various operating and design conditions such as pipe pitch, pipe location, pipe diameter and flow rate of hot water for the purpose of producing useful data, which can be used for the test and decision of efficient operating condition of the conventional heating systems or the optimal design of the new panel heating systems.

• 설비공학논문집
• /
• 제24권12호
• /
• pp.830-836
• /
• 2012

In this study, the effects of heating control methods on heating control performance and energy consumption in the floor radiant heating control system of residential apartments were research by computer simulation. A general regression neural network(GRNN) control method for reducing indoor temperature overshoot and saving energy in floor radiant heating system is suggested. The GRNN control method shows good responses in comparison with the conventional and outdoor reset control methods for improving indoor thermal environment and reducing energy consumption.

• 전기학회논문지
• /
• 제67권12호
• /
• pp.1602-1610
• /
• 2018

Induction heating can convert electrical energy to thermal energy with high conversion efficiency and quick heating. Currently, a current source rectifier/inverter-fed parallel resonant circuit is widely used as an induction heating power supply for forging applications. However, the conventional induction heating power supplies composed of phase-controlled rectifier and SCR inverter have low efficiency and low power factor at input side, and require additional starting circuitry. So this paper proposes new induction heating power supply topologies for forging applications which have high power factor, high efficiency, and large output power. It also suggests detailed design guideline.

• 설비공학논문집
• /
• 제24권2호
• /
• pp.183-189
• /
• 2012

Most of the domestic residential buildings have used the traditional radiant heating system, circulating hot water through the cross-linked polyethylene(PE-X) pipe buried in the floor panel of the heating space. New type of the heating panel was recently developed using heat pipes with double wicks. Some experiments were carried out in this study to verify the thermal characteristics of this heating system at the unit heating space which surrounded by outer space whose temperature of air be maintained scheduled value with time. Through the various experiments with several parameters, such as flow rate, inlet and outlet temperatures of hot water and the heating duration and so on, we found that the floor heating system with heat pipes was able to reduce the pumping power for hot water circulation by 4~31% compared with the conventional panel heating system using PE-X pipe. These results could be used for optimal design and efficient operation of the heating system as well as improvement of thermal comfort.

• 플랜트 저널
• /
• 제17권1호
• /
• pp.50-57
• /
• 2021

수력학적 효율측정 방법만으로는 펌프시스템 부속장치들의 개별효율 및 펌프 자체효율을 명확하게 산출해내기 매우 어렵다. 이에 본 연구에서는 국내 최초로 지역난방 중온수용 펌프시스템에 최신 열역학적 펌프 효율측정방법을 도입, 수력학적 방법과의 효율 병행측정 결과를 검토하였고, 그 결과 기존 수력학적 펌프효율 측정방법만으로는 데이터 불확실성이 높은 반면, 열역학적 및 수력학적 방법 병행측정 데이터를 적용한 펌프 및 유체커플링 효율값은 상호보완적 역할수행에 의해 펌프성능 측정방법의 신뢰성 및 적정성이 검증되는 의미 있는 결과를 도출할 수 있었다. 또한, 지역난방시스템에 열역학적 펌프효율 측정방법을 적용한 결과, 최대 120 ℃ 고온 환경에도 불구, 매우 안정적인 데이터 측정 및 측정장비의 내구성이 검증되는 등 열역학적 측정방법의 신뢰성을 검증할 수 있었다.

• 한국식품저장유통학회지
• /
• 제4권3호
• /
• pp.337-341
• /
• 1997

Texture is an important quality factor of processed chestnut products, which changes depending on the conditions of boiling process. The conventional boiling process consists of three stage(1st : 70 minutes at 60$^{\circ}C$; 2nd : 20minutes at 70$^{\circ}C$; 3rd : 80minutes at 98$^{\circ}C$). To improve the conventional boiling process of processed chestnut products, we investigated the changes of texture at different stages of boiling process and undertook the optimization of boiling process by response surface method on heating times of 2nd and 3rd heating, and amount of softening agent. The initial hardness and cohesiveness, the most important textural characteristics of chestnut, were 7.876kg and 0.189, respectively. In the third boiling stage, hardness decreased to 0.313kg and cohesiveness increased to 0.310. Using response surface method the minimum point of hardness and maximum point of cohesiveness was examined and model equations for predicting the changes of hardness and cohesiveness in the optional boiling condition were developed.

• 한국세라믹학회지
• /
• 제32권3호
• /
• pp.331-340
• /
• 1995

Microwave (Hybrid) Heating (MHH) was used to oxidize and sinter Al-Al2O3 powder mixture. For 25 v/o Al specimen and 35 v/o Al specimen, the total processing to produce low-shrinkage reaction bonded alumina was carried out within 1 hour even though conventional furnace process took more than 10 hours. Compared with conventional fast firing process, MHH process increased more than 40% oxidation at the same temperature, and these high oxidation rates were thought to be caused by the surface ohmic current on Al particles.

• 소성∙가공
• /
• 제22권1호
• /
• pp.48-53
• /
• 2013

As the adoption of injection molding technology increases, injected-molded optical products require higher dimensional accuracy and optical stability than ever before. In the present study, four kinds of molding methods, i.e., conventional injection molding (CIM), injection/compression molding (ICM), rapid heat and cooling the mold(RHCM) and rapid injection/compression molding (RICM) were selected in order to investigate the optical anisotropy of a 7 inch Light Guide Plate(LGP) by examining the gap-wise distribution of birefringence and the extinction angle. The results indicate that the compression process can decrease flow-induced birefringence over the whole region and that rapid heating can decrease the birefringence level better than conventional molding. In addition, for the combination of compression and rapid heating a reversal flow was detected from the distribution of the extinction angle near the gate.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
• /
• pp.1021-1024
• /
• 2008

콘크리트의 내부 공극을 검출로 열화상기법 적용시 일반적으로 쓰이는 열원인 자연광, 할로겐램프, 열풍과 달리 본 논문에서는 근적외선 히터를 이용하였다. 이 기법에 의한 실험 결과를 각 공극 깊이와 공극 크기별로 무차원 상대 온도로 나타내어 콘크리트 내부 공극의 식별 가능 여부를 조사하였다. 본 실험의 결과, 할로겐램프나 원적외선램프 열원에 비하여 대상 물체를 단시간 내에 가열하여 콘크리트 내부 공극 검출 시간이 상대적으로 짧은 것으로 확인되었다.

• 설비공학논문집
• /
• 제24권4호
• /
• pp.289-296
• /
• 2012

The aim of this study is to investigate the performance of a heating and cooling system with aquifer thermal energy storage(ATES heat pump system) known as one of the underground thermal energy storage application systems. The ATES system was composed of heat pump unit and ATES, which was installed in a factory building located in Anseoung. The system represented very high heating and cooling performance, and showed nearly constant COP at each heating and cooling season due to the stability of EWT. The economic analysis about an ATES system and a conventional system was also executed. The conventional system adopted an air-conditioner in the summer season and a LNG boiler in the winter season. The payback period of the ATES system was estimated by 6.62 years.