Jinkwan Son

Estimation of the Required Number of Fan Coil Unit for Surplus Solar Energy Recovery of Greenhouse

In this study, previously reported surplus solar energy-related study result and current status of fan coil unit (FCU) for cooling and heating installed in the current sites were briefly examined and then a method to determine the number of FCUs required to recover surplus solar energy was schematically proposed to provide basic data for researchers and technical engineers in this field. The maximum, mean, and minimum outside temperatures during the experiment period were about 28.2C, 4.4C, and -11.5C, respectively. The horizontal surface solar radiation level outside the greenhouse was in a range of 0.8-20.5MJ·m and mean and total solar radiation were 10.8MJ·m and 1,187.5MJ·m. The mean temperature and relative humidity in the greenhouse during the daytime were in a range of 18.8-45.5 and 53.5-77.5%. The total surplus solar energy recovered from the greenhouse during the experiment period was approximately 6,613.4MJ, which could supplement about 6.7% of the total heating energy 98,600.2 MJ. In addition, the number of FCUs installed for heating varies case to case, although similar FCUs are used. Thus, it is necessary to study the installation height, orientation and installation distance as well as the appropriate number of FCUs from the efficient and economical viewpoints. The required numbers of FCUs for surplus solar energy recovery were 8.4-10.9units and 6.1-8.0units based on air mass and circular flow rate that passed through the FCUs. Considering calculation methods and the risks such as efficiency and use environments of FCUs, it was found that about nine units (one unit per 24 m approximately) needed to be installed. The required number of FCUs for surplus solar energy recovery was around one unit per 24m approximately. Additional key words : air mass, dry bulb temperature, enthalpy, glass greenhouse, relative humidity

The Analysis of Vegetation Characteristics According to Revetment Structure at Rural Small Streams

Stream ecosystems are highly valued natural resources, however, stream environments are currently under threat in several respects. We evaluated vegetation and ecological characteristics according to different revetment types. The distribution of vegetation differed with revetment type, with a 42~45 taxa found in natural revetments, and 23~38 taxa in vertical revetments. Thus, natural revetments host more diverse vegetation than vertical revetments. We also found more plants belonging to the families Labiatae and Cyperaceae growing in natural revetments than in vertical revetments. We proposed that habitat space be apportioned to introduce annual plants as part of stream restoration projects. And, we identified 7 families and 18 taxa of naturalized plants, majority taxa were either biennial or perennial. Moreover, naturalized ratio was higher in vertical(14.3%) than natural(12.1%), we proposed a plan to promote and improve natural streams and revetments. Furthermore, we applied a waterfront evaluation method developed by the Natural Resources Conservation Service of the USDA-NRCS, which confirmed that stream health can be improved in most regions by controlling naturalized plants and ensuring shrub and tree growth. We adopted a new method to remove naturalized plants and establish natural revetments to ensure shrub and tree growth to aid in small-stream restoration and improvement. In future studies, we hope to develop methods for small-stream restoration projects in rural areas.

The Analysis of Function and Factors for the Value Assessment of Ecosystem Service at Rice Paddy Wetland

Recently, wetland and paddy wetland are being highlighted as the international environmental issues. However, research system which can assess paddy wetland is lacking. Thus, the purpose of this study is to assess the value of paddy wetland by applying RAM to paddy wetland. In addition, we would like to use this study as the data to establish assessment method for paddy wetland. 16 sites were selected as research targets based on altitude and soil. As the results of wetland assessment, 16 research target sites had total score of 212~227 and the average of 2.17~2.50. It was similar to those of Lacustrine Wetlands, Palustrine Wetland and Riverine Wetland which were sites in previous studies. The value could be recognized as the wetland. However, there was no difference in assessment results based on altitude and soil. It was found that all conservation values were the same. The factor the most closely affecting conservation value was the area. However, there was limitation to apply existing wetland assessment system to paddy wetland. In order to assess paddy wetland, factors such as rice farming methods, topography, vegetation, growth environment and biodiversity should be added. It was thought to supplement wetland assessment system through various further studies.