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Ground temperature profiles and thermal rock properties at Wairakei, New Zealand

van Manen, Saskia M. and Wallin, Erin (2012). Ground temperature profiles and thermal rock properties at Wairakei, New Zealand. Renewable Energy pp. 313–321.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1016/j.renene.2011.11.032
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Abstract

Here we present ground temperature data from Wairakei, Taupo, New Zealand. The surface zone in this area extends to 0.5 m, while the shallow zone extends to at least 7.39 m. It is expected that the deep zone starts close to this depth and will exhibit a constant temperature of approximately 14.3°C, 1–2°C higher than the mean ambient temperature at this site. Shallow ground temperatures are predominantly influenced by the ambient air temperature and to a lesser extent the amount of rainfall. Modelling of the thermal waves, taking conductive and convective heat transfer into account, enables estimates of thermal diffusivity, volumetric heat capacity and thermal conductivity, whose mean values based on data from August 2010–April 2011 were 3.48 × 10−7 m2 s−1, 2.35 × 106 J m−3 K−1 and 0.89 W m−1 K−1 respectively. These estimates are within the same ranges as previous estimates of the thermal properties at Wairakei, although the mean values are slightly higher. This finding is consistent with the increased amount of recharge that occurred during the experimental period. Increased understanding of ground temperature and thermal rock properties is valuable for the development of low enthalpy geothermal resources as well as having applications in hydrology, agronomy and climatology.

Item Type: Journal Article
Copyright Holders: 2011 Elsevier B.V.
ISSN: 0960-1481
Keywords: ground temperature; thermal diffusivity; pumice; heat transfer; thermal rock properties
Academic Unit/Department: Science > Environment, Earth and Ecosystems
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 31552
Depositing User: Saskia van Manen
Date Deposited: 24 Jan 2012 14:08
Last Modified: 24 Nov 2014 12:14
URI: http://oro.open.ac.uk/id/eprint/31552
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