SAT (Single-Axis Tracker) Creation

What to consider before creating an SAT (Single-Axis Tracker)

When creating your SAT objects it is important to understand the required dimensions and information required to make the Objects.

Modules to be used (make sure it has already been added to the catalog).
Number of modules in a string.
Total number of strings on the SAT.
Total length (This is very important as the length is how PVFARM will place the SAT's onsite)
Any gaps (motors, piles, etc.)
Pile locations (Critical when doing advanced piles and grading).

Example of tracker drawings with the information required to setup the SAT:

Creating your SAT

There are two ways to create an SAT in PVFARM; 1. Select a current SAT and make modification or 2. use the insert box to create a new SAT:

Modify your SAT

Once the SAT object is in the scene it should be select and the the object details opened. Within object details we can begin to set the parameters for the SAT.

Commercial

It is very import to enter your commercial SAT info here. When you add the SAT to the catalog the standard naming will be:

Manufacturer -> Model -> Module

For each of those configuration you will have the option to select all available tracker configurations (string lengths and number of strings) when using the layout panel. The name of the tracker will appears after the string/total length in the tracker configurations it does not affect the selection of the trackers.

Module

Use the drop down that appears under pv-module to select the module from your catalog that you would like to use when setting up this SAT. The remainder of the module properties will be added based on that module. During this and the string length setup your tracker may show up with a red "X" on it. This is to indicate that something is incorrect with the geometry and warning will appear to show you what needs to be corrected.

Row Length and String Configuration

Once you module is correct then you can update the toral row length, module orientation and string configuration. In this set you will also be able to setup the gap between module in a 2 high configuration (ie. a 2P tracker). The rows_gap is active when the rows_count is greater than 1. If you don't know the exact row length at this stage it's ok, it's best practice to enter a small number and then in future steps allow PVFARM to automatically calculate the total length for you. Note the red "X", that is ok and we will update in the next step as I do not know the exact tracker length for this example.

Frame

There are 3 ways to configure your frame in PVFARM; 1. Basic Grid, 2. Modules-Row, and 3. Exact. We will discuss all 3 of those configurations and you can pick the one that best works for you project. All will be discussed below.

Editing the frame configuration is always available in 2 locations, either in the object details or the pile tab on the left. Either can be used BUT the piles tab will update all trackers of that configuration in the model, not just the single object selected.

When using the piles tab rather than object details you select (using the slider) which option you would like. If neither slider is selected then it is the basic-grid. It can something be helpful to move between the 3 options to make your tracker setup as easy as possible.

1. Basic Grid

Basic grid is the simplest option to setup SAT objects. It evenly divides the piles and requires the smallest amount of information to setup the tracker. It is always possible to change the configuration type after you have started if you get additional information and need to update the SAT.

When using the basic grid it is important for the user to understand that there is no gaps (motor or pile) included and it may end up with a shorter tracker than indicated by the vendor. It is important to understand these limitations and ensure when using this type of tracker that is it suggested to ensure your total length matches the vendor which is longer than the autocalculated length.

Row_offset -> This controls the distance from the end of the module to the end of the row. This can be adjusted on both sides of the tracker

Piles_count -> The total number of piles in the row

motor_at_pile -> controls which pile is the motor in the row

piles_offset -> controls where the first pile on the north or south is located in relationship to the end of the tracker. If these are set to 0 then the piles start at the end of the tracker. The piles are just evenly spaced from the first and last pile location that you set based on these offsets.

Clicking on the red "X" will bring up this window indicating what is not correct. In this situation the total length was not sufficient based on my configuration so PVFARM is suggesting to increase the length. If there is a suggestion you can click on that to automatically increase the length based on the inputs you have used thus far.

2. Modules-Row

The module-row configuration places the piles and modules based on an assumption that the distance between piles is based on the module configuration. This is a higher level of detail than the basic-grid frame configuration. When setting up these SAT objects the user can control the gaps present across the piles as well as the motor. To change the number of pile the user enters the pile locations under the modules_row box. The gaps should always be greater than 0.

modules_row -> This is the number of modules between each pile. The total number of modules entered here needs to match the modules_count.

row_size -> This is the maximum number of modules and is calculated based on string length x string count. It should be used as a reference here to ensure when the gaps are established they match the row_size. If the sum of modules_rows does not match the total number of modules PVFARM will indicate there is an error to correct.

motor_at_pile -> Use this row to indicate where on the tracker the motor is located.

piles_count -> this is the sum of piles entered from modules_row.

Row_offset -> This controls the distance from the end of the module to the end of the row. This can be adjusted on both sides of the tracker

pile_bearing_gap -> The user can set the gap across the bearing piles. This is the glass to glass dimension.

motor_gap -> The user can set the gap across the motor pile. This is the glass to glass dimension. If this is set to auto it will match the pile_bearing gap.

3. Exact

This is the highest level of detail for configuring the SAT. In this mode you specify the exact location of the piles for all wind load positions. If wind load locations are not being used you can change the type to none. When setting up trackers using the exact configuration it is important to have detailed tracker drawings to validate that your piles are in the correct location.

When working in PVFARM it is possible to have all the wind load positions (including unique pile locations and pile types) within the same SAT object in your catalog. There is not a requirement to create a different SAT object for each wind load position.

When entering in offsets they are from the motor pile location.

Row_offset -> This controls the distance from the end of the module to the end of the row.

modules_row_gap -> gaps between modules at each location.

count -> number of piles

offsets_to_motor -> locations of piles away from the motor. Negative numbers are north of the motor.

offsets_to_edge -> distance from the north side of the tracker to the piles.

offsets_relative -> distance between piles. For the north most pile it is from the edge of the tracker.

types -> The types of piles, ie. standard motor, standard array, standard motor, etc.

motor_at_pile -> pile location of motor pile.

undulation -> controls which pile caps can have angle changes between adjacent torque tubes.

When working with the exact frame menu you can also click the box to pull up the detailed entering mode. In this mode you can change individual items or paste in details. This can be helpful when setting up trackers from detailed cad drawings by creating files with the exact dimensions and then pasting them into PVFARM rather than having to enter them manually.

The options detailed above is available for each tracker wind load position. The options are auto (keeps the piles the same as interior), override (allows for unique wind positions pile locations), and none (not an available wind position option for this SAT configuration).

Placement

This menu will display the details of the specific tracker that you have selected, including wind load placement and the resulting pile location info and slope information. Reminder that cumulative slopes are per tracker wing. For non terrain following tracker the cumulative slope and max bay to bay will be zero.

Piles Active

In this menu you can evaluate the pile details applicable to this tracker. You are able to edit the lengths and profiles both from this menu and from the piles tab.

count -> number of piles in this SAT

types -> pile types for this SAT including for this wind load exposure