지열 열교환시스템 개발을 위한 지중 열유동 특성분석 = Analysis of Heat Transfer Characteristics in Soil for Development of a Geothermal Heat Exchange System

다국어 초록 (Multilingual Abstract)

Importance of alternative energy has been increasing due to environmental issues and lack of fossil fuels. In addition, heating cost that occupies from 30 to 40% of the total production cost in the protected cultivation sector in Korea needs to be reduced for profitability and global competition. But, study on geothermal energy to solve these problems has not been activated for Korean protected cultivation. This study was conducted to develop an optimized geothermal exchange system through fundamental test of heat transfer characteristics in soil such as thermal diffusivity, changes in soil temperature during heating and cooling operations, and restorations of soil temperature after the heater was turned off. These issues were investigated using computer simulation for different depths. The simulated characteristics were evaluated through controlled tests. Simulated characteristics of heat transfer in the soil at different depths showed a reasonable agreement with the results of the controlled tests. All of computer simulation and controlled tests, soil temperatures changed at 10cm and 20cm distance from pipe. but don't change at more than 30cm distance. It means that distances of heat transfer of the soil ranged from 20 to 30 cm a day. Based on these results, the optimum spacing between adjacent heat exchange pipes and the pitch were selected as 50 and 40 cm, respectively.

참고문헌 (Reference)

1 "Performance analysis of an earth tube heat exchanger -Temperature variation characteristics and heat exchange performance on the mode of continuous operation- Journal of the KSAM 21" 21 (21): 436-448, 1996

2 "Feasibility and performance curves for intermittent earth-tube heat exchangers" 525-532, 1986