Heat extraction calculations for deep coaxial borehole heat exchangers: matrix analytical approach

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985891%3A_____%2F23%3A00577638" target="_blank" >RIV/67985891:_____/23:00577638 - isvavai.cz</a>

Alternative codes found

RIV/00216208:11320/23:10473624

Result on the web

<a href="https://doi.org/10.1093/gji/ggad367" target="_blank" >https://doi.org/10.1093/gji/ggad367</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1093/gji/ggad367" target="_blank" >10.1093/gji/ggad367</a>

Result language

angličtina

Original language name

Heat extraction calculations for deep coaxial borehole heat exchangers: matrix analytical approach

Original language description

Deep boreholes represent a source of clean energy. Therefore, effective calculations of potential extraction of heat from boreholes for realistic models of the Earth’s crust with variable thermal conductivity and diffusivity are needed. We deal with heat extraction in a quasi-steady state from coaxial boreholes where downward and upward flows of pumped fluid (water) are separated by an inner pipe and connected only at the bottom. We first obtain theoretical estimates of heat extraction for a thermally isolated inner pipe and a model of the ground with constant thermal diffusivity and conductivity. Then, we develop a new analytical matrix method for a general layered ground model that enables us to include depth-dependent ground properties as well as heat exchange between the downward and upward flows of fluid in the borehole. Our straightforward and fast approach is thus suitable for various parametric studies or as a tool for benchmarks of numerical software. A key role in heat extraction from coaxial boreholes is played by the inner-pipe thermal resistance. We apply our method to the parametric study showing the dependence of pumped water temperature and total heat extraction from the borehole on realistic borehole geometries under different amounts of water pumping. The calculations are performed for a 3 km deep borehole as the representative of present deep boreholes used for extraction of geothermal energy and for a 10 km deep borehole. Drilling of such a superdeep borehole has just started in China and our results demonstrate potential limits of geothermal energy extraction from such great depths.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

20704 - Energy and fuels

Project

<a href="/en/project/TP01010055" target="_blank" >TP01010055: Geophysics, geotechnics, geomaterials, geothermal energy for application</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Geophysical Journal International

ISSN

0956-540X

e-ISSN

1365-246X

Volume of the periodical

235

Issue of the periodical within the volume

3

Country of publishing house

GB - UNITED KINGDOM

Number of pages

16

Pages from-to

2323-2338

UT code for WoS article

001124759000011

EID of the result in the Scopus database

2-s2.0-85175449383