Wednesday, January 20, 2010

Tower Of Power

Here is an interesting development that may be good for continuous output solar power.

The company's approach uses calcium hydride, a simple, non-toxic salt.

Under Solar Fusion's plan, solar heat is collected by an array of heliostats directed to a central down mirror, eliminating the requirement for a power tower.

The heat, focused on a power head immersed in liquid calcium, chemically separates the calcium and hydrogen during the day. At night, the hydrogen, having been collected in a separate tank, is pumped back and reacts with the calcium to reform as calcium hydride.

The reaction runs at approximately 1,000 degrees, and powers a dual shell Stirling engine of Bliesner's design to create power after dark.

"We can generate electricity continuously unlike other solar technologies," said Bleisner, inventor of the technology and a former Boeing engineer.
They claim the system compares to the cost of fossil fuels. The question is: coal (very cheap) or natural gas (rather expensive).

It is still interesting. Now if they could develop a fuel cell along the lines of this patent [pdf] or something similar I think they would have a real winner. Getting rid of the thermal energy to mechanical motion step (Stirling engine) could greatly improve efficiency and reliability. It would mean pumping reactants around. But you would have to do that in any case, I think. More details on how the system operates would be nice.

Bleisner was originally involved in Stirling Engine development at ADI Thermal. So he may have a vested interest in the Stirling engine route. No matter. Others can now start in on the Hydrogen/Calcium fuel cell route. One breakthrough can show the path to others.

Cross Posted at Classical Values


LarryD said...

Ok, it's a novel version of Solar Thermal, and Solar Thermal has always been cheaper than Solar PV.

But I still want to see an audited cost break down before I accept any claims as to how cheap it is.

And I want to know the capacity factor, and the overall efficiency too.

And it's still bedeviled by the limits of solar insolation, seasonal variations in daylight and incident angle, and cloudiness. The inherent issues for any ground-based solar power scheme.

David Foster said...

Why a Sterling engine? With a temperature of 1000 degrees, I'd think a plain old garden-variety steam turbine would work just fine.