The test comprises of circulating warm water through a borehole at a constant rate and temperature, and measuring the drop in temperature of the water as it comes back out of the borehole loop.  
 
The standard test is run for 50 hours and the results are reported as a thermal conductivity, the essential factor for the efficient design of GSHE systems.
 
The information is interpreted by a thermogeologist who can then determine the following parameters: