scholarly journals Concepts and characteristics of a U-shaped docking well geothermal heat extraction system

2019 ◽  
Vol 37 (2) ◽  
pp. 865-883 ◽  
Author(s):  
Li Li ◽  
Xiantao Liu ◽  
Dong Xiao ◽  
Kun Huang ◽  
Shuxuan Li
Keyword(s):  
Heat Transfer ◽  
Geothermal Energy ◽  
Transfer Effect ◽  
Energy Utilization ◽  
Heat Extraction ◽  
Extraction System ◽  
Geothermal Heat ◽  
New Type ◽  
Deep Geothermal Energy ◽  
Effective Use

Environmental pollution in China is getting worse. The effective use of geothermal energy can solve the problem of greenhouse gas emissions. This paper introduces a new type of medium-deep geothermal energy utilization system named U-shaped docking well geothermal heat extraction system and analyzes its characteristics. The results show that the system can meet the needs of daily heating, and the heat transfer effect of this system is greater than the concentric casing heat exchange systems. This study provides a new idea for the use of medium-deep geothermal energy.

scholarly journals Improvement on the Calculation of Heat Transfer Rate for a New Type of Geothermal Energy Pile

IFCEE 2021 ◽  
2021 ◽  
Author(s):  
Yong Zou ◽  
Jie Huang ◽  
Fei Wang ◽  
John S. McCartney ◽  
Elahe Jafari
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Geothermal Energy ◽  
Transfer Rate ◽  
Energy Pile ◽  
New Type

The Prospects of Thermal Water Exploration in Ukraine

2017 ◽  
Vol 25 ◽  
pp. 28-34
Author(s):  
Ivan Sadovenko ◽  
Dmytro Rudakov ◽  
Oleksandr Inkin
Keyword(s):  
Water Temperature ◽  
Geothermal Energy ◽  
Thermal Water ◽  
Feasibility Studies ◽  
Heat Extraction ◽  
Circulation System ◽  
Geothermal Heat ◽  
Black Sea Coast ◽  
Environmentally Safe ◽  
Depth Ranges

The total resources of geothermal energy in Ukraine up to the depth of 10 km are estimated at 1022 J, which significantly exceeds the reserves of fossil fuel sources. Nevertheless, geothermal exploration in each specific case requires comprehensive thermodynamic and feasibility studies taking into account local geological, hydrogeological conditions, and depth ranges. To facilitate such kind of studies an analysis has been made for Ukraine’s territory with the identification of aquifers that can be potentially used including the Transcarpathian trough, the Volyn-Podil’ska plate, the Dnipro-Donets depression, and Black Sea coast area. Regarding high thermal water mineralization a geo-technological scheme has been justified for environmentally safe exploration that suggests a closed cycle including (i) pumping out water to the surface, (ii) heat extraction, and (iii) re-injection of water into the aquifer. A mathematical model developed to evaluate the geo-circulation system effectiveness for various conditions allows predicting the changes in water temperature during circulation, power consumption, and heat capacity. Besides, the model enables optimizing the system performance depending on pumped water temperature. We assessed the effectiveness of geothermal heat extraction with the geo-circulation system in terms of profitability and net the present value (NPV). According to the estimations made for aquifers in Ukraine the geo-circulation system can be operated with the positive NPV in many regions of the country depending on the aquifer depth, heat flux, and groundwater flow. The obtained results correlate to the world standards of rational exploitation of geothermal energy.

scholarly journals Simulation Analysis on the Heat Performance of Deep Borehole Heat Exchangers in Medium-Depth Geothermal Heat Pump Systems

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 754 ◽  
Author(s):  
Jiewen Deng ◽  
Qingpeng Wei ◽  
Shi He ◽  
Mei Liang ◽  
Hui Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Geothermal Energy ◽  
Heat Transfer Performance ◽  
Deep Borehole ◽  
Geothermal Heat ◽  
Temperature Heat ◽  
Geothermal Heat Pump ◽  
Borehole Heat Exchangers

Deep borehole heat exchangers (DBHEs) extract heat from the medium-depth geothermal energy with the depth of 2–3 km and provide high-temperature heat source for the medium-depth geothermal heat pump systems (MD-GHPs). This paper focuses on the heat transfer performance of DBHEs, where field tests and simulation are conducted to analyze the heat transfer process and the influence factors. Results identify that the heat transfer performance is greatly influenced by geothermal properties of the ground, thermal properties and depth of DBHEs and operation parameters, which could be classified into external factors, internal factors and synergic adjustment. In addition, the long-term operation effects are analyzed with the simulation, results show that with inlet water temperature setting at 20 °C and flow rate setting at 6.0 kg/s, the average outlet water temperature only drops 0.99 °C and the average heat extraction drops 9.5% after 20-years operation. Therefore, it demonstrates that the medium-depth geothermal energy can serve as the high-temperature heat source for heat pump systems stably and reliably. The results from this study can be potentially used to guide the system design and optimization of DBHEs.

Modeling Neighborhood-Scale Shallow Geothermal Energy Utilization - A Case Study in Berlin

2021 ◽  
Author(s):  
Shuang Chen ◽  
Jakob Randow ◽  
Katrin Lubashevsky ◽  
Steve Thiel ◽  
Tom Reinhardt ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
Model Comparison ◽  
Energy Utilization ◽  
Fluid Temperature ◽  
Load Curve ◽  
Geothermal Heat ◽  
Heating And Cooling ◽  
Shallow Geothermal Energy ◽  
Neighborhood Scale ◽  
Set Up

<p>Nowadays, utilizing shallow geothermal energy for heating and cooling buildings has received increased interest in the energy market. Among different technologies, large borehole heat exchanger (BHE) arrays are widely employed to supply heat to various types of buildings and districts. Recently, a 16-BHE array was constructed to extract shallow geothermal energy to provide heat to the newly-developed public building in Berlin. According to the previous geological survey, different non-homogeneous sedimentary layers exist in the subsurface, with variating groundwater permeabilities and thermal parameters. To estimate the performance of the BHE array system, and its sensitivity to different subsurface conditions, as well as to determine its thermal impact to the surrounding area, a comprehensive 3D numerical model has been set up according to the Berlin BHE array project. The model is simulated for 25 years with two finite element simulators, the open source code software OpenGeoSys (OGS) and the well-known commercial software FEFLOW. In the model, an annual thermal load curve is assigned to each BHE according to the real monthly heating demand. Although the way of the implementing parameters in the two programs differs from each other and some assumptions had to be made in the model comparison, the comparison result shows that both OpenGeoSys and FEFLOW produce in good agreement. Different parameters, e.g. the Darcy velocity, the thermal dispersivity of the aquifer, the surface temperature and the geothermal heat flux are investigated with respect to their impact on the underground and BHE circulation temperature. At last, the computed underground temperature and the brine fluid temperature evolution from OGS is benchmarked with the results from the model simulated in FEFLOW. The numerical experiments show that the the ground water field has the strongest influence on the brine fluid temperature within the BHEs. When the thermal dispersivity of the aquifer is considered, the mixing effect in the aquifer leads to a higher brine fluid temperature in the BHE, indicating a better thermal recharge of the system.</p>

scholarly journals Numerical Research and Parametric Study on the Thermal Performance of a Vertical Earth-to-Air Heat Exchanger System

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Zhening Zhang ◽  
Jindong Sun ◽  
Zhenxing Zhang ◽  
Xinxin Jia ◽  
Yang Liu
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Geothermal Energy ◽  
Energy Utilization ◽  
Construction Costs ◽  
System A ◽  
Air Supply ◽  
Low Energy Buildings ◽  
New Type ◽  
Condensed Water

The earth-to-air heat exchanger (EAHE) system, as a clean and efficient shallow geothermal energy application technology, has obvious effects in reducing the energy consumption of passive low-energy buildings. The traditional horizontal EAHE system is difficult to apply and popularize due to its large occupation, unfavorable shallow soil temperature, and difficulty in timely centralized discharge of condensed water. This paper proposes a new type of vertical earth-to-air heat exchanger (VEAHE) system. The VEAHE system has a number of advantages such as smaller occupation, efficient geothermal energy utilization, and centralized discharge of condensed water. In order to evaluate the influence of different parameters on the thermal performance of the VEAHE system, a mathematical model of the VEAHE system was developed. And, the data calculated by the model highly tallied with the experimental data. The results showed that laying thermal insulation layers at the outlet of risers will effectively restrain the interference of downcomers to risers. It is advisable to set thickness and length of the insulation layer at 30 mm and 3 m. Considering the compromise between thermal performance and construction costs of the VEAHE system, the length of the ducts at 30–50 m and the diameter at 150–250 mm are recommended. The air supply volume of a single shaft can reach 500–1200 m3/h as the air velocity reaches 3–7 m/s.

Heat Transfer and Thermal Balance Analysis of an Aluminum Electrolysis Cell Side Lines: A Heat Recovery Capability and Feasibility Study

2013 ◽  
Author(s):  
Yaser Mollaei Barzi ◽  
Mohsen Assadi
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Heat Recovery ◽  
Side Wall ◽  
Operating Conditions ◽  
Energy Utilization ◽  
Heat Extraction ◽  
Electrolysis Cell ◽  
Transfer Model ◽  
Side Walls

In this study, a preliminary investigation is carried out concerning the possibility and feasibility of recovering part of the side walls heat loss to use it in an energy utilization system. For this purpose, a simple smart heat transfer model is developed for the aluminum smelter side lines accounting for the dynamic ledge profile variations and phase change. Using the model, the total side wall heat loss is estimated and evaluated in different operating conditions of the cell. The system flexibility and self-adjustment ability are taken in to account to find the appropriate solution for the heat extraction system. Using the above-mentioned analysis, the heat recovery strategy and also the possible and applicable alternatives for the side walls heat collection and utilization system are investigated.

scholarly journals A WebGIS portal for exploration of deep geothermal energy based on geological and geophysical data

2016 ◽  
Vol 35 ◽  
pp. 23-26 ◽  
Author(s):  
Henrik Vosgerau ◽  
Anders Mathiesen ◽  
Morten Sparre Andersen ◽  
Lars Ole Boldreel ◽  
Morten Leth Hjuler ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
District Heating ◽  
Geophysical Data ◽  
Heat Extraction ◽  
Depth Interval ◽  
Field Energy ◽  
Geothermal Resources ◽  
Geothermal Reservoirs ◽  
Geological Conditions ◽  
Deep Geothermal Energy

The Danish subsurface contains deep geothermal resources which may contribute for hundreds of years to the mixed Danish energy supply (Mathiesen et al. 2009). At present only a limited fraction of these resources are utilised in three existing geothermal power plants in Thisted, Margretheholm and Sønderborg (Fig. 1) where warm formation water is pumped to the surface from a production well and, after heat extraction, returned to the subsurface in injection wells (Fig. 2). Deep geothermal energy has the advantage of being a sustainable and environmentally friendly energy source which is furthermore independent of climate and seasonal variations, in contrast to wind and solar energy. The implementation of deep geothermal energy for district heating replacing conventional energy sources, especially coal and oil, may thus lead to a considerable reduction in the emission of greenhouse gases. There are therefore good reasons to include geothermal energy as a central component in Denmark’s future supply of energy for district heating. Furthermore, heat-demanding industries may consider the possibility to integrate geothermal energy and energy storage in their production process. In order to facilitate the use of geothermal energy, a broad majority in the Danish parliament has granted financial support for initiatives within the geothermal field (Energy policy agreement of March 22, 2012). The present paper deals with one of the outcomes of this agreement, namely a WebGIS portal with an overview of existing and interpreted geological and geophysical data. This will be relevant for all stakeholders in the exploration of deep geothermal resources in the Danish subsurface. The portal focuses on geothermal reservoirs within the 800–3000 m depth interval and provides an overview of the amount and quality of existing geodata, the geological composition of the subsurface, and interpreted thematic products such as geological maps of potential geothermal reservoirs. A comprehensive map from the portal showing onshore and nearoffshore locations where the geological conditions are potentially suitable for extraction of deep geothermal energy in Denmark is shown in Fig. 1. Many of the thematic maps are outcomes of the project The geothermal energy potential in Denmark – reservoir properties, temperature distribution and models for utilization under the programme Sustainable Energy and Environment funded by the Danish Agency for Science, Technology and Innovation.

scholarly journals Selected technical aspects of well construction for geothermal energy utilization in Poland

2018 ◽  
Vol 7 (2) ◽  
pp. 188-199 ◽  
Author(s):  
Barbara Tomaszewska ◽  
Anna Sowiżdżał ◽  
Anna Chmielowska
Keyword(s):  
Geothermal Energy ◽  
Energy Utilization ◽  
Injection Wells ◽  
Geothermal Resources ◽  
Geothermal Heating ◽  
Current State ◽  
Exploratory Wells ◽  
Deep Boreholes ◽  
Deep Geothermal Energy ◽  
Domestic Law

Abstract Geothermal resources have been used in Poland since the 90s of the last century. Since then, several geothermal heating plants, recreation and balneological centers have been operated. Accessing geothermal resources is possible due to deep boreholes that are either brand-new wells or old but revitalized petroleum and/or exploratory wells. In this case, the construction of production and injection wells is of significant importance. The utilization of deep geothermal energy resources is strongly dependent on the binding domestic law regulations – primarily in case of acquiring the concession enabling an execution of geological and drilling works, and subsequently a proper exploitation. The paper presents the current state of development of the geothermal energy sector in Poland, indicating examples of exploitation systems based on deep boreholes. Furthermore, the constructions of existing wells are discussed extensively. The existing examples of old but reconstructed wells in Poland, are characterized. The importance of national law and its influence on the development of a geothermal investment is highlighted, as well.

The Effect of a Rotating Heat Pipe in a Brazed Diamond Grinding Wheel on Grinding Temperature

2009 ◽  
Vol 416 ◽  
pp. 274-278 ◽  
Author(s):  
Ke Ma ◽  
Hong Jun Xu ◽  
Yu Can Fu
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Transfer Effect ◽  
Grinding Wheel ◽  
Grinding Temperature ◽  
Enhanced Heat Transfer ◽  
Diamond Grinding Wheel ◽  
Diamond Grinding ◽  
New Type ◽  
Measurement Experiment

A new type of brazed diamond grinding wheel with a rotating heat pipe is developed to effectively remove the heat generated in the grinding zone meanwhile minimize the pollution and contamination of the environment. A grinding temperature-measurement experiment of titanium alloy was conducted to evaluate enhanced heat transfer effect of the rotating heat pipe on the grinding zone. The experiment results show that, when grinding using the wheel with heat pipe the grinding temperature decreases 30% than that using the wheel without heat pipe.

scholarly journals Conjugated Numerical Approach for Modelling DBHE in High Geothermal Gradient Environments

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6107
Author(s):  
Theo Renaud ◽  
Patrick G. Verdin ◽  
Gioia Falcone
Keyword(s):  
Heat Transfer ◽  
Geothermal Gradient ◽  
Numerical Approach ◽  
Heat Extraction ◽  
Working Fluid ◽  
Return Flow ◽  
Geothermal Systems ◽  
Cfd Modelling ◽  
Geothermal Heat ◽  
High Geothermal Gradient

Geothermal is a renewable energy source that can be untapped through various subsurface technologies. Closed geothermal well solutions, such as deep geothermal heat exchangers (DBHEs), consist of circulating a working fluid to recover the available heat, with less dependency on the local geological settings than conventional geothermal systems. This paper emphasizes a double numerical method to strengthen the assessment of DBHE performances. A computational fluid dynamics (CFD) commercial software and the 1D coupled wellbore-reservoir geothermal simulator T2Well have been used to investigate the heat transfer and fluid flow in a vertical DBHE in high geothermal gradient environments. The use of constant water properties to investigate the energy produced from DBHEs can lead to underestimating the overall heat transfer at high temperature and low mass flow rate. 2D axisymmetric CFD modelling improves the understanding of the return flow at the bottom of the DBHE, readjusting and better estimating the pressures losses commonly obtained with 1D modelling. This paper highlights the existence of convective cells located at the bottom of the DBHE internal tubing, with no significant effects due to the increase of injected water flow. Both codes are shown to constrain the numerical limitations to access the true potential of geothermal heat extraction from DBHEs in high geothermal gradient environments and demonstrate that they can be used for geothermal energy engineering applications.

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