Measurement of Light Intensity Profiles of Light-Emitting Diodes in a Cylindrical Tank

摘要

Hydrogen production by photo synthetic bacteria is one of the emerging and potential technologies in renewable energy area. In this study, three colors of LEDs lights, red (620.084nm), white (464.979nm), and blue (458.317nm), respectively, are used to simulate light intensity in the space of cylindrical tank where photo synthetic bacteria is supposed to be cultured inside. The illuminations inside the tank are measured by an optical fiber which is connected to the AvaSpec-2048 spectrometer. Average cosine corrector is installed on the fiber head. Photon fluxes are measured by LI-COR-190SA with LI-1400 data logger. Based upon the experimental results for three different mediums, the illumination in the aqueous medium are the highest, followed by in the air bubbled water medium, then in the air medium. If light sources of are altered, the illumination values from large to small are in the sequence of white, blue, red, respectively. Illumination experimental results show that the values in air bubbled water medium are slightly lower than in the aqueous medium, but the difference is not significant. Therefore, for hydrogen production, using the air bubbled water medium is proper because the bubble will not cause great illuminance decays and will increase the mixing effects in the cultivation container; it will be beneficial for the growth of algae and to improve the efficiency of hydrogen production purposes.