• Transactions of the KSME C: Technology and Education
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• v.4 no.1
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• pp.49-56
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• 2016

Commercial buildings are generally cooling-dominated and therefore reject more heat to a vertical ground heat exchanger(GHE) than they extract over the annual cycle. Shallow ponds can provide a cost-effective means to balance the thermal loads to the ground and to reduce the length of GHE. The objective of this work has been to develop a design tool for surface water heat exchanger(SWHE) submerged in shallow pond. This paper presents the analysis results of the impact of design parameters on the length of SWHE and its application effect on geothermal heat pump(GHP) system using vertical GHE. In order to analysis, We applied ${\epsilon}-NTU$ method on designing the length of SWHE. Analysis results show that the required pipe length of SWHE was decreased with the increase of approach temperature difference and with the decrease of pipe wall thickness. In addition, when the SWHE was applied to the GHP system, the temperature of vertical GHE was more stable than that of standalone GHE system.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.3
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• pp.24-32
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• 2016

Commercial buildings and institutions are generally cooling-dominated and therefore reject more heat to a borehole ground heat exchanger (BHE) than they extract over the annual cycle. Shallow ponds can provide a cost-effective means to balance the thermal loads to the ground and to reduce the length of BHE. This paper presents the analysis results of the impact of design parameters on the length of SWHE pipe and its application effect on geothermal heat pump (GHP) system using BHE. In order to analysis, we applied ${\varepsilon}-NTU$ method on designing the length of SWHE pipe. Analysis results show that the required pipe length of SWHE was decreased with the increase of approach temperature difference and with the decrease of pipe wall thickness. In addition, when the SWHE was applied to the GHP system, the temperature of BHE was more stable than that of standalone BHE system.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.3
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• pp.28-37
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• 2016

Through the research and analysis on the hydrological environment and soil environment of habitats through documentary and field studies over 14 habitats of Euryale ferox Salisb. within Jeollabukdo, with the objective of acquiring the basic data for forming an environment based on plantation of reservoirs that are composed with Euryale ferox, the following results were obtained. As a result of analyzing the construction period of the habitats of Euryale ferox from a total of 14 places, the average period of duration after construction of all subject reservoirs appeared to be 71.8 years. Moreover, when examining the relationship between the age of reservoirs and eutrophication, it could be judged that at least the eutrophication of subsoil and water environment is not an obstacle to the growth of Euryale ferox grows in habitats that have a reservoir age of approximately 70 years or more. As a result of analyzing the gardening of soil sediment of the Euryale ferox habitats, the component ingredients appeared to be composed of 80.2% of clay, 16.7% of silt and 3.1% of sand, and the soil class pursuant to such was classified as 'heavy clay'. The organic matter contents of soil sediment appeared to be an average of 36g/kg, and there appeared to be no noticeable difference between the habitats and non-habitats of Euryale ferox. The water quality environment of Euryale ferox habitat appeared to be pH 6.5~7.9, concentration of dissolved oxygen to be $1.8{\sim}8.8mg/{\ell}$, concentration of COD to be $6.8{\sim}74mg/{\ell}$, floating materials to be $2.0{\sim}213mg/{\ell}$, total nitrogen to be $0.422{\sim}10.723mg/{\ell}$, and phosphate to be $0.003{\sim}0.126mg/{\ell}$. The average DO concentration of Aedang Reservoir at Jeongeup, Daejeong Reservoir at Imsil, and Myeongdeokji at Gimje with high vitality and green coverage ratio of Euryale ferox appeared to be $3.5mg/{\ell}$, total nitrogen to be $1.33mg/{\ell}$, and concentration of phosphorus-phosphate to be $0.061mg/{\ell}$. When comparing such with the entire average value, the DO and total nitrogen concentration appeared to be rather low, and the phosphorus-phosphate concentration appeared to be higher by two times or more, thus, an in-depth study on the correlation of the vitality of Euryale ferox Salisb. and concentration of phosphorate-phosphorus will be needed in the future.