Design of a Graphite Based Thermal Energy Storage for Concentrated Solar Power Applications
Year: 2017
Type: dissertation
Abstract: This thesis presents the feasibility of a residential scale, low cost, high temperature, graphite \nbased sensible thermal energy storage (TES) device and proposes a design for such a device. The \nintended use for the proposed design is as a component of a larger concentrated solar power \n(CSP) generation system. A scaled down model of the prototype was tested for performance and \ndurability. Measurements of thermal properties, discharge power, charging and discharging \nefficiencies and resistance to degradation by oxidation and vibration were taken to quantify the \nperformance and durability. Oxidation rates were measured at 700 0C with SiC and Al2O3 based \nprotective coatings as well as with inert gas blanketing using argon, CO2 and evacuation. The \ngraphite was also subjected to vibration at 1000 rpm to evaluate any damage caused by contact \nwith a reciprocating heat engine. To quantify the performance, the relationship between \ntemperature and thermal conductivity was determined as well as the variation of specific heat \ncapacity with temperature. These were measured in the range of 50 0C to 400 0C. Solar irradiance \nheat flux on the heat storage was simulated on the test samples to determine the temperature \nvariation throughout the charging period of one day. All tests were done on two grades of \ngraphite that vary in density, porosity and microstructure. Results obtained from testing the \ndevice indicate an effective lifespan of 31 years before needing to be replaced and yields a \ncharging efficiency of 40.2%. Based on these results, a detailed design is presented. Finally, \nbased on the results, a more detailed design of the device is proposed.
Author: Cedric De Luca
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2769697280