폐쇄형 지열 열펌프 시스템을 포함한 지중 열 거동 정밀 시뮬레이션 모델 개발과 영향 인자별 민감도 분석
Model Development to Simulate Geothermal Heat Transport and Sensitivity Analyses on the Design Parameters of Closed-loop Geothermal Heat Pump System
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초록
To simulate geothermal heat transport associated with the closed-loop geothermal heat pump (GHP) system, a numerical model named "Modified TOUGHREACT" is developed in this study. It can simulate temperature changes in the GHP system with circulating water through the pipe as well as it computes groundwater flow and aquifer temperature changes. The proposed model is based on TOUGHREACT, a widely accepted three-dimensional numerical simulator for heat and water flow and geochemical reactions in geothermal systems. To verify the model, simulation results are compared with the analytical solution of line source model and data set from an in-situ thermal response test. Simulation results are in very close agreement with both the analytical solution and field test data. The proposed model is used to analyze the sensitivities of design parameters that can affect the performance of closed-loop GHP system. The most sensitive parameters on the system are the thermal conductivity of aquifer and the Darcian groundwater velocity considering acceptable distribution range in the realm of nature. Maximum change of the circulating fluid temperature at the outlet is about 4°C when thermal conductivity of the aquifer changes from 2 W/m-K to 5 W/m-K and the Darcian groundwater velocity changes from 10-8 m/s to 10-6 m/s, respectively. The numerical model can be applied to the optimal design and the evaluation of long-term performance of the GHP system.
Abstract
To simulate geothermal heat transport associated with the closed-loop geothermal heat pump (GHP) system, a numerical model named "Modified TOUGHREACT" is developed in this study. It can simulate temperature changes in the GHP system with circulating water through the pipe as well as it computes groundwater flow and aquifer temperature changes. The proposed model is based on TOUGHREACT, a widely accepted three-dimensional numerical simulator for heat and water flow and geochemical reactions in geothermal systems. To verify the model, simulation results are compared with the analytical solution of line source model and data set from an in-situ thermal response test. Simulation results are in very close agreement with both the analytical solution and field test data. The proposed model is used to analyze the sensitivities of design parameters that can affect the performance of closed-loop GHP system. The most sensitive parameters on the system are the thermal conductivity of aquifer and the Darcian groundwater velocity considering acceptable distribution range in the realm of nature. Maximum change of the circulating fluid temperature at the outlet is about 4°C when thermal conductivity of the aquifer changes from 2 W/m-K to 5 W/m-K and the Darcian groundwater velocity changes from 10-8 m/s to 10-6 m/s, respectively. The numerical model can be applied to the optimal design and the evaluation of long-term performance of the GHP system.
참고문헌 (18)
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