Temperature based mass flow rate sensor for algae photobioreactors

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Photobioreactors are an alternative to traditional methods for microalgae growth of open ponds and lakes. In spite of their construction cost, photobioreactors exhibit higher productivity and avoid contamination problems. The current work is aimed at improving the use of photobioreactors for continuous growth through the development of minimally invasive mass flow rate sensor that can be used as an alternative to more expensive commercially available sensors (e.g. ultrasonic). A mathematical model that allows for the determination of the system temperature distribution is developed using a Volume Element Model (VEM) approach to assist in the sensor design. The VEM combines principles of classical thermodynamics and heat transfer and discretizes the system in space, resulting in a system of ordinary differential equations with respect to time. The mathematical model is implemented in Fortran and the data acquisition and information processing of the sensors is handled with a microcontroller.