Solar panels

[Enoki]

I noticed, at least with MT, that there is no method within the rules for determining the efficiency of solar panels. That is, a formula for determining ambient (sun)light at the panel as a function of distance from the star.

Just wondering if anyone's done this calculation and has a formula. After all the Annic Nova adventure / ship uses solar cells for power generation so I figure someone's already done this.

 

[AnotherDilbert]

Rated performance is in the habitable zone. After that it's the inverse square law. If you double the distance to the star you get ¼ the power. If you quadruple the distance you get ¹⁄₁₆ the power. Fortunately it works in reverse too, halve the distance and you get 4 timed the power etc.

 

[Enoki]

Habitable zone for what star? The watt density is going to change depending on the star significantly.

 

[BlackBat242]

Habitable zone for what star? The watt density is going to change depending on the star significantly.

For the star that is closest to the solar panel, of course!

 

[mike wightman]

The habitable zone for any star type is the distance at which a world receives sufficient light/heat that liquid water can exist. The watt density will be similar, it's the distance that changes.

You can find habitable zone orbit distance in LBB6 or similar sources.

 

[Xerxeskingofking]

Habitable zone for what star? The watt density is going to change depending on the star significantly.

since the zone is defined as the distances between which water can be found as a liquid (i.e. is not too cold to freeze it but not so hot to boil it all off), a hotter star simply has a hab zone further out, and within that zone, the total energy hitting a panel is, roughly, the same. It doesn't matter if a garden planet orbits a cool star at half a AU, or a hot star at 4 AU, because if they are both earhtlike planets, the ambient solar radiation is about the same.

 

[BlackBat242]

Now the frequencies of the majority of the light from that star will likely be different from those of another star, so depending on the materials used in the panels they may generate more energy from a bluer star than a redder one - or vice-versa.

That would be the biggest factor in choosing which model/brand of panel to use in which system.

 

[Whipsnade]

FF&S only adjusts solar panel output by inner zone, hab zone, and outer zone rather than by either orbit or distance. The adjustments are also simple orders of magnitude changes to the area of panels required for a given output; first ten, than one hundred, and then ten thousand square meters.

Even FF&S doesn't make adjustments for stellar types.

If memory serves, the charging time for Annic Nova was a 1D6 roll in weeks with some vague talk about distance from the star in question.

I suppose you could use the 0.01MJn formula in HG2 for the EPs required to jump although AN's two (!) jump drives are non-standard. AN can jump up to 3 parsecs, IIRC, so you'd have work out an "EP needed for jump X" table, apply the 250MW per EP conversion, and work out your "MW per stellar distance" and "MW adjustment per stellar type" tables.

Or you could tell your players "Role 1D6 for the number of weeks needed, -1 for inner zones, +1 for outer zones".

 

[aramis]

Habitable zone for what star? The watt density is going to change depending on the star significantly.

The Habitable zone is effectively defined in watts per m^2, as it's the range at which the star can heat a body to a 1-sigma temperature range including temperatures within the range 274 - 373 kelvins. That is directly dependent upon watts/m^2 and albedo, as well as atmosphere type. for most versions of the definition, the inner edge approaches Albedo = 0.95 and Atmosphere none, an the outer edge Albedo about 0.5 and a dense CO2 based atmosphere.

(Remember, 1 sigma means 1 std deviation either side of mean, or about 73% of the data range.)

 

[mike wightman]

(Remember, 1 sigma means 1 std deviation either side of mean, or about 73% of the data range.)

Wrong.
One sigma is 68% of the data range.

 

[whartung]

Wrong.

"Wrong." Not "close", not "sorta". Black and white. Wrong, wrong, wrong.

One sigma is 68% of the data range.

Cuz the difference between 68% and 73% is night and day, life and death, especially in a RPG.

 

[aramis]

Wrong.
One sigma is 68% of the data range.

Wrong, mike.
66% is one 1 sigma either side, exclusing >1 sigma on both.

however, we can't exclude the other end from the calc, so, I'm using <=+1 sigma, which is 66+ 34/2= 66+17=83%...

 

[mike wightman]

One standard deviation either side of the mean - +/-one sigma - is 68% of the distribution.

I had the number 66 stuck in my head too for a while, but I checked it in my maths books and online.

https://en.wikipedia.org/wiki/68–95–99.7_rule

http://libweb.surrey.ac.uk/library/skills/Number Skills Leicester/page_17.htm

The other way to do your calculation by the way is to add one sigma to the mean - so 50% +34% for a total of 84%

 

[aramis]

One standard deviation either side of the mean - +/-one sigma - is 68% of the distribution.

I had the number 66 stuck in my head too for a while, but I checked it in my maths books and online.

https://en.wikipedia.org/wiki/68–95–99.7_rule

http://libweb.surrey.ac.uk/library/skills/Number Skills Leicester/page_17.htm

The other way to do your calculation by the way is to add one sigma to the mean - so 50% +34% for a total of 84%

either you're being dense or ignorant - I'm excloding only one side past the cutoff.
given the range -(infinity) sigma to +1 sigma, that's 84% give or take, excluding only the range +1 sigma to +(Infinity) sigma.

 

[mike wightman]

I am neither dense nor ignorant - I was just correcting your maths error. The last bit of my post you quoted shows how I would arrive at a similar number to your corrected value by an alternative route.



Your original point was:

(Remember, 1 sigma means 1 std deviation either side of mean, or about 73% of the data range.)

which is incorrect.