• Journal of the Korean housing association
• /
• v.3 no.2
• /
• pp.51-61
• /
• 1992

The aims of this study are to imvestigate the changes seen in rural kitchens and the factors affecting the modernization of agrarian kitchen space in mountain areas, and to compare them with those in the plains. The major findings are as follows. 1) The kitchen space in mountain areas remained in the state of a combined style(depicting both western and traditional styles), while the kitchen space in the plains after the 1980s showed a tendency toward the western style. Generally speaking, the physical state of kitchens in mountain farmhouses, therefore, was at a low level in comparison with that of the plains. 2) The kitchen improvement projects of Sae-Ma-Eul Movement fostered a trend toward the western and combined style kitchens in the plains, but it did exert a little influence only on a part of the four mountain areas, and it resu]led in a combination of both styles. 3) Among the socio-demographic characteristics under consideratien. only the level of education achieved by the wi fe was found to be a determinant factor of the kitchen type in the mountain areas. but the level of education achieved by the husband and the family life cycle were two determinant factors in the plains. Under the category of family life style. the factors affecting the kitchen type in the mountain areas were cooking-heating fuel and the position of the refrigerator, while the main factors in p]ains were the place and the method of eating. cooking-heating fuel, the position of refrigerator, and numbers of family-memorials.

• Journal of environmental and Sanitary engineering
• /
• v.7 no.2
• /
• pp.141-152
• /
• 1992

Simple correlation analysis, factor analysis, and multi-verite analysis have been performed to analyze the relationship between air pollution and meteorological factors for air pollution and meteorological data measured at Kwanghwamun in Seoul during the period of one year (January 1990" December 1990). As a result of simple correlation and factor analysis, $SO_2$, TSP and CO concentrations have shown high negative correlation with temperature and among these indicating that these are related with pollutants emission trend based upon heating fuel usage. Ozone has a good correlation with solar radiation and relative humidity to have a closed relation with $0_3$ generation reaction mechanism. The result of multi-variate correlation analysis shows that the concentration of $SO_2$ and CO are adequate for correlation model with ambient temperature and wind speed and 0$_{3}$ concentrations are adequate for that with solar radiation and wind speed. $SO_2$ and CO levels are considered to be affected first of all by heating fuel usage as a emission source and wind speed as a dispersion effect. The $SO_2$ concentration in the condition that the temperature fall below zero is explained by multiplicative model with wind speed, only one variable.

• New & Renewable Energy
• /
• v.16 no.2
• /
• pp.47-53
• /
• 2020

The amount of food waste and its water content depends on both the season and region. In particular, the water content typically varies between 73.8 wt.% and 83.3 wt.%, depending on the proportion of vegetables. Current food waste drying technologies are capable of reducing the water content to less than 10 wt.%, while increasing the heating value. Ongoing studies aim to utilize dried food waste as fuel. Food waste can be used to produce solid refuse fuel (SRF) by mixing it with various solid fuels or other types of waste. The analysis of specimens is very important when considering the direct combustion of food waste or its co-firing with solid fuels. In this study, the weight reduction of specimens after burning them in a small combustor, and compared with the results of thermogravimetric analysis (TGA). The concentration of various chemicals was also measured to define the characteristics of waste generation. Performed proximate analysis, elemental analysis, TGA, combustion experiment, the heating value, and derivative thermogravimetry (DTG).

• Journal of the Korean housing association
• /
• v.22 no.2
• /
• pp.35-42
• /
• 2011

In the energy consumption of buildings in Korea, the housing sector accounts for 53% of a total energy consumption. Although the researches of energy consumption on the new detached houses and apartment houses have been conducted numerous times, the researches of energy consumption characteristics on the existing detached houses are lack of studies. Thus in this study, the actual condition of energy consumption characteristics on the existing detached houses in Daegu city was examined, and then energy consumption unit and green house gas emission unit was compiled to present a fundamental data for an effective way of reducing energy consumption and greenhouse gas emission in the buildings. The results showed that the energy consumption for heating in the existing detached house was greater than other energy consumption and the heating energy sources were city gas and fuel oil. As the fuel oil consumption got larger, the energy consumption unit and greenhouse gas emission unit became bigger. Based on these results, it will be able to develop a plan for reducing energy and greenhouse gas emission in the existing detached houses in the future.

• 한국연소학회:학술대회논문집
• /
• 2015.12a
• /
• pp.131-134
• /
• 2015

국내 천연가스 열량제도를 현행 표준 열량제 $10,400kcal/Nm^3(43.54MJ/Nm^3)$에서 중간 조정기간을 두고 2012.07.01부터는 최저 $10,100kcal/Nm^3(42.28MJ/Nm^3)$을 유지하고 2015년 이후 $9,800(41.1MJ/Nm^3){\sim}10,600kcal/Nm^3(44.4MJ/Nm^3)$ 열량범위제도로 변경 추진되고 있다. 산업현장에서 열량변동을 측정하여 공연비 제어기술을 개발하고자 60ton Al 용해로에 열량대응기술 개발을 위한 내용으로 열량측정시스템설치 및 열량 값과 연계하여 공연비 제어기술개발연구 내용으로 결과는 다음과 같다. 단순히 표준열량으로 에 맞춰 프로그램된 제어로직에 열량변동에서 검출된 신호를 이용하여 연료보정 값을 추가한 로직을 재구성할 필요가 있다. 이 혀장의 경우는 용탕의 온도가 목표온도 근처까지 올리기가 어려워진 상황으로 주로 공급열량 저열량화에 따른 과잉공기영향으로 온도상승이 어려워 보이며 적절한 공연비로 최적화 되면 이러한 문제가 개선되리라 생각된다.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.24 no.5
• /
• pp.1-12
• /
• 2020

In this paper, the heat transfer characteristics of Jet A-1, which is used as a coolant and fuel in a regeneratively cooled thrust chamber, were experimentally studied. By varying the applied current for heating the cooling channel, the simulated specimen diameter, the specimen outlet pressure and the coolant flow rate, the wall temperatures of the specimen and the Jet A-1 temperatures at the specimen inlet/outlet were measured. It was found that the specimen diameter and the flow rate were important factors for the characteristics of heat transfer and the outlet pressure did not affect the performance of heat transfer. The results of the heat transfer experiments were compared with the previous Nusselt number empirical equations and novel Nusselt number empirical equations were finally derived.

• Nuclear Engineering and Technology
• /
• v.54 no.1
• /
• pp.30-35
• /
• 2022

In a nuclear reactor, gamma radiation is the dominant energy deposition in non-fuel regions. Heat is generated upon gamma deposition and consequently affects the mechanical and thermal structure of the material. Therefore, the safety of samples should be carefully considered so that their integrity and quality can be retained. To evaluate relevant parameters, an in-core gamma thermometer (GT) was used to measure gamma heating (GH) throughout the operation of the McMaster nuclear reactor (MNR) at four irradiation sites. Additionally, a Monte Carlo reactor physics code (Serpent-2) was utilized to model the MNR with the GT located in the same irradiation sites used in the measurement to verify its predictions against measured GH. This research aids in the development of modeling, calculation, and prediction of the GH utilizing Serpent-2 as well as implementing a new GH measurement at the MNR core. After all uncertainties were quantified for both approaches, comparable GH profiles were observed between the measurements and calculations. In addition, the GH values found in the four sites represent a strong level of radiation based on the distance of the sample from the core. In this study, the maximum and minimum GH values were found at 0.32 ± 0.05 W/g and 0.15 ± 0.02 W/g, respectively, corresponding to 320 Sv/s and 150 Sv/s. These values are crucial to be considered whenever sample is planned to be irradiated inside the MNR core.

• Nuclear Engineering and Technology
• /
• v.55 no.7
• /
• pp.2454-2465
• /
• 2023

Film boiling may lead to burnout of the heating element. Even though burnout does not occur, the heating element is subject to deformation because it is not sufficiently strong to withstand external loads. In particular, the ballooning and rupture of a tube under film boiling are important phenomena in the field of nuclear reactor safety. If the tube-type cladding of nuclear fuel ruptures owing to high internal pressure and thermal load, radioactive materials inside the cladding are released to the coolant. Therefore, predicting the ballooning and rupture is important. This study presents numerical simulations to predict the ballooning behavior and rupture time of a horizontal tube at high internal pressure under saturated film boiling. To do so, a multi-step coupled simulation of conjugated film boiling heat transfer and ballooning using creep model is adopted. The numerical methods and models are validated against experimental values. Two different nonuniform heat flux distributions and four different internal pressures are considered. The three-step simulation is enough to obtain a convergent result. However, the single-step simulation also successfully predicts the rupture time. This is because the film boiling heat transfer characteristics are slightly affected by the tube geometry related to creep ballooning.

• Journal of the Korean Applied Science and Technology
• /
• v.33 no.2
• /
• pp.264-270
• /
• 2016

This Study is to into fuel using a torrefation reaction to food waste. When the fuel of only food waste alone, fuel value is was performed at a ratio of sewage sludge constant attempts to prevent low. Mixing ratios of food waste and sewage sludge, 10:0, 8:2, 6:4, 5:5. Regardless mixing ratio, it was possible to confirm that decreases the moisture content of 10% or less at a reaction temperature of $240^{\circ}C$ or higher. As the ratio of the reaction temperature and the sewage sludge is high, the fixed carbon content is increased. It was measured at up to 36%(mixing ratios6:4, reaction temperature $270^{\circ}C$) from the initial 1.1%. From the reaction temperature $240^{\circ}C$ satisfied with 3000Kcal/Kg or more is a SRF criteria shows the calorific value. It was possible to obtain a heating value that is increased from the raw sample approximately sextuple. As reaction temperature is heightened, Van krevelen Diagram moved to the range of Lignite range. It was possible to obtain high fuel ratio and 5,500Kcal/kg or less of a combustility index as the sewage sludge mixing ratio becomes high. Increase the fixed carbon content, than those food waste alone solid fuel into and improved fuel costs, it is necessary to ensure that the quality of the fuel is improved.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.23 no.4
• /
• pp.63-73
• /
• 2015

This study was carried out to evaluate the change of heating value of cow manure by applying pre-treatment process. Three types of treatment precess; Composting, Dry anaerobic digestion and Physical compression were applied as a pre-treatment method. Composting and anaerobic digestion of cow manure were cause of caloric value reduction of the cow manure. The heating value of cured compost was 5% lower than that of initial composting material. The heating value of dry anaerobic digestion residue was 25.7% lower than that of fresh cow manure. By physical compression of cow manure, heating value and VS/TS ratio (Volatile solids/Total solids ratio) of compressed cow manure were higher than that of fresh cow manure. On the other hand, heating value and VS/TS ratio of leachate generated by compression process were lower than those of fresh cow manure.