Session: 10-04: Alternative Energy Conversion Technology (including Wind, Geothermal, Hydro, and Ocean)

Paper Number: 142435

142435 - Comprehensive Analysis of Large-Scale Isothermal Compressed Air Energy Storage (Icaes) System With Various Droplet Injection Methodology 

Abstract: 

There is a substantial gap present in the energy sector. Non-renewable sources of energy have well documented drawbacks and global implications from prolonged use. The presence and growth of renewable and clean energy systems indicates a shift towards addressing increasing energy demands and mitigating the negative effects of non-renewable energy sources. This growth can be seen primarily in biofuel, solar and wind energy. While taking advantage of naturally occurring phenomena, the development of key technology (i.e. wind and solar farms) continues to advance and lead to the production of more sustainable energy systems. This study explores the design and analysis of a large-scale liquid piston isothermal compressed air energy storage (iCAES) system.

There are various methods to obtain near isothermal conditions for systems of different sizes. As with any design, drawbacks can be seen in both active and passive technologies. Some work has pointed to the implementation of intricate mesh structures that take advantage of their porosity to control the thermal gradient across a given volume. Other work has led to the implementation of active cooling methods like micro cooling channels that enable stable boundary temperatures over a specific area. Examples of immediate drawbacks are additional power requirements for the active systems and increased volume dimension for the passive systems. Optimization of active and/or passive technologies can aid in creating a stable thermal environment however, the system discussed in this study does not employ either of the aforementioned technologies, primarily to reduce system complexity.   

The ideal platform for such a system is a 15 MW wind turbine. The proposed iCAES system can theoretically increase the rated power of wind turbines and serve as a power reserve during off peak times when there is a demand for energy that the turbines cannot supply. While expanding on previously validated work, this study further explores a design space for a cylindrical chamber undergoing compression and expansion processes. These processes take advantage of the injection of micron scale water droplets to mitigate the substantial thermal gradient generated. This system leverages the relatively high heat capacity of water to mitigate waste heat generated from operation of the liquid piston. The system maintains a near isothermal nature by regulating the amount of mass introduced. The near isothermal nature of the resulting processes enables high efficiency. This study also explores unique conditions where the roundtrip efficiency can approach 90%. The impact of mass loading via droplets and pressure ratio is also explored over various system and process parameters.

Presenting Author: Darryl Jennings University of Virginia

Presenting Author Biography: Darryl Jennings is a doctoral student and graduate researcher in the Department of Mechanical and Aerospace Engineering at the University of Virginia (UVA). He is currently conducting research with his advisor Professor Eric Loth, PhD in the Fluid Research and Innovation Laboratory (FRIL) at UVA. His current work focuses on isothermal compressed air energy storage and additional heat transfer mitigation methods. He also obtained a Bachelor of Science in Aerospace Engineering and a Master of Science in Mechanical Engineering from Embry-Riddle Aeronautical University (ERAU) in Daytona Beach, Florida.

Authors:

Darryl Jennings University of Virginia