Energy analysis and performance assessment of a hybrid deep borehole heat exchanger heating system with direct heating and coupled heat pump approaches

Wang, Zeyuan; Wang, Fenghao; Li, Jun; Li, Yizhen; Wang, Ming; Luo, Yongqiang; Ma, Longxia; Zhu, Chao; Cai, Wanlong

doi:10.1016/j.enconman.2022.116484

Cited by 27 publications

(4 citation statements)

References 42 publications

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“…In earlier studies, field tests [19][20][21] and numerical simulations were carried out for a single MBHE in order to ensure its thermal extraction capacity. Due to the difference from the field test results (for example, the measured thermal extraction capacity of the single MBHE ranged from 158~288 kW [20]), the effects of the influencing factors, including the operating parameters (such as the inlet temperature [22,23] and flow velocity [24][25][26]), geological parameters (such as the rock-soil thermal conductivity [27,28], rock-soil heat capacity [29], and the geothermal gradient [30,31]), and the design parameters (such as the pipe depth [32], pipe diameter [33], and inner pipe thermal conductivity [34]) on the thermal extraction capacity of the MBHE were investigated using numerical analysis, which contributed an accurate evaluation of the thermal extraction capacity. However, relevant studies found that thermal interference exists in MBHE arrays [18,35,36].…”

Section: Introductionmentioning

confidence: 99%

Medium Rock-Soil Temperature Distribution Characteristics at Different Time Scales and New Layout Forms in the Application of Medium-Deep Borehole Heat Exchangers

Liu,

Zhang,

Wang

et al. 2023

Energies

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Medium-deep borehole heat exchangers (MBHEs) have received increasing attention with respect to building heating. To avoid the thermal interference of adjacent MBHEs, the temperature distribution characteristics of medium-deep rock soil were investigated in this work. The evolution of the maximum rock-soil thermal affected radius (MTAR) over a full lifecycle was analyzed. The results showed that the rock-soil thermal affected area (RTAA) continuously expanded in both the radial and vertical directions when the MBHE continuously extracted geothermal energy during a heating season. The factors of the thermal extraction load, fluid velocity, geothermal gradient, and pipe length, impacted the RTAA in the vertical direction, while rock-soil thermal conductivity affected the RTAA in both the radial and vertical directions. Furthermore, the thermal affected radius (TAR) in deeper formations was larger, reaching even 96 m, such that thermal interference between adjacent MBHEs was more likely to occur. The MTAR in shallow formations was limited to 20 m. Consequently, a new layout form, achieved by inclining the borehole, was proposed to increase the distance between adjacent MBHEs in deep formations. The recommended incline angle was equal to or larger than four times the TAR angle. This work provides a scientific reference for promoting the application of multiple MBHE arrays.

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Section: Introductionmentioning

confidence: 99%

Medium Rock-Soil Temperature Distribution Characteristics at Different Time Scales and New Layout Forms in the Application of Medium-Deep Borehole Heat Exchangers

Liu,

Zhang,

Wang

et al. 2023

Energies

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“…With the annual increase in atmospheric greenhouse gas emissions, global warming has become the most serious environmental problem mankind has ever faced. Tests show that from 1880 to 2012, the average global temperature rose by 0.85 owing to the influence of the greenhouse effect [2,3], which will continue to have a significant impact on natural ecology and social economy in the future [4,5].…”

Section: Introductionmentioning

confidence: 99%

A Review of Building Carbon Emission Accounting and Prediction Models

Gao

Wang

Wu³

et al. 2023

Buildings

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As an industry that consumes a quarter of social energy and emits a third of greenhouse gases, the construction industry has an important responsibility to achieve carbon peaking and carbon neutrality. Based on Web of Science, Science-Direct, and CNKI, the accounting and prediction models of carbon emissions from buildings are reviewed. The carbon emission factor method, mass balance method, and actual measurement method are analyzed. The top-down and bottom-up carbon emission accounting models and their subdivision models are introduced and analyzed. Individual building carbon emission assessments generally adopt a bottom-up physical model, while urban carbon emission assessments generally adopt a top-down economic input-output model. Most of the current studies on building carbon emission prediction models follow the path of “exploring influencing factors then putting forward prediction models based on influencing factors”. The studies on driving factors of carbon emission mainly use the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model, the Logarithmic Mean Divisia Index (LMDI) model, the grey correlation degree model, and other models. The prediction model is realized by the regression model, the system dynamics model, and other mathematical models, as well as the Artificial Neural Network (ANN) model, the Support Vector Machine (SVM) model, and other machine learning models. At present, the research on carbon emission models of individual buildings mainly focuses on the prediction of operational energy consumption, and the research models for the other stages should become a focus in future research.

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“…It is mentioned that there are many types of pipe materials used in the literature. It has been experimented with the use of steel pipes, − copper, , and ground pipes in GHE made of polyvinyl chloride (PVC). − As stated in prior works, − they used plastic tubes in their experiments, while , used polyethylene (PE). The last pipe (PE pipe) consists of (60%) polybutylene, then steel (14%) and PVC (8%), and it is one of the most widely used pipes in GHE systems. − HDPE pipes are currently being adopted in GHEs applications due to their high corrosion resistance despite their low thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

“… 35 It is mentioned that there are many types of pipe materials used in the literature. It has been experimented with the use of steel pipes, 36 − 38 copper, 25 , 39 and ground pipes in GHE made of polyvinyl chloride (PVC). 40 − 44 As stated in prior works, 45 − 47 they used plastic tubes in their experiments, while 48 , 49 used polyethylene (PE).…”

Section: Introductionmentioning

confidence: 99%

Cooling of a PVT System Using an Underground Heat Exchanger: An Experimental Study

Majeed,

Abdul-Zahra,

Mutasher

et al. 2023

ACS Omega

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In the recent decades, the researchers have been focused on the use of photovoltaic thermal (PVT) systems that provide the best performance and cooling for the photovoltaic panels. In this study, a PVT system consisting of a monocrystalline PV panel and a spiral heat exchanger was connected to an underground heat exchanger that is buried at a depth of 4 m below the surface of the earth. The procedure of the current study can be considered the first of its kind in the Middle East and North Africa region (based on the researchers' knowledge). The study was carried out on agricultural land in Baghdad-Iraq during months of July and August-2022, which are considered the harshest weather conditions for this city. The heat exchanger consists of a copper tube with a length of 21 m and formed in the shape of 3U, and it was buried in the earth and connected with a PVT system. The results of the study showed that the site chosen to bury the heat exchanger (4 m deep) has a stable soil temperature at 22.5 °C. From various volumetric flow rates, a flow rate of 0.18 l/s was selected which is considered the highest flow rate that can show vibration in the PVT system which may harm the system. The practical measurements showed that the largest difference in the surface temperatures of standalone PV and PVT was around 20 °C in favor of the latter. The electrical efficiency of the studied PVT system also increased to outperform the standalone PV system by 127.3%. By comparing the results of the current study with studies of water-cooled PVT systems from the literature, it is clear that the proposed system is feasible and has an acceptable efficiency in such harsh weather conditions tested during the experiment.

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Energy analysis and performance assessment of a hybrid deep borehole heat exchanger heating system with direct heating and coupled heat pump approaches

Cited by 27 publications

References 42 publications

Medium Rock-Soil Temperature Distribution Characteristics at Different Time Scales and New Layout Forms in the Application of Medium-Deep Borehole Heat Exchangers

Medium Rock-Soil Temperature Distribution Characteristics at Different Time Scales and New Layout Forms in the Application of Medium-Deep Borehole Heat Exchangers

A Review of Building Carbon Emission Accounting and Prediction Models

Cooling of a PVT System Using an Underground Heat Exchanger: An Experimental Study

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