A process has been invented to inject and withdraw water from an aquifer for purposes of energy storage under some abnormal conditions. This transfer system is for thermal energy storage applications where the transfer water pressure is higher than the normal aquifer pressure at the point of withdrawal or injection. Applications include systems where water temperatures are in excess of the normal boiling point and the water must be pressurized, to prevent boiling and/or and where an aquifer has a water head well below ground level creating excess pressure from the column of water from the surface to the acquifer. Water is injected through a process which reduces the pressure at the aquifer to the pressure required for injecting the correct water flow rate. In recovering the thermal energy, or withdrawal, the system provides the proper pressurization at aquifer level to the required pressure. The pressure is reduced by a uniquely controlled throttling valve or a uniquely controlled turbine-generator-valve combination.

The system uses a well drilled deep into the ground and filled with water. The well is encased and sealed at its bottom to prevent the loss of water. The casing of the well is in contact with the surrounding earth for heat conduction. A pipe is placed within the well with a pump at its distal end. The pump draws cold water from within the well into the pipe, out of the well into a heat exchanger where it cools the air which, in turn, cools the house. After the water has gone through the heat exchanger, it is returned to the well. Heat pipes are used to dissipate, in winter, the heat accumulated during the summer cooling months. The heat pipes extend outwardly from near the top of the well and contain a substance that will absorb heat and evaporate at the end in the well and condense and release heat at the opposite end. An upward slant of the heat pipe ensures that this heat transfer occurs only in the direction away from the well.

Systems and methods for storing heat or cold in aquifers in the form of hot or cold water, making use of one or more above-ground subsystems for collecting or utilizing the aquifer-stored heat and/or cold. A salient feature of the aquifer storage systems and methods of the present invention includes means and techniques for at least partially controlling or neutralizing the hydraulic gradients in the aquifer area.

A method and means for using ground water in an aquifer as a heat source and heat sink are disclosed wherein heat is exchanged between the uniform temperature ground water and heat-exchanging apparatus at the earth's surface through a single well bore. The ground water is exchanged between an upper and lower portion of the aquifer, alternatively depending on the operating mode, in such a manner that a stratified lateral flow of the water after heat exchange is produced following natural convective paths in the top or bottom of the aquifer and resulting in wide laminar dissipation of the altered temperature water while avoiding thermal mixing between that water and the remaining uniform temperature water in the aquifer. This manner of exchange provides a continuous flow of heating or cooling water at or near the ambient aquifer temperature without any depletion of the aquifer. Embodiments are described wherein the aquifer water is brought to the earth's surface and wherein a separate heat-exchanging fluid is circulated between the aquifer and the earth's surface, and modifications are also disclosed involving a valved plenum device for use with the former embodiments and whereby the aquifer may be used to store solar heat.