Written Paper

Effects of flashing light-emitting diodes on algal biomass productivity  [2013]

Lunka, Alex A. Bayless, David J.

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To reduce power consumption and enhance algal biomass productivity in a thin flat-plate bioreactor (called a sliver tank bioreactor), flashing (pulsing) light was used. Biomass productivity and power consumption were monitored in controlled experiments using various photon flux levels, including a constant (non-flashing) flux of 75� μmol photons m⁻²� s⁻¹ and three flashing experiments with photon fluxes of 375, 275, and 175� μmol photons m⁻²� s⁻¹. Flashing experiments were performed at 10� kHz and a duty cycle of 20� %. A sliver tank bioreactor with a chamber width of 6.4� mm was used for its short optical path. Data from the experiments where light was flashed with a photon flux of 375� μmol photons m⁻²� s⁻¹ indicated 9.6� % less power and 2.86 times the biomass productivity compared to the constant photon flux experiments. Similar results were obtained for the other flashing light regimes, which had lower biomass yields but also less input power per unit biomass produced, indicating that a large fraction of the continuously applied photons are shed or wasted, even at levels approximately 1/30th the intensity of full sun.

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Journal of applied phycology

ISSN : 0921-8971