Thermal conductivity testing of energy piles: Field testing and numerical modeling

Heat exchange capacity of an Energy Pile is a key parameter in the design of these elements as ground sourced heat exchangers. In most cases, field thermal conductivity tests are necessary to verify design assumptions similar to running a conventional pile load test to prove pile capacity. Current standards for measuring the heat exchange performance of geothermal systems are limited and do not directly apply to Energy Piles. Most importantly, current guidelines limit the maximum diameter of a tested geothermal heat exchange element to 6 inches. We have developed a 3D numerical model to simulate thermal conductivity testing and calibrated the numerical model with a thermal conductivity field test. This model will allow us to perform a series of numerical analyses to test the validity of the assumptions underlying current thermal conductivity testing procedures.