LightSail Energy. Regenerative Air Energy Storage
914 Heinz Avenue, Berkeley, CA, 94710 P: 510 268 9770. F: 510 268 9774
contact@lightsailenergy.com
We Store Energy in Compressed Air. Air is the world's cleanest and most economical energy storage medium; we aim to produce the world's cleanest and most economical energy storage systems. Compressing air creates heat energy. Until now, this was wasted, drastically reducing efficiency. Our innovation: an elegant method of capturing this heat energy and regenerating useful energy from it. We inject a fine, dense mist of water spray which rapidly absorbs the heat energy of compression and provides it during expansion.
Our Approach. 1. During air compression, mechanical energy is converted into heat. Spray water directly into the air during compression. 2. Store the compressed air in a tank. 3. Exchange heat between the water and heat storage. During air expansion, spray warm water into the expanding air. Heat energy in the water is absorbed by the air and is converted into mechanical energy.
Our System is Fully Reversible. To store energy, an electric motor drives an air compressor. To deliver energy, we reverse the process -- the air compressor becomes an expander, and the electric motor becomes a generator. Heat from compression is storage or routed to nearby building, providing heating. During expansion, heat is extracted from storage, or building providing air conditioning. This dramatically increases building energy efficiency. Figure: Storage: Energy and air flows during storage.
Experimental Results: 90% Thermal efficiency, roundtrip. %lt 10 C Final temperature difference. 1200 RPM, 100 kW scale, 500+ hrs reliable operation, reciprovating piston compressor/expander. We have shown the we can achieve very high thermodynamic efficiencies without sacrificing performance. We have achieved these high thermodynamic efficiencies at higher RPMs than many thought possible. This is crucial to achiving low cost: the higher the RPM, the higher the power of the same machine, and the lower the cost per kW.
Storage: 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 undergrade caverns which is the standard for large scale natural gas storage.
Our First Product: LightSail RAES-V1. Since our compressor/expander and our tanks are only connected by pipes, more or less energy storage can be added, depending on the application. Power unit: $900/ kW. Linked 250 kW modules. 70% round-trip efficiency. 20+ year lifetime. Storage unit: $150 / kWh. 1 Mwh modules. Proprietary filament-wound tanks. Shipping container form factor. ASME certified. First shipment: Fourth quarter 2013.