Danielle Fong, Chief Scientist at LightSail Energy, has created a novel way to use tanks of compressed air for energy storage. Compressed air storage is not new but the problem with current methods is that compressing air creates heat energy as the air reaches temperatures of almost 1000 degrees Celsius. Energy is then lost through heat.
LightSail has designed a method of capturing this heat energy and regenerating useful energy from it by injecting a fine, dense mist of water spray which rapidly absorbs the heat energy of compression and provides it during expansion. Fong created a technique for separating the heated water from the compressed air and diverting it into a tank so the heat can be recaptured to reduce energy loss.
To store energy, an electric motor drives an air compressor. To deliver energy, the process is reversed and the air compressor becomes the expander and the electric motor becomes a generator. Heat from compression is stored or routed to nearby buildings, providing heating. During expansion, heat is extracted from storage, or buildings providing air conditioning. This dramatically increases building energy efficiency.
Experimental results show that very high thermodynamic efficiencies can be achieved without sacrificing performance. Air can be stored in simple, low cost air storage tanks packed in a convenient shipping container form factor using industry standard pipes and matching ASME and ISO safety standards. For truly massive installations, air can be stored in underground caverns, which is the standard for large scale natural gas storage.
Fong says the LightSail system will be cheaper than batteries and last for a decade. First shipments are expected in the fourth quarter of 2013.
Credit and top image of proposed storage tank: LightSail Energy