DOI: https://doi.org/10.15368/theses.2013.232
Available at: https://digitalcommons.calpoly.edu/theses/1156
Date of Award
12-2013
Degree Name
MS in Mechanical Engineering
Department/Program
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.