Mohammad Al-Azawii PhD Dissertation Defense
- Monday, June 29, 2020 at 1:00pm
- Roberts Hall, 301 and via WebEx Meeting number: 120 144 0997 Password: Ug2p523cmPj - view map
Thermal Energy Storage with Sensible Heat in an Air-Alumina Packed Bed Using Axial Flow, Axial Flow with Layers and Radial Flow
Energy demand continues to increase with a steadily growing global population. Many researchers are working to find new sources of energy while concurrently developing existing technologies. Renewable energy sources such as solar, wind and ocean currents can be used to extract energy. However, these renewable energy sources have inherently low energy densities and are not continuously available as compared to fossil sources. To compete with this, renewable energy sources such as solar energy can be stored in the form of heat when there is a surplus of energy and subsequently used to continue operation when there is a shortage of solar flux or increase in the demand. Systems such as packed beds can be used to store this energy with thermal energy storage (TES). TES systems are considered a promising solution to integrate renewable energy sources. In these TES packed bed systems, the thermal exergy efficiency is an important component in any application with a goal of high exergetic efficiencies. Exergetic efficiency can be affected by different parameters such as thermocline, heat losses and axial thermal dispersion. Reducing heat and dispersion losses can improve the thermocline and thus thermal efficiency. In this thesis, the thermal performance of normal axial flow is studied and quantified for multiple repeated cycles, and two new methods (axial pipe injection with layers and radial pipe injection) are proposed and studied. A significant increase in the exergetic efficiency is achieved by dividing the bed into several layers (from 55.4% to 80.3%). The dispersive losses are reduced and the thermocline is improved with the number of layers and flow rate. In radial flow, several tube designs are considered to improve even flow and the temperature distribution in the storage packed bed. The radial flow configuration showed higher energy and charging efficiency (from 75% to 80%) than the axial flow process. Our results show new pipe injection techniques are capable of storing more energy, improving the thermocline, and reducing heat and dispersion losses in packed bed thermal energy storage systems.
- Department of Mechanical & Industrial Engineering