Why Silicon Valley Funds Instagrams, Not Hyperloops

[Lamplighter]

Ummm..... what's wrong in the lead paragraph:

Stanford researchers have developed an inexpensive device that uses light
to split water into oxygen and clean-burning hydrogen.
The goal is to supplement solar cells with hydrogen-powered fuel cells
that can generate electricity when the sun isn't shining
or demand is high.

If the Stanford process works, why not just use it instead of solar cells
Is it because there is always a loss of energy in every process.

Somehow the "something from nothing" never seems to work out quite right.
That is, Lucy always yanks the football away.

[Happy Monkey]

Originally Posted by Lamplighter

Ummm..... what's wrong in the lead paragraph:



If the Stanford process works, why not just use it instead of solar cells
Is it because there is always a loss of energy in every process.

Somehow the "something from nothing" never seems to work out quite right.
That is, Lucy always yanks the football away.

For the experiment, the Dai team applied a 2-nanometer-thick layer of nickel onto a silicon electrode, paired it with another electrode and placed both in a solution of water and potassium borate. When light and electricity were applied, the electrodes began splitting the water into oxygen and hydrogen, a process that continued for about 24 hours with no sign of corrosion.

The solar cells would provide the electricity, presumably, to generate and store hydrogen to burn at night.

No doubt Lucy will pull the football away, but it isn't inherently suspicious to have them work in tandem. Burning stored hydrogen WILL be more effective at night than solar cells, but burning hydrogen as it is produced may not be as effective as the cells in the daylight. This would essentially be a way to set aside a certain amount of sunlight for use at night.

There are any number of potential football-yanking opportunities, though.
- How long past 24 (or 80) hours it goes without corrosion.
- Whether the potassium borate (and lithium, mentioned elsewhere) get used up either chemically or mechanically as water goes through the system.
- How expensive those chemical are, or become (with electric cars, lithium could get more expensive).
- How to deal with impurities in the water accumulating as the water is turned to gas. The chemicals added to the water make this a huge issue, as you can't as easily rely on the flow of water to clean the system if the water needs additives for the chemical process to work. If you feed water into a reservoir at a replenishment rate, then impurities will build up. If you let it flow through, then you need to continually dump more chemicals into the intake, and potentially clean them out again on the other side.
- How much solar real estate needs to be allocated to this mechanism instead of solar cells
- How much power from the solar cells goes to the mechanism instead of going out to the grid

[edit - ] Or does this work as a closed system, without a water intake, where a set amount of water is converted to gas and back as needed? That could mitigate the impurities issue.

[xoxoxoBruce]

Instead of systems based on standard solar panels, Duke engineer Nico Hotz proposes a hybrid option in which sunlight heats a combination of water and methanol in a maze of glass tubes on a rooftop. After two catalytic reactions, the system produces hydrogen much more efficiently than current technology without significant impurities. The resulting hydrogen can be stored and used on demand in fuel cells.

For his analysis, Hotz compared the hybrid system to three different technologies in terms of their exergetic performance. Exergy is a way of describing how much of a given quantity of energy can theoretically be converted to useful work.

"The hybrid system achieved exergetic efficiencies of 28.5 percent in the summer and 18.5 percent in the winter, compared to 5 to 15 percent for the conventional systems in the summer, and 2.5 to 5 percent in the winter," said Hotz, assistant professor of mechanical engineering and materials science at Duke's Pratt School of Engineering.

link

I guess KISS is passé.

[Lamplighter]

...how much of a given quantity of energy can theoretically be converted to useful work.

Actually, xoB, I see the point of hybrid systems.
In driving around Oregon/Washington, we have "wind farms" with similar constraints.
If the wind is not blowing...

...and we don't yet have ranches to raise enough gerbils to keep the blades turning.

[xoxoxoBruce]

They're claiming hydrogen is more efficient than batteries for energy storage, with the present state of both technologies. That's only because they think they've found a way around the energy intensive production, but it still has to be compressed for meaningful storage results unless they plan on driving around with giant gas bags like WW II.