Orientation to optimize for EV-A plan in San Francisco Bay area

[subdriver97]

Why can't the panels be mounted at an angle. i.e not aligned with the roof.

The most common rail systems for roof mounted PV systems align the panels in the same direction of the roof. As far as I know the common rail system allow for some adjustment for tilt, but tilt has a pretty minor affect on power generation.

I suppose it's possible to build a structure to mount panels to any azimuth on a roof, but I'm quite sure the cost for design, construction, and materials far outweighs any additional benefit in power generation. Additionally, it would look pretty ridiculous on the roof.

So assuming you're not going to build a custom structure you'll be limited to the azimuths which your roofing surfaces are perpendicular to. This also greatly simplifies the calculations since you're not limited to just a few azimuths.

[araghava]

So did you figure it out? I'm curious to know what you used for input and what you got for results.

I have the raw data but don't know how to sum up the different time blocks. i.e. add up all the blocks for 7am to 2pm, 7pm to 9pm (partial peak) and 2pm to 7pm (peak).
However i can see that production for peak period increases as you orient westward while partial comes down.

[araghava]

I don't understand how you will get an orientation of 225/SW if your home is facing west. Is there a roofing surface that faces 225? You're options for a roof mount are essentially limited to the directions in which your roofing surfaces face. If you provide your street address it would probably resolve a lot of confusion. (Then folks can get a look at your roof on google maps.)

Why can't the panels be mounted at an angle. i.e not aligned with the roof.

[subdriver97]

PVWATTs allow you to download monthly and hourly estimates for production. This can be used to compare different orientations.

So did you figure it out? I'm curious to know what you used for input and what you got for results.

[subdriver97]

Running the numbers in PVWATT doesn't really answer the question. When i plug in 225 degree (SW) i get slight lower overall production. However what i need to know is how much more i'll produce during the peak hours.

I don't understand how you will get an orientation of 225/SW if your home is facing west. Is there a roofing surface that faces 225? You're options for a roof mount are essentially limited to the directions in which your roofing surfaces face. If you provide your street address it would probably resolve a lot of confusion. (Then folks can get a look at your roof on google maps.)

[subdriver97]

1. I'll be getting the permit this week.
2. Roof mount. House faces west. Roof has no obstacles in either south or west directions.
3. The original design was to have the panels in 2 rows facing directly south. However i'm thinking at having them maybe facing south west might maximize my output during peak hours. (2 -> 9pm)

What is the azimuth (compass direction) of the south and west facing directions of your roof?

[araghava]

PVWATTs allow you to download monthly and hourly estimates for production. This can be used to compare different orientations.

[Bikerscum]

I want to maximize output during peak hours. I charge at night during off peak.
The idea is to generate maximum electricity during peak hours since in summer i get paid 40c/kwh during those times.

Here is some real time info in the SF Bay area...

Go to here... public page of my online motitoring

Choose the layout tab up top. At the top left click the arrowhead that says show playback. Choose the weekly option just above that. Drag the red cursor slowly across 11/27.... that day had little or no cloud cover from about noon on.

The four horizontal panels at the bottom are 2 each east & west, the rest are all facing south. You can see in 15 minute increments the output from west vs south. Use only the top row of south panels for comparison, the others may get some shading late from dormers on the roof.

My guess is you'll find little if any advantage to west facing panels.

Have fun.

[araghava]

Run the numbers and get that answer. That's what I did.

Running the numbers in PVWATT doesn't really answer the question. When i plug in 225 degree (SW) i get slight lower overall production. However what i need to know is how much more i'll produce during the peak hours.

[control4userguy]

1. I'll be getting the permit this week.
2. Roof mount. House faces west. Roof has no obstacles in either south or west directions.
3. The original design was to have the panels in 2 rows facing directly south. However i'm thinking at having them maybe facing south west might maximize my output during peak hours. (2 -> 9pm)

Run the numbers and get that answer. That's what I did.

[control4userguy]

^I see.

[araghava]

I don't know diddly about EV-A but why would you want to be charging during that peak period anyway?

I want to maximize output during peak hours. I charge at night during off peak.
The idea is to generate maximum electricity during peak hours since in summer i get paid 40c/kwh during those times.

[araghava]

You haven't provided much information so folks are going to have a difficult time helping you.

If this is a roof mount:
- what is the orientation of your roofing surfaces?
- can all the panels fit on a single orientation? if not, come many can face which direction?

Or is this a ground mount?

1. I'll be getting the permit this week.
2. Roof mount. House faces west. Roof has no obstacles in either south or west directions.
3. The original design was to have the panels in 2 rows facing directly south. However i'm thinking at having them maybe facing south west might maximize my output during peak hours. (2 -> 9pm)

[control4userguy]

I don't know diddly about EV-A but why would you want to be charging during that peak period anyway?

[control4userguy]

Yeah, well, regardless of where you are with permitting, just plug in your needed azimuth and tilt into PVWatts until you feel like you need to make a change. For me, it didn't matter on tilt as I watch annual production and not daily. As far as compass orientation, well, that might be limited by your roof. You didn't say what kind of install you are planning though. My westies carry-on production a little longer in the day than my neighbor's all-south system but so what? My consumption overrides production that time of late afternoon by a factor of three or more.