Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Thermal conductivity and diffusivity estimations for shallow geothermal systems

Jon Busby
Thermal conductivity and diffusivity estimations for shallow geothermal systems
Quarterly Journal of Engineering Geology and Hydrogeology (March 2016) 49 (2): 138-146

Abstract

Horizontal closed-loop ground collectors for ground source heat pumps are located within the soil and the top of the underlying superficial deposits. Estimating thermal properties for this zone is difficult as it is heterogeneous and is subject to seasonal water content variations. Soil thermal diffusivity values have been calculated at 56 sites using temperature data from UK Met Office weather stations. The technique utilizes the decrease in amplitude and increase in phase shift with depth of a transmitted heat pulse in the ground, the magnitudes of which are determined by thermal diffusivity. The weather stations are located throughout Great Britain and incorporate different soil types. The apparent thermal diffusivities derived from seasonal temperature cycles spanning several years generate seasonally averaged site-specific estimates that can be considered alongside diffusivity values determined in the laboratory or obtained by point measurements using field needle probes. Associated thermal conductivities have been estimated from the thermal diffusivities from knowledge of soil texture. Median thermal conductivities for the sand, loam and clay soil types have been estimated as 1.56, 1.15 and 1.81Wm (super -1) K (super -1) respectively with corresponding thermal diffusivities of 0.9961 X 10 (super -6) , 0.7173 X 10 (super -6) and 1.0295 X 10 (super -6) m (super 2) s (super -1) respectively.


ISSN: 1470-9236
EISSN: 2041-4803
Serial Title: Quarterly Journal of Engineering Geology and Hydrogeology
Serial Volume: 49
Serial Issue: 2
Title: Thermal conductivity and diffusivity estimations for shallow geothermal systems
Author(s): Busby, Jon
Affiliation: British Geological Survey, Nottingham, United Kingdom
Pages: 138-146
Published: 20160317
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 33
Accession Number: 2016-033039
Categories: Economic geology, geology of energy sources
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 201616
Close Modal

or Create an Account

Close Modal
Close Modal