To reduce the uplift pressure of groundwater, many wells, deep into the Chingmei gravel stratum underneath Taipei city, were installed during construction of Taipei MRT underground stations. These wells can also be used to establish a circulating groundwater system for air-conditioning. To study the feasibility of this circulating cooling system and the thermal response of the Chingmei gravel stratum, some groundwater parameters of the Chingmai gravel stratum were studied such as pumping and recharging capacities, flow direction, and flow velocity etc. Two small scale in-situ discharge tests and numerical simulations were used for this purpose. However, the tests could not be performed for a long period to prove the purpose, the computer modeling provided the predicted long time response of the stratum. The discharge tests on the wells confirmed the discharge capacity of the Chingmei stratum and the numerical results also indicate that circulating groundwater with a steady temperature can be provided to cool down air-conditioners, as long as groundwater is flowing at a slow velocity. This study confirms the feasibility of using the groundwater of the Chingmei gravel stratum as a steady and clean cool source for air-conditioners. (C) 2011 Elsevier Ltd. All rights reserved.