Interesting new commercial solar generator

[Mary B]

Just ran across this on a silver site(has a section on prepping) and it is an interesting idea of the costs can be brought low enough.

http://www.planetarypower.com/products/sunsparq/

[boB]

Well, at least they have an artists' conception.

I don't think you can actually go and buy one though.

[Mary B]

Supposedly prototypes out there from what I could find. Their diesel generator is 4 times the price of any other the same size so it will likely be super expensive

[CraigM]

If you Google "Micro Turbine Engine" you'll find a lot of information on small turbine engines used for power generation or combined heat and power units.

Claims are made for multi-fuel operation and higher efficiency over piston type engines.

What I'm failing to see is how heat alone from the solar collector would drive a turbine engine. Isn't combustion, steam or pressure of some sort required?

[joestue]

I've spent a lot of time on this concept, basically you need a mix of propane and isobutane for a heat fluid, and you need to find an oil that can dissolve in it, yet not break down at the high boiler temperatures.
you need a CVT to run the pump directly geared down off the radial inflow turbine, and the electric generator needs to be able to spin up the turbine to run the pump to start it up in the morning.

as for the collector, you need a funnel type design filled with stainless steel. $$$ (its simply not possible to get coatings to take the heat, protect from corrosion at 1 megawatt per square meter heat flux and keep an emissivity of .95, so you have to get creative, picture sun light striking the inside of the letter 'M' rotated about a cone, so you can get 10 fold surface area for free.)

As for the mirror, it needs to be cheap and made from unobtainium, doesn't rust, doesn't warp, doesn't loose its reflectivity after 5 years...

As for 35% efficiency as they claim.. maybe if you had a river nearby to cool off the condenser via a cooling tower.
But its simply not possible given the upper limits on the boiler temperature, and practical limits such as 1000:1 concentration ratio, practical emissivity of the collector, etc

supposing it might be possible to run it without oil, have the generator shaft fully support the radial inflow turbine (ie, no exposed bearings), and have a teflon lubricated pump that would help out quite a bit.

[electrondady1]

if your doing all that, light to heat to steam to turbine to alternator to electricity  to get electricity.
 what about simply using the mirror array to reflect light on to a smaller p.v. panel

[Mary B]

Output from PV drops off with heat, and they do have an upper limit where melt down occurs. I have played with this with a 6 foot aluminum dish antenna and square mirrors siliconed to the surface of the dish, melted everything I tried as a heat exchanger(copper, brass, aluminum... it would deform and then lose water seals). It would flash water to steam easily

[prasadbodas2000]

Would this be by use of a Sterling engine installed at the focus of the concentrating mirrors?

[MattM]

I find it interesting that white is better for cooling a roof than silver, yet doesn't work on these collectors.

This stuff is too complex.  A simpler, flat plate collector using vacuum sealed glass insulation around it and active cooling to collect the heat would crush it in producibility and cost.

[bob golding]

Would this be by use of a Sterling engine installed at the focus of the concentrating mirrors?

sterling engine designs have been around since the 70's. sandia labs had one that worked for a long time. you need helium at pressure to make it effecient. all the details are on the web somewhere. using  a heliostat to heat sodium for a sulfer ammonia battery seems a better option.  look up sulfer sodium batttery to find the links. and it has been priced up as well for the DOE.

[Ungrounded Lightning Rod]

As for the mirror, it needs to be cheap and made from unobtainium, doesn't rust, doesn't warp, doesn't loose its reflectivity after 5 years...

They call it "silvered glass".

As for 35% efficiency as they claim.. maybe if you had a river nearby to cool off the condenser via a cooling tower.
But its simply not possible given the upper limits on the boiler temperature, and practical limits such as 1000:1 concentration ratio, practical emissivity of the collector, etc

If you've got a turbine spinning, why not use one more set of vanes to pump air past a veined heat sink or radiator, to cool the cold end of the heat engine?  It works great for computer chips - to the tune of several kW of heat per rack.  Why not for the heat dump side of a sterling?

[joestue]

As for the mirror, it needs to be cheap and made from unobtainium, doesn't rust, doesn't warp, doesn't loose its reflectivity after 5 years...

They call it "silvered glass".

too expensive. Glass and the aluminum frame and mounting hardware is half the cost of a solar panel.

As for 35% efficiency as they claim.. maybe if you had a river nearby to cool off the condenser via a cooling tower.
But its simply not possible given the upper limits on the boiler temperature, and practical limits such as 1000:1 concentration ratio, practical emissivity of the collector, etc

If you've got a turbine spinning, why not use one more set of vanes to pump air past a veined heat sink or radiator, to cool the cold end of the heat engine?  It works great for computer chips - to the tune of several kW of heat per rack.  Why not for the heat dump side of a sterling?

the desert air is too warm, you need that extra 30C drop to get the claimed 35% efficiency.
and it takes too much work to push air through the condenser.

[WindriderNM]

In the fall of 2009 a ribbon cutting ceremony for the first ever carbon neutral commercial application of Infinia Corporation's   PowerDishâ„¢ technology took place in the parking lot at Belen City Hall, New Mexico. Three solar dishes, each generating as much as 3kW of power,
http://www.belen-nm.gov/news/Stirling_Power.htm

[Bruce S]

Thanks for the link.
It is a nice read.
Only thing I take issue with, is the sentence "removes 1,867 tons of carbon dioxide,etc" .
This is not actually true IMO. They can help reduce the possibility of adding more to the air, but it doesn't remove them since there's no current scrubber on these.

[Mary B]

They mean removes as in offsets that much coal generation.