Design parameters of solar concentrating systems for CO2-mitigating algal photobioreactors

The strategy of exploiting photosynthesizing microalgal cultures to remove carbon dioxide (CO2) from flue gases through fixation has potential in effectively diminishing the release of CO2 to the atmosphere, helping alleviate the trend toward global warming. The use of fiberoptic-based solar concentrating systems for microalgal photobiorectors has the potential to meet the two essential criteria in the design of a lighting system for algal photobioreactors: (1) electrical energy efficiency; and (2) lighting distribution efficiency. The overall efficiencies of solar concentrating systems have significantly improved in recent years, exceeding 45%. Meanwhile, achieving uniform lighting distribution within photobioreactors constitutes probably the greatest challenge in using fiberoptic-based solar concentrators as a lighting system for photobioreactors. The light-emitting fibers appeared to be a most promising candidate in achieving such uniform light distribution in photobioreactors. Also, when a hybrid-solar-and-electric-lighting scheme is adopted to augment solar lighting whenever needed, the hybrid lighting distribution needs to be designed accordingly.