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.