• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.1209-1214
• /
• 2009

Various automatic temperature control systems have been used widely in Korea for the conservation of heating energy and the enhancement of thermal comfort in residential buildings. But the heating control performance for automatic temperature control systems extensively vary with the design and operational conditions of the heating system, the climate condition and others. It was introduced in this study a numerical calculation program package to analyze heating control characteristics of the automatic temperature control system. This package is able to analyze the room air temperature, return water temperature, supplied heating flux and flow rate, and so on. One the other hand, the simulation results were verified by comparing with the field test results.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2007년도 동계학술발표대회 논문집
• /
• pp.161-166
• /
• 2007

Various thermostatic valves have been used widely in Korea for conservation of heating energy and enhancement of thermal comfort in residential buildings. But heating control performances of thermostatic valves extensively vary with the design and operational conditions of the heating system, climate condition and others. An experimental method was carried out in this study to analyze heating control characteristics by temperature sensing methods of thermostatic valves for various parameters, such as supply temperatures and flow rate of hot water, the position of room thermostats and outdoor air temperatures. As a result, the heat flow rate per day of S-Valve($34^{\circ}C$-Type) of water temperature sensing method was liked that of C-Valve of indoor air temperature sensing method with stage 3.3 of room thermostat in case supply temperature of hot water was $45^{\circ}C$, flow rate was 1.3 L/min and outdoor air temperature was $7.8^{\circ}C$.

• 한국통신학회논문지
• /
• 제42권3호
• /
• pp.698-701
• /
• 2017

현재 우리나라의 130만여 가구는 지역난방 열에너지를 사용하고 있다. 이러한 지역난방 열에너지 시스템은 한국지역난방공사에서 공급하는 1차측과 이를 개별 가구에 공급하는 2차측으로 구분되어 있다. 본 논문에서는 체계적이지 않고, 전문인력에 대한 의존도가 높은 2차측의 관리 및 유지보수 시 문제점을 보완하기 위한 IoT 기반 열에너지 원격 관리시스템의 구축에 대하여 논의한다.

• Nuclear Engineering and Technology
• /
• 제50권7호
• /
• pp.1079-1087
• /
• 2018

There are many parameters that affect the natural circulation flow, such as height difference, heating power size, pipe diameter, system pressure and inlet temperature and so on. In general analysis the heating power is often regarded as a uniform distribution. The ANSYS-CFX numerical analysis software was used to analyze the flow heat transfer of supercritical water under different heating power distribution conditions. The distribution types of uniform, power increasing, power decreasing and sine function are investigated. Through the analysis, it can be concluded that different power distribution has a great influence on the flow of natural circulation if the total power of heating is constant. It was found that the peak flow of supercritical water natural circulation is maximal when the distribution of heating power is monotonically decreasing, minimal when it is monotonically increasing, and moderate at uniform or the sine type of heating. The simulation results further reveal the supercritical water under different heat transfer conditions on its flow characteristics. It can provide certain theory reference and system design for passive residual heat removal system about supercritical water.

• 한국에너지공학회:학술대회논문집
• /
• 한국에너지공학회 2008년도 춘계학술 발표회
• /
• pp.143-148
• /
• 2008

• Food Science and Biotechnology
• /
• 제16권5호
• /
• pp.836-842
• /
• 2007

In this study, we investigated the effects of heating ($80^{\circ}C$, 30 min) on the physicochemical and functional attributes of acid (cottage) and sweet (Edam and Cheddar) whey powders. The water holding capacity (WHC) of the whey powders was not affected by heating or pH value. The heated Cheddar whey powder had a significantly lower (p<0.05) WHC than that of the other wheys. Heating detrimentally impacted the emulsifying and foaming properties, On the other hand, heating significantly enhanced the heat stabilities (HS) of all powders, This was best demonstrated at the acidic pH values of 3.0 and 4.5, where the HS increased by 57 and 53, 181 and 167, and 31 and 48%, for the cottage, Edam, and Cheddar, respectively. Overall, this data provides useful insights into the manufacture of pasteurization and retort-stable whey powders.

• 설비공학논문집
• /
• 제21권8호
• /
• pp.456-461
• /
• 2009

Recently, an increasing interest in district heating system has emerged rapidly, In this paper, the physical measurements and data to be monitoring through the internet were carried out with regard to hot water heating energy consumption at the three apartment housings with district heating system in Sang-am district of Seoul, Korea, Measurements were made of the thermal factors such as the pressure of heating pipe, flow rates, hot water temperature and etc, The objective of this study is to compare the design capacity of reheat exchanger with that of preheat exchanger in order to evaluate for the number of plates of two exchangers to be distributed properly.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2007년도 동계학술발표대회 논문집
• /
• pp.105-112
• /
• 2007

Recently developed raised floor heating system is not only capable of basic function to reduce noise between floors, but also is a multi-functional floor heating system enabling natural ventilation. The procedure of this system for natural ventilation is to import outdoor air through bottom space of the floor heating system, circulate indoor space and discharge it out of ceiling. In winter, powerless natural ventilation is possible with buoyancy effect caused by temperature difference between outdoor and indoor. And it also allows saving of energy by importing pre-heated air in bottom space of the floor heating system. To evaluate ventilation performance of this system, on-site measurement was conducted in 2 test laboratories, and the nominal air change rate was satisfied as 0.4$\sim$0.8 h-1 under the condition of outdoor temperature $5^{\circ}C{\sim}-5^{\circ}C$, which was evaluated as highly possible to be applied as a natural ventilation system in multi-family houses.

• Nuclear Engineering and Technology
• /
• 제54권2호
• /
• pp.469-478
• /
• 2022

Tritium was extracted from tritium-contaminated aluminum samples by heating it in a high-temperature furnace at 200, 300, or 400 ℃ for 15 h. The extracted tritium was analyzed by using a liquid scintillation counter (LSC); the sample thicknesses were 0.4 and 2 mm. The differences in tritium extraction over time were also investigated by cutting aluminum stick samples into several pieces (1, 5, 10, and 15) with the same thickness, and subsequently heating them. The results revealed that there are most of the hydrated material based on tritium on the surface of aluminum. When the temperature was increased from 200 or 300 ℃-400 ℃, there are no large differences in the heating duration required for the radioactivity concentration to be lower than the MDA value. Additionally, at the same thickness, because the surface of aluminum is only contaminated to tritiated water, cutting the aluminum samples into several pieces (5, 10, and 15) did not have a substantial effect on the tritium extraction fraction at any of the applied heating temperatures (200, 300, or 400 ℃). The proportion of each tritium-release materials (aluminum hydrate based on tritium) were investigated via diverse analyses (LSC, XRD, and SEM-EDS).

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.497-501
• /
• 2009

Effect of angle of supply air on cooling and heating performances of office space is studied by numerical simulation. For a constant air volume(CAV) air-conditioning system, air is supplied vertically($90^{\circ}$) and horizontally($10^{\circ}$). Due to buoyancy, the supply angle affects the performance of cooling and heating. In cooling, since the cold supply air tends to move downward due to its high density, horizontal supply angle is better for uniform temperature distribution. In heating, however, vertical supply angle is preferred for better mean and uniform temperature distribution.