Open Access

ARTICLE

Performance Characteristics of Geothermal Single Well for Building Heating

by Jingying Li¹, Tiejun Zhu¹, Fengming Li¹, Dong Wang¹, Xianbiao Bu², Lingbao Wang^2,*

1 New Energy Development Center, Shengli Petroleum Administration Bureau, Ltd., Sinopec Group, Dongying, 257000, China
2 Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, 510640, China

* Corresponding Author: Lingbao Wang. Email:

(This article belongs to the Special Issue: Advanced Heat Pump Technologies for Renewable Energy Utilization)

Energy Engineering 2021, 118(3), 517-534. https://doi.org/10.32604/EE.2021.014464

Received 29 September 2020; Accepted 28 October 2020; Issue published 22 March 2021

Abstract

The single well geothermal heating (SWGH) technology has attracted extensive attention. To enhance heat extraction from SWGH, a mathematical model describing heat transfer is set up, and the key influence factor and heat transfer enhancement method are discussed by thermal resistance analysis. The numerical results show that the thermal resistance of rock is far greater than that of well wall and fluid. So, reducing rock thermal resistance is the most effective method for enhancing the heat extraction power. For geothermal well planning to drill: rock thermal resistance can be reduced by increasing well diameter and rock thermal conductivity; the temperature difference between liquid and rock can be raised by increasing well depth. For already existing geothermal well: an insulator with thermal conductivity of 0.2 W/(mK) is sufficient to preserve fluid enthalpy; a decrease in injection water temperature causes the increase of heat extraction power from geothermal well and heat output from heat pump simultaneously; increasing injection velocity causes the increase of pump power consumption and heat extraction power from geothermal well as well as net heat output between them. The entrepreneurs may refer to the above data in actual project. Furthermore, filling composite materials with high thermal conductivity into leakage formation is proposed in order to reduce the thermal resistance of rocks.

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Keywords

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