The Imaginary Lines on the Planet Explained - Planning Solar?

[LowGear]

Hi,

I ran into this very easy to understand explanation of the Sun's attitude to the earth during a couple of important days of the year.

http://curious.astro.cornell.edu/physics/160-our-solar-system/the-earth/seasons/15-what-is-the-significance-of-the-tropic-of-cancer-tropic-of-capricorn-arctic-circle-and-antarctic-circle-beginner

I set my panels to about 20 degrees as that's the angle of sun rays at equinox.  That means half the year the sun is above the panel azimuth and below the other half.  A bit steeper might have been smarter as October through March are our best solar collection months.  While there is more atmosphere for the energy to get through there are far fewer clouds during the "dry" season.  At a latitude of about 19 degrees this means that the sun will only go about 4 degrees past 90 degrees to the planet.

Cheers

Casey

[mike90045]

i've set my PV panels to enhance my winter harvest, in summer with long clear days I have no problems, winter is when I need every bit of power

[Dualfuel]

I move my panels for the seasons...and in summer move them daily. I was looking at a site for optimum tilt...
http://www.solarpaneltilt.com/
I always just subtracted 23.5 from 48 to get 24.5 degrees. I was pleased to discover this was close to how they figure it on their site. To get 24.5, I turn the panels til they run north and south, lay them horizontal or perpendicular to the vertical support pole. Then I crank on the azimuth adjuster until the north end of the panels are 24.5 degrees from horizontal.
Casey, even though the panels are angled south at noon, at dawn and dusk, the whole mount rotates around and points north of the east-west line. Perhaps that makes more sense. By doing that, I catch quite a bit of extra power. For example, if the panels are pointed northwest by west at dawn, I can charge my bank fully by 10am with 250ish watts worth of panels.
From 10 to 4, is prime chainsaw/air compressor/ refrigerator time.
DF

[LowGear]

Hi,

My panels are fixed.  I wish I could manipulate them for the seasons not to discount the daily sun tracking - Wow!

I was all over the web looking for the optimum orientation.  And then the Spring equinox came along and it was noon.  I took a four foot piece of 3" ABS and oriented towards the Sun and when the light came through the tube at it's brightest, least drag and tightest circle shadow I felt confident I had the best orientation I could get.  As bright morning sun is more forecastable here many of my neighbors push the panels somewhat eastward. 

I'm putting in another set of panels this year.  I'm going to contact SolarWorld this week to find out how much more power I'll realize by tilting them at 20 degrees will produce than just laying flat on a 1/12 East-West roof.  At over 40 cents a KWH it can add up in just a couple of years.

Casey

[Dualfuel]

 The Griddies pay $0.26 a Kwh here....supposedly the highest rate in the continental US. Ironically, the power company is refusing to accept more applications from solar power plants wishing to sell power back to the grid.
I am seriously thinking about using my extra power to run a methanol still to recover Methanol from glycerine. I tried heating a batch of oil with the electric, and was amazed to heat the tank for 2hrs before the inverter started to peep at me.

[LowGear]

I contacted SMA and they indicated that flat vs. 20 degrees at our 18 degree latitude would only cost about three percent.  I think that pencils out to a couple of hundred dollars a year.  Now for the bad news.  Our electric rates are dropping due to the drop in oil prices.  We're down to 34 cents a kilowatt or about where it was when we moved here 15 years ago.  Just when I'm trying to justify a $7000 plus adventure and they kick the pay back numbers out from under me.

Thinking back to the $200 a year has to be reinforced with the understanding that we work on an eight year payback program.  And with the rates falling we're looking at a pretty sure bet of $1000 for setting the panels at 20 degrees over eight years.  And we get the greater part of our solar energy December through March due to the dry season phenomena we enjoy here in South Kona (this is when the 20 degrees would have it's greatest yield).

I'm going ahead with the project which should put us right at break even with the grid each month (averaged over 12 months) and then if Tesla actually comes through with a hot dog battery system we could even walk away from our good friends at HELCO.

Casey

[Thob]

They really named the power company Helco?  As in Hell, Inc.  

[Dualfuel]

Casey,
Good news, oil will go right back up. Have no fear. I have always counted on the fact that the prices for solar are less volatile then oil.

[LowGear]

Aloha Thob,

Or the company from Hell.

Hawaii Electrical Company

They try to discourage the HELCO reference but I haven't come across anyone not using this acronym.

Dualfuel:

I agree.

Casey