Field investigation on geothermal pavements

This article investigates the thermal response of a geothermal pavements located in Adelaide, South Australia. This geothermal pavement field trial is believed to be the first full-scale instrumented system of its kind in the country, and one of the handful around the world to date providing a rare set of experimental data. The ground temperature and weather parameters were monitored for over two years, including during two thermal response tests (TRTs) undertaken under different weather conditions. The annual ground temperature profile under the pavement provides helpful information for geothermal pavements design and model validation. Results revealed the significant impact of weather conditions on the TRTs due to the shallow burial depth of the pipe heat exchanger. To minimise these effects, it is then recommended to perform TRT or thermal performance testing during mid-season. Comparison of test results showed that the effect of ambient temperature was more intensive in summer due to the presence of heat-absorbing asphalt at the surface. In addition, the high amount of absorbed heat at the surface reduced the pavement depth-temperature fluctuations in winter as well as the temperature difference between days and nights, leading to a better performance.