On Mon, 18 Nov 2013 09:34:17 -0700, Dan Marotta wrote:

At the risk of sounding political...

Someone comes up with a way to make a lot of money off of those who
don't know any better, but it sounds like it'll save the planet from
demon coal, oil, and nuclear power. Does Solyndra ring a bell?

Let's see...

good reasons for doubting it chopped

The question that needs answering is why dive in with an untested
technology when its opposite, the solar UPdraft tower, is known and
tested technology. There is a decent summary (with numbers) of solar
downdraft technology he

https://en.wikipedia.org/wiki/Solar_downdraft_tower

and similar detail of its opposite he

https://en.wikipedia.org/wiki/Solar_updraft_tower


I think these points are also worth looking at:

- the energy cost of pumping water to the top and spraying into the tower
has been estimated as about 50% of the turbine's output, but AFAICT that
excludes the cost of desalinating the sea water and pumping it to the
base of the tower. Desalination is energetically expensive, so the
overall system efficiency might be very small or even negative.

- against that the solar updraft tower has the cost of building and
maintaining a large solar roof at its base, but only maintenance costs
thereafter. The 50kW Manzanares pilot project had a 0.53% efficiency, but
calculations show a more modern 100kW unit might reach 1.3%

- Billions of public money. A key point: always follow the money!
Are the project sponsors putting their money where their mouth is?


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |