To enhance biomass productivity, irradiance on the surface of the solar receiver tubes must be maximised. Solar irradiance is the power of electromagnetic radiation on the tubular surface which varies with location and weather conditions. The solar receiver tubes must be configured to maximise the irradiance on the surface tubes; thus the appropriate configuration should be chosen for the designated location.

The surface on which the tubes are located can be painted or covered with white sheeting to take advantage of the albedo effect. The albedo effect refers to improved irradiance by means of reflection [1]. In retrospect, the design of the photobioreac­tor is not as significant as the source of illumination. Generally, light is always the limiting factor with regard to algal cultures [7] .