Analysis of heat extraction performance and long-term sustainability for multiple deep borehole heat exchanger array: A project-based study

Cai, Wanlong; Wang, Fenghao; Chen, Shuang; Chen, Chaofan; Li, Jun; Deng, Jiewen; Kolditz, Olaf; Shao, Haibing

doi:10.1016/j.apenergy.2021.116590

Cited by 84 publications

(42 citation statements)

References 36 publications

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“…The related calculation model is proved to be of the capability to reproduce the variation of long-term heat extracting performance for the DBHE system. As for the DBHE model, a thorough model validation has been conducted based on a multi-DBHE pilot project in Xi'an (Cai et al, 2021). In this study, the DBHE model established in OpenGeoSys considering the geothermal gradient is also verified based on the analytical DBHE solution proposed by Beier (2020).…”

Section: Model Verificationmentioning

confidence: 99%

“…Based on the parameter settings in Table 1, the models in this study are then further extended for several different drilling depths from approximately 2,000 to 3,000 m to meet our purpose in solving the scientific questions proposed in Section 1. According to the published geological data (Ren et al, 2020) and in situ test results from realistic projects (Cai et al, 2021), the scenarios are configured based on the geological conditions and geothermal features in Weihe Basin (see Table 2).…”

Section: Model Configurationmentioning

confidence: 99%

“…Moreover, based on the assumption of homogeneous media in the subsurface, the typical linear geothermal gradient in Xi'an is set as 35.0 °C/km (Ren et al, 2020), serving as the initial condition of the model. To prevent the thermal plume from interfering with the domain boundary, the domain size is set to be 300 × 300 × (depth + 200) m. The mesh density and time step size of the simulation are chosen based on our previous work (Cai et al, 2021), in which the time step size of the simulation is first chosen to be 1 h in the heating season and later increased to 6 h during the recovery period. Furthermore, the heat pump and water pump units are introduced to our model.…”

Section: Model Configurationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…In our previous work (Chen et al, 2019a;Cai et al, 2021), a numerical model established by OpenGeoSys (OGS) software was developed for simulating the coaxial DBHE and surrounding soil. The model had been validated against experimental data measured from several pilot projects in Xi'an, Weihe Basin (Cai et al, 2021). In these studies, the accuracy of our model simulating the long-term heat extraction performance of a DBHE and the surrounding subsurface is thoroughly illustrated.…”

Section: Introductionmentioning

confidence: 99%

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Long-term Performance Evaluation and Economic Analysis for Deep Borehole Heat Exchanger Heating System in Weihe Basin

et al. 2022

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To reduce carbon emission and achieve carbon neutrality, deep geothermal energy has been widely extracted for building heating purpose. In recent years, deep borehole heat exchanger (DBHE) heating system has gained more attention, especially in densely populated urban areas in Weihe Basin, northern China. The long-term performance and the economic feasibility are essential for the system application. In this work, the DBHE model implemented in OpenGeoSys software is verified against an analytical solution and a comprehensive economic analysis approach is further proposed. Then the short-term thermal performance tests are conducted to obtain the tentative heat extraction capacity for long-term simulation. The long-term simulations are further performed with the heat pump unit under the adjusted tentative heat extraction rate imposed on the DBHE. Finally, a comprehensive economic analysis is applied to the DBHE heating system over 15 heating seasons. Results show that the minimum coefficient of performance value of the heat pump is 4.74 over the operation of 15 heating seasons. With the increase of depth for the DBHE, the total electricity consumption of heat pumps and circulation pumps has a prominent promotion. With the comprehensive approach of economic analysis, the depth of 2,600 m has the lowest levelized cost of total heating amount, which is the best system design for the application in Weihe Basin. The present results are specific to the conditions in Weihe Basin, but the proposed economic analysis approach is generic.

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Section: Model Verificationmentioning

confidence: 99%

Section: Model Configurationmentioning

confidence: 99%

Section: Model Configurationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Long-term Performance Evaluation and Economic Analysis for Deep Borehole Heat Exchanger Heating System in Weihe Basin

et al. 2022

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Performance analysis of deep borehole heat exchangers for decarbonization of heating systems

Lund

2024

Deep Underground Science and Engineering

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Meeting the climate change mitigation targets will require a substantial shift from fossil to clean fuels in the heating sector. Heat pumps with deep borehole exchangers are a promising solution to reduce emissions. Here the thermal behavior of deep borehole exchangers (DBHEs) ranging from 1 to 2 km was analyzed for various heat flow profiles. A strong correlation between thermal energy extraction and power output from DBHEs was found, also influenced by the heating profile employed. Longer operating time over the year typically resulted in higher energy production, while shorter one yielded higher average thermal power output, highlighting the importance of the choice of heating strategy and system design for optimal performance of DBHEs. Short breaks in operation for regenerating the borehole, for example, with waste heat, proved to be favorable for the performance yielding an overall heat output close to the same as with continuous extraction of heat. The results demonstrate the usefulness of deep boreholes for dense urban areas with less available space. As the heat production from a single DBHE in Finnish conditions ranges from half up to even a few GWh a year, the technology is best suitable for larger heat loads.

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A geothermal energy heat exchange system suitable for abandoned mines and its optimization

Sun

Zhang

et al. 2023

Heat Mass Transfer

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Analysis of heat extraction performance and long-term sustainability for multiple deep borehole heat exchanger array: A project-based study

Cited by 84 publications

References 36 publications

Long-term Performance Evaluation and Economic Analysis for Deep Borehole Heat Exchanger Heating System in Weihe Basin

Long-term Performance Evaluation and Economic Analysis for Deep Borehole Heat Exchanger Heating System in Weihe Basin

Performance analysis of deep borehole heat exchangers for decarbonization of heating systems

A geothermal energy heat exchange system suitable for abandoned mines and its optimization

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