Environmental Engineering Reference
In-Depth Information
Figure 7.6 Measured open-circuit voltage V
oc
as a function of illumination strength, for cell
similar to that shown in Figure 7.3. A slightly
different cell has achieved 41.6% efficiency as
opposed to the 30% shown here. Note that
these data support the enhanced power and
efficiency in tandem cells predicted for
concentrated illumination. (Spectrolab press
release. http://www.spectrolab.com/
DataSheets/TerCel/tercell.pdf)
flowing from the work of Shockley and
Quiesser has been validated by the results obtained from the GaAs-based tandem
junction cells, as described.
What is not clear is what cost levels would be attainable with such devices in mass
production. An attempt at cost analysis has been offered by the Spectrolab Boeing
group [90].
The curves in Figure 7.7 are a claim by the manufacturer [90] that costs in a large-
scale technology based on concentrating multijunction cells, with attendant tracking
mirrors and water-cooling, can be competitive with large-scale installations such as
It appears largely that the basic theory
Figure 7.7 Projected cell costs [90] under different assumptions for efficiency (related to
concentration) and volume of production.
