Simulation-based study of the energy requirements linked to the temperature control of micro-algae culture in outdoor photobioreactors.

Abstract

Outdoor microalgae photobioreactors are exposed to continuously variable weather conditions, causing permanent fluctuations of culture temperature that must be limited within a strain-dependent range. The optimization of photobioreactor performance requires to be able to predict the culture temperature evolution and related power requirements as a function of weather conditions as well as photobioreactor design. Based on this perspective, a thermal model for vertical tubular photobioreactors was proposed and validated using experimental data from industrial-scale photobioreactors. The model was then used to predict the annual amount of energy required to maintain the culture temperature within a desired range, for different reactor configurations and for several locations in the world. The use of weather databases is of major importance to choose the best location to build microalgae production facilities and to optimize influent geometrical and operating parameters, which can play wanted or unwanted roles depending on the meteorological conditions of the site.