Microalgae have the potential to contribute to carbon dioxide utilization, resulting in the production of valuable chemical products. This study reports a novel PhotoBioCREC prototype able to evaluate both the CO2-derived carbon fixation and the photon absorption efficiency. This unique design involves 1-2 mm alumina particles, which keep photoreactor walls always clean without compromising photon transmittance. Experiments in PhotoBioCREC were carried out using the microalgae Chlorella vulgaris and sodium bicarbonate (NaHCO3). The microalgal growth was followed by the quantification of organic and inorganic carbon, with the simultaneous transmission of radiation measurements every 24 h. The pH was also monitored and adjusted every day to 7.0. When NaHCO3 was used, 29.6 and 15.2% maximum carbon conversion at 2.5 and 5.0 g/L were obtained, respectively. Quantum yields (QYs) were in the 3.6 and 2.8% maximum levels for 2.5 and 5.0 g/L of NaHCO3 concentrations, respectively. These QYs are the first ones to be reported in the technical literature, using the rigorous methodology of the present study.