[Tfug] OT: Big Oil? Windows Vista!

[Ronald Sutherland]

hmmm... fish is in the air
the MST-43 is rated at 43W and has an area of .8m^2, which in 1000 W/m^2
light is only 5.3% efficiency.

On Sat, May 31, 2008 at 2:36 PM, Ronald Sutherland <
ronald.sutherland at gmail.com> wrote:

> The monocrystalline panels I tried make a peak power output of 80W when
> pointed straight at the sun, so no insolation effects, at least if I under
> stand that correct. If I assumed 1000 watts/m^2 during that peak (duplicated
> on many clear days) then I can add up the area of silicon and get an
> efficiency, I recall something like 14%, but when I add up the full area of
> the panel (it has unused space) I get about 8%. I did not think there are
> any big PV based systems doing any where near 20% conversion (that is light
> in to DC out, never mind any inverter losses to get AC), but it looks like
> I'm wrong.
>
> http://en.wikipedia.org/wiki/Solar_cell
>
> That Springerville generating station with 34,980 modules (MST-43) each is
> 26" x 48"
> 1248 in^2 = 0.805 m^2
>
> 34980 * 0.805 = 28158 m^2 off pv area or 28,158,000 W at 1000 W/m^2
>
> if we discount 20% for insolation effects we have (they are at an angle so
> not sure on this)
> 22,527,000 W of solar radiation hitting the pv
> the pv is rated at 4,590 kW DC
> so the efficiency is 20% ???? wow that is much better
> than I would have thought possible.
>
> Kramer Junction solar power plants are steam turbine Rankine cycle not
> Brayton. Oil is pumped into the solar absorbers at the focal point of the
> parabolic trough (371 deg C) and then back to the boiler to make steam (at
> night CH4 is burned to make steam).
>
> The carnot engine is the ideal, in other words no heat engine can do better
> (although reusing waste heat is possible). So the best possible heat engine
> could get 51.3% out of a heat difference of 371C and 40.5C.
>
> http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/carnot.html
>
> There is a lot of room for improving heat engines. Also Solar cells have an
> important place but I don't think we should lose sight of the fact that they
> cost so much energy to make.
>
>
>
> On Sat, May 31, 2008 at 11:11 AM, johngalt1 <johngalt1 at uswest.net> wrote:
>
>> That explanation is spot on.  Thank you.
>>
>> I challenge anyone to substantially refute the assertions or
>> facts contained in the previous message.
>>
>> It is interesting that 20 percent is cited as the efficiency
>> in conversion of insolation
>> http://en.wikipedia.org/wiki/Insolation
>> to DC electricity via photovoltaic panels. I note this
>> because that is the same efficiency as the world's largest
>> solar electric plants...
>> http://en.wikipedia.org/wiki/SEGS
>> http://www.fplenergy.com/portfolio/contents/segs_viii.shtml
>> ...with Brayton cycle heat engines employing
>> sophisticated turbomachinery and heat transfer methods.
>> http://www.flagsol.com/SEGS_tech.htm
>> http://www.p2pays.org/ref/22/21026.pdf
>>
>> Unfortunately, what this means is that most of the solar
>> power collected is wasted.
>> There is no evil, villianous oil company to blame on that
>> one... The reason for that is simple applied physics.
>>
>
>
>
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