Date of Award

12-2013

Degree Name

MS in Mechanical Engineering

Department

Mechanical Engineering

Advisor

Thomas Mackin

Abstract

This study investigates Compressed Air Energy Storage (CAES) application in the

electrical power and transportation industries. Information concerning current CAES projects is

presented. A thorough thermodynamic analysis of the CAES process is completed; including

theoretical efficiency determination for several variants of the compression and expansion

processes. Industry claimed efficiencies ranging from 26% to 82% are presented and explained.

Isothermal and Isentropic efficiency baselines are developed. Energy density of compressed air

on both a mass and volume basis is compared to other energy storage methods. Best expected

efficiency of a hypothetical CAES system is determined to be 34% using currently achievable

efficiencies and 63% considering 100% efficient compression and expansion. A .5 kW CAES

system, built from commercial off the shelf components (COTS) to demonstrate the CAES

concept, is documented and discussed. This system includes a LabView data acquisition system

which was used to record all test results. LabView was also used to develop a complete test bed

program that determined real time thermodynamic state properties, component efficiencies, mass

flow rates, power outputs and several other performance characteristics of the demonstration

system. The LabView program allowed real time efficiency and power optimization of the

demonstration system. Results of demonstration system testing are thoroughly discussed. Total

system efficiency was very poor; 3.6% electrical conversion efficiency, .040 refrigeration

coefficient of performance (COP) and a 5.0% overall efficiency which considers both cooling and

electrical storage properties. Several paths for possible future projects involving the

demonstration system and CAES are presented.

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