Array layout

Click the "Array layout" button in the toolbar to open the interface.

Quick start

Upon user open the interface, the designated zones can be selected by using the left mouse button. Once a zone is selected, the interface will automatically refresh to display the previously set parameters for that zone (if no previous settings, default parameters will be displayed).

When "Fill selected", Please select layout zones (you can press ctrl to click selection or frame selection multiple PV zone) first, then modify the parameters of the interface, click "fill selected" finally.

Layout Parameters

Pitch calculate time

The time entered here is true solar time, will be used to calculate pitch.

Array type

User can select one or more array type, the result is as follows:

Array orientation

Nominal tilt

The default tilt displayed is the one that maximizes the annual radiation when only place a single array.

There is a indicator light behind the setting item of "Nominal tilt":

When it is green, it indicates that the current pitch time period, the selected array, as well as the "Tilt" and "Azimuth" are consistent with the settings of "Create zones".

Set tilt equals to slope

Taking the azimuth angle of the array is 0 as an example: If the north-south slope angle (x°) of the selected layout zone is greater than the set tilt, the tilt value will be automatically change to x or the closest value within the "tilt range".

Tilt range

Take "20,2,30" as example, it indicates [20,22,24,26,28,30], where 20 is the lower limit, 30 is the upper limit, and 2 is the step.

Nominal azimuth

0 indicates facing south, -90 indicates facing east and 180 indicates facing north. 

By edge

Select a edge to determine the azimuth of the array, and finally click the "Fill all" or "Full selected" button.

Set azimuth equals aspect

If the average aspect of the selected layout zone is x°, the azimuth value will be automatically change to x or the closest value within the "azimuth range".

Azimuth range

• When inputting -50, 1, 50, for northern hemisphere, it represents: lower limit is -50, upper limit is 50, with a step of 1.
• When inputting -50,1,50, for southern hemisphere, it represents: lower limit -180, upper limit -130, with a step of 1; and, lower limit is 130, upper limit is 180, with a step of 1.
• Special note: For southern hemisphere projects, to limit the azimuth range from due north to no more than 50 ° deviation with a step of 1 °, just enter -50, 1, 50.

Max. base slope

Base slope is the angle between the length of array and the horizontal plane.

This parameter can be used to avoid arrays being placed in location with sudden changes in terrain or avoid the rack failing to meet structural requirements.

Regarding the distinctions between nominal tilt, nominal azimuth, base slope, real tilt, and real azimuth, user can refer to the PVsyst software - Shading scene construction - Tools - Orientation understanding educational tool.

Ground clearance

Ground clearance

It refers to the height of the lowest point of the array above the ground.

User can adjust the number of "Check points for the array's round clearance" in the "User settings" section. Increasing the number of check points will raise the array to avoid embedding the arrays into the terrains.

User can choose whether to lower the ground clearance verification for some points in the "User settings" - "Check type for arrays' round clearance". The ignored points are only required not to embedded into the terrain, but not need to meet the set ground clearance value.

It should be noted that choosing to ignore the verification of the ground clearance of some points will result in a lower ground clearance for certain arrays in certain terrains, thereby reducing the shading to the rear arrays. In the "Auto pitch" - "Optimize" and "Maximum" modes, the layout capacity will increase, and the possible shading between east and west adjacent arrays in the layout results may also change. Below are the layout capacities under different verification methods when user use "Auto pitch" - "Optimize" for a certain layout zone:

Note:

Check points for the array's ground clearance: 15.

Delete shaded: Checked - 0min. Calculate pitch without shading from 9am to 3pm.

Ground clearance: 0.5m.

Max. pile height difference

The height of the array's pile points to the ground, with the value of (max. - min.) not exceeding the setting; when using double piles, both the front and rear piles need to meet the requirements.

Layout form

Pitch type

There are five modes to choose from: "Auto fixed pitch", "Auto vary pitch (Average, Maximum, Optimize)", and "Customize pitch".

Auto fixed pitch

It is average pitch (Use area of the triangle as the weight) of each triangle within the selected zone. The pitch of each triangle is calculated similar with "Color triangles".

So, it cannot be ensured that the placed array will be completely unshaded during the specified time period. Therefore, when user use "Auto fixed pitch", the following suggestions are recommended:

• Check the "Delete shaded" option. It is recommended to set the offset time to 60 minutes.
• Users can adjust the "Shadow threshold" value in the interface of "Array layout" according to the situation.
• Reasonably set the "Pitch margin". The most suitable "Pitch margin" can be found through an automatic optimization method for the "Pitch margin". For example, entering "0.5,0.5,3" indicates a minimum margin of 0.5, a maximum margin of 3, and a step size of 0.5. When the regional terrain is relatively consistent, the minimum margin can be set to 0. when the regional terrain varies greatly, the minimum margin can be appropriately increased.

Auto vary pitch - maximum

The pitch between the front and back rows of arrays is based on the principle of ensuring completely unshaded between rows during a specified time period, and thus, the pitch will dynamically adjust according to changes in the terrain.

If the shadow of even one of the front rows is longer, it will result in a larger pitch between the two rows. Therefore, this mode may lead to lower land utilization.

Auto vary pitch - Average

For a certain zone selected, after placing the first row, the software will calculate the pitch of the arrays in the first row, and calculate the position of the next row based on their average value.

So, it cannot be ensured that the placed array will be completely unshaded during the specified time period. Therefore, when using it, the following suggestions are provided:

• Check the "Delete shaded" option. It is recommended to set the offset time to 60 minutes.
• Users can adjust the "Shadow threshold" value in the interface of "Array layout" according to the situation.
• Reasonably set the "Pitch margin". The most suitable "Pitch margin" can be found through an automatic optimization method for the "Pitch margin". For example, entering "0.5,0.5,3" indicates a minimum margin of 0.5, a maximum margin of 3, and a step size of 0.5. When the regional terrain is relatively consistent, the minimum margin can be set to 0. when the regional terrain varies greatly, the minimum margin can be appropriately increased.

Auto vary pitch - Optimize

Assume the quantity of arrays that can be placed in a row is "m", and the pitch between the front rows is "p", the optimal pitch is chosen by using "m/p". The main functions are as follows:

• The layout is orderly and has a larger capacity.
• When calculate the pitch for each row, this method has already taken into account the impact of mutual shading between arrays. however, it is still necessary to check "Delete shaded" .
• When use this method, it is recommended to set the "Pitch margin" to 0.

Customize pitch

The user can set the pitch value, which is entered in the input box following "Customize pitch".

Uniformity (applicable only to "Optimize")

The calculation of uniformity is based on the condition where the "Pitch margin" in the "Array Layout" interface is set to 0, "Delete shaded" is checked, and the "offset adjustment" is 0. When the "Pitch margin" not equals 0 or the "Delete shaded" is not checked, there will be a discrepancy between the actual uniformity and the expected uniformity.

"Uniformity" refers to the ratio of the actual number of arrays placed in a row to the number of arrays that can be placed in the row (excluding the gray area).

Sequence

User can choose to place arrays from left to right or from right to left. Here's an example for reference.

Align rows

There three Type: "Yes", "No" and "Align by array".

"Yes" Type refers to the align of the placed arrays in the north-south and east-west orientation.

"No" type refers to align in the east-west orientation, and align is not considered in the north-south orientation.

"Align by array":

Align angle

0 indicates alignment perpendicular to the array orientation.

 

Pitch

Pitch range

Auto fixed pitch: Those pitch that exceeding the up-limit of "pitch range" will not be included in the calculation of the average pitch. When the average pitch is less than the low-limit of "pitch range", the low-limit of "pitch range" will be used

User defined pitch: This parameter has no effect. Layout pitch = User defined pitch.

Auto vary pitch - Average: When the pitch of an array in a row is greater than 1.5 times the up-limit of "pitch range", that array will not participate in the calculation of the average terrain pitch. The final pitch are controlled within the North-south pitch range.

Auto vary pitch - Maximum: The low-limit of "pitch range" is effective, while the upper limit has no effect.

Auto vary pitch - Optimize: When the shadow area of a certain array in the current row exceeds the up-limit of "pitch range", the shadow will be eliminated. Decreasing the up-limit of "pitch range" can make the layout more compact. The final pitch are controlled within the North-south pitch range.

Pitch margin

The final pitch used = Calculated pitch + Pitch margin, it can be zero, positive or negative. 

Row spacing type

There are two types: as "Virtual rectangle" or as "Parallelogram".

"Virtual rectangle": If the length of an array is "L" and the "E-West space" set by the interface is "E", then the projection distance between the center points of two adjacent arrays on the horizontal plane is "L+E", as shown in the figure below:

"Parallelogram": The minimum gap between two adjacent arrays is "E", as shown in the figure below: 

Row spacing

It is the gap between adjacent arrays.

 

Layout adjustment

Left and right gap

Left gap: When the software places the arrays from left to right, it will skip this Gap and then start to fill.

Right gap: When the software places the arrays from right to left, it will skip this Gap and then start to fill.

The actual gaps on both the left and right sides will be no less than the set value.

Offset adjustment

It only perform left and right shifts for the layout, without any north-south shifts.

First row posotion

The software starts from this position and determines whether it can place the first row. User can input a sequence, such as: "1,3,10", indicating a minimum of 1, a maximum of 10, and a step size of 3. The software will place arrays according to these four scenarios: [1,4,7,10], list the results under different settings, or automatically select the value with the largest capacity.

Min. number of arrays per row

The min. number of arrays per row before "Delete shaded" applied.

It is only effective under the conditions of "Auto vary pitch - Average" and "Auto vary pitch - Optimize".

When using aligned layout or selecting "Delete shaded", there may be situations where the minimum number of arrays per row is less than the set value.

 

Delete shaded

Delete shaded

If checked, arrays shaded by the front row will be deleted.

The shadow calculate time is the pitch calculate time with time offset in the slider.

Shadow threshold

If only a little area (that is the shadow threshold) been shaded by the front row, it will not be delete.

 

Other

Shadings of placed arrays effect the 1st and last row

When the software places the first row, if it is shaded by the already placed arrays, it will automatically step back to the appropriate position.

When the software places the last row, if arrays A in that row shade an already placed array, arrays A maybe removed. When the quantity of arrays in the last three rows does not exceed 50, all three rows will be considered in this manner. Arrays A will ultimately be determined whether to be deleted based on the "Delete shaded" option.

Fill in coedge areas

It is allowed for arrays to be placed at the common edge of two Layout zones, which is usually used in scenarios where the "alignment" is yes.

Fill using last param

When Fill all, each layout zone is placed according to the last fill parameters, but Regarding "delete shaded" option, "use of coedge regions" options, the set values on the interface will be used.

 

Set in "User settings"

Decimal point

See in user settings xxxx

Delete arrays in invalid areas

See in user settings xxxx

Min. inner spacing

See in user settings xxxx

 

Optimal layout

Variables that can be optimized

Click "Fill selected" or "Fill all" and meet one of the following conditions will trigger the optimized layout interface:

• The "Tilt" is a sequence (e.g., input: 5,5,30).
• The "Azimuth" is a sequence (e.g., input: -30,5,30).
• The "Pitch margin" is a sequence (e.g., input: -2,0.5,2).
• The "First row position" is a sequence (e.g., input: 0,1,6).

"-30,5,30" means that start from -30 to 30 with a step of 5.

Optimization can be conducted on four parameters simultaneously. For example, with 5 values for "Tilt", 5 values for "Azimuth", and 5 values for "Pitch margin", the software will calculate 5*5*5=125 times, it is not advisable to have too small a step size or too many optimization parameters.

Special function for "Pitch margin and "First row position"

If the "Pitch margin" or/and the "First row position" are/is a sequence, the software will prompt:

It is faster if user chose "Yes".

When user optimize the "First row position" and "Pitch margin", the software automatically selects the starting row position with the maximum capacity for each layout zone under a certain layout parameter.

When user optimize the "Pitch margin" with other variables, the software prompts:

Taking the example of a total of 10 layout zones with tilt angles of [20, 2, 24] (3 types) and pitch margin of [0.5, 0.5, 2] (4 types):

If user choose "Yes", for each layout zone and "Tilt", the software will calculate which has the largest "Pitch margin", and select the largest one. The optimized layout results only list three schemes, with fast calculation speed (as each scheme requires calculation of yield).

If "No" is selected, all layout zones will be placed according to combinations of "Tilt" and "Pitch margin" (a total of 3*4=12 types). A list of 12 layout schemes will be provided, where the "pitch margin" for each layout zone remains the same under each scheme, rather than being the optimal "Pitch margin" for each area individually. 

Optimization objectives

The optimization objectives are optional for maximum capacity, lowest CAPEX, highest yield, or most economical.

Note:The IRR refers to the internal rate of return on total investment (after tax).

Parameters to be set

Parameters required for yield calculation, CAPEX estimation, and revenue forecasting.

Detailed losses

Cost estimation settings

It is necessary to set accurate "Grid voltage", "Module type" and "Site condition", etc.

Price library

Users can make adjustments to the default cost database.

IRR calc. settings

Users need to accurately set parameters such as "Grid-connected type", "Elec. rates for PV", and "Discount Rate", etc.

Optimization Process

When user optimize the layout of certain zones, if other zones have not been placed with arrays, a virtual layout will be done by using the median values of the sequence (if already placed, they remain unchanged). Only the current zone undergoes optimized layout, and the yield calculation, cost, and revenue are calculated based on the overall project layout results.

Presentation of optimization results

The optimized layout results display the yield, cost, and revenue under various combinations of tilt angles, azimuth angles, and pitch. Click "Select" to choose the desired layout result.

Cache of optimization results

When user use the optimized layout function in "Fill all", the optimized layout results can be cached.

The next time user use "Fill all" and enter the optimized layout interface, the previously cached results will be displayed, and user can select a scheme for layout.

After re-optimizing the layout, the previous cache will be replaced.

Fill and clear zones

When use "Array layout", user should first select the zone, then modify the parameters of the interface, and finally click "Fill selected".

When use "Clear selected", user should also select the zone first and then click the button.

For "Fill all" and "Clear all", there is no need to select any zone first.

Capacity viewing

When the "Array layout" interface is opened, user can click on any zone with the mouse and it will display basic information about the layout of that zone in the lower left corner of the interface, including slope, capacity, pitch, and so on.

To view the overall layout capacity, user can view the legend in the upper left corner of the "Array layout" interface or the "Device hierarchy".

Import layout from CAD drawing

"Import" function involves importing array layout, power blocks, inverters, and transformer (two-dimensional layout drawing) from a *.c2c file into Candela3D. This *.c2c file is generated by the Candela3D-CAD Plugin. For the method of generating the *.c2c file, please refer to the chapter "Candela3D-CAD Plugin".

Layout of horizontal single-axis tracker

The horizontal single-axis tracker is usually oriented in the east-west orientation, and can be placed with "Customize pitch" and azimuth angle of 90°.

The pitch of horizontal single-axis tracker (east-west direction) is typically determined through optimization and comparison. On the aforementioned interface, the reference pitch can be entered in the "Customize", while the optimization range can be input in the "Pitch margin". For example, "-2,1,2" indicates "-2,-1,0,1,2", the software will calculate the yield and cost for each margin.

Terrace layout

The Array in the layout area can be arranged along the contour line.

Operation steps:

Step 1:  Create PV zones manually according to the Terrain of terrace

Step 2:  Open the Array layout interface

Step 3:Interface Parameter settings - "Select array", "Nom. tilt", "Ground clearance" and "E-W space".

Step 4:Select one or more zones then click "Terrace layout", or do not select any zone and click "Terrace layout" to fill all zones.

Step 5:User can draw centerline manually when fill only one zone.

FAQ about layout

Selection of pitch type

• Users can adopt "Auto fixed pitch" or "Auto vary pitch" according to their design preferences.
• For layout that demand high uniformity and also require a large capacity, the "Auto vary pitch" - "Optimize" mode can be adopted.
• For specific projects, the following four combinations of layout parameters can be considered, comparing layout capacity, array uniformity, and yield. (The parameters are for reference only and should be determined based on specific circumstances.)

Some zones are not placed with an array

Automatic creating zones may result in some areas are used, and can not be placed with arrays. Please create zones for these areas.

The pitch is too large when use "Auto vary pitch"- "Maximum"

There may be array placed in the gray areas, and the shadows of these arrays are very long. Please check "Delete arrays in invalid areas" in user settings.

The uniformity is low

Taking the following image as an example. After placing by "Auto vary pitch-average", there are many deleted arrays. The quantity of arrays placed is 323.

The reason for the uniformity is that the pitch of "Auto vary pitch-average" cannot satisfy all arrays. There are several methods to solve this issue:

Method 1 :Use "Auto vary pitch - Optimize", 390 arrays with high uniformity.

Method 2 :Optimize "pitch margin". Input a sequence e.g."0.5,0.5,3", 374 arrays can be placed, significantly improving the uniformity.

Method 3 :The slider of "Delete shaded" is set as 30 mins. 412 arrays will be placed, with a noticeable improvement in uniformity.

Method 4 :Use "Auto vary pitch - Maximum". The result is as follows: the uniformity is particularly good, but the quantity of arrays has been reduced to 380.

Method 5 :Still use "Auto vary pitch - Average", and do not check "Delete shaded". After the layout is completed, user can filter out the arrays with annual shadow loss greater than 3% (for reference only, without considering terrain shading) through the "Array annual shading loss". There are 446 arrays placed in a relatively regular manner. 

The capacity is small

There are some suggestions:

• User can reduce the requirements of "Terrain analysis" which may increase the difficulty of construction.
• User can reduce the time period setting for "Hill-shading analysis".
• Reduce "Time" in the interface of "Array layout" for pitch calculation.
• Reduce the requirement for "Delete shaded".
• Reduce the tilt angle of the array.
• Choose "Set azimuth equals aspect".
• Optimize the position of the starting row.
• Chose "No" in "Alignment" will result in a larger capacity compared to "Yes".
• Compare the capacity of "From left" and "From right".
• When use "Yes" in "Alignment", user can check the "Use the coedge region".
• Do not select "Delete shaded". User can use the "Array annual shading loss" function to analyze the total radiation received by the array throughout the year (after considering shading loss) and filter the array accordingly.
• For projects in complex terrain, user can increase the "Shadow threshold" to over 5% to significantly increasing installed capacity without a noticeable decrease in yield.