A Simple and Reliable Method to Determine Mean Incident Light Flux Densities on Cylindrical Photoreactors and Photobioreactors from a Unique Fluence Rate Measurement

• Published in: Industrial & engineering chemistry research Vol. 62; no. 12; pp. 4875 - 4884
• Main Authors: Cornet, Jean-François, Dauchet, Jérémi, Vourc’h, Thomas, Arnau, Carolina, Garcia-Gragera, David, Gòdia, Francesc, Gros, Fabrice, Peiro, Enrique
• Format: Journal Article
• Language: English
• Published: American Chemical Society 29.03.2023
• Subjects: Chemical Sciences; Engineering Sciences; Kinetics, Catalysis, and Reaction Engineering
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.2c04151

A new method to determine the hemispherical incident light (photon) flux density onto cylindrical photoreactors or photobioreactors is presented. It applies to situations where the photo­(bio)­reactor is radially illuminated by surrounding artificial sources or solar light. It relies on the direct measurement of a fluence rate with a spherical sensor put at the center of the reactor. Theoretical relations leading to the calculation of the hemispherical incident light flux density from the fluence rate value are established, and a web application performing those calculations is made available. It relies on a view factor, the expression of which, established for the first time with any assumption of the angular distribution of light at the boundary, is given. This requires a proper definition of the degree of collimation for the incident radiation field. Two different and complementary experimental devices are used to validate the method. As a result, the proposed method appears to be simple and reliable; it even looks faster and more accurate than actinometry for this particular geometry.