THE EVALUATION AND ENHANCEMENT OF CLEAN ENERGY SYSTEMS

Abstract

Clean (and specifically renewable) energy is steadily improving its global share. However, the finite availability of fossil fuels and the growing effects of climate change make it an urgent priority to convince the industry and governments to incentivize investment in the renewable energy field and to make it more attractive by decreasing the capital cost. Until recently, uncertainties in funding limited renewable energy development, especially in the US. That limitation has been one of the barriers to progress. Another limitation of many renewable energy systems is the variability in their output, which makes them unsuitable for baseline power production. Therefore, fossil fuels are still the dominant source of energy globally. The estimated US energy consumption in 2015 relied heavily on fossil fuels which generated about 82% of US primary energy. The share of solar energy in 2015 US energy consumption was just 0.43%. This is a disappointingly small share of a zero-carbon source of energy. Nuclear energy as another clean energy source has a small share of 8% of the total US energy consumption. Although it is one of the most reliable/stable and low carbon sources of energy, the nuclear power industry is currently facing several challenges. First, nuclear-generated electricity is not cost-competitive with other types of generation. Second, there is a diminished availability of cooling water to reject heat from large power plants. Third, the penetration of solar and wind generation systems into the electrical power market is producing significant fluctuations in the demand for nuclear generation. Open Air-Brayton systems are one of the solutions here since the ultimate heat sink for nuclear-supplied power is the atmosphere, so a more direct method of dumping this heat would be useful. An open Air-Brayton system can also provide a great deal of flexibility in adjusting power plant electrical output without significantly ramping reactor power output. This dissertation develops a common framework for understating and improving the solar and nuclear clean energy system components which are based on Brayton cycles. For this purpose, experimental and numerical studies of solar and nuclear systems are conducted.