No. of Recommendations: 16
I personally know of this project and worked directly side by side with the Hydro Geologist who designed that system in Minnesota.
https://underground-energy.com/Get a primer for ATES and BTES at the link above.
ATES (Aquifer Thermal Energy Storage) is an OPEN loop system where ground conditions are highly sensitive to effective efficiency of the system. If karst formations are prevalent in the area AND the hydro gradients are very low (milli darcy or less), efficiencies can be very high.
This is a battery in the form of delta T captured in the summer and released in the winter.
Ground temperature gradients are exceptionally important here, as well as free cooling days.
These systems do not work south of Virginia, for data centers (imbalanced load) or in coastal areas where the imbalance is mitigated by high darcy gradients. (E.g. Florida Keys and a constant flow through the limestone carries away the heat of a data center.)
Fun fact, many of these systems fail to launch because the wells are $100,000's a pair and require relatively adjacent thermal loads (buildings full of HVAC people), with suitable groundwater conditions and free cooling days.
An early system in New Jersey is a poster child for poor early development. Their inlet screens plugged at the well, causing a couple of reworks because the design flow from the pumps was simply too disruptive to the soil conditions locally.
The Dutch and the Danes are EXCEPTIONALLY good at this. Their installation networks show well pairs numbering in the 10,000s.
They have:
Great hydro gradients
Excellent free cooling days
Less demanding HVAC culture
No big oil company influence or governance restricting drilling and ground rights use.
