Molten Storage and Thermophotovoltaics Offer New Solar Power Pathway

Estimated reading time: 4 minutes

If the TPV power block could be made 60 percent efficient, it could compete with most cost effective and efficient heat engine that has ever been achieved commercially, which is accomplished through a tandem turbine based cycle. The cost of turbines is well established and unlikely to see significant decrease, hence the only way to reduce their cost is by increasing their efficiency. However, because current turbines are extremely efficient and operate near their thermodynamic limit, there is little room for efficiency enhancement. TPV power block not only has the potential for lowering the cost but also has much more room for efficiency improvement, Seyf said.

The computational model shows that a TPV system coupled with concentrated solar and storage could be as much as 65 percent efficient. But attaining that would require a long-term research initiative.

In their model, the group studied the effects of a silver-based back surface reflector (BSR) to bounce unused light back to the emitter. The study quantified the importance of the BSR reflectivity to the overall system performance.

Henry’s research group has recently demonstrated pumps, storage containers and other components that can operate at extreme temperatures of 1,300 degrees Celsius and above.

The researchers hope their new paper encourages others to pursue TPV improvements – including fabrication of TPV cells on reusable substrates – that could lead to development of real-world systems at costs competitive with fossil fuels.

“My hope is that this paper will help bring together the thermophotovoltaics and PV community with the CSP community to realize that the thermal and PV system takes advantage of both sides,” said Henry. “This is a heat engine that realistically may have a shot at beating the current record. This is a completely different technology, and there is a lot of research yet to be done.”

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