• 설비공학논문집
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• 제16권12호
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• pp.1234-1268
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• 2004

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2002 and 2003 has been carried out. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment/design. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation in diverse facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat transfer, humidity was also interesting to promote comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing research topics. Well developed CFD technologies were widely applied for analysis and design of various facilities and their systems. (2) Heat transfer characteristics of enhanced finned tube heat exchangers and heat sinks were extensively investigated. Experimental studies on the boiling heat transfer, vortex generators, fluidized bed heat exchangers, and frosting and defrosting characteristics were also conducted. In addition, the numerical simulations on various heat exchangers were performed and reported to show heat transfer characteristics and performance of the heat exchanger. (3) A review of the recent studies shows that the performance analysis of heat pump have been made by various simulations and experiments. Progresses have been made specifically on the multi-type heat pump systems and other heat pump systems in which exhaust energy is utilized. The performance characteristics of heat pipe have been studied numerically and experimentally, which proves the validity of the developed simulation programs. The effect of various factors on the heat pipe performance has also been examined. Studies of the ice storage system have been focused on the operational characteristics of the system and on the basics of thermal storage materials. Researches into the phase change have been carried out steadily. Several papers deal with the cycle analysis of a few thermodynamic systems which are very useful in the field of air-conditioning and refrigeration. (4) Recent studies on refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement when new alternative refrigerants are applied. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and new alternative refrigerants including natural refrigerants. Efficiency of various compressors and performance of new expansion devices are also dealt with for better design of refrigeration/air conditioning system. In addition to the studies related with thermophysical properties of refrigerant mixtures, studies on new refrigerants are also carried out. It should be noted that the researches on two-phase flow are constantly carried out. (5) A review of the recent studies on absorption refrigeration system indicates that heat and mass transfer enhancement is the key factor in improving the system performance. Various experiments have been carried out and diverse simulation models have been presented. Study on the small scale absorption refrigeration system draws a new attention. Cooling tower was also the research object in the respect of enhancement its efficiency, and performance analysis and optimization was carried out. (6) Based on a review of recent studies on indoor thermal environment and building service systems, it is noticed that research issues have mainly focused on several innovative systems such as personal environmental modules, air-barrier type perimeterless system with UFAC, radiant floor cooling system, etc. New approaches are highlighted for improving indoor environmental conditions and minimizing energy consumption, various activities of building energy management and cost-benefit analysis for economic evaluation.

• 한국학교ㆍ지역보건교육학회지
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• 제1권1호
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• pp.11-43
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• 2000

The purpose of this study was, through analyzing the previous researches, to grasp the present status of environment of school building(ESB), research the sundry records of each element and, through comparative analysis of the standard of ESB in Korea, the United States, and Japan, select the normative standard of ESB, to clarify the point at issue presented in Regulation of Construction & facility Management for Elementary and and Secondary School in Korea, and to suggest an alternative preliminary standard of ESB. To carry out a research for this purpose, these were required: 1. to investigate the existing present status of ESB, 2. to make a comparative analysis of the standard of ESB in each country, 3. to suggest the normative standard of preliminary standard of ESB, 4. to analyze the controversial points of the standard of ESB in Korea, 5. to suggest an alternative preliminary standard of ESB. The conclusions were as follows: 1. Putting, through analyzing the previous researches, the existing present status of ESB together, it seemed that lighting environment, indoor air environment and noise environment were all in poor conditions. 2. In the result of a comparative analysis of the standard of ESB in Korea, Japan and the United States, in Korea the factors of each lighting and indoor air environment were not presented properly, in Japan, in lighting environment aspect, the standard on natural lighting and the factors on brightness were not presented., and in the USA the essential factors of each environment were throughly presented. In the comparison of the standards on each factor, Korea showed that the standard level presented was less properly prescribed than those of the USA and Japan but it also showed that the standard levels prescribed in the USA and in Japan were mostly similar to the standard levels in records investigated. 3. With the result of the normative standard selection on School Builiding environment factor of prescribed in this study, the controversial points of the standard of ESB in Korea were analyzed and the result was utilized to suggest new preliminary standard of ESB. 4. As the result of the analysis of the controversial points of the standard of ESB in Korea, it was found that the standard of ESB in Korea should be established on a basis of School Health Act and be concretely presented in School Health Regulation and School Health Rule. The factors of each environment was improperly presented in the existing standard of ESB in Korea. Moreover the standard of them was inferior to that of the records investigated and those of in the USA and in Japan and it also showed that the standard of it in Korea was improper to maintain Comfortable Learning Environment. 5. A suggested preliminary standard of ESB acquired through above study as follows: 1) In this study a new kind of preliminary standard of ESB is divided into lighting environment, indoor air environment, noise environment, odor environment and for above classification, reasonable factor and standard should be established and the controling way on each standard and countermeasures against it should be considered. 2) In lighting environment, the factors of natural lighting are divided into daylight rate, brightness, glare. In the standard on each factor, daylight rate should secure 5% of a mean daylight rate and 2% of a minimum daylight rate, brightness ratio of maximum illumination to minimum illumination should be under 10:1, and in glare there should not be an occurrence factor from a reflector outside of the classroom. And the factors of unnatural lighting are illumination, brightness, and glare. In the standard on each factor, illumination should be 750 lux or more, brightness ratio should be under 3 to 1, and glare should not occur. And Optimal reflection rate(%) of Colors and Facilities of Classroom which influences lighting environment should be considered. 3) In indoor air environment factors, thermal factors are divided into (1) room temperature, (2) relative humidity, (3) room air movement, (4) radiation heat, and harmful gases (5) CO, (6) $CO_2$ that are proceeded from using the heating fuel such as oval briquettes, firewood, charcoal being used in most of the classroom, and finally (7) dust. In the standard on each factor, the next are necessary; room temperature: $16^{\circ}C{\sim}26^{\circ}C$(summer : $E.T18.9{\sim}23.8^{\circ}C$, winter: $E.T16.7{\sim}21.7^{\circ}C$), relative humidity: $30{\sim}80%$, room air movement: under 0.5m/sec, radiation heat: under $5^{\circ}C$ gap between dry-bulb temperature and wet-bulb temperature, below 1000 ppm of ca and below 10ppm of $CO_2$, dust: below 0.10 $mg/m^3$ of Volume of dust in indoor air, and ventilation standard($CO_2$) for purification of indoor air : once/6 min.(about 7 times/40 min.) in an airtight classroom. 4) In the standard on noise environment, noise level should be under 40 dB(A) and the noise measuring way and the countermeasures against it should be considered. 5) In the standard on odor environment, odor level under Physical Method should be under 2 degrees, and the inspecting way and the countermeasures against it should be considered.

• 한국산업보건학회지
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• 제24권2호
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• pp.122-129
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• 2014

Objectives: Because of its properties such as resistance to heat, chemicals and corrosion; tensile strength; sound absorption; and affordable price, asbestos has been widely used as a building material, fire resistant and retardant, thermal and heat insulator, soundproofing material, and electrical insulation. Since the prolonged inhalation of asbestos can cause serious illnesses such as lung cancer, mesothelioma, and asbestosis after an incubation period of 20 to 40 years, the mineral was classified as a Group 1 carcinogen by the International Agency for Research on Cancer, an intergovernmental agency forming part of the World Health Organization. Children and infants are more at risk than are adults if they are exposed to carcinogens, due to aweaker immunity that has not yet been fully developed. Most childcare centers are operated all day and children tend to spend a great amount of time in the centers. This is why it is important for them to be systematically isolated from environments that may expose them to asbestos. Materials: In order to understand both indoor and outdoor hazards to which children may have been exposed, the study focused on actual surveys of asbestos used in childcare centers, paying special attention to slate-roofed buildings in the vicinity of the centers. Results: A survey of a total of 211 childcare centers showed that the buildings of 18.1% of the centers contained asbestos, with 60.53% of the material being found in classroom ceilings. "Tex" was the most used material for ceilings, making up 89.47% of all ceilings. An outdoor survey showed that childcare centers in Daegu Metropolitan City had an average of 143 slate-roof buildings within a distance of 1km. Conclusions: Buildings housing mainly toddlers, children, teenagers and others more vulnerable to the toxicity of asbestos are not subject to asbestos investigation by law. A legal and practical basis for asbestos control is required for such buildings. In particular, housing materials which contain asbestos in day care centers require asbestos control. GIS should be used to identify the location of buildings with slate roofing materials in the vicinity of daycare centers in order to gauge toxicity of exposure to asbestos caused by potential asbestos friability possibility in outdoor conditions.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.919-924
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• 2008

Power consumption in the building thermal load could be the sum of the building fabric conduction load, building ventilation convection load and other such as radiation loss load. Dynamic Breathing Building (DBB) is the state-of-the-art to improve the wall insulation and indoor air quality(IAQ) performance as making air flow through the wall. This heat recovery type DBB contributes the power consumption saving due to the improved dynamic U-value. KIER twin test cell with static insulation(SI) and dynamic insulation(DI) at KIER was developed to test building power consumption at the real outside conditions. Then, the actual results were compared with the theory to predict the power consumption at the KIER twin test cell and introduced the building new radiation loss factor $\alpha$ to explain the difference between the both the theory and the actual case. As the results, the power consumption at the breathing DI wall building could saved 10.8% at the 2ACH(Air change per hour) compared with conventional insulation. The building radiation loss factor $\alpha$ for this test condition to calibrate the actual test was 0.55 in the test condition.

• 설비공학논문집
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• 제12권12호
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• pp.1098-1125
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• 2000

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 1998 and 1999 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. 1) A review of the recent studies on fluid flow, turbomachinery and pipe-network shows that many experimental investigations are conducted in applications of impingement jets. Researches on turbulent flows, pipe flows, pipe-networks are focused on analyses of practical systems and prediction of system performance. The results of noise reduction in the turbomachinery are also reported. 2) A review of the recent studies on heat transfer analysis and heat exchanger shows that there were many papers on the channel flow with the application to the design of heat exchanger in the heat transfer analysis. Various experimental and numerical papers on heat exchanger were also published, however, there were few papers available for the analysis of whole system including heat exchanger. 3) A review of the recent studies on heat pump system have focused on the multi-type system and the heat pump cycle to utilize treated sewage as the heat source. The defrosting and the frosting behaviors in the fin-tube heat exchanger is experimentally examined by several authors. Several papers on the ice storage cooling system are presented to show the dynamic simulation program and optimal operation conditions. The study on the micro heat pipes for the cooling of high power electronic components is carried out to examine the characteristics of heat and mass transfer processed. In addition to these, new type of separate thermosyphon is studied experimentally. 4) The recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. New systems operating with natural refrigerants are drawing lots of attention. In addition to these, evaporation and condensation heat transfer characteristics of traditional and new refrigerants are investigated for plain tubes and also for microfin tubes. Capillary tubes and orifice are main topics of research as expansion devices and studies on thermophysical properties of new refrigerants and refrigerant/oil mixtures are widely carried out. 5) A review of the recent studies on absorption cooling system shows that numerous experimental and analytical studies on the improvement of absorber performance have been presented. Dynamic analysis of compressor have been performed to understand its vibration characteristics. However research works on tow-phase flow and heat transfer, which could be encountered in the refrigeration system and various phase-change heat exchanger, were seemed to be insufficient. 6) A review of recent studies on duct system shows that the methods for circuit analysis, and flow balancing have been presented. Researches on ventilation are focused on the measurement of ventilation efficiency, and variation of ventilation efficiency with ventilation methods by numerous experimental and numerical studies. Furthermore, many studies have been conducted in real building in order to estimate indoor thermal environments. Many research works to get some information for cooling tower design have been performed but are insufficient. 7) A review on the recent studies on architectural thermal environment and building mechanical systems design shows that thermal comfort analysis is sitting environment, thermal performance analysis of Korean traditional building structures., and evaluation of building environmental load have been performed. However research works to improve the performance of mechanical system design and construction technology were seemed to be insufficient.

• 생물환경조절학회지
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• 제26권3호
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• pp.181-187
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• 2017

간척지 온실의 환경설계 기술 개발을 위한 기초자료 제공을 목적으로, 첨단 시설원예단지 설치 계획이 있는 국내 7개 대규모 간척지 주변의 기후조건을 분석하였으며, 새만금 간척지 내에 설치된 3연동 플라스틱 온실을 대상으로 하절기에 시설 내외의 열적 환경계측 실험을 통하여 자연환기 및 온도 상승 특성을 분석하고, 간척지 온실의 환경 설계에 적용해야 할 부분을 검토하였다. 작물의 유무에 따른 온실의 환기율을 비교한 결과, 작물이 있으면 온실의 환기율은 낮아지지만 작물의 증발산에 의해 실내기온 상승은 감소하는 것으로 나타났다. 작물이 있는 경우 온실의 환기회수는 대체로 0.3~0.9회/min의 범위에 있었고, 평균 0.7 회/min으로 나타났다. 실외기온 대비 실내기온 상승은 $1{\sim}5^{\circ}C$정도의 범위에 있었고, 평균 $2.5^{\circ}C$로 나타났다. 간척지에 설치된 실험온실의 자연환기 성능은 여름철 권장 환기율을 거의 만족시키고, 실외기온 대비 실내기온 상승도 작물재배 환경을 크게 벗어나지 않으므로 새만금 간척지에서는 냉방설비 없이 자연환기 만으로 온실의 작물 재배가 가능할 것으로 판단된다. 간척지는 해안에 위치하고 있어 내륙지역에 비하여 바람이 강하고, 안개가 자주 끼는 특성을 보이는 것으로 나타났다. 이와 같이 강한 풍속은 온실의 환기율을 증가시키므로 냉방부하의 감소요인으로 작용하게 될 것으로 판단된다. 또한 안개지속시간이 내륙지역에 비하여 현저하게 길기 때문에 기간냉방부하는 감소할 것으로 예상되며 이는 냉방설비의 운전경비 측면에서 유리할 것으로 판단된다. 또한 간척지 온실의 환기 및 냉방시스템 설계 시에는 주변의 기상관측소 자료를 그대로 이용하지 말고, 온실 설치 지역에서 실측한 기상자료 또는 현장 여건을 반영하여 보정된 기상자료를 사용하여 설계하도록 할 필요가 있다.

• 한국식품조리과학회지
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• 제31권1호
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• pp.33-40
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• 2015

For the globalization of Korean food restaurants, the kitchens should be equipped with proper ventilation systems and space to keep clean and ensure food safety. This study aimed to examine the ratio of kitchen to total space of restaurant and the suitability of the ventilation systems employed at Korean food restaurants. Data were collected by on-site survey of 12 Korean foods restaurants in Seoul. Length and width of the restaurants were measured with scale. Temperatures and air velocity around the heating equipment, working area, and hood were measured with a thermal imaging camera anemometer and thermometer. Statistical analyses were conducted with the SPSS program. The average space of the restaurants was $25.7m^2$. The ratio of kitchen to space was 0.22 for restaurants sized $32m^2$, 0.28 for $33-66m^2$, 0.21 for $66.1-99m^2$, 0.16 for $99.1-148.5m^2$, and 0.35 for those above $148.5m^2$. Average maximum and minimum air velocity around the hood were 0.28 m/sec and 0.22 m/sec, respectively. Under these conditions, the temperature of the working area was $41^{\circ}C$, presenting an uncomfortable indoor temperature for kitchen employees to work. When classifying 3 groups based on the minimum and maximum air velocity, the temperatures near the cooking area and in the hood of the restaurants showed significant differences among the three groups. When the maximum air velocity was over 0.3 m/sec, the temperature of the cooking area was as $30.1^{\circ}C$, showing a significantly lower temperature (p<0.01). Based on these results, the kitchen space rate of 0.25 to the total space and a ventilation system maintaining a maximum air velocity over 0.3 m/sec were recommended for ensuring the food safety of Korean foods restaurants sized 66 to $99m^2$.

• 설비공학논문집
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• 제14권12호
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• pp.1102-1139
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• 2002

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2000 and 2001 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD technologies were widely applied for developing facilities and their systems. (2) Most of papers related with heat transfer analysis and heat exchanger shows dealt with convection, evaporation, and channel flow for the design application of heat exchanger. The numerical heat transfer simulation studies have been peformed and reported to show heat transfer characteristics. Experimental as well as numerical studies on heat exchanger were reported, while not many papers are available for the system analysis including heat exchanger. (3) A review of the recent studies on heat pump system shows that performance analysis and control of heat pump have been peformed by various simulations and experiments. The research papers on multi-type heat pump system increased significantly. The studies on heat pipe have been examined experimently for change of working characteristics and strut lure. Research on the phase change has been carried out steadily and operation strategies of encapsulated ice storage tank are reported experimentally in several papers. (4) A review of recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. Evaporation and condensation heat transfer characteristics are investigated for tube shapes and new alternative refrigerants. Studies on components of refrigeration/air conditioning system are carried to examine efficiency for various compressors and performance of new expansion devices. In addition to thermophysical properties of refrigerant mixtures, studies on new refrigerants are also carried out, however research works on two-phase flow seemed to be insufficient. (5) A review of the recent studies on absorption cooling system indicates that heat and mass transfer phenomena have been investigated to improve absorber performance. Various experimental data have been presented and several simulation models have been proposed. A review of the recent studies on duct and ventilation shows that ventilation indices have been proposed to quantify the ventilation performance in buildings and tunnels. Main efforts have been focused on the applications of ventilation effectiveness in practice, either numerically using computational fluid dynamics or experimentally using tracer gas techniques. (6) Based on a review of recent studies on indoor thermal environment and building service systems, research issues have mainly focused on many innovative ideas such as underfloor air-conditioning system, personal environmental modules, radiant floor cooling and etc. Also, the new approaches for minimizing energy consumption as well as improving indoor environmental conditions through predictive control of HVAC systems, various activities of building energy management and cost-benefit analysis for economic evaluation were highlighted.

• Asian-Australasian Journal of Animal Sciences
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• 제17권11호
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• pp.1615-1634
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• 2004

A review was undertaken to obtain information on the sustainability of pig free-range production systems including the management, performance and health of pigs in the system. Modern outdoor rearing systems requires simple portable and flexible housing with low cost fencing. Local pig breeds and outdoor-adapted breeds for certain environment are generally more suitable for free-range systems. Free-range farms should be located in a low rainfall area and paddocks should be relatively flat, with light topsoil overlying free-draining subsoil with the absence of sharp stones that can cause foot damage. Huts or shelters are crucial for protecting pigs from direct sun burn and heat stress, especially when shade from trees and other facilities is not available. Pigs commonly graze on strip pastures and are rotated between paddocks. The zones of thermal comfort for the sow and piglet differ markedly; between 12-22$^{\circ}C$ for the sow and 30-37$^{\circ}C$ for piglets. Offering wallows for free-range pigs meets their behavioural requirements, and also overcomes the effects of high ambient temperatures on feed intake. Pigs can increase their evaporative heat loss via an increase in the proportion of wet skin by using a wallow, or through water drips and spray. Mud from wallows can also coat the skin of pigs, preventing sunburn. Under grazing conditions, it is difficult to control the fibre intake of pigs although a high energy, low fibre diet can be used. In some countries outdoor sows are fitted with nose rings to prevent them from uprooting the grass. This reduces nutrient leaching of the land due to less rooting. In general, free-range pigs have a higher mortality compared to intensively housed pigs. Many factors can contribute to the death of the piglet including crushing, disease, heat stress and poor nutrition. With successful management, free-range pigs can have similar production to door pigs, although the growth rate of the litters is affected by season. Piglets grow quicker indoors during the cold season compared to outdoor systems. Pigs reared outdoors show calmer behaviour. Aggressive interactions during feeding are lower compared to indoor pigs while outdoor sows are more active than indoor sows. Outdoor pigs have a higher parasite burden, which increases the nutrient requirement for maintenance and reduces their feed utilization efficiency. Parasite infections in free-range pigs also risks the image of free-range pork as a clean and safe product. Diseases can be controlled to a certain degree by grazing management. Frequent rotation is required although most farmers are keeping their pigs for a longer period before rotating. The concept of using pasture species to minimise nematode infections in grazing pigs looks promising. Plants that can be grown locally and used as part of the normal feeding regime are most likely to be acceptable to farmers, particularly organic farmers. However, one of the key concerns from the public for free-range pig production system is the impact on the environment. In the past, the pigs were held in the same paddock at a high stocking rate, which resulted in damage to the vegetation, nutrient loading in the soil, nitrate leaching and gas emission. To avoid this, outdoor pigs should be integrated in the cropping pasture system, the stock should be mobile and stocking rate related to the amount of feed given to the animals.