제어 기법에 따른 수직 밀폐형 심부지열 순환 시스템의 난방 성능 분석에 관한 연구

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Deep geothermal, Real time, Coefficient of performance, VVVF control, On-off control
Shallow geothermal system uses a water temperature of 15 ℃ through borehole depth of 150 ~ 200 m. The heat pump must be used in order to supply sufficient energy to the heating horticulture of facility. Shallow geothermal system requires the use of heat pump, which results in high maintenance costs. In addition, the heat pump consumes a large amount of power and degrades the system performance. On the other hand, in deep geothermal vertical closing systems, high temperature can be attained in a single borehole and a heat pump is not required this reduces the power consumption and improves the system performance.
In this study, the circulation simulator was designed in order to analyze circulation system’s heating performance of deep geothermal facilities for a 2,002 m borehole in Naju-Sanpo-myeon.
Temperature variation, flow rate and power consumption of variables that affect the heating coefficient of the system were measured. VVVF control system was applied to the submerged pump and on-off control system to the circulation pump. In addition, the heating performance of system was analyzed.
The submerged pump was operated by VVVF control on the simulator. When the submerged pump was operated at 40 Hz, system coefficient of performance recorded 28.95. The circulation pump was operated by on-off control on the simulator. When temperature of water in tank is 55 ℃, system coefficient of performance was 27.32.
Demonstration data of heating performance was acquired at 2,002 m borehole. As a result, the coefficient of heating system when the system operated for one month was kept from 7 to 12.5. The experimental results of variable speed control for submerged pump was showed the same trend of experiments in the simulator. The coefficient of heating performance when submerged pump was operated at 45 Hz recorded 18. When the outside temperature of greenhouse was greater than 12 ℃ and the circulation pump was operated by on-off control, coefficient of heating performance recorded from 7 to 8.5.
Alternative Title
A Study on Heating Performance Analysis of Vertically Closed Deep Geothermal Circulation System according to Control Technique
Alternative Author(s)
Bae, Jung Hyeong
조선대학교 일반대학원
일반대학원 기계공학과
Awarded Date
Table Of Contents
목 차


제1장 서 론 1
제1절 연구 배경 1
제2절 연구 동향 3
제3절 연구 내용 및 방법 5

제2장 이론적 고찰 7
제1절 시스템 난방 성능 7

제3장 심부지열 시뮬레이터 시스템 9
제1절 심부지열 시뮬레이터 제작 9
제2절 심부지열 순환 시뮬레이터 실험 19
1. 시뮬레이터의 성능 계수 실험 조건 19
2. 실험 결과 분석 21
가. 수조 내 수온 변화에 따른 시스템의 성능 계수 21
나. 수중 펌프의 주파수 변화에 따른 시스템의 성능 계수 24
다. 순환 펌프 On-off 제어에 따른 시스템의 성능 계수 27

제4장 심부지열 현장 실증 실험 34
제1절 심부지열 현장 시스템 34
제2절 실증 데이터 결과 분석 37
1. 실험 방법 및 순서 37
2. 실증 실험 결과 분석 41
가. 장기 운전 일자별 시스템 난방 성능 실험 41
나. 수중 펌프의 변속 운전 시스템 난방 성능 실험 44
다. 순환 펌프 On-off 제어 운전 시스템 난방 성능 실험 46
라. 온실 외기 온도 고정 일자별 시스템 난방 성능 분석 49

제5장 결 론 51
1. 연구 결과 51
2. 향후 연구 방향 52

참 고 문 헌 53
조선대학교 일반대학원
배정형. (2016). 제어 기법에 따른 수직 밀폐형 심부지열 순환 시스템의 난방 성능 분석에 관한 연구.
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