Light attenuation dynamics in flat-plate photobioreactors: Experimental analysis and empirical modeling

Creative Commons License

Rajendran A., UĞUZ S., Koromyslova E., Kumar P., Yang X., Anderson G.

Gumushane Universitesi Fen Bilimleri Dergisi, cilt.16, sa.3, ss.698-717, 2026 (Scopus, TRDizin)

Özet

The growing interest in low-carbon energy systems has led to increased study on microalgae as a high-yield, land-efficient bioresource. Although photobioreactors (PBRs) are controlled systems for algal cultivation, lighting limitations remain a significant issue in system performance. Understanding light attenuation mechanisms is essential for improving reactor design and operational efficiency. This study investigates the optical behavior in flat-plate photobioreactors under varying optical depth, aeration rate, and biomass concentration. Experiments were conducted in a laboratory-scale flat-plate photobioreactor with optical depths ranging from 102 to 305 mm, aeration rates between 0 and 10 L min-1, and biomass concentrations from 0 to 1 g L-1 using Chlorella vulgaris. Transmitted irradiance was measured to quantify the influence of these parameters on light attenuation within the reactor. Based on the experimental measurements, empirical correlations were developed to describe the relationship between transmitted light intensity and key operating variables. The results showed that increasing optical depth significantly increased light attenuation, with irradiance loss rising from 15.8% at 102 mm to 44.83% at 305 mm. Aeration also affected light distribution due to bubble-induced scattering, resulting in attenuation levels between 7.04% and 36.6%. Biomass concentration exhibited the strongest influence, reducing transmitted irradiance by up to 99.2% at 1 g L-1. The developed empirical extinction coefficients provide useful parameters for predicting light attenuation and improving the design and operation of flat-plate photobioreactors.