Concentrating Photovoltaic Technology
NREL continues to further research and develop concentrating photovoltaic (CPV) technology—a viable alternative to dish Stirling engines.
Concentrating photovoltaic systems use lenses or mirrors to concentrate sunlight onto high-efficiency solar cells. These solar cells are typically more expensive than conventional cells used for flat-plate photovoltaic systems. However, the concentration decreases the required cell area while also increasing the cell efficiency.
Concentrating photovoltaic technology offers the following advantages:
- Potential for solar cell efficiencies greater than 40%
- No moving parts
- No intervening heat transfer surface
- Near-ambient temperature operation
- No thermal mass; fast response
- Reduction in costs of cells relative to optics
- Scalable to a range of sizes.
The high cost of advanced, high-efficiency solar cells requires the use of concentrated sunlight for systems to achieve a cost-effective comparison with both the cost of concentrator optics and other solar power options. NREL has focused on the development of multi-cell packages (dense arrays) to improve overall performance, improve cooling, and install reliable prototype systems.
We've tested numerous dense arrays at the High-Flux Solar Furnace where both the level and distribution of the concentrated solar flux can be controlled and the cooling source temperature can be varied. The combination of test conditions and measurement capabilities allow for a complete mapping of optical, thermal, and electrical performance.