Patent ID: 7579700

Claim:
A system for converting electrical energy into pressurized air that can be stored, comprising: a pump-motor section comprising: a pump having an inlet and an outlet; and an electrical motor; a pressurized air reservoir; a first tank and a second tank having approximately the same inner volume; and controllable valves that enable the first and second tanks to be connected or disconnected independently to the inlet and the outlet of the pump, to the open atmosphere and to the pressurized air reservoir; the first and second tanks containing together a total volume of liquid that is approximately equal to the inner volume of one of the first and second tanks; the system operating such that when the pump is operating, liquid is pumped from the first tank into the second tank, and causes the air pressure in the second tank to increase to a point at which it is approximately equal to the pressure inside the pressurized air reservoir, and wherein at this equilibrium pressure status, one of the valves is opened and allows pressurized air to flow from the second tank into the pressurized air reservoir; when approximately all of the air in the second tank has been passed to the pressurized air reservoir, and the second tank is approximately full of liquid, the position of the valves is changed to a position wherein the first and second tanks will have opposite roles, whereby the system can operate reciprocally and continuously to convert electrical energy into pressurized air that can be storage in the pressurized air reservoir, while the roles of the first and second tanks are changing and are opposite in each cycle.