Automatic changing of tilt angle of solar panels |Single Axis Solar Tracker with linear actuator

Mike_Venus

Hello! I’m beginner on this forum. I’m from Russia. I haven’t got a PV system yet, but I’m really interested of solar power. While I was calculating settings of my future system, I thought about the tilt angle of solar panels. I want to arrange my solar array on the rooftop for a start. I understood that the best tilt angles of summer and of winter differ. I decided that the automatic changing of the tilt angle is a good idea.

I invented the following facility: there is a platform (solar panel) where solar modules are located. The lower edge of this platform is based on the rooftop, the higher edge is based on the linear actuators which will change the tilt angle of the solar panel.
I’m going to use the Arduino microcontroller, a simple single axis solar tracker and 12DC actuators for setting more efficient tilt angle of solar panels.

As I’m beginner I need your advice and help. What do you think about my idea? Is the automatic changing of the tilt angle of solar panels really good idea? Is this efficiently?
If I’m right, that it’s really good idea, estimate and comment the proposed facility. Is it rational, cheap and efficient? Share your experience if you have!

BB.

Assuming you are in the "far north"... It is possible that tilt adjust is not "good enough" as you get towards winter.

You may need the array to turn on the vertical axis (axis tilted roughly to your latitude) if you are near the arctic circle (tilt does not matter as much and the sun stays low in the sky).

Also vertical axis tracking gives you many hours of sun worth of charging current--Much better for a lead acid type battery bank.

Just tilting the array on a horizontal axis may not buy all that much...

Here is a pretty good program for checking out the options... Fixed, 1-axis (axis tilted to latitude, rotates east to west), and full 2-axis.

https://pvwatts.nrel.gov/pvwatts.php

I set the DC array size to 1 (1 kW or 1,000 Watts)... Then the next page gives us Hours of Sun per day... Which is what many of our other programs provide, like this one (fixed arrays):

http://www.solarelectricityhandbook.com/solar-irradiance.html

The big issue is that there is not very much sun as you approach winter, and you are not going to harvest very much energy.

-Bill "not in the far north" B.

Estragon

Changing tilt continually as the sun rises and sets could be a problem, especially in summer at higher latitudes when the arc of the sun might almost require a backflip to track. The array would be sitting nearly vertical at dusk, and might not wake up to flatten until the sun got quite high the next morning. In summer, I suspect you'd get close to or even more production leaving them quite flat. East/west tracking can make a difference in summer, but I have my doubts about continuous tilt tracking.

In winter, the arc of the sun is narrow and low, so tilting to track isn't going to do much. It might flatten panels to a point where snow doesn't shed well, which can be a problem.

For tilt, changing quarterly or half-yearly would get you most of the benefits, and if actuators able to handle weight and wind loads could be used, that may make it easy enough that it gets done.

I have tilt adjustable racking, but don't bother with adjusting. I get more than enough power in spring/summer, so I've just left the arrays at winter tilt. If I was grid-tied and got paid for the extra production, maybe I'd bother.

bill von novak

Mike_Venus said:

Hello! I’m beginner on this forum. I’m from Russia. I haven’t got a PV system yet, but I’m really interested of solar power. While I was calculating settings of my future system, I thought about the tilt angle of solar panels. I want to arrange my solar array on the rooftop for a start.

Rooftop arrays are difficult to track. 

Given how cheap panels have gotten you might be best off just doing south/east/west facing panels and combining them all at the inverter.  Many inverters have three independent tracking inputs which makes it a lot easier to combine dissimilar strings.

Mike_Venus

BB. said:

Assuming you are in the "far north"... It is possible that tilt adjust is not "good enough" as you get towards winter.

You may need the array to turn on the vertical axis (axis tilted roughly to your latitude) if you are near the arctic circle (tilt does not matter as much and the sun stays low in the sky).

Also vertical axis tracking gives you many hours of sun worth of charging current--Much better for a lead acid type battery bank.

Just tilting the array on a horizontal axis may not buy all that much...

Here is a pretty good program for checking out the options... Fixed, 1-axis (axis tilted to latitude, rotates east to west), and full 2-axis.

https://pvwatts.nrel.gov/pvwatts.php

I set the DC array size to 1 (1 kW or 1,000 Watts)... Then the next page gives us Hours of Sun per day... Which is what many of our other programs provide, like this one (fixed arrays):

http://www.solarelectricityhandbook.com/solar-irradiance.html

The big issue is that there is not very much sun as you approach winter, and you are not going to harvest very much energy.

-Bill "not in the far north" B.

Is 55 degreeses latitude really "far north"? I think not. I'm in the Central region of Russia, it's not Siberia, but somewhere insolation is larger than here.
Thank you for your link to your service. I will try to use it. I used the website http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php for estimation of PV System. I'm attaching the file with estimation of the system with 1kW power without system losses (because now I don't know they) in my location.
I want to install inclided axis tracking system with linear actuators. But I have not experience with this devices. I could not find any information of this solution of solar tracking. If you have such experience or experience with linear actuators, please, answere me here.

westbranch

quick facts;  I am at  ~51.8* N and ~ 124.7* W so a bit S of your spot 

I currently have ~1680W for winter use and ~1120 W for summer use. 

From April to October +/-  we have lots of power,  Into ABSORB at around noon daily ( when sunny) but in winter I need to add at least another 560 W... this is in the longer term plan, there are other projects before that can be done...

I would, if you and you are hoping to live there year round, design your arrays to be at least 2500 W...  on the ground!

Also investigate 'virtual arrays' and as suggested face ~ 1/3 of them each in SE, S, and SW  directions. 

To start I would optimize tilt for the winter intake ...  more later.

Dave Angelini

Look at Array technology. I use them and the current model the HZLA is typical of what most commercial large scale solar solar uses world wide. It makes more sense to track and even with lower panel costs this is true now more than ever. The HZLA or similar is really just 45 degrees from flat to the east and 45 degrees to the west.. A total of 90 degrees. 
http://www.arraytechinc-old.com.php7-32.phx1-2.websitetestlink.com/duratrack-hzla-residential/

If you are grid tied you do this for total harvest. For offgrid, we do tracking for longer hours of power. We can't sell the excess. I like the chart below because it shows this. I am at latitude 37 and get reliable power at 6am  to 8pm this time of year. Our batteries last long because they are not cycled as deeply. The link above also has single and dual axis trackers which I use and there is a picture link on my web page below that you can take a look at. Good Luck!  удачи !