said by New York City Geothermal Heat Pump Manual :As closed loop piping and the required grouting material add
another layer of heat transfer resistance, the closed loop system is
designed for lower winter entering water temperatures and higher
summer entering temperature. These wider temperature ranges
reduce the effective capacity and efficiency of the heat pump
system. Closed loop piping costs are typically in the same range
as the cost of the heat pumps and thus add to the overall cost of
the installation. Generally, these closed loop systems are more
first cost than the above systems. A compensating increase in the
overall system efficiency can be anticipated by the reduction in
loop pumping costs. However, the requirement for slightly larger
equipment remains a disadvantage.
You won't find anything that will say that closed-loop is unconditionally better then open-loop because in most situations where both open-loop and closed-loop are feasible the open-loop system tends to have a lower initial cost. The cost difference may not be large (or even in favor of the closed-loop system) when new wells need to be drilled but the difference is significant when an existing well can be utilized for the open-loop.
It is easy to determine operational costs for the small circulation pump in a closed-loop system (the effort to circulate the water in a closed loop is the same no matter how deep the loops are buried). The same does not apply for open-loop systems where it makes a big differences on the lifting power of the well pump depending on the depth of the water table.
This means a true comparison of the operational costs of open-loop and closed-loop systems requires a site-specific analysis.
Even with operational costs likely to be lower in a closed-loop system the question remains whether the difference is large enough to make up for the higher up front installation costs ?