I'd like to estimate the rate of heat transfer between an underground water storage tank and the surrounding earth. Basically, water would be pumped out of the tank through a coil and returned to the tank. The system would function like a groundwater source heat pump with two big differences:

1. the system will use a tank instead of vertical wells so there will be much less transfer area/volume of water
2. the tank is enclosed, water will not be drawn from the water table

Does anyone know of a study or software that would estimate the rate of heat transfer between the tank's walls and the surrounding earth?

Thanks,

Jon Bruneau, PE, LEED AP BD+C