• 설비공학논문집
• /
• 제29권3호
• /
• pp.97-104
• /
• 2017

Reinforcement of insulation in apartment buildings reduces the heating and cooling energy consumption by lowering the heat transfer in the building envelope. There are differences between internal and external insulation methods in heat transmission properties. However, some building load calculation programs cannot analysis the differences between the two. This is because these programs do no account for the timelag or thermal storage effect of the wall according to the location of insulation. In this study, the heat transmission characteristics of internal and external insulation were analyzed by EnergyPlus, and heating and cooling energy demand was compared. The results showed that external insulation system had lower heating and cooling loads than internal insulation system. Also the heat transfer rate of external insulation is steadier than internal insulation. About 13.6% of heating and cooling energy demand decreased when the outdoor wall was finished with external insulation compared to the demand with internal insulation.

• 한국지열·수열에너지학회논문집
• /
• 제8권2호
• /
• pp.61-69
• /
• 2012

Geothermal heat pump(GHP) systems have been shown to be an environmentally-friendly, efficient alternative to traditional cooling and heating systems in both residential and commercial applications. Although some experimental work related to performance evaluation of GHP systems with vertical borehole ground heat exchangers for commercial buildings has been done, relatively little has been reported on the performance simulation of these systems. The aim of this study is to evaluate the cooling and heating performance of the GHP system with 30 borehole ground heat exchangers applied to an commercial building($1,210m^2$) in Seoul. For this purpose, a typical design procedure was involved with a combination of design parameters such as building loads, heat pump capacity, circulating pump, borehole diameter, and ground effective thermal properties, etc. The cooling and heating performance prediction of the system was conducted with different prediction methods and then each result is compared.

• 한국전자통신학회논문지
• /
• 제6권5호
• /
• pp.717-722
• /
• 2011

본 논문은 원통형 세라믹관에서 온수를 순간적으로 가열하여 설정된 온도 및 수량으로 제어하고자 전자 제어기를 개발하였다. 순간온수기의 구조는 유입되는 온수가 원통형 세라믹 히터를 통하여 열량을 공급하여 온도를 제어하고자 설계하였고, 또한 수량센서와 임펠러를 이용한 수량을 제어하는 전자 제어기를 설계하였다. 순간온수의 제어방법은 유입되는 유량에 열량을 공급하는 원통형 세라믹 히터의 수학적인 모델링을 수립하여 제어기 적용하였고, 이에 대한 실험결과는 설정온도에 따라 제어가 잘 적용되어, 효율적이고 실용성 결과를 보였다. 따라서 원통형 세라믹 순간온수기는 향후 실용제품에 적용할 수 있는 제품구조와 제어 방법을 제시하였다.

• International Journal of Aerospace System Engineering
• /
• 제2권2호
• /
• pp.50-53
• /
• 2015

It would encounter some complicated flow fields, such as transition, separation, reattachment and disturbances, in the hypersonic flight. Thus, it is difficult to theoretically analyze the hypersonic aerothermodynamics effects, so that the ground-test simulation is thought of as one of the most important methods to improve the understanding level of the hypersonic aerothermodynamics. However, the aero-heating tests could not simulate all aerodynamics and geometry parameters in the real flight due to the differences between the experimental environments supplied by the ground facilities and the flight, so that the feasible technique for the ground-test simulation of the hypersonic aerothermodynamics effects is required to be advanced. The key parameters that are especially required to simulate for aero-heating tests are analyzed and one detailed approach is suggested to perform the experimental investigation on the hypersonic aero-heating effects in the ground facilities in this paper, and the tests are performed in the FD-20 gun tunnel of CAAA (China Academy of Aerospace Aerodynamics) to give out the data which could be used to confirm the equation from the theoretical analysis.

• 대한약침학회지
• /
• 제23권2호
• /
• pp.79-87
• /
• 2020

Objectives: Ginsenosides found in ginseng, and the hydrolysates derived from their conversion, exhibit diverse pharmacological characteristics [1]. These have been shown to include anti-cancer, anti-angiogenic, and anti-metastatic effects, as well as being able to provide hepatic and neuroprotective effects, immunomodulation, vasodilation, promotion of insulin secretion, and antioxidant activity. Therefore, the purpose of this study was to examine how quickly the ginsenosides decompose and what kinds of degradation products are created under physicochemical processing conditions that don't involve toxic chemicals or other treatments that may be harmful. Methods: The formation of ginsenoside-Rg2 and ginsenoside-Rg3 was examined. These demonstrated diverse pharmacological effects. Results: We also investigated physicochemical factors affecting their conversion. The heating temperatures and times yielding the highest concentration of ginsenosides (-Rb1, -Rb2, -Rc, -Rd, -Rf, -Rg1, and -Re) were examined. Additionally, the heating temperatures and rates of conversion of these ginsenosides into new 'ginseng saponins', were examined. Conclusion: In conclusion, obtained provide us with effective technology to control the concentration of both ginsenosides and the downstream converted saponins (ginsenoside-Rg2, Rg3, Rg5, and Rk1 etc.), as well as identifying the processing conditions which enable an enrichment in concentration of these compounds.

• 전력전자학회논문지
• /
• 제24권5호
• /
• pp.365-371
• /
• 2019

This study shows the feasibility of the parameter of the 1st RC parallel equivalent circuit as a factor of the heat generation of lithium-ion cell. The internal resistance of a lithium-ion cell consists of ohmic and polarization resistances. The internal resistances at various SOCs of the lithium-ion cell are obtained via an electrical characteristic test. The internal resistance is inversely obtained through the amount of heat generated during the experiment. By comparing the resistances obtained using the two methods, the summation of ohmic and polarization resistances is identified as the heating factor of lithium-ion battery. Finally, the amounts of heat generated from the 2C, 3C, and 4C-rate discharge experiments and the COMSOL multiphysics simulation using the summation of ohmic and polarization resistances as the heating parameter are compared. The comparison shows the feasibility of the electrical parameters of the 1st RC parallel equivalent circuit as the heating factor.

• 한국지열·수열에너지학회논문집
• /
• 제15권2호
• /
• pp.10-16
• /
• 2019

In this study, the present regulation of heat metering for the ground source heat pump was investigated. The ground source heat pump has been adopting the heat metering system used in the district heating system for estimating the heating and cooling energy production amount. The accuracy of the present heat metering systems for a water to water ground source heat pump is low, because the system for district heating has a relatively high temperature range comparing with the ground source heat pump operating conditions. Even though the heat amount for the building side should be measured, the heat absorption and extraction amount from or to the ground was measured for the water to air ground source heat pump due to the difficulty of estimating the air side heating and cooling capacity in the present regulation. It is highly recommended to validate the heat metering system to have reliability for the ground source heat pump and develop the system to be applicable water to air ground source heat pump.

• 천문학회지
• /
• 제55권6호
• /
• pp.215-220
• /
• 2022

To seek an atmospheric heating mechanism operating on the Sun we investigated a heating source generated by a downflow, both of which may arise in a magnetic loop dynamically formed on the Sun via flux emergence. Since an observation shows that the illumination of evolving magnetic loops under the dynamic formation occurs sporadically and intermittently, we performed a magnetohydrodynamic simulation of flux emergence to obtain a high-cadence simulated data, where temperature enhancement was identified at the footpoint of an evolving magnetic loop. Unlike a rigid magnetic loop with a confined flow in it, the evolving loop in a low plasma β atmosphere is subjected to local compression by the magnetic field surrounding the loop, which drives a strong supersonic downflow generating an effective footpoint heating source in it. This may introduce an energy conversion system to the magnetized atmosphere of the Sun, in which the free magnetic energy causing the compression via Lorentz force is converted to the flow energy, and eventually reduced to the thermal energy. Dynamic and thermodynamic states involved in the system are explained.

• 한국식품조리과학회:학술대회논문집
• /
• 한국식품조리과학회 2003년도 춘계학술대회
• /
• pp.104-104
• /
• 2003

The study was designed to revive and suit flour Dasik(Korean traditional cookies) to modern people's taste. The treatments were used according to the ratio of honey and oligosaccharide(H 100, H75:O25, H50:O50, H25:O75, and 0100) and 3 heating methods. In color, the more the honey, the lower the lightness as well as redness. There were no significant differences in sweetness, but the higher the oligosaccharides, the higher the moistness, hardness, cohesiveness and springiness. (omitted)

• 한국분말재료학회지
• /
• 제16권3호
• /
• pp.167-172
• /
• 2009

This study has been carried out to investigate the non-isothermal behaviors and kinetic parameter of calcium carbonate by different thermal analysis methods. At the heating rate of $10^{\circ}C$/min, the onset calcination temperature, the peak and final temperatures of calcium carbonate were $612^{\circ}C$, $748^{\circ}C$, and $890^{\circ}C$ respectively. As the heating rate of the calcium carbonate increased from $5^{\circ}C$/min to $20^{\circ}C$/min, the peak temperature increased from $719^{\circ}C$ to $782^{\circ}C$. The activation energies of the calcium carbonate calculated by the methods of Kissinger and Freeman-Carroll were 40.15 kcal/mol and 43.47 kcal/mol, respectively.