Measured and simulated heat transfer to foundation soils

Abstract

The drive towards energy-efficient, low-carbon buildings is a clear priority for many countries. Furthermore, ground heat transfer is understood to play an important role in the overall thermal performance of buildings. This paper presents the results of an in-depth investigation of heat transfer from buildings to the ground. The research involved in situ measurements of heat transfer to the ground from full-scale buildings. The results have been utilised to help develop and validate suitable predictive tools to aid thermal design. Numerical simulations have been undertaken that reveal the transient form of energy losses from typical buildings to the ground over a seasonal time frame. Comparisons are made between numerical results and measured data over an annual cycle. Overall, good correlation of results has been achieved. The thermal properties of foundation soils are known to be dependent on water content. A preliminary assessment of the significance of this aspect of the problem is also considered. In particular, it has been shown that an increase in soil moisture content may cause an increase in heat flux of over 20% for a two-dimensional test case. In summary, innovative low-energy sustainable design is receiving increasing attention. The current work will contribute to this overall objective by ensuring that adequate attention is given to subsurface heat transfer.