Single Axis tracking simulation

[Ahmad Elghobashy]

I need help on how to simulate a single axis tracking system with a rotation angle +/- 52°

what would be the right parameters to simulate such system

Rotation axis incline: ?

Rotation angle of Opening: ?

Surface Usage Factor: ?

Also if the land has a natural tilt angle towards South, how can this be taking into consideration in the simulation ?

[developer_mh]

Hi Ahmad,

there are three different kinds of single axis tracking:

1. Rotation around one axis in the North-South plane (Single North-South Axis in PV*SOL)
2. Rotation around the East-West axis (Single East-West Axis in PV*SOL)
3. Rotation around the vertical axis (Single Vertical Rotation Axis in PV*SOL)

First you will have to decide what kind of tracking system you want to simulate. There are small images in PV*SOL that will help you to understand the differences. And here are some more explanations:

https://help.valentin-software.com/pvsol/2018/pages/pv-modules/#tracking

The Surface Usage Factor (space utilization factor) is explained as follows:

Quote

The space utilisation factor indicates the distance between successive module rows. A space utilisation factor of 1 means that the distance from one row of modules to the next is equal to the width or height of the module. If the space utilisation factor is 0, the next row of modules is infinitely far away. A space utilisation factor of 0.5 means that the distance is two module lengths or widths.

If the land itself is inclined, you will have to adapt the surface usage factor according to the trigonometry. If you need help with that, let us know.

Kind regards,

Martin

 

[Ahmad Elghobashy]

the tracking system to be used in North-South rotation axis tracking, the modules would start tracking the sun from East to West, with a rotation angle between +/- 52

[developer_mh]

ok, so are your modules mounted vertically on the tracking system? If not, you would have to enter the tilt angle at "Rotation Axis Incline". Your Rotational Angle of Opening would be 104° (2 x 52°). The surface usage factor really depends on how close you want to install the trackers, how high they are, the tilt angle of your land and so on. If you just want to simulate one tracking system, set it 0.

Kind regards,

Martin

[Ahmad Elghobashy]

the modules is single portrait module and the row distance is 4 meters, that is almost twice the max. height to the panel, the tracking system has a backtracking function. so would the SUF=0.5 be correct?

and what about the rotation axis incline?

[developer_mh]

yes, you are right about the surface usage factor, given that your land is levelled.

The rotation axis incline is the angle around which your rotation axis is rotated It is hard to explain in words I guess...

• If you set this value to 90°, the rotation axis is vertical, so your modules will rotate like a revolving door, around a vertical axis.
• If you set this value to 0°, then the rotation axis is horizontal, from South to North, and the modules will rotate like a lid from trash can perhaps. Or like a seesaw, where one kid is sitting in the West and the other in the East.
• Any value in between would be comparable to the rotation of a revolving door when the whole floor is tilted.

Does that help?

Kind regards,

Martin

 

 

[Ahmad Elghobashy]

If I understand this correctly this is the tilt angle, or the angle inclined between the ground and the rotation axis,

and I believe this would mean that if the angle is 0 that the rotation angle is horizontal not vertical

[developer_mh]

ah, yes, of course, sorry. I will correct it my post above..

[Ahmad Elghobashy]

Now I need your help to determine the correct Surface usage factor, as it has a much significance on the yield, even a small increase can decrease the yield big time

as for details

we have 72 cells panels with 2 meter height single module in portrait orientation and the row distance is 4 meter

What would be the SUF?

[developer_mh]

Hi Ahmad,

see this diagram here:

Your surface usage factor is (width or height of PV) / (distance of trackers). If row distance is 4 meters and your trackers are 2 meters high, the surfacce usage factor is 0.5. It is important that the dimension or axis in which you measure your module (width or height) is the same as the distance of your trackers.

Kind regards,

Martin

[Ahmad Elghobashy]

thanks that was helpful

could you please explain why would the yield increase with increasing the row distance, provided that the tracking system is equipped with backtracking function?

[developer_mh]

the backtracking function ensures that there is no shadow from adjacent trackers on the module. To accomplish that, the trackers must stop following the sun at some point, so that the modules don't have the optimal angle towards the sun anymore. So the solar irradiation on the modules will always be a bit smaller with backtracking enabled compared to shading-free tracker rows with larger distance.

If the row distance increases, the backtracking can start later and the losses due to suboptimally oriented modules decrease.

Kind regards,

Martin

[developer_mh]

see our new tracking videos here: