도시환경개선을 위한 산림 기반 바람길 관리 계획- 낙동정맥을 사례로 -

성욱제,손정민,엄정희,민진규 한국지리정보학회 2023 한국지리정보학회지 Vol.26 No.1

This study analyzed the cold air characteristics of the Nakdong Jeongmaek, which is advantageous for the formation of cold air that can flow into the city, in order to suggest the wind ventilation corridor plans, which have recently been increasing interest as a way to improve the urban thermal environment. In addition, based on the watershed analysis, specific cold-air watershed areas were established and management plans were suggested to expand the cold air function of the Nakdong Jeongmaek. As a result of the analysis of cold air in the Nakdong Jeongaek, cold air was strongly generated in the northern forest of the Jeongamek, and flowed into nearby cities along the valley topography. On average, the speed of cold air was high in cities located to the east of the Jeongmaek, while the height of cold air layer was high in cities located to the west. By synthesizing these cold air characteristics and watershed analysis results, the cold-air watershed area was classified into 8 zones, And the plans were proposed to preserve and strengthen the temperature reduction of the Jeongmaek by designating the zones as‘Conservation area of Cold-air’,‘Management area of Cold-air’, and ‘Intensive management area of Cold-air’. In addition, in order to verify the temperature reduction of cold air, the effect of night temperature reduction effect was compared with the cold air analysis using weather observation data. As a result, the temperature reduction of cold air was confirmed because the night temperature reduction was large at the observation station with strong cold air characteristics. This study is expected to be used as basic data in establishing a systematic preservation and management plan to expand the cold air function of the Nakdong Jeongmaek. 본 연구는 도시 환경 개선을 위한 방안으로 최근 관심이 높아지고 있는 바람길 관리방안을 제안하고자, 도시로 유입될 수 있는 찬공기 형성에 유리한 낙동정맥을 대상으로 찬공기 특성을 분석하였다. 또한 유역 분석을 기반으로 낙동정맥의 구체적인 바람길 유역을 설정하고 유역별 찬공기 기능 확대를 위한 방안을 제안하였다. 낙동정맥의 찬공기 분석 결과, 찬공기는 낙동정맥의 북부 산림에서 강하게 생성되었으며, 계곡 지형을 따라 인근 도시로 유입되었다. 평균적으로는 낙동정맥의 동쪽에 위치한 도시에서 찬공기 풍속이 높았으며, 반면 서쪽에 위치한 도시에서는 찬공기층 높이가 높게 나타났다. 이러한 찬공기 특성 및 유역 분석 결과를 종합하여 낙동정맥의 바람길 관리유역을 8개로 분류하였으며, 이를‘찬공기 기능 보전유역’,‘찬공기 기능 관리유역’,‘찬공기 기능 집중관리구역’으로 설정하여 정맥의 기온 저감 기능을 보전 및 강화하기 위한 방안을 제안하였다. 또한, 찬공기의 기온 저감 기능을 검증하고자 기상관측 정보를 활용하여 야간 기온 저감 효과를 찬공기 분석 결과와 비교하였다. 그 결과 찬공기 특성이 강한 지점의 관측소에서 야간 기온 저감 효과가 상대적으로 크게 나타나 찬공기의 기온 저감 기능을 확인할 수 있었다. 본 연구의 결과는 낙동정맥의 찬공기 기능 확대를 위한 체계적 보전 및 관리계획 마련 시 기초자료로 활용될 수 있을 것으로 기대한다.

바람길 활용을 위한 정맥의 찬공기 관리 방안 - 낙남정맥을 사례로 -

엄정희 ( Jeong-hee Eum ) 한국지리정보학회 2019 한국지리정보학회지 Vol.22 No.1

As urban heat environment problems occur due to climate change, urban thermal environmental problems such as heat waves and tropical nights are becoming more serious in cities. In South Korea, forest areas favorable for generating cold air account for about 63 percent of the land area. Furthermore, the Jeongmaek, the axis of the main mountain ranges of Korea, is located close to the cities. Hence, the management of cold air is an effective way to improve the thermal environment of Korean cities. We selected the Nak-nam Jeongmaek located in the southern part of Korean Peninsular as well as two cities (Jinju-si and Sancheong-gun) located at the Jeongmaek to analyze its cold air characteristics and suggest management strategies of cold air. We used KALM (Kaltluftabflussmodell), a cold air simulation model developed in Germany and identified both the cold air flow and the height of cold air layer generated during 6 hours at night. As a result, the cold air flow generated in the Jeongmaek became clear and the height of cold air layer increased with time. Based on the results, we proposed management plans to maintain and expand the cold air flow. For example, forest areas with active cold air generation were designated as‘cold air conservation areas’, and areas requiring management for good cold air flow were as‘cold air management areas’. This study is expected to be useful for establishing systematic urban ventilation plan to improve thermal environment in Korea cities.

LNG 냉열을 이용한 공기액화분리시스템의 시뮬레이션 및 공정 해석

한단비,백영순 한국수소및신에너지학회 2019 한국수소 및 신에너지학회논문집 Vol.30 No.3

The process of separating oxygen and nitrogen from the air is mainly performed by electric liquefaction, which consumes a lot of electricity, resulting in higher operating costs. On the other hand, when used for cold energy of LNG, electric power can be reduced compared to the electric Linde cycle. Currently, LNG cold energy is used in the cold refrigeration warehouse, separation of air-liquefaction, and LNG cold energy generation in Japan. In this study, the system using LNG cold energy and the Linde cycle process system were simulated by PRO/II simulators, respectively, to cool the elevated air temperature from the compressor to about –183°C in the air liquefaction separation process. The required amount of electricity was compared with the latent heat utilization fraction of LNG, the LNG supply pressure, and the LNG cold energy usage. At the air flow rate of 17,600 m3/h, the power source unit of the Linde cycle system was 0.77 kWh/m3, compared with 0.3 kWh/m3.

냉풍 및 적외선 건조에 따른 건조 복숭아의 품질 특성

이혜림 ( Hye Lim Lee ),윤광섭 ( Kwang Sup Youn ) 한국식품저장유통학회(구 한국농산물저장유통학회) 2012 한국식품저장유통학회지 Vol.19 No.4

This study was conducted to investigate the pH, soluble solid contents, color difference, mineral contents, free sugar contents, and sensory quality of infrared- and cold-air-dried peaches. The pH, soluble solid contents, and free sugar contents of the infrared-dried peaches were higher than those of the cold-air-dried peaches. In the Hunter`s color value, the L and ΔE values of the infrared-dried peaches were higher than those of the cold-air-dried peaches; but the a and b values of the cold-air-dried peaches were higher than those of the infrared-dried peaches. The major organic acids of the dried peaches were citric acid, malic acid, and oxalic acid. The minerals with the highest to lowest contents, in that order, were K, Mg, Ca, Na, Fe, Zn, Cu, and Al. The mineral contents of the cold-air-dried peaches were higher than those of the infrared-dried peaches. The appearance and taste of the infrared-dried peaches were better than those of the cold-air-dried peaches. These results indicate that infrared drying is the effective drying method for the production of high-quality dried peaches.

LNG 냉열이용 액체수소 제조공정의 예냉 및 Cold box의 성능 개선 연구

윤상국,윤나은 한국가스학회 2020 한국가스학회지 Vol.24 No.4

For the hydrogen liquefaction, the large amount of energy is consumed, due toprecooling, liquefaction and o-p conversion processes. The aim of this work is to improve theperformance of hydrogen liquefaction process by introducing the new energy saving processes,that are the liquid nitrogen precooling process by using LNG cold energy, and the new designof cold box insulation using cold air circulation. The results show that the indirect use of LNGcold energy in precooling process enables not only to get energy saving, but to make saferoperation of liquefaction plant. In new cold box, the energy loss of equipments could be reducedby nearly 35%~50% compared to the present perlite insulation, if insulation structureis organised as 3mm steel wall/20cm PUF/5cm air/20cm PUF/equipment. Additionally theequipments installed in cold box can get cooling effect, if the temperature is higher than thetemperature of cold air. The application of this results can gives to increase the liquid yieldof about 50% substantially in industrial hydrogen liquefaction plant. 수소의 액화에는 예냉 에너지, 상변화 에너지, 수소 변환열 제거 등 다량의 에너지가 요구되어진다. 본 논문의 목적은 예냉공정에 필요한 에너지로 LNG냉열로 액체질소를 제조하여 사용하는 LNG냉열 간접 이용 방식과, Coldbox의 단열에 냉공기를 이용하는 새로운 에너지절약 공정을 제안하여 수소액화 수율을 향상시키고자 하였다. 분석 결과를 보면, LNG냉열 간접이용 방식은 에너지 절약과 함께 액체수소 플랜트의 안전성을 제공하는 장점을 갖는다. 새로운 Cold box 단열 방식은 외벽 철판 3mm/우레탄폼 20cm/공기 5cm/우레탄폼 20cm/설비의 구조일 때 현재펄라이트 단열에 비교하여 열유입량이 약 35%~50%가 감소하게 된다. 또한 냉공기 보다 온도가 높은 설비는 냉각의 효과를 얻게 된다. 수소액화 플랜트의 공정에 본 결과를 적용한다면 액체 수율이 50% 내외로 크게 향상되는 효과를 제공하게 된다.

냉각에너지를 활용한 바람길 구성요소 분류 - 대구광역시를 사례로 -

성욱제,엄정희 한국조경학회 2023 韓國造景學會誌 Vol.51 No.5

최근 산림청이 기후 변화 대응 대책으로써 지자체 바람길숲 조성 사업을 시행함에 따라 다양한 바람길에 대한 연구가 수행되어 오고 있다. 바람길숲 조성을 위해서는 바람길 기능에 대한 평가가 선행되어야 한다. 하지만, 현재 바람길을 직접적으로 평가하고, 바람길의 유형에 따라 공간을 구분할 평가 지표가 없어 간접적인 지표를 기준으로 분석을 수행하고 있다. 따라서 본 연구에서는 냉각에너지 분석을 찬공기 생성에 대한 평가 지표로 활용함으로써 바람길을 평가 및 분류하는 방법을 제안하였다. Kaltluftabflussmodell_21(KLAM_21)이라는 찬공기 분석 모형을 활용하여 냉각에너지 분석을 하였다. 그리고 시뮬레이션 분석 결과에 따라 바람길을 찬공기 생성지역, 찬공기 취약지역, 찬공기 유동지역으로 분류하였다. 냉각에너지량을 기준으로 상위 5퍼센트를 찬공기 생성지역, 하위 5퍼센트를 찬공기 취약지역으로 분류하였다. 또한 찬공기 유동지역은 찬공기 생성지역에서 이동하는 찬공기의 흐름을 파악하여 분류하였다. 분석 결과, 대구광역시의 바람길 6개의 바람 생성지역이 존재하며, 찬공기 취약지역은 시가지 내부에 집중되어 있었고, 찬공기 유동지역은 대구광역시의 주요 하천과 도로를 따라 형성되어 있었다. 본 연구의 방법론을 통해 바람길의 효과를 정량적 평가 방법으로 활용될 수 있을 것으로 기대된다. 또한 바람길숲 조성 사업지 선정에 제시할 수 있는 평가 지표로 활용될 것으로 판단된다. Recently, the Korea Forest Service has implemented a planning project about wind corridor forests as a response measure to climate change. Based on this, research on wind corridors has been underway. For the creation of wind corridor forests, a preliminary evaluation of the wind corridor function is necessary. However, currently, there is no evaluation index to directly evaluate and spatially distinguish the types of wind corridors, and analysis is being performed based on indirect indicators. Therefore, this study proposed a method to evaluate and classify wind corridors by utilizing heat deficit analysis as an evaluation index for cold air generation. Heat deficit was analyzed using a cold air analysis model called Kaltluftabflussmodell_21 (KLAM_21). According to the results of the simulation analysis, the wind path was functionally classified. The top 5% were classified as cold-air generating Areas (CGA), and the bottom 5% as cold-air vulnerable Areas (CVA). In addition, the cold-air flowing Areas (CFA) were classified by identifying the flow of cold air moving from the cold air generation area. It is expected that the methodology of this study can be utilized as an evaluation method for the effectiveness of wind corridors. It is also anticipated to be used as an evaluation index to be presented in the selection of wind corridor forest sites.

대관령에서의 기온 급하강 사례에 대한 기상학적인 연구

이재규,김유진,Lee. Jae Gyoo,Kim. Yu Jin 한국방재학회 2014 한국방재학회논문집 Vol.14 No.1

일기도, 위성영상, AWS 관측 자료, 단열선도, GDAS FNL 분석자료를 이용하여, 대관령 관측소에서 2013년 4월 16일에 일어난 짧은 시간동안의 극심한 기온 하강(9분 동안에 약 <TEX>$15.5^{\circ}C$</TEX>의 기온 하강) 현상이 발생한 이유를 분석하여 종합하면 다음과 같다. 첫째, 남서 기류의 유입과 일중 일사 가열로 영서 및 대관령에서는 지속적인 기온상승이 있는 반면에, 영동 해안지대에서는 북동쪽에서 내려 온 찬공기의 이류로 저온 현상이 일어나는 중이었으며, 둘째, 이러한 상태에서 영동과 영서지역을 분리하는 태백산맥의 지형에 의해, 영서지역과 영동지역 사이의 열 교류가 억제되어 영서지역에서는 지속적인 기온 상승내지는 유지가 이루어졌으며, 영동지역에서는 찬 공기의 이류에 따른 저온 현상이 계속 유지되어 영동과 영서지역의 기온 차이가 크게 증가하였다. 셋째, 시간이 지남에 따라 기압골이 동진하여 이 기압골이 울릉도 부근에 위치함에 따라 이 기압골의 후면에 해당하는 동한만과 영동 동해안에서는 이전 시간보다도 북동 기류가 더욱 더 강해져 영동지역에서는 찬 공기의 누적이 보다 더 강화되었으며, 이렇게 누적된 찬 공기가 북동 기류를 따라 대관령을 넘어 서쪽으로 이동하여 대관령 부근에 위치하였던 따뜻한 공기를 빠르게 대체하였기 때문에 대관령 관측소에서 짧은 시간동안에 가장 극심한 기온 하강 현상이 일어나게 되었다. From the analysis of weather charts, satellite imagery, AWS (Automatic Weather Station) observation data, skew T-log P diagram and GDAS (Global Data Assimilation System) FNL (Final analyses) data, we could infer the reasons for the sharp drop over a short amount of time (<TEX>$-15.5^{\circ}C$</TEX>/9 minutes) in surface temperatures at the Daegwallyeong observation station on 16 April 2013 as follows: (1) there was a continuous temperature increase near the Daegwallyeong area under the influence of the warm southwestern air current and solar radiation in the daytime. Meanwhile, there was a steady temperature decrease over the Yeongdong coastal area due to the cold-air advection form the northeast, (2) under this circumstance, the topography of the Taebaek Mountains separating the Yeongseo and Yeongdong Regions prohibited heat exchange between the Yeongseo and Yeongdong Regions to increase the temperature contrast between the two regions, and (3) as a trough moved toward Ulleung-do, the easterly flow strengthened in the gulf of Donghan and over the Yeongdong coastal area which was located behind this trough. Accordingly, the cold air damming was magnified, leading to the overflow of the cold air. Thus, the accumulated cold air moved westward over the Daegwallyeong, and the warm air staying there until this time was replaced rapidly by the cold air. Consequently, the surface temperature at the Daegwallyeong Observation station dropped sharply.

단보 : 적외선 영상 복사계를 이용한 산간집수역의 찬공기 배수와 온난대 형성 관측

윤진일 ( Jin I. Yun ) 한국농림기상학회 2011 한국농림기상학회지 Vol.13 No.2

Cold-air drainage and pooling occur in most mountain valleys at night. Local climates with cold-air pooling could affect phenology and distribution of crop plants. A high resolution infrared imaging radiometer was used to visualize the cold-air drainage and thermal belt formation over a small mountainous watershed (ca. 10×5×1 km for the maximum length×width×depth). Thermal images on 640×480 pixels were scanned across the Akyang valley (south of Mt. Jiri National Park) by the radiometer installed at a local peak (``Hyongjebong``, 1,117 m a.s.l.) at dawn of 17 May 2011, when the synoptic condition was favorable for the surface cooling and cold-air drainage. Major findings are: (1) Cold-air drainage and accumulation was clearly identified by the lowest brightness temperature mainly at the valley bottom. (2) So-called ``thermal belt`` with higher brightness temperature was found partway up the valley sidewalls and showed up to 5oC departure from the valley bottom temperature. (3) Digital thermography showed feasibility for validation of the high definition geospatial temperature models currently in use for the plot-specific agrometeorological service.

고밀도 관측자료를 이용한 야간 지면냉각과 찬공기 이동 분석 -서울 은평구 뉴타운 사례

이채연 ( Chae Yeon Yi ),김규랑 ( Kyu Rang Kim ),최영진 ( Young Jean Choi ),원혜영 ( Hye Young Won ),( Dieter Scherer ) 한국지리정보학회 2012 한국지리정보학회지 Vol.15 No.4

Climate analysis is important in urban planning for human comfort. Synoptic weather conditions can only resolve the 30% of local variance of wind conditions whereas 70% of the variance arise from local terrain, buildings, and other small scale thermal conditions. Climate Analysis Seoul (CAS) was developed to resolve such micro-scale climate. The Local-scale air temperature Deviation (LD) analysis map from CAS showed the co-existence of built-up and suburban areas in the study region (CR, Cold-air analysis Region) despite its small extent. Temperature, humidity, wind speed, and wind direction were monitored in CR. Hourly observed cooling rate agreed well with LD. Cold air production, transportation, and stagnation was visualized by the observed Vertical Temperature Gradient (VTG) along the small stream in CR. VTG observed at the upper-most stream can be divided into two components: radiative cooling and cold air inflow from outside. Radiative cooling exists regardless of the wind speed whereas cold air inflow occurs only with calm wind. From the regression analyses based on the wind speed, the inflow portion was determined as 84% of radiative cooling. Climate analysis in the future will be able to characterize the changes in cold air by urban development plan to support the human comfort.

KLAM_21을 활용한 바람생성기능 평가분석 연구 -대구시를 대상으로-

류지원 ( Ji Won Ryu ),정응호 ( Eung Ho Jung ),김대욱 ( Dae Wuk Kim ),차재규 ( Jae Gyu Cha ),손경수 ( Kyung Su Son ) 한국지리정보학회 2008 한국지리정보학회지 Vol.11 No.2

This study, the one concerning the evaluation analysis of the function of the wind generation using KLAM_21, has examined closely how the wind really flows on the space of the city, working with the object of case location. In the first place, the cold air formed at upper stream of Sincheon river, a ravine of whole area of Gachang gully and an inclined plane of neighboring mountainous district, flows to the north and expands itself along the upper stream of the Sincheon river, and as the time passes, it is tending upwards in the change of the volume and height as well as of the velocity and direction, of the cold air. It was learned that this phenomenon has made it clear that the spatial features of this area give rise to very good condition in generating and flowing the cold air. Meanwhile, it has been shown that in the area of park in the Ap-mountain, the generation and flow of the cold air are much interrupted because of the overpass traversing the whole area of the park of Ap-mountain, the congested area of large-scaled apartments and the urban development activities constructing the building in the park, and the volume and height of the cold air has been grown very small. In conclusion, It has been learned that for maximization of the spatial effect of the wind corridor, the areas where the cold air is generated, flowed, accumulated, and maintained, have to be connected spatially, and this spatial connection has a close relation with spatial features of the area.