solar steam

Interesting development: [www.gizmag.com]

Dear Bill, Someone should look at this critically. At first blush it seems strange that they are now able to generate steam at lower temperatures. The books in my library do not mention the possibilities of generating steam in any other way than is carefully laid out in the Keenan and Keyes steam tables. The pressures and temperatures appear to be standard. What may have happened is that the reporter attempted to understand what was being explained and did not quite follow the discussion. What the steam world does need is a flat plate collector with a high enough saturation temperature to make steam at a reasonable pressure, say 50-100 psi. For many off-grid or third-world situations these pressures are workable and with them one may be able to make a plastic engine. Anyhow, this topic illustrates the fact that steam information comes from many sources. Tom Kimmel

One thing that needs to pointed out is this is not "makeup water" there are dissolved gases and that would explain a lot.

Bill and Tom

There may be an issue with semantics here. "Boiling" is evaporation, but evaporation is not necessarily boiling. Water boils in the kettle on the stove at 212° F and water evaporates from the cup on the table at 70° F. In either case, the latent heat of evaporation must be supplied.

The difference is pressure. Think in terms of partial pressure.

The water in the kettle is boiling under a vapor cloud consisting of 100% water vapor at 14.7 PSIA.

The water evaporating from the cup on the table is doing so under air that is perhaps 2% water. The pressure of the water vapor above the cup on the table is 2% of 14.7 PSIA or 0.294 PSIA.

It is clever of the boffins at MIT to improve solar evaporation of water with their carbon foam/flakes. This may be valuable with solar desalination. It may also be valuable with high pressure solar steam generators.

This notwithstanding, Keenan and Keyes steam tables still hold sway.

Kerry

Kerry,

We might consider that what this actually does is simply greatly expand the wetted surface?
Every time i have tried to outline something technical to a reporter, the final edition read like Alice in Wonderland, even when you use Sesame Street language.
Remember the great flap about cold fusion, same thing then. All the engineering disadvantaged leaped on it.
Definitely, K & K still rule.

Jim

PS. What's this rumor going around that the Cyclone facility in Florida is closed and gone?

Jim,
I don't know about the Cyclone building being empty, but the stock is. Seems the assets are being moved to another company, and the stock is showing zero value, while all sorts of good news is being posted on the website.

Tom