# Solar Playtime



## Maryak (Aug 16, 2011)

Hi Guys,

I spent most of today developing a solar path diagram for Adelaide. 

I found a paper from Cambridge University with all the formulae so I set to with a spreadsheet and then transferred the info to Cad.







Best Regards
Bob


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## steamer (Aug 16, 2011)

Good Morning Bob....at least from here it's morning.

What does a solar path diagram represent?

Dave


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## tel (Aug 16, 2011)

The basis for a sundial?


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## Noitoen (Aug 16, 2011)

A means to optimize solar panel output or to build an heliostat behind the house to reflect some sunlight onto windows and rooms which otherwise never get direct sun shine :big: :big:


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## Maryak (Aug 16, 2011)

steamer  said:
			
		

> Good Morning Bob....at least from here it's morning.
> 
> What does a solar path diagram represent?
> 
> Dave



I'll try and explain 

The concentric circles represent from the horizon at 0o to directly overhead at 90o

The 2 Orange arcs represent the suns path at the solstices.

The Red arc represents the suns path at the equinoxes. It is also a check that your equations are correct, if they are not then the arc will not give sunrise and sunset due East and West.

The green arcs represent the middle of the months in between.

The purple arcs represent local solar time, (well almost because the equation of time has been ignored).

e,g, if we look at the green arc representing April/August we can see that the sun rises at around 06:40 and sets at around 17:20. Its' highest altitude is around 50o. Finally the number of peak sun hours, i.e. the number of hours the sun is at or higher than the latitude, (35o), is around 7 hours. It is during these hours that a solar array sited at the angle of latitude will develop the most power as the light from the sun strikes it at right angles, absorbing all of the available light, which in turn generates the arrays best output in kWh.

As I understand it, this is one of the reasons why solar power is more suited to lower latitudes because there are more peak sun hours per day.

Hope this helps.

Best Regards
Bob


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## Admiral_dk (Aug 16, 2011)

Sorry, but as I se it, you've made it for the Northern hemisphere - at least if you want Zero to point North ....


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## Maryak (Aug 16, 2011)

I don't wish to rain on your parade but for the latitude of 35o North the suns path will always be to the South of you. As you can see in my diagram the suns path is always to the North i.e. Southern Hemisphere.

Have a look at this NASA site http://www.gaisma.com/en/location/adelaide.html

Birmingham UK






Best Regards
Bob


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## Admiral_dk (Aug 16, 2011)

Looking at the link you provided, I can clearly see that it's similar to the one you posted. It still doesn't make sense to me, but I might have misunderstood what you're about to make. I thought of it as a sundial and the simplest I know of is a stick in the ground and that gives me a pattern like the one you show on the ground (the difference is that I'm 21 degree futher north - 56). You yourself say that the Sun is to the north from you and this should give you a shadow pattern to the south, not north.


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## Maryak (Aug 16, 2011)

Admiral_dk  said:
			
		

> Looking at the link you provided, I can clearly see that it's similar to the one you posted. It still doesn't make sense to me, but I might have misunderstood what you're about to make. I thought of it as a sundial and the simplest I know of is a stick in the ground and that gives me a pattern like the one you show on the ground (the difference is that I'm 21 degree futher north - 56). You yourself say that the Sun is to the north from you and this should give you a shadow pattern to the south, not north.



Aha..............It's not a shadow pattern, it's looking up at the sky. To look at the sun moving across the sky from 56o North one would face South as the Birmingham UK image shows.

Birmingham 52oNorth                    Adelaide 35o South









You can also see that the amount of time per year the sun is at or above the latitude is considerably less for Birmingham than for Adelaide.

Hope this helps.

Best Regards
Bob


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## steamer (Aug 16, 2011)

Cool!

What are you going to do with the money you make selling the power back?  ;D

Hopefully endmills or something _useful_!

Dave


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## Maryak (Aug 16, 2011)

steamer  said:
			
		

> Cool!
> 
> What are you going to do with the money you make selling the power back? ;D
> 
> ...



Our electricity price has just risen by 22%   ....................So I may just be able to pay my next bill 

Best Regards
Bob


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## steamer (Aug 18, 2011)

Maryak  said:
			
		

> Our electricity price has just risen by 22%   ....................So I may just be able to pay my next bill
> 
> Best Regards
> Bob



 Rof}

I hear you buddy.....

Dave


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