• Journal of the Korean housing association
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• v.15 no.3
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• pp.73-82
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• 2004

The objective of this study is to demonstrate the potential of radiant cooling systems using Ondol as an alternative cooling system in residential buildings. For this purpose, computer simulation and model experiments have been performed for the system performance analysis regarding comfort, floor surface condensation, and supply water temperature. The results of this study is the following: In radiant floor cooling system, room air temperatures were maintained within the set temperature range of $\pm$1$^{\circ}C$ without any discomfort condition. And taking into account only the condensation occurrence, it was possible to achieve radiant floor cooling for a period of about 77% of the total cooling period in weather condition of Seoul. The minimum supply water temperature is about 15$^{\circ}C$, so renewable energy system such as ground heat exchange system can be used as an alternative in cooling source. Also, floor surface condensation can be prevented by integrating with the dehumidification system.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.411-422
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• 2016

Recently, because the wet pool storage facilities of NPPs in Korea has become saturated, there has been much active R&D on an interim dry storage system using a transportation and storage cask. Generally, the shielding evaluation for the design of a spent fuel transportation and storage cask is performed by the design basis fuel, which selects the most conservative fuel among the fuels to be loaded into the cask. However, the loading of actual spent fuel into the transportation metal cask is not limited to the design basis fuel used in the shielding evaluation; the loading feasibility of actual spent fuel is determined by the shielding evaluation that considers the characteristics of the initial enrichment, the maximum burnup and the minimum cooling period. This study describes a shielding analysis method for determining the minimum cooling period of spent fuel that meets the domestic transportation standard of the dual purpose metal cask. In particular, the spent fuel of 3.0~4.5wt% initial enrichment, which has a large amount of release, was evaluated by segmented shielding calculations for efficient improvement of the results. The shielding evaluation revealed that about 81% of generated spent fuel from the domestic nuclear power plants until 2008 could be transported by the dual purpose metal cask. The results of this study will be helpful in establishing a technical basis for developing operating procedures for transportation of the dual purpose metal cask.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.2
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• pp.16-21
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• 2017

In this study, the flow effect of warming and cooling in the air supply of a pit for air conditioning were evaluated in BS art museum. We simulated the flow temperature for a pit winter and summer seasons using computational fluid dynamics. Consequential, energy saving, energy saving costs and initial payback periods were calculated and the following conclusions were drawn. The warming effect of the winter increased by $18.1^{\circ}C$ and $0.2^{\circ}C/m$ and the cooling effect of the summer decreased by $6.1^{\circ}C$ and dropped to $0.07^{\circ}C/m$. Energy saving appeared to be 19.1 kW in the summer and 54.3 kW in winter. Energy saving costs ranged from 2,567,119 won/year to 5,134,238 won/year and at minimum, initial payback period for initial investment was 3.9 years. As a result, the air supply system using an existing pit without any burden on initial investment costs is believed to contribute to energy saving through warming and cooling of unutilized energy effects.

• Journal of Environmental Science International
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• v.26 no.9
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• pp.1023-1029
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• 2017

We studied the distribution of air temperature using the high density urban climate observation network data of Daegu. The observation system was established in February 2013. We used a total of 38 air temperature observation points (23 thermometers and 18 AWSs). From the distribution of monthly averaged air temperatures, air temperatures at the center of Daegu were higher than in the suburbs. The daily minimum air temperature was more than or equal to $25^{\circ}C$ and the daily maximum air temperature was more than or equal to $35^{\circ}C$ at the elementary school near the center of Daegu. Also, we compared the time elements, which are characterized by the diurnal variation of surface air temperature. The warming and cooling rates in rural areas were faster than in urban areas. This is mainly due to the difference in surface heat capacity. These results indicate the influence of urbanization on the formation of the daily minimum temperature in Daegu.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.61-64
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• 2002

We constructed climagraphs for 16 regions of Korea by using the average monthly minimum air temperature, maximum air temperature and global radiation. We characterized the outside climate requirements corresponding to the climate requirements of crops in greenhouses. The climagraphs allow to decide the appropriate climate periods for greenhouse cultivation without heating and cooling equipment. These graphs may be used for analyzing climatic characteristic of a given area, selecting the suitable region and greenhouse and making a rational plan for greenhouse cropping in Korea. We found difficulty in deciding the beginning and end of greenhouse heating and cooling period due to insufficient references.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4077-4082
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• 2023

Large areas must be rapidly screened to monitor radiation in marine environments. For this purpose, this study developed a mobile real-time gamma-ray measurement system for shipboard use and evaluated its performance. The system was developed to measure engine or generator cooling water by installing a canister inside the ship. The minimum detectable activity of the system is about 0.8 Bq/L for a 60 s measurement period, and real-time data transmission and remote control are possible. The system was tested in the field and is currently being installed and operated on ships in service. Such a ship-based real-time gamma-radiation measurement system is suitable for a wide range of marine radiation surveillance applications and is expected to be rapidly deployed.

• Journal of Bio-Environment Control
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• v.23 no.3
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• pp.174-180
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• 2014

Standard weather data available to greenhouse environmental design are limited in most regions of the country. So, instead of using standard weather data, in order to find the method to build design weather data for greenhouse heating and cooling, design outdoor weather conditions were analyzed and compared by TAC method and frequency analysis using climatological normal and thirty years from 1981 to 2010 hourly weather data provided by KMA and standard weather data provided by KSES. Average TAC values of outdoor temperature, relative humidity and insolation using thirty years hourly weather data showed a good agreement with them using standard weather data. Therefore, in regions which are not available standard weather data, we suggest that design outdoor weather conditions should be analyzed using thirty years hourly weather data. Average of TAC values derived from every year hourly weather data during the whole period can be established as environmental design standards, and also minimum and maximum of them can be used as reference data.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.1
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• pp.79-88
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• 2007

We investigated the characteristics of temperature variations under different land covers (paddy field, upland, urban park, and urban residential area) during hot summer (July 15 to August 19, 2005). The temperatures were monitored using data loggers at one hour intervals in study sites. The mean temperature generally increased with the distance from edge of paddy fields, being $1.5^{\circ}C$ higher at a site 170-m far from paddy fields than at a paddy field area at 22 h. The mean daily temperatures in the study period followed the ordo. of paddy field $(26.6^{\circ}C)$ < upland $(27.0^{\circ}C)$ < park $(27.5^{\circ}C)$ < residential area $(28.0^{\circ}C)$. The paddy field area has shown remarkable cooling effects compared to the residential area: Mean duration of temperature below $25^{\circ}C$ in the paddy field area was longer (8.6 hrs) than in the residential area; The time to fall to below $25^{\circ}C$ in the paddy field area was sooner (22.4 hr) than in the residential area; Mean daily minimum temperature in the paddy field area was much lower $(2.4^{\circ}C)$ than in the residential area. More research is needed to better clarify the mechanism of cooling effect of a paddy field area by investigating heat balance of a paddy field.

• Journal of Bio-Environment Control
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• v.9 no.2
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• pp.107-114
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• 2000

We constructed climagraphs for 16 regions of Korea by using the average monthly minimum air temperature, maximum air temperature and global radiation. We characterized the outside climate requirements corresponding to the climate requirements of crops in greenhouses. The climagraphs allow to decide the appropriate climate periods for greenhouse cultivation without heating and cooling equipment. These graphs may be used for analyzing climatic characteristic of a given area, selecting the suitable region and greenhouse and making a rational plan for greenhouse cropping in Korea. We found difficulty in deciding the beginning and end of greenhouse heating and cooling period due to insufficient references.

• Journal of Acupuncture Research
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• v.18 no.6
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• pp.171-187
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• 2001

Objective : Moxibustion has been proved efficacious for many diseases, but isn't widespread in the clinics due to a danger of skin burning, the smoke produced while burning a moxa combustion and so on. Therefore, another type of moxa that can be resolved these troubles is required. To improve the effect of moxibustion and develop the new thermal stimulating treatment, the performance of commercial moxibustion widely used are studied systematically and found out quantitatively. Methods : We have selected two types (small-size moxa A(sMA), small-size moxa B (sMB)) among small-size moxaes used widely in the clinic. We examined combustion time, various temperatures, temperature gradient in each period during a combustion of moxa. Results : 1. The combustion time in the preheating period appeared somewhat longer in sMA than in sMB. 2, The combustion time in the heating period appeared longer in sMA by 26% than in sMB. 3. The average temperature in the heating period was $37.6{\sim}37.8^{\circ}C\;in\;sMA\;and\;36.2{\sim}36.8^{\circ}C$ in sMB and the maximum temperature measured at a center of contact surface in sMA was $48.6^{\circ}C$, higher by over $2.8^{\circ}C$ than that of sMB moxibustion. 4. The average ascending temperature gradient in the heating period was $0.08{\sim}0.1^{\circ}C/sec$ in both moxaes, and the average ascending temperature gradient of heating period in sMB appeared larger. The maximum ascending temperature gradient appeared higher in sMB, and the time reaching maximum ascending temperature gradient appeared much earlier in sMA than in sMB. 5. The combustion time in the retaining period was around 100 sec in sMA and around 275 sec in sMB. 6. The average temperature in the retaining period was $42.2{\sim}46.0^{\circ}C\;in\;sMA\;and\;39.3{\sim}41.4^{\circ}C/sec$ in sMB. The minimum temperature in the retaining period was over $38.80^{\circ}C$ in sMA but just $34.7^{\circ}C$ in sMB. 7. The average descending temperature gradient in sMA was $-0.050{\sim}0.067^{\circ}C/sec$ and in sMB was $-0.030{\sim}0.037^{\circ}C/sec$ 8. The combustion time in the cooling period appeared longer over two times in sMA than in sMB, and the time which the cooling period (minimum temperature) finished at appeared later in sMB by 55 sec. 9. We classified the combustion process that the measured temperature rose over body heat($37^{\circ}C$) into the effective combustion period. The effective combustion time was 233.3 sec in sMA and 300.4 sec in sMB respectively, and was longer by about 29% in sMB. The average temperature and maximum temperature in the effective combustion time appeared higher in sMA. The time taken until the maximum temperature was reached was 225.1 sec in sMA and 244.5 sec in sMB, faster by about 20 sec in sMA. The maximum ascending temperature gradient during the effective combustion period appeared larger about 1.4 times in sMB, but the time when the maximum ascending temperature gradient happened was faster in sMA. Conclusion : It appears that sMB, compared with sMA, is proper if necessary to apply the long time and weak stimulus, because of the gentle stimulus during the relatively longer time. In contrast, sMA that the symmetrical combustion happened is proper if necessary to apply the short time and strong stimulus.