Release Notes 1.42

In this release:

• Energy Simulation (Beta)
• Voltage Drop enhancements:
  • Add minimum cable cross-section in cable sizing
  • NEC resistance values added
• Convert to PVcase Roof Mount enhancements:
  • Convert to modules from more object properties
  • Base Points
  • Capability to keep existing objects after conversion

Energy Simulation (Beta)

The Energy Simulation feature is powered by PVcase Yield, which can handle highly complex scenarios and capture the intricate details of your system. Simulations are performed at hourly timestamps, resulting in 8,760 values aggregated into annual results. The Beta version is not fully based on PVcase Yield’s thermal-electric model (thus provides less accuracy) but it does leverage the detailed irradiance analysis by PVcase Yield’s ray tracing technology, which is one of the most advanced algorithms in the market.

Learn more in this article.

What information is used for Energy simulation:

• Detailed 3D drawing, including shading objects and objects around the building
• Module position (tilt angle, azimuth)
  • Supported modules:
    • Only c-Si (crystalline silicon) PV modules.
    • Only monofacial PV modules.
    • Only 1 type of module; must be the same dimensions and same power
  • Inverter weighted efficiency

Assumptions:

The energy simulation model currently used by PVcase Roof Mount is based on the following assumptions:

• All PV modules have an anti-reflective coating.
• Losses associated with the electrical design of the PV system are approximated considering:
  • 2% DC cabling loss under Standard Test Conditions.
  • 2% module current mismatch loss (also called electrical shading loss).
  • 1.5% AC cabling loss under Standard Test Conditions.
  • 0% inverter clipping loss.
• Module mismatch loss is constant at 1%.
• Low light and module temperature losses are calculated applying the ADR model [1] and generalized coefficients for mono c-Si PV modules [2]. According to this model, the maximum power temperature coefficient of the PV module is -0.4%/°C and the low light efficiency at 200 W/m² is -2.2%.
• Soling loss is 1% constant.
• Maximum power point tracking loss is constant at 1%.
• DC/AC conversion loss is approximated by the inverter weighted efficiency.
• System unavailability loss is 1% of the total AC energy yield.

What information will I get in the Energy Simulation report?

• System characteristics
• Performance information:
  • AC annual yield
  • AC specific yield
  • AC performance ratio
  • AC monthly yield (graph)
• Generalized losses

Get Energy simulation report in Roof Mount

Steps:

1. Go to Energy simulation in the ribbon menu

2. Ensure your project location is correct

3. Enter Module power, W.

4. Enter Inverter efficiency, %.

5. Click Calculate.

6. Once the calculation is complete, you can see a preview of the PDF in the Overview section.

7. Click Review report to review and download the full PDF report.

Voltage Drop Enhancements

Add minimum cable cross-section in cable sizing

Under “Cable Sizing”, you can find a new field called “Minimum cable CSA, mm²” where you can select the minimum cable size that you’d like the system to not go under when suggesting a cable size in the SLD or in the BOM export.

NEC resistance values added

As NEC standard operates at a higher temperature (75°C), the resistivity values are slightly different from the IEC standard. We’ve updated the resistance values for Copper to 12.873 ΩCM/ft and Aluminum to 21.182 ΩCM/ft for when users select the Voltage Drop calculations in NEC.  

Voltage Drop calculation

Calculation for voltage drop is performed according to IEC 60364-1 and NEC 2020 Article 690 standards. In practice, the formula below is applied for a DC string voltage drop (V_drop) calculation:

String Cable cross section mm² (CSA) = (L * I * R) / ( V% * V_nom * 1000)
V_drop = (L * I * R) / ( CSA * V_nom * 1000)

where
L = cable length (m)
I = module Impp (A)
R = resistivity (23.7 Ohm mm²/km for copper, 37.6 Ohm mm²/km for aluminium)
Vnom = number of modules in string * Voltage Mpp
V% = desired voltage drop

Convert to PVcase enhancements

Convert to modules from more object properties

We have added support for more objects to be converted into PVcase Roof Mount modules. With 1.42, you can now convert the following Object Properties into modules:

• 2D rectangles made from a single polyline
• 2D rectangles made from a single polyline inside a blockref
• 2D rectangles made from AutoCAD’s rectangle tool
• 2D rectangles made of separate lines inside a blockref

Base Points

Choose between each base point (First, Second, Third, Fourth) to try and match the converted module’s position with the original one to get the correct point. We recommend to try conversion with a small subset of modules first to get the compatible “Base Point”, before converting for an entire area.

Capability to keep existing objects after conversion

If you would like to keep existing drawings after conversion, you can select “Keep original objects” to enable this feature. This is useful for cases where you have objects or references you’d like to keep, such as lines indicating the locations of mounting racks.