The Green Solar Collector; converting sunlight into algal biomass
02 / 2005 - 06 / 2008
The sun is an enormous source of cheap and environmentally friendly energy, which is unfortunately only used to a limited extend. The most common use of solar energy is by the cultivation of plants. Unfortunately, plants can only convert solar energy into biomass with a photosynthetic efficiency of 0,2 % - 2 %. Unicellular algae (phototrophic micro-organisms) can use solar energy for the production of biomass with higher photosynthetic efficiencies. The goal of the research project the green solar collector is, to develop a photo bioreactor in which the algae are cultivated with the sun as energy source. aThe reactor has to be designed in such a way that it can be placed outdoor and used with a limited input of labor. To investigate if algae can be grown economically, the costs per kg biomass will be compared to conventional systems (open ponds, tubular reactors). Previous research has shown that algae grow optimally in flat-panel bioreactors, because high light efficiencies can be achieved in this type of reactor due to the short light/dark cycles and the small optical path. This will result in a high biomass concentration at a certain light intensity compared to other reactor systems. The reactor we designed can be regarded as a number of flat-panel bioreactors within one reactor housing. The advantage of this approach is that there is a relatively large reactor volume per surface, compared to single flat-panel reactors placed separately. The challenge of our approach is to design an efficient mechanism to capture the sunlight in and to diffuse the sunlight out of the plates between the reactor volumes.