Until now, thermodynamic engines that use compressible working fluids have generally been mechanical devices. These devices have inherent difficulties in achieving high compression ratios and in achieving the near constant temperature compression and expansion processes needed to approximate Carnot equivalent cycles. Solid-state thermoelectric converters that utilize semiconductor materials have only been able to achieve single digit conversion efficiency. Extensive resources have been applied toward Alkali Metal Thermoelectric Converters (AMTEC), which operate on a modified Rankine cycle and on the Stirling engine. However, because of inherent limitations, these systems have not achieved envisioned performance levels.
The JTEC is an all solid-state engine that operates on the Ericsson cycle. Equivalent to Carnot, the Ericsson cycle offers the maximum theoretical efficiency available from an engine operating between two temperatures. The JTEC system utilizes the electro-chemical potential of hydrogen pressure applied across a proton conductive membrane (PCM). The membrane and a pair of electrodes form a Membrane Electrode Assembly (MEA) similar to those used in fuel cells. On the
high-pressure side of the MEA, hydrogen gas is oxidized resulting in the creation of protons and electrons. The pressure differential forces protons through the membrane causing the electrodes to conduct electrons through an external load. On the low-pressure side, the protons are reduced with the electrons to reform hydrogen gas. This process can also operate in reverse. If current is passed through the MEA a low-pressure gas can be "pumped" to a higher pressure.
He uses a plastic exchange membrane and hydrogen gas in lieu of Alumina and Sodium, which makes me wonder how high will really be the "high temperature heat source"
chrismb wrote:I think it meant to say "hydrogen gas is ionised", no?
I highly doubt. Even if we consider a cold plasma the proton exchange membrane should not be able to withstand it.
Understandable. The areticle said "Hydrogen gas is oxidized", chrismb wanted to change it to "Hydrogen gas is ionized" which would naturally lead to "plasma".
There is no mention of H2O anywhere in the article, and since H2O is the result when oxidizing hydrogen, he meant "ionized." He is using a proton exchange membrane, PEM, which operates on protons, the result of ionized hydrogen. IMO.
Aero wrote:There is no mention of H2O anywhere in the article, and since H2O is the result when oxidizing hydrogen, he meant "ionized." He is using a proton exchange membrane, PEM, which operates on protons, the result of ionized hydrogen. IMO.
You can "oxidize" Hydrogen with MANY things, not just oxygen.
The wikipedia article on fuel cells wrote:At the anode a catalyst oxidizes the fuel, usually hydrogen, turning the fuel into a positively charged ion and a negatively charged electron.
