Condition Sets in HelioScope V2 – HelioScope

A Condition Set describes the environment around the modeled solar array. A Condition Set includes a number of assumptions around the specific weather conditions, shading patterns, soiling losses, and more. In many cases, the default values are appropriate, though they can always be modified.

To create or edit a Condition Set, inside a Project, click the Conditions Tab

To create a New Condition Set, click the button "+ New Condition Set"

Weather Source:

While creating a New Condition Set, you can select your preferred Weather Source (available weather sources vary based on project location). Weather stations are sorted by distance from the Project. The source of each file (TMY3, EPW, Prospector) is shown in parentheses.

You can also upload your own Weather File

Production Probability

Production Probability can also be selected (available only to Pro and Enterprise users)

Horizon Shading

If the Project has shading, choose the relevant Horizon Profile to be included in the Condition Set. Note: Horizon Profiles must first be uploaded before they can be added to a Condition Set.

Example of Horizon file format accepted: dtmh_31_-110.hor

Irradiance Loses

Confirm the assumptions by adding your value to the 'update all months' section. Or modify the monthly soiling factors, which will pull the total average of your values to be included in the assumptions.

Soiling Loses

Soiling losses are reductions in the irradiance that reaches the module, taken at the surface of the module.

Snow Loses

Snow losses are reductions in the irradiance that reaches the module, taken at the surface of the module.

There are three popular methods for calculating snow losses, known as the Townsend (or BEW) model, the Marrion model, and the Andrews model. Of these models, the most widely used is the Townsend model, which is described in this article from Renewable Energy World.

Calculating snow loss requires data on historical snow fall for the project location. For locations in the U.S., the National Oceanic and Atmospheric Administration (NOAA) provides such data via their National Climatic Data Center (NCDC) portal. Another tool for soiling data is the Solar Resource Compass.

Once calculated, you can add them to your Condition Set

Energy Losses

AC Losses

If a detailed AC System is not defined in the Electrical Design, HelioScope will apply a Derate Factor to compensate for AC System losses. The Derate Factor can be modified in the Condition Set.

Note: when using micro-inverters, AC conductors are automatically modeled and their losses are calculated.

Additional Losses

Additional losses can be added in the Energy Losses section of the Condition Set. Click "Add Loss..." and select the loss to add from the drop-down.

Cell Temperature

HelioScope supports both the Sandia Labs Temperature Model, including the Linear Diffusion model (used by PVsyst). For either model, you can edit the temperature coefficients.

Sandia Model

Diffusion Model

Bifacial Modeling

You can improve simulation accuracy by accounting for rear-side energy gains with certain Bifacial Modules. Note: Bifacial modeling is only available for Fixed Tilt and Single-Axis Tracker racking types. For more information about this feature.

Mismatch

There are three drivers of mismatch, each of which creates a random distribution between modules in the array:

A. Difference in POA irradiance (normally distributed)

B. Temperature differences (uniform distribution)

C. Module manufacturing tolerance (uniform distribution). Note that this parameter has two inputs to account for positive-tolerance module binning.

Components Characterizations

The Design defines the specific module SKU used, but if a module has multiple PAN files, these are configured as part of the Condition Set. You can manage the characterizations used for each module or inverter from this page.

A. The window will show the full list of components used in any design in the existing project.

B. If a custom PAN file has been loaded or multiple PAN files are available, they are configurable via the drop-down menu.

C. Where possible, the source of the PAN file is indicated.

D. Bifaciality will be shown as true or false for modules

Advanced

A. Choose the transposition model (the mathematics used to convert diffuse light to plane-of-array irradiance). Perez can generally be used with high-quality weather files, while the Hay model is better used with lower-quality weather files.

B. Choose the location used for calculating solar angles (either the location of the weather file, or the project latitude and longitude).

Trackers

For Designs with SAT (Single-axis trackers) you can determine the Maximum tilt angle and enable or disable backtracking.

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