A research program at the Eindhoven University of Technology (TU/e, the Netherlands ) has lead to a revolutionary solar energy system that enables the production of low-cost solar electricity.  We have chosen for a production unit size of 100.000 m² as this size seems to be optimal in view of the anticipated volume growth. Every one or two years a new unit should be erected in order to meet the anticipated demand from the market.

The solar energy system is based on a Luminescent Solar Concentrator (LSC). The operating principle is that sunlight is captured and concentrated by a large, low-cost, plastic plate and transported to a small, efficient solar cell that converts the sunlight into electricity (Figure 1).

 

Figure 1: Right: lab-scale samples of the LSC solar energy system. Left: a schematic diagram of the LSC technology.

The LSC technology, as developed at the TU/e, has the following competitive advantages compared to conventional solar panels:

Low-cost solar electricity (< € 0,25/kWh)

Low investment cost

Aesthetic advantages (color, shape)

 
Maxxun solar systems are based on Luminescent Solar Concentrator (LSC) technology in combination with a small solar cell. The LSC system consists of four elements: a fluorescent dye impregnated plastic waveguide, mirrors on three sides and bottom, and a wavelength selective mirror (Figure 2). Sunlight shines on the LSC system, passing through the wavelength selective mirror on the surface and is absorbed by dye molecules in the plastic waveguide. These dye molecules re-emit the light at higher wavelengths (resulting in a change in color). A significant fraction of the re-emitted light will be emitted by the dye molecules at such an angle as to be trapped in the waveguide and prevented from escaping the LSC by total internal reflection (situation 1). Light emitted at steeper angles is reflected by mirrors at the bottom and three sides and by the wavelength selective mirror covering the top surface (situation 2). Light is thus first passed through the wavelength selective mirror, but the emitted light from the dye molecules is reflected. Light is thus trapped in the LSC system until it reaches the solar cell and is converted into electricity. The strength of this principle is that light from a relatively large, inexpensive surface is efficiently concentrated and transported to the edge where a small solar cell is connected, rather than using a large solar cell for both collection and conversion.



Figure 2: Schematic overview of internal reflection (situation 1) and reflection by mirror and wavelength-selective mirror (situation 2).