Rapid Aging in Dense, Self-Healing Carbon/Carbon Composites for Use in Concentrating Solar Power
Faculty Mentor Information
Dr. Todd Otanicar (Mentor), Boise State University
Abstract
Concentrating solar power (CSP) is a form of renewable energy that transforms solar irradiance into a form of useful heat. This is accomplished by collecting heat from the sun in thermal receivers and using a heat transfer fluid to carry the thermal energy from thermal receivers to heat engines . Although CSP is an efficient energy production technology, there are limitations due to the current technologies. The major drawbacks of current CSP technologies are the failure of thermal receivers due to the transient temperature changes and high temperature gradients.In order to combat this, a dense, self-healing carbon/carbon composites has been tested through a cyclic rapid aging process using a High Heat Flux Solar Simulator. Throughout the rapid aging process, the temperature of the carbon/carbon composite sample is monitored to ensure the sample is experiencing the minimum and maximum operating temperatures, creating a valid and accurate experiment. Between rapid aging cycles the mass of the sample and the spectral reflectivity are measured, typically every 25 rapid aging cycles. To ensure that the sample is a suitable candidate for use as a thermal receiver, the solar weighted reflectance is calculated between rapid aging cycles, as well as the mass loss. After 500 rapid aging cycles, the sample underwent an initial decrease in both solar weighted reflectance and mass; however, after this initial decrease, the values of both mass and solar weighted reflectance remained fairly constant. The findings of these experiments validate that this carbon/carbon composite would be a viable alternative for solar receivers as they can withstand extreme temperatures, transient temperature changes, high amounts of solar irradiation, and extremely high temperature gradients.
Rapid Aging in Dense, Self-Healing Carbon/Carbon Composites for Use in Concentrating Solar Power
Concentrating solar power (CSP) is a form of renewable energy that transforms solar irradiance into a form of useful heat. This is accomplished by collecting heat from the sun in thermal receivers and using a heat transfer fluid to carry the thermal energy from thermal receivers to heat engines . Although CSP is an efficient energy production technology, there are limitations due to the current technologies. The major drawbacks of current CSP technologies are the failure of thermal receivers due to the transient temperature changes and high temperature gradients.In order to combat this, a dense, self-healing carbon/carbon composites has been tested through a cyclic rapid aging process using a High Heat Flux Solar Simulator. Throughout the rapid aging process, the temperature of the carbon/carbon composite sample is monitored to ensure the sample is experiencing the minimum and maximum operating temperatures, creating a valid and accurate experiment. Between rapid aging cycles the mass of the sample and the spectral reflectivity are measured, typically every 25 rapid aging cycles. To ensure that the sample is a suitable candidate for use as a thermal receiver, the solar weighted reflectance is calculated between rapid aging cycles, as well as the mass loss. After 500 rapid aging cycles, the sample underwent an initial decrease in both solar weighted reflectance and mass; however, after this initial decrease, the values of both mass and solar weighted reflectance remained fairly constant. The findings of these experiments validate that this carbon/carbon composite would be a viable alternative for solar receivers as they can withstand extreme temperatures, transient temperature changes, high amounts of solar irradiation, and extremely high temperature gradients.