A review on heat transfer and energy conversion in the enhanced geothermal systems with water/CO2as working fluid

2015 ◽  
Vol 39 (13) ◽  
pp. 1722-1741 ◽  
Author(s):  
Ruina Xu ◽  
Le Zhang ◽  
Fuzhen Zhang ◽  
Peixue Jiang
Keyword(s):  
Heat Transfer ◽  
Energy Conversion ◽  
Working Fluid ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems

Heat Flux to Fluids Within a Rock Fracture in a Geothermal System

2010 ◽  
Author(s):  
Dustin Crandall ◽  
Goodarz Ahmadi ◽  
Grant Bromhal
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Rate ◽  
Numerical Study ◽  
Rock Fracture ◽  
Working Fluid ◽  
Geothermal System ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Ct Scanner

Fractures in rocks enable the motion of fluids through the large, hot geologic formations of geothermal reservoirs. The heat transfer from the surrounding rock mass to the fluid flowing through a fracture depends on the geometry of the fracture, the fluid/solid properties, and the flow rate through the fracture. A numerical study was conducted to evaluate the changes in heat transfer to the fluid flowing through a rock fracture with changes in the flow rate. The aperture distribution of the rock fracture, originally created within Berea sandstone and imaged using a CT-scanner, is well described by a Gaussian distribution and has a mean aperture of approximately 0.6 mm. Water was used as the working fluid, enabling an evaluation of the efficiency of heat flux to the fluid along the flow path of a hot dry geothermal system. As the flow through the fracture was increased to a Reynolds number greater than 2300 the effect of channeling through large aperture regions within the fracture were observed to become increasingly important. For the fastest flows modeled the heat flux to the working fluids was reduced due to a shorter residence time of the fluid in the fracture. Understanding what conditions can maximize the amount of energy obtained from fractures within a hot dry geologic field can improve the operation and long-term viability of enhanced geothermal systems.

Enhanced Geothermal Systems Projects and its Potential for Carbon Storage

2013 ◽  
Vol 732-733 ◽  
pp. 109-115 ◽  
Author(s):  
Chao Yin Feng
Keyword(s):  
Carbon Dioxide ◽  
Power Plants ◽  
Subsurface Water ◽  
Working Fluid ◽  
Low Permeability ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Geothermal Fields ◽  
Geological Conditions ◽  
Geothermal Wells

Enhanced Geothermal Systems represent a series of technology, which use engineering methods to improve the performance of geothermal power plant. In some geothermal fields, the rocks are in high temperature but a low permeability, or the subsurface water is scarce. In these geological conditions, cool water was injected into the geothermal wells to fracture the tight rock and create man-made reservoir for thermal exploitation. Furthermore, these engineering methods can be utilized to improve the productivity of pre-existing hydrothermal power plants. To save water and treat the global warming, using carbon dioxide instead of water as working fluid was proposed. Numerical simulation reveals that the carbon dioxide has numerous advantages over water as working fluid in the heat mining process. The precipitation caused by carbon dioxide will restore part of carbon dioxide in the rock and reduce the micro-seismicity risk.

Experimental investigation of seepage and heat transfer in rough fractures for enhanced geothermal systems

2019 ◽  
Vol 135 ◽  
pp. 846-855 ◽  
Author(s):  
Yibin Huang ◽  
Yanjun Zhang ◽  
Ziwang Yu ◽  
Yueqiang Ma ◽  
Chi Zhang
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems

Numerical investigations of CO2 and N2 miscible flow as the working fluid in enhanced geothermal systems

Energy ◽  
2020 ◽  
Vol 206 ◽  
pp. 118062
Author(s):  
Jiawei Li ◽  
Wanju Yuan ◽  
Yin Zhang ◽  
Claudia Cherubini ◽  
Alexander Scheuermann ◽  
...  
Keyword(s):  
Working Fluid ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Numerical Investigations ◽  
Miscible Flow

scholarly journals Longevity of Enhanced Geothermal Systems with Brine Circulation in Hydraulically Fractured Hydrocarbon Wells

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 63
Author(s):  
Zuo ◽  
Weijermars
Keyword(s):  
Limit State ◽  
Extraction Process ◽  
Heat Extraction ◽  
Working Fluid ◽  
Heat Equations ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Geothermal Heat ◽  
Horizontal Fracture ◽  
Rock Temperature

A simple, semi-analytical heat extraction model is presented for hydraulically fractured dry reservoirs containing two subparallel horizontal wells, connected by a horizontal fracture channel, using injected brine as the working fluid. Heat equations are used to quantify the heat conduction between fracture walls and circulating brine. The brine temperature profiles are calculated for different combinations of fracture widths, working fluid circulation rates, and initial fracture wall temperatures. The longevity of the geothermal heat extraction process is assessed for a range of working fluid injection rates. Importantly, dry geothermal reservoirs will not recharge heat by the geothermal flux on the time scale of any commercial heat extraction project. A production plan is proposed, with periodic brine circulation maintained in a diurnal schedule with 8 h active production alternating with 16 h of pump switched off. A quasi-steady state is achieved after both the brine temperature and rock temperature converge to a limit state allowing fracture-wall reheating by conduction from the rock interior in the diurnal production schedule. The results of this study could serve as a fast tool for assisting the planning phase of geothermal reservoir design as well as for operational monitoring and management.

Finite Time Thermodynamics: Realizability Domain of Heat to Work Converters

2019 ◽  
Vol 44 (2) ◽  
pp. 181-191 ◽  
Author(s):  
M. A. Zaeva ◽  
A. M. Tsirlin ◽  
O. V. Didina
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Finite Time ◽  
Heat Engine ◽  
Energy Conversion Efficiency ◽  
Maximum Power ◽  
Working Fluid ◽  
Finite Time Thermodynamics

Abstract From the point of view of finite time thermodynamics, the performance boundaries of thermal machines are considered, taking into account the irreversibility of the heat exchange processes of the working fluid with hot and cold sources. It is shown how the kinetics of heat exchange affects the shape of the optimal cycle of a heat engine and its performance, with a focus on the energy conversion efficiency in the maximum power mode. This energy conversion efficiency can depend only on the ratio of the heat transfer coefficients to the sources or not depend on them at all. A class of kinetic functions corresponding to “natural” requirements is introduced and it is shown that for any kinetics from this class the optimal cycle consists of two isotherms and two adiabats, not only for the maximum power problem, but also for the problem of maximum energy conversion efficiency at a given power. Examples are given for calculating the parameters of the optimal cycle for the case when the heat transfer coefficient to the cold source is arbitrarily large and for kinetics in the form of a Fourier law.

Sign in / Sign up

Export Citation Format

Share Document