Numerical Analysis on Thermal Characteristics of an Open Loop Geothermal System in a Single Well

The energy reserves in hot dry rock and hydrothermal systems are abundant in China, however, the developed resources are far below the potential estimates due to immature technology of enhanced geothermal system (EGS) and scattered resources of hydrothermal systems. To circumvent these problems and reduce the thermal resistance of rocks, here a shallow depth enhanced geothermal system (SDEGS) is proposed, which can be implemented by fracturing the hydrothermal system. We find that, the service life for SDEGS is 14 years with heat output of 4521.1 kW. To extend service life, the hybrid SDEGS and solar energy heating system is proposed with 10,000 m2 solar collectors installed to store heat into geothermal reservoir. The service life of the hybrid heating system is 35 years with geothermal heat output of 4653.78 kW. The novelty of the present work is that the hybrid heating system can solve the unstable and discontinuous problems of solar energy without building additional back-up sources or seasonal storage equipment, and the geothermal thermal output can be adjusted easily to meet the demand of building thermal loads varying with outside temperature.

Download Full-text

Numerical analysis of injected current effects on thermal characteristics of vertical-cavity surface-emitting laser

Journal of Mechanical Science and Technology ◽

10.1007/s12206-018-0250-5 ◽

2018 ◽

Vol 32 (3) ◽

pp. 1463-1469

Author(s):

Jung Hee Lee ◽

Joo Hyun Moon ◽

Pei-Chen Su ◽

Seong Hyuk Lee

Keyword(s):

Numerical Analysis ◽

Thermal Characteristics ◽

Cavity Surface ◽

Vertical Cavity Surface ◽

Surface Emitting Laser ◽

Vertical Cavity

Download Full-text

Dipole and Convergent Single-Well Thermal Tracer Tests for Characterizing the Effect of Flow Configuration on Thermal Recovery

Geosciences ◽

10.3390/geosciences9100440 ◽

2019 ◽

Vol 9 (10) ◽

pp. 440 ◽

Cited By ~ 1

Author(s):

Jérôme de La Bernardie ◽

Olivier Bour ◽

Nicolas Guihéneuf ◽

Eliot Chatton ◽

Laurent Longuevergne ◽

...

Keyword(s):

Fractured Rock ◽

Tracer Tests ◽

Crystalline Rock ◽

Industrial Applications ◽

Thermal Recovery ◽

Geothermal System ◽

Distributed Temperature Sensing ◽

Flow Configuration ◽

Single Well ◽

Flow Configurations

Experimental characterization of thermal transport in fractured media through thermal tracer tests is crucial for environmental and industrial applications such as the prediction of geothermal system efficiency. However, such experiments have been poorly achieved in fractured rock due to the low permeability and complexity of these media. We have thus little knowledge about the effect of flow configuration on thermal recovery during thermal tracer tests in such systems. We present here the experimental set up and results of several single-well thermal tracer tests for different flow configurations, from fully convergent to perfect dipole, achieved in a fractured crystalline rock aquifer at the experimental site of Plœmeur (H+ observatory network). The monitoring of temperature using Fiber-Optic Distributed Temperature Sensing (FO-DTS) associated with appropriate data processing allowed to properly highlight the heat inflow in the borehole and to estimate temperature breakthroughs for the different tests. Results show that thermal recovery is mainly controlled by advection processes in convergent flow configuration while in perfect dipole flow field, thermal exchanges with the rock matrix are more important, inducing lower thermal recovery.

Download Full-text

Thermoporoelastic Analysis of a Single-Well Closed-Loop Geothermal System

Poromechanics VI ◽

10.1061/9780784480779.074 ◽

2017 ◽

Author(s):

Milad Ahmadi ◽

Arash Dahi Taleghani

Keyword(s):

Closed Loop ◽

Geothermal System ◽

Single Well

Download Full-text

Performance Analysis of Single-Well Enhanced Geothermal System for Building Heating

The Scientific World JOURNAL ◽

10.1155/2020/7927052 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Haijun Liang ◽

Xiaofeng Guo ◽

Tao Gao ◽

Lingbao Wang ◽

Xianbiao Bu

Keyword(s):

Volume Flow Rate ◽

Water Reservoir ◽

Hot Water ◽

Heat Extraction ◽

Geothermal System ◽

Enhanced Geothermal System ◽

Artificial Reservoir ◽

Reservoir Volume ◽

Thermal Output ◽

Single Well

Deep borehole heat exchanger (DBHE) technology does not depend on the existence of hot water reservoir and can be used in various regions. However, the heat extraction from DBHE can hardly be improved due to poor thermal conductivity of rocks. Here, a single-well enhanced geothermal system (SWEGS) is proposed, which has a larger heat-exchange area of artificial reservoir created by fracturing hydrothermal technology. We find that, due to heat convection between rocks and fluid, the extracted thermal output for SWEGS is 4772.73 kW, which is 10.64 times of that of DBHE. By changing the injection water temperature, volume flow rate, and artificial reservoir volume, it is easy to adjust the extracted thermal output to meet the requirement of building thermal loads varying with outdoor air temperature. Understanding these will enable us to better apply SWEGS technology and solve the fog and haze problem easily and efficiently.

Download Full-text