• Advances in Energy Research
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• v.2 no.1
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• pp.11-20
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• 2014

This paper examines the climatic and technical feasibilities of zero energy buildings in Seoul, Shanghai, Singapore and Riyadh. Annual and seasonal energy demands of office buildings of various scales in the above cities were compared. Using optimally tilted rooftop PV panels, solar energy production potentials of the buildings were estimated. Based on the estimates of onsite renewable energy production and building energy consumption, the energy self-sufficiencies of the test buildings were assessed. The economic feasibilities of the PV systems in the four locations were analyzed. Strategies for achieving zero energy buildings are suggested.

• Journal of Hydrogen and New Energy
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• v.29 no.6
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• pp.606-619
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• 2018

This study focuses on the performance of hydrogen energy based hybrid system in terms of system reliability of electricity generation. With this aim to evaluate the off-grid system of photovoltaic (PV), wind turbine, electrolyzer, fuelcell, $H_2$ tank and storage batteries, 14 different sites in South Korea are simulated using HOMER. Performance analysis includes simulation on the different sites, verification of operational behaviors on regional and seasonal basis, and comparison among a control group. The result shows that the generation performance of hydrogen powered fuelcell is greatly affected by geographical change rather than seasonal effect. In addition, as the latitude of the hybrid systems location decrease, renewable power output and penetration ratio (%) increase under constant electrical load. Therefore, the hydrogen based hybrid system creates the stability of electricity generation, which best suits in the southern part of South Korea.

• Journal of Ocean Engineering and Technology
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• v.15 no.4
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• pp.53-59
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• 2001

The Primary Production of phytoplanktons produces organic matter in high concentration in eutrophicated Hakata Bay, Japan, even during the winter season in spite of low water temperature. Phytoplanktons are considered to have any biological capabilities to keep activities of photosynthesis under the unfavorable conditions, and this affects water quality of the bay. In this study, seasonal variations in primary production efficiency were predicted by using a simple box-type ecosystem model, which introduced the concept of efficiency for absorption of solar radiation energy in relation to growth of phytoplanktons under the low solar radiation intensity. According to the simulation result of primary production, it was organic pollution comes from dissolved organic carbon (DOC) throughout the year, DOC of which is originated from the primary production of phytoplanktons on biological response of the seasonal variation of ambient conditions.

• Korean Journal of Community Nutrition
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• v.6 no.4
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• pp.592-603
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• 2001

Seasonal variations of nutrient intake ware evaluated through a 3-day dietary records in 196 Korean adolescents(86 males, 108 females) aged 13 - 15 years and living in urban and rural areas of Chungnam. The seasonal differences of nutrient intake were tested by repealed measure ANOVA. Comparing nutrient intakes among flour seasons using repealed measure ANOVA, mean values of daily intakes were higher in winter and autumn for most nutrients, and were the lowest in summer in the urban areas and in spring in rural areas. Girls recieved the largest amount of nutrients, except Ca and vitamin $B_12$, in winter and the lowest amount in summer, while in boys significant differences were not observed among the four seasons for meet nutrients, except fats, Mg, and vitamin E. Interestingly, the seasonal differences for many nutrients were more evident in rural areas than in urban areas. Vitamin A intake in urban areas was higher in winter and spring, while in rural oreas, in summer. Mean values of daily intakes as a percent of the RDA throughout the year in boys and girls ware 82.2% and 84.2% for energy and 88.9% and 82.7% for protein, respectively. Ca and vitamin A intakes were as low as 32.4% and 24.2% of the RDA in boys and 39.7% and 30.6% in girls. Intakes of Fe, Zn, folic acid and vitamin B$_{12}$ ranged from 40 - 60% of the RDA. The nutrients which showed the largest seasonal difference in the percent of RDA were vitamin E in boys and vitamin C, vitamin E, and Fe in girls. The index of nutritional quality(INQ) for Fe was significantly lower in autumn in both genders. The INQ for vitamin C in girls of both areas was much higher in winter. Annual mean adequacy ratio(MAR), an index of overall nutritional quality, ranged from 0.57 - 0.69, which was higher in winter than in other seasons. Conclusively, nutrient intakes of Korean adolescents showed seasonal variations, particularly in girls and in rural area. Thus, seasonal variations should be considered in the assessing nutritional status, particularly ill the rural areas of Korea.a.

• Nutrition Research and Practice
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• v.12 no.4
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• pp.315-323
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• 2018

BACKGROUND/OBJECTIVES: Available data suggest that seasonal changes may influence the nutritional status and overall health of elderly individuals. Therefore, this study was conducted to investigate the effects of seasonal changes and related factors on energy and nutrient intake of older adults. SUBJECTS/METHODS: Individuals aged 65 years or over were prospectively enrolled in this single-center study (male: 11, female: 20). Data were collected between May 2013 and February 2014 during winter, spring, summer and autumn. Food consumption and biochemical parameters were taken during each season to assess the seasonal nutrition status of the elderly. Upon analysis of biochemical parameters (retinol, vitamin D and vitamin C), an high-performance liquid chromatography device was utilized whereas an Immulite 2000 device was utilized during analysis of serum folic acid and parathyroid hormone. RESULTS: Fruit, fat, egg and bread consumption varied seasonally in males and females (P < 0.05). During winter, daily energy intake was found to be greater than in other seasons in males (557 kcal) and females (330 kcal) (P < 0.05). Additionally, carbohydrates, vegetable protein, n-3 fatty acid and sodium intake increased in winter, while the n-6/n-3 ratio increased in summer among males (P < 0.05). Dietary fiber and sodium intake in winter, vitamin C, iron and zinc intake in spring, and cholesterol, retinol, vitamin D and niacin intake in autumn were found to be higher in females when compared to other seasons (P < 0.05). Serum parathyroid hormone level was higher in winter, and vitamin D level was higher in autumn in both genders (P < 0.05). In males, blood folic acid level was higher in winter, while vitamin C level was higher in females, and there was no seasonal variation in retinol concentration (P < 0.05). CONCLUSION: Food consumption and biochemical parameters showed significant seasonal variations in older adults. It is not clear if nutrition plans in older adults will benefit from consideration of seasonal changes in eating habits.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.4
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• pp.31-38
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• 2017

The heating and cooling air conditioning field has been increasing the problems of energy consumption and global warming in the world. A geothermal heat pump has been known as one of the highest efficient heating and cooling system. In this study, the analysis about the test standards of the geothermal heat pump of the Republic of Korea was executed. From the research, the following results were given. It is needed to address the domestic test standard for direct heat exchange geothermal heat pump. Water to air multi geothermal heat pump test standard was only developed in Korea. The test standard to calculate a seasonal energy efficiency ratio for cooling period and heat seasonal performance factor for heating period should be newly developed to estimate actual annual energy consumption and $CO_2$ emission.

• International Journal of Air-Conditioning and Refrigeration
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• v.11 no.4
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• pp.209-217
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• 2003

The term “energy saving is economical” is appropriate for the national view point and for design and assessment of one system, but not appropriate when choosing the system by comparing alternative systems in the early design step. Sometimes, non-energy saving system is more economical than energy saving system because of the price of electricity, gas or oil, which are used for operating the air conditioning system. Therefore, when designing a system, we should consider the efficient alternatives through economic assessment of energy saving method. However, research on non-operating number control of the system is not sufficient because it is more common to use operating number control of the system for most economic assessment of air conditioning systems. For this reason, this research can provide the economic operating number control method as basic design data. The data obtained through analysis of life cycle cost based on amount of yearly energy use, are produced by system simulation of HASP/ACLD/8501 and HASP/ACSS/8502 for six alternative heating$.$cooling systems based on seasonal air conditioning system, which is widely used for medium and large size office buildings in Busan.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3878-3887
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• 2022

For the future energy-mix policy for carbon neutrality, demand for the capability of load-follow operation has emerged in nuclear power plants in order to accommodate the intermittency of renewable energy. The short-term decay heat analysis is also required to evaluate the decay heat level varied by the power level change during the load-follow operation, which is a very important parameter in terms of short-term decay heat removal during a grace time. In this study, the short-term decay heat level for 10 days after the shutdown was evaluated for both seasonal and daily load-follow cases. Additionally, the nuclide-wise contribution to the accumulated decay heat for 10 days was analyzed for further understanding of the short-term decay heat behavior. The result showed that in the seasonal case, the decay heat level was mainly determined by the power level right before the shutdown and the amount of each nuclide was varied with the power variation due to the long variation interval of 90 days. Whereas, in the daily case, the decay heat level was strongly impacted by the average power level during operation and meaningful mass variations for those nuclides were not observed due to the short variation interval of 0.5 days.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.33-43
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• 2019

Considerable efforts have been made to reduce greenhouse gas emission around the world to cope with climate change. The government is implementing G-SEED certification to promote energy efficient building design. This study aims to verify the effectiveness of the G-SEED certification system by analyzing the actual energy use of certified and non-certified office buildings. For this purpose, the energy consumption of 135 certified and 142 non-certified office buildings was analyzed according to the seasonal characteristics, building size and number of floors, approval year, and certification grade. The energy saving effects of certified buildings was about 50% higher than that of non-certified buildings. The seasonal energy consumption of buildings is closely related to the heating degree-days. The energy consumption of certified and non-certified buildings decreases with increasing approval year. On the other hand, the energy consumption according to building size and certification grade is not related. This study provides meaningful basic data of G-SEED certification system for future improvement. As the building energy performance standards are strengthened over the years, it is necessary to make the individual score of G-SEED certified projects open to the public to configure the factors of energy efficiency.

• The Korean Journal of Quaternary Research
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• v.18 no.2 s.23
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• pp.19-22
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• 2004

Seasonal changes of topograpy, sediment grain size and accumulation rate on the Gomso-Bay tidal flat(Fig. 1), west coast of Korea, have studied in order to understand the seasonal accumulation pattern and preservation potential of tidal-flat sediments. Seasonal levelings across the tidal flat show that the landward movement of both intertidal sand shoals and cheiers accelerates during the winter and typhoon period, but it almost stops in summer when mud deposition is instead predominant on the middle to upper tidal flat. Seasonal variations of mean grain size were largest on the upper part of middle tidal flat where summer mud layers were eroded during the winter and typhoon periods(Fig. 2). Measurements of accululation depths from sea floor to basal plate reveal that accumulation rates were seasonally controlled according to the elevation of tidal-flat surface(Table 1) : the upper flat, where the accumulation rate of summer was generally higher than that of winter, was characterized by a continuous deposition throughout the entire year, whereas on the middle flat, sediment accumulations were concentrated in winter realtive to summer, and were intermittently eroded by typhoons. The lower tidal flat were deposited mostly in winter and eroded during summer typhoons. Cancores taken across the tidal flat reveal that sand-mud interlaers resulting from such seasonal changes of energy regime are preserved only in the upper part of the deposits and generally replaced by storm layers downcore(Fig. 3). Based on above results, it is suggested that the storm deposits formed by winter stors and typhoons would consist of the major part of the Gomso-Bay deposits(Fig. 4).