Energy Storage, Renewable Energy

SustainX earns patent for isothermal compressed air energy storage

West Lebanon, N.H., January 25, 2011 — SustainX, Inc., a New Hampshire-based startup that is developing a transformational technology for utility-scale energy storage using compressed air, has received its third patent.

U.S. Patent No. 7,874,155 expands the patent portfolio surrounding SustainX’s isothermal compressed-air energy storage technology by protecting core elements of the company’s heat-transfer technology.

To store energy, SustainX uses electricity to drive pistons that compress air. The basis of the new patent, and a key element of SustainX’s energy storage process, is the use of a water spray to keep the air at a constant temperature.

During compression, the sprayed water absorbs heat from the air. The compressed air is then stored in above ground storage vessels and the heated water is stored in a constant-temperature reservoir.

To produce energy from storage, compressed air is used to drive the same pistons, which in turn drive an electric generator. Warm water from the reservoir is sprayed into the air during expansion to keep it from cooling.

Keeping the air at a constant temperature during compression, storage, and expansion yields a more efficient storage cycle.

The new patent covers the use of a liquid spray injected into air continuously during compression or expansion and solidifies SustainX’s position as a leader in the field of compressed-air energy storage.