An analysis of an advanced compressed air energy system (CAES) using turbomachinery for energy storage and recovery and for continuous on-site power augmentation as an air brayton cycle

Abstract

A thermodynamic analysis of an advanced CAES for Distributed Power Generation (DPG) is presented that utilizes turbomachinery for energy recovery, but also gives continuous power generation to augment on-site power. The advanced CAES uses renewable energy such as wind power and solar PV in the power range of 1500 to 2500 kW plus recuperation of waste heat from the existing on-site prime mover to improve the utility of the energy storage system. The proposed system also utilizes battery storage to maintain high energy density storage, preferably without the need for costly electrical rectifying and inversion systems to improve the stabilization of power generation. This proposed system may be thought of as a “cross-over” system that combines CAES technology with electric battery storage technology, particularly if the stored electric power is used directly as D.C. power at an industrial facility. The direct use of stored energy from a battery as heat input to the proposed “cross-over” system also may be considered in some limited applications. The ideal application of the proposed system is for isolated DPG systems perhaps in remote sites utilizing “power islands” of renewable energy augmented with on-site fossil fuel prime mover, power generation systems. The proposed “cross-over” system enables higher reliability, faster response to transient power loads, and the efficient use of renewable energy, as well as heat recovery from conventional prime mover systems that are on site.