Open Access

ARTICLE

Thermal Performance and Economic Efficiency Comparison of Typical Shallow and Medium-Deep Borehole Heat Exchanger Heating Systems in Xi’an, China

Yuze Xue¹, Li Kou^2,3, Guosheng Jia^4,*, Liwen Jin⁴, Zhibin Zhang⁴, Jianke Hao⁴, Lip Huat Saw^5,*

1 Key Laboratory of Coal Resources Exploration and Comprehensive Utilization, Ministry of Natural Resources, Xi’an, 710021, China
2 Shanghai Engineering Research Center for Shallow Geothermal Energy, Shanghai, 200072, China
3 Shanghai Geological Engineering Exploration (Group) Co., Ltd., Shanghai, 200072, China
4 School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an, 710049, China
5 Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Kajang, 43000, Selangor, Malaysia

* Corresponding Authors: Guosheng Jia. Email: ; Lip Huat Saw. Email:

Energy Engineering 2025, 122(3), 1005-1024. https://doi.org/10.32604/ee.2025.059198

Received 30 September 2024; Accepted 26 December 2024; Issue published 07 March 2025

Abstract

Geothermal energy, a form of renewable energy, has been extensively utilized for building heating. However, there is a lack of detailed comparative studies on the use of shallow and medium-deep geothermal energy in building energy systems, which are essential for decision-making. Therefore, this paper presents a comparative study of the performance and economic analysis of shallow and medium-deep borehole heat exchanger heating systems. Based on the geological parameters of Xi’an, China and commonly used borehole heat exchanger structures, numerical simulation methods are employed to analyze performance and economic efficiency. The results indicate that increasing the spacing between shallow borehole heat exchangers can effectively reduce thermal interference between the pipes and improve heat extraction performance. As the flow rate increases, the outlet water temperature ranges from 279.3 to 279.7 K, with heat extraction power varying between 595 and 609 W. For medium-deep borehole heat exchangers, performance predictions show that a higher flow rate results in greater heat extraction power. However, when the flow rate exceeds 30 m³/h, further increases in flow rate have only a minor effect on enhancing heat extraction power. Additionally, the economic analysis reveals that the payback period for shallow geothermal heating systems ranges from 10 to 11 years, while for medium-deep geothermal heating systems, it varies more widely from 3 to 25 years. Therefore, the payback period for medium-deep geothermal heating systems is more significantly influenced by operational and installation parameters, and optimizing these parameters can considerably shorten the payback period. The results of this study are expected to provide valuable insights into the efficient and cost-effective utilization of geothermal energy for building heating.

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