• Journal of the Korean Geographical Society
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• v.40 no.5 s.110
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• pp.584-593
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• 2005

The spatial and temporal variations of heating degree-days (HDDs) and cooling degree-days (CDDs) are closely related with the temperature field. The spatial distribution of 30-year mean HDDs shows that the higher values locates in the northern part of South Korea while the lower values locates in the southern part. The 30-year mean CDDs shows a more randomized distribution than the HDDs. The changing trends of HDDs and CDDs show a different feature: HDDs have a distinct decreasing trend while CDDs have an insignificant change. The decreasing trends of HDDs are consistent over South Korea and most of stations have experienced the statistically significant change. As significant changing areas of HDDs are much broader than those of annual mean temperature, HDDs can be more useful than annual mean temperature to detect the climate change impact on a regional level. In other words, an insignificant change on the mean temperature field can induce the significant change of thermal climatology in a region. The temporal pattern of climatic departure index (CDI) for South Korea HDDs series shows a general decreasing, but a sharp increase during recent years. The drastic decrease of HDDs induces higher CDI indicating larger variability among stations. However, the decrease of South Korea HDDs series cannot totally attribute to the global warming due to urban effects. By the early 1980s, there were no big differences of HDDs between urban and rural series, but later the differences are getting larger. This was expected to be with the intensification of urbanization in South Korea. However, still there is a decreasing trend of HDDs for rural stations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5430-5437
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• 2011

The objective of this study is to investigate the cooling performances of the electrical air-conditioning system using electric driven scroll compressor for zero emission passenger vehicles. This air conditioner with air source was used R-134a as a refrigerant and installed in a real zero emission passenger vehicle for tests under various driving conditions. The cooling performance of the electrical air conditioner was affected by driving velocities and conditions of the tested vehicle. The condensing rate of the condenser during driving is better than that of the idle condition. The average cool down temperature in the cabin room decreased on average $5.2^{\circ}C$ with the increase of the outdoor temperature from $20.0^{\circ}C$ to $30.0^{\circ}C$. In addition, the cooling performances were sufficient for cooling loads of the tested passenger car under tested conditions.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.328-334
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• 2021

This study was conducted to analyze the effect of fog cooling during daytime and heatpump cooling at night in greenhouses in summer. During daytime, the average temp. and RH of the control greenhouse which had shading screen were 32.1℃ and 59.4%. and the average temp. and RH of the test greenhouse which had fog cooling were 30.0℃ and 74.3%. At this time, the average outside temp. and RH were 31.4℃ and 57.7%. So, the temp. of the control was 0.7℃ higher than outside temp., but the temp. of the test was 1.4℃ lower than outside and 2.1℃ lower than control. The average RH was 74.3% in the test and 59.4% in control. The average temp. and RH of the control greenhouse which had natural ventilation at night were 25.2℃ and 85.1%, and the average temp. and RH of the test greenhouse which had heat pump cooling were 23.4℃, 82.4%. The average outside temp. and RH at night were 24.4℃ and 88.2%. The temp. of the control was 0.8℃ higher than outside temp., but the temp. of the test was 1.0℃ lower than outside and 1.8℃ lower than control. The average RH was 82.4% in test and 85.1% in control greenhouse. There was no significant difference between the plants growth eight weeks after planting. But after the cooling treatment, the values of stem diameter, plant height, chlorophyll in test were higher than control. The total yield was 81.3kg in test, 73.8kg in control, so yield of test was 10.2% higher than control. As a result of economic analysis, 142,166 won in profits occurred in control greenhouse, but 28,727 won in losses occurred in test greenhouse, indicating that cooling treatment was less economical.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.2
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• pp.97-109
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• 2019

Degree days have been determined using temperature data measured at nearby weather stations to a site of interest to produce information for supporting decision-making on agricultural production. Alternatively, the data products of Moderate Resolution Imaging Spectroradiometer (MODIS) can be used for estimation of degree days in a given region, e.g., Korean Peninsula. The objective of this study was to develop a simple tool for processing the MODIS product for estimating cooling degree days (CDD), which would help assessment of heat stress conditions for a crop as well as energy requirement for greenhouses. A set of scripts written in R was implemented to obtain temperature profile data for the region of interest. These scripts had functionalities for processing spatial data, which include reprojection, mosaicking, and cropping. A module to extract air temperature at the surface pressure level was also developed using R extension packages such as rgdal and RcppArmadillo. Random forest (RF) models, which estimate mean temperature and CDD with a different set of MODIS data, were trained at 34 sites in South Korea during 2009 - 2018. Then, the values of CDD were calculated over Korean peninsula during the same period using those RF models. It was found that the CDD estimates using the MODIS data explained >74% of the variation in the CDD measurements at the weather stations in North Korea as well as South Korea. These results indicate that temperature data derived from the MODIS atmospheric products would be useful for reliable estimation of CDD. Our results also suggest that the MODIS data can be used for preparation of weather input data for other temperature-based agro-ecological models such as growing degree days or chill units.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.2872-2877
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• 2012

This paper discusses the development of the wearable personal cooling system for reducing thermal stress in hot environment. The personal cooling system is operated with the compact refrigeration system by compressing refrigerant. The compact refrigeration system is applied with the miniaturization and weight reduction for portable and wearable cooling system. The body heat is reduced by heat conduction with evaporator in direct cooling type. The cooling capacity of the wearable personal cooling system is approximately 100W and, the system could maintain the inside temperature of approximately 12-$13^{\circ}C$ lower than the ambient temperature. The weight of the wearable cooling system is about 3kg including vest, case, battery and all parts.

• Journal of Climate Change Research
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• v.4 no.2
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• pp.141-158
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• 2013

In this study, the projection of future heating and cooling degree days (HDDs and CDDs) has been conducted over South Korea for the period 1996~2005 with 2046~2055 and 2091~2100, using CCSM3 and MM5 simulations driven by the six IPCC SRES emission scenarios (A2, A1B, A1FI, A1T, B1, and B2). Annual mean surface air temperature increases by $1.2{\sim}3.4^{\circ}C$ at the end of the 21st century comparing to the present-day (1996~2005) in South Korea. HDDs decrease by 8~25% and CDDs increase up to 242~1,448% with corresponding changes in temperature. These increases and decreases also change the duration of HDDs and CDDs. HDDs duration decreases by 1 month, while the expansion of CDDs duration is much longer than 2 months. Thus, projected future HDDs and CDDs changes appear that cooling energy demand in summer season would increase and heating energy demand in winter would decrease in the future. Especially, these remarkable changes would be obvious at high mountain area, Gangwon-do and at south area, Jeju island. In the sense of future energy supply and policy, electrical energy for cooling in summer could be getting much more its importance rather than fossil energy used for heating in winter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4308-4313
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• 2011

The objective of this study is to investigate the cooling performance of the roof mounted air-conditioning system using electric driven scroll compressor for zero emission vehicles. This air conditioner with air source was used R-134a as a refrigerant and tested under various operating conditions such as refrigerant charge amount and indoor temperature, and compressor frequencies. Experimental results revealed that at all tested compressor frequencies, heat transfer rate of the evaporator increased and the cooling COP increased with the indoor temperature. In addition, the heat transfer rate of the evaporator was over 25.0kW sufficient for the cooling loads of an electric bus.

• Proceedings of the KGS Conference
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• 2005.05a
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• pp.80-81
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• 2005

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.511-512
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• 2015

최근 냉방장치의 사용증가로 전력수요가 크게 증가하고 있고, 이로 인해 전력수급 문제가 야기되고 있다. 이를 해결하기 위하여 여러 조치를 취하고 있지만 사실상 아직까지도 미흡한 실정이다. 최근에는 스마트 그리드의 구축이 진행 중이며, 스마트 그리드의 일환으로 실시간 요금제의 도입도 고려되고 있다. 따라서 부하제어 등의 수요관리를 통한 적절한 대처가 필요하다. 하지만 부적절한 부하제어는 사용자의 만족도를 해칠 우려가 있다. 이에 본 논문에서는 거주자의 쾌적도를 해치지 않는 조건에서 수용가에게 전기요금절감을 유도하는 냉방 시스템의 최적 부하제어 방법을 제안하는 바이다.

• 건강소식
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• v.37 no.7
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• pp.34-35
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• 2013

뙤약볕 아래에서 수분 섭취 없이 활동을 하다가 걸릴 수 있는 일사병, 일사병의 사촌 격이지만 그 위험도는 훨씬 높은 열사병, 바깥 날씨와 달리 서늘한 실내에서 생활하다 걸릴 수 있는 냉방병. 이는 모두 한여름에 조심해야 할 열 관련 질환이다.