The Cutting Edge: Computing / Technology / Innovation : A Better Path to Power?

Most electric power is produced by burning fuel to boil water into steam, which turns the fan-like blades of a turbine, generating electricity. The steam is then condensed back into water for reuse in what is known as a thermodynamic cycle.

Traditional power generation relies on the Rankine cycle, which uses ordinary water. But the proposed new Kalina cycle appears to be much more efficient, thanks to a mixture that starts out in the boiler as 70% ammonia, 30% water. Such mixes are more efficient in boilers but have been difficult to condense. The Kalina technology uses a new process that takes advantage of efficiencies obtained by varying the ratio of ammonia to water at successive stages during condensation.

The invention of Alexander Kalina, an engineer who emigrated to the United States from Russia in 1978, the Kalina technology is billed by proponents as the first new electricity-generating thermodynamic cycle in a century. It could dramatically increase the generating efficiency--by 20% or more--of the immense utility steam-turbines that produce 70% of the nation’s electric power, using virtually any fuel.

The cycle’s principles have already been successfully demonstrated by researchers at the Energy Technology Engineering Center, a Department of Energy facility near Simi Valley that is operated by the Rocketdyne unit of Rockwell International. The center has the sole operating model in the world.

How the Kalina Cycle Works:

A 70% ammonia solution is first boiled (1) to produce steam to turn the generator (2). Then the used steam is condensed back to liquid in a complex system that replaces the single condenser in conventional power plants. Energy is saved as parts of the stream are split off and remixed at different temperatures, pressures and ammonia mixtures. Finally, the separate streams are reformed as a 70% solution (3) to return to the boiler.

Source: U.S. Department of Energy; Exergy Inc.