Taking the Gaoshangpu-Liuzan geothermal field in the Nanpu sag of the Bohai Bay Basin as the research object, this paper discusses the geological conditions and potential of the geothermal resources of the Guantao For...Taking the Gaoshangpu-Liuzan geothermal field in the Nanpu sag of the Bohai Bay Basin as the research object, this paper discusses the geological conditions and potential of the geothermal resources of the Guantao Formation in the study area, and introduces the development practice of geothermal energy heating in Caofeidian. The average buried depth of the Guantao Formation is 1500–2500 m, the lithology is dominated by sandy conglomerate, and the average thickness of thermal reservoir is 120–300 m. The average porosity of thermal reservoir is 28%–35%, the permeability is(600–2000)×10^(-3) μm^(2), and the temperature of thermal reservoir is 70–110 ℃. The formation has total geothermal resources of 13.79×10^(18) J, equivalent to 4.70×10^(8) t of standard coal. Based on a large amount of seismic and drilling data from oil and gas exploration, this study carried out high quality target area selection, simulation of sandstone thermal reservoir, and production and injection in the same layer. The geothermal heating project with distributed production and injection well pattern covering an area of 230×10^(4) m^(2) was completed in the new district of Caofeidian in 2018. The project has been running steadily for two heating seasons, with an average annual saving of 6.06×10^(4) t of standard coal and a reduction of 15.87×10^(4) t of carbon dioxide, achieving good economic and social benefits. This project has proved that the Neogene sandstone geothermal reservoir in eastern China can achieve sustainable large-scale development by using the technology of "balanced production and injection in the same layer". It provides effective reference for the exploration and development of geothermal resource in oil and gas-bearing basins in eastern China.展开更多
This study, using laboratory experiments and scaling analysis, evaluates the influence of geothermal heating on global oceanic circulation. Upon a well-developed large-scale convective flow, an additional heat flux pe...This study, using laboratory experiments and scaling analysis, evaluates the influence of geothermal heating on global oceanic circulation. Upon a well-developed large-scale convective flow, an additional heat flux perturbation 5F/F is employed. The increments of flow and thermal properties, including eddy diffusivity K7, flow velocity Vand bottom temperature Tb, are found to be independent of the applied heat flux F. Together with the scaling analysis of convective flow at different configurations, where the flow is thermally driven in the relatively low or extremely high turbulent thermal convections or the horizontal convection, the variances of flow properties, 6KT/KTand 6V/V, are found to be close to 0.5% and 0.75% at 5F/F=2%. This means that the small heat flux perturbation plays a negligible role in the global convective flow. However, 6Tb/ATis found to be 1.5% at 8F/F=2%, which would have a significant effect in the local region. The results might provide a clue to understanding the influence of geothermal heating on global oceanic circulation. It is expected that geothermal heating will contribute less than 1% in turbulent mixing and volume flux to global oceanic circulation, so its influence can be negligible in this situation. However, when it comes to the local environment, the influence of geothermal heating cannot be ignored. For example, temperature increases of about 0.5℃ with geothermal heating would have a significant effect on the physical environments within the benthic boundary layer.展开更多
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 buildi...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 simulationmethods 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 m^(3)/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.展开更多
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 t...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.展开更多
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.Her...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.展开更多
Geothermal heat flow(GHF)is crucial for characterizing the Earth's thermal state.Compared to other regions worldwide,GHF measurements of South America are relatively sparse for mapping GHF over the continent based...Geothermal heat flow(GHF)is crucial for characterizing the Earth's thermal state.Compared to other regions worldwide,GHF measurements of South America are relatively sparse for mapping GHF over the continent based on traditional models.Here we apply the machine learning(ML)techniques to predict the GHF in South America.By comparing the global model,ML finds that South American subduction zones are hotter than the global model due to large-scale magmatism,which leads to the higher shallow arc temperatures than canonical thermomechanical and global models.Combining ML model with the local singularity analysis of heat flows,active volcanoes,and igneous rock samples,it is suggested that geothermal anomalies along the Andean Mountain Range are spatially correlated with magmatic activity in the subduction zone.It is concluded that the ML methods may provide reliable GHF prediction in regions like South America,where GHF measurements are limited and uneven.展开更多
Geothermal energy utilization in China had been promoted actively during the 13^(th)Five-Year Plan period(2016-2020),with resultant achievements showing unique Chinese characteristics.Buildings(measured by areas)heate...Geothermal energy utilization in China had been promoted actively during the 13^(th)Five-Year Plan period(2016-2020),with resultant achievements showing unique Chinese characteristics.Buildings(measured by areas)heated/cooled by intermediate-to-deep geothermal energy increased more rapidly than those by shallow geothermal energy.Geothermal power generation was restricted by the distribution of the resource and the sufficiency of local power supply.With the proposition of“dual carbon goal”by the central government of China and the coming era of great development of renewable energy,geothermal energy will be provided more development opportunities in room heating/cooling and power generation in the country ever than before.However,tackling technology bottlenecks and introduction of appropriate policy support are still urgently needed for nurturing a healthy environment for geothermal industry.Analysis suggests that a near-to medium-term development of geothermal energy shall be focused on a comprehensive and efficient utilization both through heating/cooling and power generation.Room heating/cooling by intermediate-to-deep and shallow geothermal energy shall be promoted nationwide according to local resource endowment and economic conditions.Geothermal power generation in Yunnan and Xizang shall be pushed forward in an orderly way.For medium-and long-term development,focus shall be put on power generation by using low to medium temperature geothermal energy and hot dry rocks.The"hot spring+"model shall be adapted in steps on a regular basis.To achieve these,measures including attaching importance to tackling key technologies,promoting standards for geothermal energy development and utilization,strengthening geothermal energy exploration and evaluation,and seeking for necessary policy support shall be taken.展开更多
Hujiatai Village, Xiong County, Hebei Province was nominated as the experimental unit of new countryside construction by Hebei Province in 2008. In order to make Hujiatai Village become a new countryside model with fr...Hujiatai Village, Xiong County, Hebei Province was nominated as the experimental unit of new countryside construction by Hebei Province in 2008. In order to make Hujiatai Village become a new countryside model with friendly ecological and environmental conditions, local energy resources should be considered. In this study, a mode of 'geothermal energy extraction-heat exchange-space heating-reinjection' was adopted to supply heat to resident houses in Hujiatai Village cooperating with a geothermal development entity based on the abundant geothermal resources, thereby constructing a clean, economic and autarkic new countryside energy system, which avoids utilization of fossil-energy, reduces emission of greenhouse gases and generation of solid coal cinder, protecting air and land environment, improving life quality of the people and building a typical model for Hebei Province and even for the whole country.展开更多
The renewable energy will play significant role in the world primary energy consumption in the future. Geothermal energy is immense with 5 000 EJ/a of technical potential, and geothermal heat pumps (GHPs) are one of t...The renewable energy will play significant role in the world primary energy consumption in the future. Geothermal energy is immense with 5 000 EJ/a of technical potential, and geothermal heat pumps (GHPs) are one of the fastest growing applications of renewable energy in the world with annual increases of 10 % and much faster in China. With high coefficient of performance (COP) up to 6, GHPs make efficiency of primary energy more than 240 % with assumed a 40 % of electricity generation efficiency, which means energy savings and CO2 emission reduction. In this paper,the geothermal resources and its utilization are talked about, and GHPs technology was introduced. Due to its high efficiency, there will be energy savings by using GHPs. There is also CO2 emission reduction because of using geothermal heat pumps, which is analyzed in the end.展开更多
The Oligocene Yacheng Fm contains the most important source rocks that have been confirmed by exploratory wells in the Qiongdongnan Basin.The efficiency of these source rocks is the key to the breakthrough in natural ...The Oligocene Yacheng Fm contains the most important source rocks that have been confirmed by exploratory wells in the Qiongdongnan Basin.The efficiency of these source rocks is the key to the breakthrough in natural gas exploration in the study area.This paper analyzes the hydrocarbon potential of each sag in this basin from the perspective of control of both source rocks and geothermal heat.Two types of source rocks occur in the Yacheng Fm,namely mudstone of transitional facies and mudstone of neritic facies.Both of them are dominated by a kerogen of type-III,followed by type-II.Their organic matter abundances are controlled by the amount of continental clastic input.The mudstone of transitional facies is commonly higher in organic matter abundance,while that of neritic facies is lower.The coal-measure source rocks of transitional facies were mainly formed in such environments as delta plains,coastal plains and barrier tidal flat-marshes.Due to the control of Cenozoic lithosphere extension and influence of neotectonism,the geothermal gradient,terrestrial heat flow value(HFV)and level of thermal evolution are generally high in deep water.The hot setting not only determines the predominance of gas generation in the deep-water sags,but can promote the shallow-buried source rocks in shallow water into oil window to generate oil.In addition to promoting the hydrocarbon generation of source rocks,the high geothermal and high heat flow value can also speed up the cracking of residual hydrocarbons,thus enhancing hydrocarbon generation efficiency and capacity.According to the theory of joint control of source quality and geothermal heat on hydrocarbon generation,we comprehensively evaluate and rank the exploration potentials of major sags in the Qiongdongnan Basin.These sags are divided into 3 types,of which type-I sags including Yanan,Lingshui,Baodao,Ledong and Huaguang are the highest in hydrocarbon exploration potential.展开更多
There are two sets of thermal reservoirs with different rock types in the Gucheng geothermalfield of Hebei Province,namely the Ordovician fractured carbonate thermal reservoir and the Neogene Guantao sandstone thermal...There are two sets of thermal reservoirs with different rock types in the Gucheng geothermalfield of Hebei Province,namely the Ordovician fractured carbonate thermal reservoir and the Neogene Guantao sandstone thermal reservoir,each developed using independent well networks.The energy demand per unit area in the region is high,and the existing geothermal development methods cannot meet the regional energy demand.For this type of block,combined with the development characteristics of different types of thermal reservoirs,numerical simulation methods were used to study the geothermal development trends of Ordovician fractured carbonate reservoirs and Neogene Guantao Formation sandstone reservoirs.When simulating sandstone thermal storage,priority should be given to demonstrating the optimal rechargeflow rate,while in simulating carbonate thermal storage,the focus should be on considering the influence of fracture development direction on development trends.Through numerical simulation of thermal storage development and combined with well network design,the optimal well spacing,production reinjectionflow rate,and reinjection temperature for two sets of thermal reservoirs developed using the same well network were determined.It is predicted that the average heatflow in the study can increase by 47.8%.This study presents reasonable development technical countermeasures to maximize the heating capacity of the geothermal development zone and provides an effective reference for the efficient development of similar geothermal resources in the Bohai Bay Basin.展开更多
In 2017,China’s central government approved the national strategy to build Xiong’an New Area(XNA,100 km southwest to Beijing),which was announced as a"millennium strategy"and a"demo area"for a su...In 2017,China’s central government approved the national strategy to build Xiong’an New Area(XNA,100 km southwest to Beijing),which was announced as a"millennium strategy"and a"demo area"for a sustainable,modern,and innovative urban model.Xiong’an will draw in as much as$380 billion investment and is expected to help accelerate the development of the wider Beijing-Tianjin-Hebei(Jingjinji)Area.In this paper,present subsidence in the XNA area is investigated using InSAR observations for the first time.The 24 SAR images acquired by European Space Agency’s Sentinel-1 satellites during the period from June 2017 to July 2018 suggest that in the north of Xiong County,the subsidence rate reaches up to 90 mm/y,which is highly correlated with the exploitation of geothermal drilling.As the construction in the XNA area will significantly accelerate and its high-quality development,the InSAR findings could provide valuable information for future sustainable urban planning and underground infrastructure construction.展开更多
The Elkon Horst is a geological structure that consists of heterogeneous strata with highly variable geocryological and temperature conditions. Gaining accurate knowledge of permafrost distribution patterns within thi...The Elkon Horst is a geological structure that consists of heterogeneous strata with highly variable geocryological and temperature conditions. Gaining accurate knowledge of permafrost distribution patterns within this structure is of both scientific and practical importance. In mountainous terrain, the ground thermal regime is controlled by both surface and subsurface conditions. Surface conditions include snow cover characteristics, the presence or absence of vegetation, vegetation density, etc.. In contrast, subsurface conditions involve rock lithology or petrography, density, quantity and depth of fissures, groundwater, etc.. This article examines ground thermal regimes in various geomorphological settings based on temperature measurement data from geotechnical boreholes. The occurrence and extent of permafrost were evaluated for the entire horst area using direct and indirect methods. The maximum permafrost thickness measured in the Elkon Horst is 330 m, and the estimated maximum is 450 m at higher elevations. Thermophysical properties were determined for the major rock types, and the geothermal heat flux was estimated for the study area. The thermal conductivities were found to vary from 1.47 to 4.20 W/(m·K), and the dry bulk densities to range between 2,236 kg/m~3 and 3,235 kg/m~3. The average geothermal heat flux was estimated to be 44 mW/m~2.展开更多
To effectively enhance the energy utilisation rate of the park integrated energy system(PIES),and to strengthen the stability and reliability of PIES power supply,geothermal heat pumps and thermal/cool storage devices...To effectively enhance the energy utilisation rate of the park integrated energy system(PIES),and to strengthen the stability and reliability of PIES power supply,geothermal heat pumps and thermal/cool storage devices are introduced.An optimisation scheduling method for PIES based on maximum power point tracking(MPPT)and mixed integer linear programming is proposed.Firstly,taking into account the fluctuating and unpredictable nature of wind and solar power generation,the tip speed ratio(TSR)and incremental conductance(IncCond)methods are applied for MPPT of wind and solar power output.Secondly,geothermal heat pumps and thermal/cool storage devices are integrated into PIES to construct a typical daily multienergy flow coupled optimisation scheduling model.Lastly,the overall operational expenses and ecological impacts of PIES are comprehensively considered for an economic and environmental comparison analysis.Case study results verify that the introduction of geothermal heat pumps and thermal/cool storage devices enhances the energy efficiency and bolsters the overall economic and ecological effectiveness of PIES.展开更多
Ground source heat pump (GSHP) systems for HVAC have aroused more and more interest in China in recent years because of their higher energy efficiency compared with conventional systems. The design and performance...Ground source heat pump (GSHP) systems for HVAC have aroused more and more interest in China in recent years because of their higher energy efficiency compared with conventional systems. The design and performance simulation of the geothermal heat exchangers is vital to the success of this technology. In GSHP systems, the load of the geothermal heat exchanger varies greatly and is usually discontinuous even during a heating or cooling season. This paper outlines a heat transfer model for geothermal heat exchangers. The model was used to study the influence of the discontinuous operation of the heat pumps on the performance of the geothermal heat exchangers. A simple and practical approach is presented for sizing the geothermal heat exchangers.展开更多
The heat transfer perfonmance of a vertical two-phase closed thermosyphon(TPCT)used in a geothermal heat pump was experimentally investigated.The TPCT is a verticalplain steel pipe with inner diameter of 114 mm and bo...The heat transfer perfonmance of a vertical two-phase closed thermosyphon(TPCT)used in a geothermal heat pump was experimentally investigated.The TPCT is a verticalplain steel pipe with inner diameter of 114 mm and bored 368 m deep underground.Carbon dioxide(CO_(2))is used as working fluid.In the TPCT there is no condensation section.CO_(2)is condensed by the evaporator pf the heat pump,flows into the head of the TPCT and nuns down as a falling film along the inner wall of the pipe.For the heat transfer simulation in the TPCT,a quasi-dynamic model in which the mass transfer between the liquid and vapor phases as well as the conduction heat transfer from the surrounding soil towards the pipe is treated dynamically.However the film flow modeling is based on the Nusselt theory of frilm condenssation.The compauison of the experimental data with the numerical simulation is presented and discussed.展开更多
A comprehensive thermo-economic model combining a geothermal heat mining system and a direct supercritical CO_(2) turbine expansion electric power generation system was proposed in this paper.Assisted by this integrat...A comprehensive thermo-economic model combining a geothermal heat mining system and a direct supercritical CO_(2) turbine expansion electric power generation system was proposed in this paper.Assisted by this integrated model,thermo-economic and optimization analyses for the key design parameters of the whole system including the geothermal well pattern and operational conditions were performed to obtain a minimal levelized cost of electricity(LCOE).Specifically,in geothermal heat extraction simulation,an integrated wellbore-reservoir system model(T2Well/ECO_(2)N)was used to generate a database for creating a fast,predictive,and compatible geothermal heat mining model by employing a response surface methodology.A parametric study was conducted to demonstrate the impact of turbine discharge pressure,injection and production well distance,CO_(2) injection flowrate,CO_(2) injection temperature,and monitored production well bottom pressure on LCOE,system thermal efficiency,and capital cost.It was found that for a 100 MWe power plant,a minimal LCOE of$0.177/kWh was achieved for a 20-year steady operation without considering CO_(2) sequestration credit.In addition,when CO_(2) sequestration credit is$1.00/t,an LCOE breakeven point compared to a conventional geothermal power plant is achieved and a breakpoint for generating electric power generation at no cost was achieved for a sequestration credit of $2.05/t.展开更多
INTRODUCTION Community Housing Partners(CHP)is a 501(c)(3)community development corporation that serves the needs of low-income and low-wealth individuals and families in the southeast.CHP’s mission is to create affo...INTRODUCTION Community Housing Partners(CHP)is a 501(c)(3)community development corporation that serves the needs of low-income and low-wealth individuals and families in the southeast.CHP’s mission is to create affordable,green,sustainable housing opportunities and services for the people and communities they serve.Since 1975,CHP has served over 206,000 people,including the elderly,women and children in transition,formerly homeless people,single female heads-of-household.展开更多
基金This study was supported and helped by Professor Yan Jiahong with China Petroleum Exploration and Development Research Institute,Yao Yanhua,Chief Geologist of the Hydrology Institute of PetroChina Liaohe Oilfield Company,and Dr.Kong Yanlong with the Institute of Geology and Geophysics,Chinese Academy of Sciences.
文摘Taking the Gaoshangpu-Liuzan geothermal field in the Nanpu sag of the Bohai Bay Basin as the research object, this paper discusses the geological conditions and potential of the geothermal resources of the Guantao Formation in the study area, and introduces the development practice of geothermal energy heating in Caofeidian. The average buried depth of the Guantao Formation is 1500–2500 m, the lithology is dominated by sandy conglomerate, and the average thickness of thermal reservoir is 120–300 m. The average porosity of thermal reservoir is 28%–35%, the permeability is(600–2000)×10^(-3) μm^(2), and the temperature of thermal reservoir is 70–110 ℃. The formation has total geothermal resources of 13.79×10^(18) J, equivalent to 4.70×10^(8) t of standard coal. Based on a large amount of seismic and drilling data from oil and gas exploration, this study carried out high quality target area selection, simulation of sandstone thermal reservoir, and production and injection in the same layer. The geothermal heating project with distributed production and injection well pattern covering an area of 230×10^(4) m^(2) was completed in the new district of Caofeidian in 2018. The project has been running steadily for two heating seasons, with an average annual saving of 6.06×10^(4) t of standard coal and a reduction of 15.87×10^(4) t of carbon dioxide, achieving good economic and social benefits. This project has proved that the Neogene sandstone geothermal reservoir in eastern China can achieve sustainable large-scale development by using the technology of "balanced production and injection in the same layer". It provides effective reference for the exploration and development of geothermal resource in oil and gas-bearing basins in eastern China.
基金The National Natural Science Foundation(NSF)of China under contract Nos 41176027 and 11072253the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11030302the State Key Laboratory of Tropical Oceanography(LTO)grant,South China Sea Institute of Oceanography,Chinese Academy of Sciences,under contract No.LTOZZ1304
文摘This study, using laboratory experiments and scaling analysis, evaluates the influence of geothermal heating on global oceanic circulation. Upon a well-developed large-scale convective flow, an additional heat flux perturbation 5F/F is employed. The increments of flow and thermal properties, including eddy diffusivity K7, flow velocity Vand bottom temperature Tb, are found to be independent of the applied heat flux F. Together with the scaling analysis of convective flow at different configurations, where the flow is thermally driven in the relatively low or extremely high turbulent thermal convections or the horizontal convection, the variances of flow properties, 6KT/KTand 6V/V, are found to be close to 0.5% and 0.75% at 5F/F=2%. This means that the small heat flux perturbation plays a negligible role in the global convective flow. However, 6Tb/ATis found to be 1.5% at 8F/F=2%, which would have a significant effect in the local region. The results might provide a clue to understanding the influence of geothermal heating on global oceanic circulation. It is expected that geothermal heating will contribute less than 1% in turbulent mixing and volume flux to global oceanic circulation, so its influence can be negligible in this situation. However, when it comes to the local environment, the influence of geothermal heating cannot be ignored. For example, temperature increases of about 0.5℃ with geothermal heating would have a significant effect on the physical environments within the benthic boundary layer.
基金support by the Shanghai Engineering Research Center for Shallow Geothermal Energy(DRZX-202306)Shaanxi Coal Geology Group Co.,Ltd.(SMDZ-ZD2024-23)+4 种基金Key Laboratory of Coal Resources Exploration and Comprehensive Utilization,Ministry of Natural Resources,China(ZP2020-1)Shaanxi Investment Group Co.,Ltd.(SIGC2023-KY-05)Key Research and Development Projects of Shaanxi Province(2023-GHZD-54)Shaanxi Qinchuangyuan Scientist+Engineer Team Construction Project(2022KXJ-049)China Postdoctoral Science Foundation(2023M742802,2024T170721).
文摘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 simulationmethods 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 m^(3)/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.
基金National Natural Science Foundation of China(No.41972314).
文摘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.
文摘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.
基金partially supported by the Guangdong Province Introduced Innovative R&D Team of Big Data—Mathematical Earth Sciences and Extreme Geological Events Team(No.2021ZT09H399)the National Natural Science Foundation of China(No.42430111)。
文摘Geothermal heat flow(GHF)is crucial for characterizing the Earth's thermal state.Compared to other regions worldwide,GHF measurements of South America are relatively sparse for mapping GHF over the continent based on traditional models.Here we apply the machine learning(ML)techniques to predict the GHF in South America.By comparing the global model,ML finds that South American subduction zones are hotter than the global model due to large-scale magmatism,which leads to the higher shallow arc temperatures than canonical thermomechanical and global models.Combining ML model with the local singularity analysis of heat flows,active volcanoes,and igneous rock samples,it is suggested that geothermal anomalies along the Andean Mountain Range are spatially correlated with magmatic activity in the subduction zone.It is concluded that the ML methods may provide reliable GHF prediction in regions like South America,where GHF measurements are limited and uneven.
文摘Geothermal energy utilization in China had been promoted actively during the 13^(th)Five-Year Plan period(2016-2020),with resultant achievements showing unique Chinese characteristics.Buildings(measured by areas)heated/cooled by intermediate-to-deep geothermal energy increased more rapidly than those by shallow geothermal energy.Geothermal power generation was restricted by the distribution of the resource and the sufficiency of local power supply.With the proposition of“dual carbon goal”by the central government of China and the coming era of great development of renewable energy,geothermal energy will be provided more development opportunities in room heating/cooling and power generation in the country ever than before.However,tackling technology bottlenecks and introduction of appropriate policy support are still urgently needed for nurturing a healthy environment for geothermal industry.Analysis suggests that a near-to medium-term development of geothermal energy shall be focused on a comprehensive and efficient utilization both through heating/cooling and power generation.Room heating/cooling by intermediate-to-deep and shallow geothermal energy shall be promoted nationwide according to local resource endowment and economic conditions.Geothermal power generation in Yunnan and Xizang shall be pushed forward in an orderly way.For medium-and long-term development,focus shall be put on power generation by using low to medium temperature geothermal energy and hot dry rocks.The"hot spring+"model shall be adapted in steps on a regular basis.To achieve these,measures including attaching importance to tackling key technologies,promoting standards for geothermal energy development and utilization,strengthening geothermal energy exploration and evaluation,and seeking for necessary policy support shall be taken.
基金Supported by the Major Program of Water Resources Exploration in Beijing City(Exploration and Assessment Project of Karst Water Resources in Beijing City
文摘Hujiatai Village, Xiong County, Hebei Province was nominated as the experimental unit of new countryside construction by Hebei Province in 2008. In order to make Hujiatai Village become a new countryside model with friendly ecological and environmental conditions, local energy resources should be considered. In this study, a mode of 'geothermal energy extraction-heat exchange-space heating-reinjection' was adopted to supply heat to resident houses in Hujiatai Village cooperating with a geothermal development entity based on the abundant geothermal resources, thereby constructing a clean, economic and autarkic new countryside energy system, which avoids utilization of fossil-energy, reduces emission of greenhouse gases and generation of solid coal cinder, protecting air and land environment, improving life quality of the people and building a typical model for Hebei Province and even for the whole country.
文摘The renewable energy will play significant role in the world primary energy consumption in the future. Geothermal energy is immense with 5 000 EJ/a of technical potential, and geothermal heat pumps (GHPs) are one of the fastest growing applications of renewable energy in the world with annual increases of 10 % and much faster in China. With high coefficient of performance (COP) up to 6, GHPs make efficiency of primary energy more than 240 % with assumed a 40 % of electricity generation efficiency, which means energy savings and CO2 emission reduction. In this paper,the geothermal resources and its utilization are talked about, and GHPs technology was introduced. Due to its high efficiency, there will be energy savings by using GHPs. There is also CO2 emission reduction because of using geothermal heat pumps, which is analyzed in the end.
基金National Key Basic Research and Development Plan(973 plans)“Basic research on oil and gas formation and distribution in deep water basins in South China Sea”(No.2009CB219400)Special and Significant Project of National Science and Technology“Key technology of marine oil and gas exploration in deep water area”(No.2008ZX05025 and 2011ZX05025)Investigation and Evaluation Project of National Strategic Petroleum Resource Provinces of the Ministry of Land and Resources(No.XQ-2004-05 and XQ-2007-05).
文摘The Oligocene Yacheng Fm contains the most important source rocks that have been confirmed by exploratory wells in the Qiongdongnan Basin.The efficiency of these source rocks is the key to the breakthrough in natural gas exploration in the study area.This paper analyzes the hydrocarbon potential of each sag in this basin from the perspective of control of both source rocks and geothermal heat.Two types of source rocks occur in the Yacheng Fm,namely mudstone of transitional facies and mudstone of neritic facies.Both of them are dominated by a kerogen of type-III,followed by type-II.Their organic matter abundances are controlled by the amount of continental clastic input.The mudstone of transitional facies is commonly higher in organic matter abundance,while that of neritic facies is lower.The coal-measure source rocks of transitional facies were mainly formed in such environments as delta plains,coastal plains and barrier tidal flat-marshes.Due to the control of Cenozoic lithosphere extension and influence of neotectonism,the geothermal gradient,terrestrial heat flow value(HFV)and level of thermal evolution are generally high in deep water.The hot setting not only determines the predominance of gas generation in the deep-water sags,but can promote the shallow-buried source rocks in shallow water into oil window to generate oil.In addition to promoting the hydrocarbon generation of source rocks,the high geothermal and high heat flow value can also speed up the cracking of residual hydrocarbons,thus enhancing hydrocarbon generation efficiency and capacity.According to the theory of joint control of source quality and geothermal heat on hydrocarbon generation,we comprehensively evaluate and rank the exploration potentials of major sags in the Qiongdongnan Basin.These sags are divided into 3 types,of which type-I sags including Yanan,Lingshui,Baodao,Ledong and Huaguang are the highest in hydrocarbon exploration potential.
基金Science and Technology Project of China Petroleum and Chemical Corporation Limited(No.KLJP23008).
文摘There are two sets of thermal reservoirs with different rock types in the Gucheng geothermalfield of Hebei Province,namely the Ordovician fractured carbonate thermal reservoir and the Neogene Guantao sandstone thermal reservoir,each developed using independent well networks.The energy demand per unit area in the region is high,and the existing geothermal development methods cannot meet the regional energy demand.For this type of block,combined with the development characteristics of different types of thermal reservoirs,numerical simulation methods were used to study the geothermal development trends of Ordovician fractured carbonate reservoirs and Neogene Guantao Formation sandstone reservoirs.When simulating sandstone thermal storage,priority should be given to demonstrating the optimal rechargeflow rate,while in simulating carbonate thermal storage,the focus should be on considering the influence of fracture development direction on development trends.Through numerical simulation of thermal storage development and combined with well network design,the optimal well spacing,production reinjectionflow rate,and reinjection temperature for two sets of thermal reservoirs developed using the same well network were determined.It is predicted that the average heatflow in the study can increase by 47.8%.This study presents reasonable development technical countermeasures to maximize the heating capacity of the geothermal development zone and provides an effective reference for the efficient development of similar geothermal resources in the Bohai Bay Basin.
基金National Natural Science Foundation of China(Nos.41941019,41801391)UK NERC through the Centre for the Observation and Modelling of EarthquakesVolcanoes and Tectonics(No.come30001)。
文摘In 2017,China’s central government approved the national strategy to build Xiong’an New Area(XNA,100 km southwest to Beijing),which was announced as a"millennium strategy"and a"demo area"for a sustainable,modern,and innovative urban model.Xiong’an will draw in as much as$380 billion investment and is expected to help accelerate the development of the wider Beijing-Tianjin-Hebei(Jingjinji)Area.In this paper,present subsidence in the XNA area is investigated using InSAR observations for the first time.The 24 SAR images acquired by European Space Agency’s Sentinel-1 satellites during the period from June 2017 to July 2018 suggest that in the north of Xiong County,the subsidence rate reaches up to 90 mm/y,which is highly correlated with the exploitation of geothermal drilling.As the construction in the XNA area will significantly accelerate and its high-quality development,the InSAR findings could provide valuable information for future sustainable urban planning and underground infrastructure construction.
基金part of the Siberian Branch, Russian Academy of Sciences under project IX.135.2.1."Geo-Temperature Field and Transformation of the Permafrost Zone of North Asia and the Mountainous Regions of Central Asia"financial support from the RFBR (No.18-55-53041, No.20-55-53036)Natural Science Foundation of China (No.41811530089)。
文摘The Elkon Horst is a geological structure that consists of heterogeneous strata with highly variable geocryological and temperature conditions. Gaining accurate knowledge of permafrost distribution patterns within this structure is of both scientific and practical importance. In mountainous terrain, the ground thermal regime is controlled by both surface and subsurface conditions. Surface conditions include snow cover characteristics, the presence or absence of vegetation, vegetation density, etc.. In contrast, subsurface conditions involve rock lithology or petrography, density, quantity and depth of fissures, groundwater, etc.. This article examines ground thermal regimes in various geomorphological settings based on temperature measurement data from geotechnical boreholes. The occurrence and extent of permafrost were evaluated for the entire horst area using direct and indirect methods. The maximum permafrost thickness measured in the Elkon Horst is 330 m, and the estimated maximum is 450 m at higher elevations. Thermophysical properties were determined for the major rock types, and the geothermal heat flux was estimated for the study area. The thermal conductivities were found to vary from 1.47 to 4.20 W/(m·K), and the dry bulk densities to range between 2,236 kg/m~3 and 3,235 kg/m~3. The average geothermal heat flux was estimated to be 44 mW/m~2.
基金supported by Liaoning Revitalization Talents ProgramXLYC2008005.
文摘To effectively enhance the energy utilisation rate of the park integrated energy system(PIES),and to strengthen the stability and reliability of PIES power supply,geothermal heat pumps and thermal/cool storage devices are introduced.An optimisation scheduling method for PIES based on maximum power point tracking(MPPT)and mixed integer linear programming is proposed.Firstly,taking into account the fluctuating and unpredictable nature of wind and solar power generation,the tip speed ratio(TSR)and incremental conductance(IncCond)methods are applied for MPPT of wind and solar power output.Secondly,geothermal heat pumps and thermal/cool storage devices are integrated into PIES to construct a typical daily multienergy flow coupled optimisation scheduling model.Lastly,the overall operational expenses and ecological impacts of PIES are comprehensively considered for an economic and environmental comparison analysis.Case study results verify that the introduction of geothermal heat pumps and thermal/cool storage devices enhances the energy efficiency and bolsters the overall economic and ecological effectiveness of PIES.
基金Supported by the Natural Science Foundation of Shandong ProvinceChina( No.Y99F0 2 )
文摘Ground source heat pump (GSHP) systems for HVAC have aroused more and more interest in China in recent years because of their higher energy efficiency compared with conventional systems. The design and performance simulation of the geothermal heat exchangers is vital to the success of this technology. In GSHP systems, the load of the geothermal heat exchanger varies greatly and is usually discontinuous even during a heating or cooling season. This paper outlines a heat transfer model for geothermal heat exchangers. The model was used to study the influence of the discontinuous operation of the heat pumps on the performance of the geothermal heat exchangers. A simple and practical approach is presented for sizing the geothermal heat exchangers.
基金The present research work was supported by the Federal Ministry for Economic Affairs and Energy of Germanyunder the funding code FKZ:03ET1050B.
文摘The heat transfer perfonmance of a vertical two-phase closed thermosyphon(TPCT)used in a geothermal heat pump was experimentally investigated.The TPCT is a verticalplain steel pipe with inner diameter of 114 mm and bored 368 m deep underground.Carbon dioxide(CO_(2))is used as working fluid.In the TPCT there is no condensation section.CO_(2)is condensed by the evaporator pf the heat pump,flows into the head of the TPCT and nuns down as a falling film along the inner wall of the pipe.For the heat transfer simulation in the TPCT,a quasi-dynamic model in which the mass transfer between the liquid and vapor phases as well as the conduction heat transfer from the surrounding soil towards the pipe is treated dynamically.However the film flow modeling is based on the Nusselt theory of frilm condenssation.The compauison of the experimental data with the numerical simulation is presented and discussed.
基金funded by the Mexican National Council of Science and Technology(CONACYT in Spanish),under the Sectorial Fund for Energy Sustainability,CONACYT-Secretaiy of Energy(No.S0019-2012-04).
文摘A comprehensive thermo-economic model combining a geothermal heat mining system and a direct supercritical CO_(2) turbine expansion electric power generation system was proposed in this paper.Assisted by this integrated model,thermo-economic and optimization analyses for the key design parameters of the whole system including the geothermal well pattern and operational conditions were performed to obtain a minimal levelized cost of electricity(LCOE).Specifically,in geothermal heat extraction simulation,an integrated wellbore-reservoir system model(T2Well/ECO_(2)N)was used to generate a database for creating a fast,predictive,and compatible geothermal heat mining model by employing a response surface methodology.A parametric study was conducted to demonstrate the impact of turbine discharge pressure,injection and production well distance,CO_(2) injection flowrate,CO_(2) injection temperature,and monitored production well bottom pressure on LCOE,system thermal efficiency,and capital cost.It was found that for a 100 MWe power plant,a minimal LCOE of$0.177/kWh was achieved for a 20-year steady operation without considering CO_(2) sequestration credit.In addition,when CO_(2) sequestration credit is$1.00/t,an LCOE breakeven point compared to a conventional geothermal power plant is achieved and a breakpoint for generating electric power generation at no cost was achieved for a sequestration credit of $2.05/t.
文摘INTRODUCTION Community Housing Partners(CHP)is a 501(c)(3)community development corporation that serves the needs of low-income and low-wealth individuals and families in the southeast.CHP’s mission is to create affordable,green,sustainable housing opportunities and services for the people and communities they serve.Since 1975,CHP has served over 206,000 people,including the elderly,women and children in transition,formerly homeless people,single female heads-of-household.
