Sensitivity Analysis of the Design Factor for Vertical Closed-loop Geothermal System using Numerical Analysis : Focused on Heating Operation

KIEAE Journal ◽  
2018 ◽  
Vol 18 (5) ◽  
pp. 55-61
Author(s):  
Sangmu Bae ◽  
Hongkyo Kim ◽  
Jae-Young Jeon ◽  
Yujin Nam
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Analysis ◽  
Closed Loop ◽  
Geothermal System ◽  
Design Factor

Numerical analysis of the heat production performance of a closed loop geothermal system

2018 ◽  
Vol 120 ◽  
pp. 365-378 ◽  
Author(s):  
Xianzhi Song ◽  
Yu Shi ◽  
Gensheng Li ◽  
Zhonghou Shen ◽  
Xiaodong Hu ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Heat Production ◽  
Closed Loop ◽  
Production Performance ◽  
Geothermal System

scholarly journals Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): sensitivity analysis on the Newberry volcanic setting

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hannah R. Doran ◽  
Theo Renaud ◽  
Gioia Falcone ◽  
Lehua Pan ◽  
Patrick G. Verdin
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Energy Flow ◽  
Closed Loop ◽  
Working Fluid ◽  
Valuable Insight ◽  
Deep Borehole

AbstractAlternative (unconventional) deep geothermal designs are needed to provide a secure and efficient geothermal energy supply. An in-depth sensitivity analysis was investigated considering a deep borehole closed-loop heat exchanger (DBHE) to overcome the current limitations of deep EGS. A T2Well/EOS1 model previously calibrated on an experimental DBHE in Hawaii was adapted to the current NWG 55-29 well at the Newberry volcano site in Central Oregon. A sensitivity analysis was carried out, including parameters such as the working fluid mass flow rate, the casing and cement thermal properties, and the wellbore radii dimensions. The results conclude the highest energy flow rate to be 1.5 MW, after an annulus radii increase and an imposed mass flow rate of 5 kg/s. At 3 kg/s, the DBHE yielded an energy flow rate a factor of 3.5 lower than the NWG 55-29 conventional design. Despite this loss, the sensitivity analysis allows an assessment of the key thermodynamics within the wellbore and provides a valuable insight into how heat is lost/gained throughout the system. This analysis was performed under the assumption of subcritical conditions, and could aid the development of unconventional designs within future EGS work like the Newberry Deep Drilling Project (NDDP). Requirements for further software development are briefly discussed, which would facilitate the modelling of unconventional geothermal wells in supercritical systems to support EGS projects that could extend to deeper depths.

Evaluation of bridge support condition using bridge responses

2018 ◽  
Vol 18 (3) ◽  
pp. 767-777 ◽  
Author(s):  
Young-Soo Park ◽  
Sehoon Kim ◽  
Namgyu Kim ◽  
Jong-Jae Lee
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Analysis ◽  
Field Test ◽  
Laboratory Tests ◽  
Spring Constant ◽  
Scale Model ◽  
Support Condition ◽  
Bridge Responses ◽  
Spring Constants

This article presents a method for evaluating the support condition of bridges. This is done by representing the aging and deteriorated supports as rotation springs with equivalent spring constants. Sensitivity analysis was performed to obtain a relationship between the spring constant and the bridge responses (deflections/slopes). From this relationship, measured bridge responses can be used to estimate the equivalent spring constants through interpolation. Numerical analysis was performed to check whether the method can be used to calculate equivalent spring constants. Then, the method was verified by performing laboratory tests on a scale model bridge and field test on an actual bridge. In both tests, spring constants were estimated using the proposed method and then verified by calculating the displacements and frequencies and comparing them to the measured values.

scholarly journals Numerical evaluation of building heating potential from a co-axial closed-loop geothermal system using wellbore–reservoir coupling numerical model

2019 ◽  
Vol 38 (3) ◽  
pp. 733-754 ◽  
Author(s):  
Tianfu Xu ◽  
Zixu Hu ◽  
Bo Feng ◽  
Guanhong Feng ◽  
Fengyu Li ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
Closed Loop ◽  
Heating System ◽  
Coupling Model ◽  
Production Performance ◽  
Heat Extraction ◽  
Geothermal System ◽  
Renewable Energy Resources ◽  
Practical Engineering ◽  
System Maintenance

Geothermal energy is one of the most potential renewable energy resources. How to efficiently extract and utilize geothermal energy has been a worldwide hot topic. Co-axial closed-loop geothermal system is a novel method using a continuously closed wellbore without water exchange with. It is more suitable for reservoirs with medium or low temperature and permeability because many problems could be avoided such as lack of in situ groundwater or low infectivity of the reservoir. Many companies and research institutes have applied closed-loop geothermal system in building heating engineering and some fine results have been gained. However, in practical engineering construction, the area of a closed-loop geothermal system heating system is a very important parameter. It directly determines the cost accounting and initial design of the project. Accurate and reliable estimation of heating capacity becomes very important. In this study, a wellbore–reservoir coupling model is established, which is calibrated using measured data from a short-term field trial operation. We have carried out mixed convective–conductive fluid-flow modeling using a wellbore flow model for TOUGH2 called T2Well to investigate the heat extraction performance of closed-loop geothermal system. The system evolution and the effect of flow rate and injection temperature on heat production performance are discussed. The result shows that the intermittent production cycles are more beneficial for heat extraction and system maintenance, and the temperature recovery between two heating seasons is enough to maintain system heating. And we can calculate that a geothermal well can ensure heating of buildings of 10,000–20,000 m2 and the heating area of intermittent operation is 4000 m2 more than continuous operation. Besides, the sensitivity analysis of parameters is also carried out.

NUMERICAL ANALYSIS OF SMART STRUCTURES WITH UNCERTAINTIES

2004 ◽  
Vol 01 (02) ◽  
pp. 227-239 ◽  
Author(s):  
S. VALLIAPPAN ◽  
C. K. CHEE
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Fuzzy Sets ◽  
Numerical Method ◽  
Smart Structures ◽  
Sensitivity Index ◽  
Material Parameters ◽  
Element Technique ◽  
Fuzzy Parameters

In this paper, a numerical method for the analysis of smart structures with uncertainties involved in the material parameters is presented. This method combines the finite element technique, concepts of fuzzy sets and optimization. For the optimization of fuzzy parameters, a sensitivity index is proposed. The sensitivity analysis based on the proposed sensitivity index can be effectively used to reduce the number of variables to be fuzzified and thus reducing the computational efforts considerably.

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