Internal illumination and wireless, traceable sensors for photoreactors

Photoreactors are reactors that amongst other things are used to cultivate photosynthetic active microorganisms or cells like microalgae and cyanobacteria. The most important quantity which makes the photosynthesis possible is light. However, the weak penetration depth of light is a common problem of those reactors. To manage higher culture volumes the reactors are usually scaled up in the length in order to maintain a small diameter. This enables a higher illuminated surface to volume ratio. A disadvantage of this approach is the resulting poor mass and heat transfer.

Another method used for upscaling is to use internally mounted light emitters. However, the structure of such systems is complex, and the static mounted light emitters also make the heat and mass transport more difficult.

In this project, we develop a novel type of internal illumination for photoreactors consisting out of many small light sources, the so-called wireless light emitters (WLE).

WLEs are small light-emitting spheres which are supplied with energy from outside through an inductive link. The overall density of a WLE is similar to the density of water. This characteristic enables them to float around in the reactor medium which leads to homogeneous WLE-distribution.

To better control the processes in those photoreactors, the further step in this project is to include wireless traceable sensors. To counteract the drawback of measuring the desired quantity only at one point, wireless traceable sensors lead to a spatial resolution of the registered parameters of interest. This advantage should enable further optimization in the cultivation of photosynthetic active microorganisms and cells.

The sensors are supplied with the same inductive link as the WLEs, and the communication and the localization of the sensors are realized through a second inductive link.

Herefore the well-defined propagation characteristic of the magnetic field of a coil is used to calculate the position of the sensor inside the reactor.

 

Principal Investigator (Tyrolean private university UMIT): Univ.-Prof. Dr. Alexander Sutor

Co-operation partner: Lehrstuhl für Bioverfahrenstechnik, Universität Erlangen, DECHEMA (http://dechema-dfi.de/WLE.html?highlight=wireless)