[Solar Turbine] precision and collector efficency [graphs]

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May 11, 2010, 1:13:38 PM5/11/10
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Hi,

I plotted a graph of collector efficency Vs Usage temperture which shows the effect of tracking accuracy.  For any temperature we use the collector at, there will be radiative and conductive/convective losses.  Radiative is the big one because it varies with T^4 where the others are linear for T.  The efficency of the collector is how much energy we can extract vs energy that came in, the rest being radiated away.

see http://www.openfarmtech.org/index.php/Solar_Collector_Calculations#Absorber_efficiency_and_operating_temperature for other graphs on this subject.

This is a rough model and uses an arbitrary coefficents for conductive/convective losses (linear with temp).  I also attached a graph of how an order of magnitude change in these coefficents effects the shape of the graph.

See attached files, and read the scipy code that generated this data for details on the model used.  The shape of the graph is probably true, and rough relations, but the numbers are for scale only.

so

here are some specific numbers:

[mirror accuracy (degrees), Efficency, Concentration ratio]

at  20.0  degrees C
['0.0', 1.0, [11.999999999999979]]
['0.01', 1.0, [11.327794975546459]]
['0.02', 1.0, [10.726904316321555]]
['0.05', 1.0, [9.2542072595727518]]
['0.1', 1.0, [7.530951279076695]]
['0.2', 1.0, [5.4871643649255599]]
['0.5', 1.0, [3.023742334108527]]

at  120.0  degrees C
['0.0', 0.96346028793428573, [11.999999999999979]]
['0.01', 0.96213970884946054, [11.327794975546459]]
['0.02', 0.96081912812873027, [10.726904316321555]]
['0.05', 0.95685735979188868, [9.2542072595727518]]
['0.1', 0.95025422715542318, [7.530951279076695]]
['0.2', 0.93704653027634144, [5.4871643649255599]]
['0.5', 0.89739724548647404, [3.023742334108527]]

at 220.0  degrees C
[mirror accuracy (degrees), Efficency, Concentration ratio]
['0.0', 0.90162983786857132, [11.999999999999979]]
['0.01', 0.89748789678464369, [11.327794975546459]]
['0.02', 0.89334595056976784, [10.726904316321555]]
['0.05', 0.88092002982944262, [9.2542072595727518]]
['0.1', 0.8602095804032186, [7.530951279076695]]
['0.2', 0.81878419137793612, [5.4871643649255599]]
['0.5', 0.69442586743761103, [3.023742334108527]]

at  310.0  degrees C
[mirror accuracy (degrees), Efficency, Concentration ratio]
['0.0', 0.81256287851942832, [11.999999999999979]]
['0.01', 0.80389855495336793, [11.327794975546459]]
['0.02', 0.7952342206541283, [10.726904316321555]]
['0.05', 0.76924104602444299, [9.2542072595727518]]
['0.1', 0.72591787184322598, [7.530951279076695]]
['0.2', 0.63926213070829285, [5.4871643649255599]]
['0.5', 0.37912304738501945, [3.023742334108527]]



-elliot

 


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See http://openfarmtech.org/index.php?title=Solar_Power_Generator_Distillation_Transcript
col_eff.png
collector_eff.py
insulation_eff.png

Ozheliguy

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May 21, 2010, 11:34:28 AM5/21/10
to Solar Turbine
Keep up the good work!

On 11 maio, 14:13, "..." <offonoffoffon...@gmail.com> wrote:
> Hi,
>
> I plotted a graph of collector efficency Vs Usage temperture which shows the
> effect of tracking accuracy.  For any temperature we use the collector at,
> there will be radiative and conductive/convective losses.  Radiative is the
> big one because it varies with T^4 where the others are linear for T.  The
> efficency of the collector is how much energy we can extract vs energy that
> came in, the rest being radiated away.
>
> seehttp://www.openfarmtech.org/index.php/Solar_Collector_Calculations#Ab...
> Seehttp://openfarmtech.org/index.php?title=Solar_Power_Generator_Distill...
>
>  col_eff.png
> 43KExibirDownload
>
>  collector_eff.py
> 4KExibirDownload
>
>  insulation_eff.png
> 44KExibirDownload
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