Geotechnical engineering lecture 2014, London

Overview

Thermal conductivity of the ground is an important parameter in the design of ground energy systems, which have an increasing role to play in providing renewable heat to the built environment. This presentation explores some of the uncertainties and limitations of thermal response testing with reference to two case studies.

First an instrumented thermal response test carried out in a 150m deep borehole in east London will be examined. This test shows how a single unique value of bulk thermal conductivity may not be appropriate in all cases due to ground stratification and the presence of groundwater flow.

Secondly the potential pitfalls of applying thermal response testing to energy piles will be explored using data from an instrumented test site in Texas. Here the effect of pile size and construction materials on the required test time will be discussed.