Effect of anthropogenic heat sources in the shallow subsurface at city-scale

¹ Engineering Department, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, United Kingdom
² School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052 Australia
³ British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
⁴ British Geological Survey, Cardiff University, Park Place, CF10 3AT

^* Corresponding author: mk2040@cam.ac.uk

Abstract

Rapid rates of urbanisation are placing growing demands on cities for accommodation and transportation, with increasing numbers of basements and tunnel networks being built to meet these rising demands. Such subsurface structures constitute continuous heat sources and sinks, particularly if maintained at comfortable temperatures. At the city-scale, there is limited understanding of the effect of heat exchange of underground infrastructures with their environments, in part due to limited availability of long-term underground temperature data. The effects of underground temperature changes due anthropogenic heat fluxes can be significant, impacting ventilation and cooling costs of underground spaces, efficiency of geo-energy systems, quality and quantity of groundwater flow, and the health and maintenance of underground structures. In this paper we explore the impact of anthropogenic subsurface structures on the thermal climate of the shallow subsurface by developing a heat transfer model of the city of Cardiff, UK, utilising a recently developed semi-3D modelling approach.