Salinity Gradient Power: Effects of Temperature and Nanopore Size

Salinity gradient power is a promising, challenging, and readily available renewable energy. Among various methods for harvesting this clean energy, the reverse elecrtodialysis based on charged nanochannels/nanopores (NRED) is of great potential. Since ionic transport depends highly on the temperature, so is the efficiency of the associated power generated. In this thesis, we conduct a theoretical analysis on the influences of temperature and nanopore size on NRED, focusing on temperature in Chapter 1 and nanopore size in Chapter 2. In Chapter 1, results gathered reveal that the maximum power increases with increasing temperature, but the conversion efficiency dependents weakly on temperature. In Chapter 2, a larger power density can be obtained by choosing a narrower and/or shorter nanopore, and a larger salt gradient for both a negatively and a positively charged nanopore generally. In contrast, a narrower and/or longer nanopore, and a smaller salt gradient should be adopted for a higher efficiency. The performance of a positively charged nanopore is better than that of a negatively charged one because it is easier for counterions to diffuse through in the former, thereby enhancing both power and efficiency. Regression relationships for the dependence of the maximum power density and the corresponding efficiency on the radius and length of a nanopore, and the salt gradient across it are recovered for design purposes.