Introduction Prototype Light Guides Air Flow 500 Gallon PBR PBR Project Group Publications

Photo Bio Reactor

Light Guide Development

One of the parameters which influence the growth of algae biomass is light.  Apart from selecting the right kind of light source, it is also important to develop a transmission system, that will transmit the light from exterior of reactor deep in to the reactor.  As the algal biomass density increases in the reactor, light penetration into the reactor decreases because light incident upon an algae cell is absorbed by it and not transmitted. The absorption of light near the sides of the reactor limits growth of algal biomass at the interior of the reactor. To utilize all the reactor volume, light intensity on all algal cells should be the same throughout the reactor volume. A light guide (acrylic rods) is one method that may be employed to illuminate the interior of the reactor.  The following figures, show different light guides tested and their light transmission characteristics.

Types of light guides

Surface Finished

Light emitting from corresponding light guide
Saw cut finish
Saw cut finish
Light emitted
Light emitted from saw cut end
Abraded finish
Saw cut end and abraded on the side
Light emitted from abraded guide
Light emitted from abraded guide
Saw cut and lathe cut finished end
Saw cut and lathe cut finished end
Light emitted after lathe finished
Light emitted after lathe finished
Saw cut lathe + wet sanding + buffing finish
Saw cut,  lathe + wet sanding + buffing finish
Light emitted after buffing
Light emitted after buffing
Saw cut, lathe + wet sanding + buffing finish with  30 degree cone end
Saw cut, lathe + wet sanding + buffing finish with
30 degree cone end
Light emission after buffing with angle 30 on the edge

Light emission after buffing with angle 30 on the edge