The feasibility study will determine how much cooling the system could provide and how much energy and money it could potentially save.
The City and MTA will also examine whether geothermal infrastructure can absorb, store and transport heat between the subway stations and nearby municipal buildings.
That means the current announcement is a study, not a promise that riders will soon find air-conditioned platforms.
The MTA recently announced plans to rebuild the Chambers Street J/Z station, one of the oldest stations in the system.
The project will rebuild structures, replace tiles, upgrade stairways and restore the station.