Helioscope

Quick Facts

What is Helioscope?

Formal definition

Helioscope is a web-based commercial solar design and simulation platform that combines site definition, module layout, automated stringing, shading analysis, and annual energy yield modeling in one workflow.

Engineering definition

Helioscope uses an internal simulation engine that performs hourly time-step calculations with simplified loss modeling — IAM, soiling, mismatch, DC/AC losses, and inverter efficiency curves applied as derate factors rather than full physical models.

Industry definition

The default tool for commercial solar designers in the United States. Used to produce stringing diagrams, layouts, and “good-enough” yield estimates for sales proposals and pre-bankable engineering.

Permitting definition

Helioscope’s auto-generated SLD and report pack accelerate permit submission for small commercial systems. Most AHJs require additional PE-stamped drawings, but the Helioscope output is a strong starting point.

Helioscope Explained Simply

For installers: Draw a roof, place panels, route strings — Helioscope gives you a layout and an annual production number in 15 minutes.

For commercial designers: Helioscope is your design iteration tool. PVsyst is for the final bankable yield report. Use Helioscope to nail down the layout, then validate in PVsyst.

For new engineers: Helioscope abstracts away most physics. Understand what assumptions it bakes in so you know when to question its output.

Analogy: Helioscope is to PVsyst what Excel is to MATLAB — easier and faster for routine work, but the more powerful tool has lower-level access for serious analysis.

Why Helioscope Matters

Design speed. A commercial designer can produce a complete layout + stringing + report in 1–2 hours, vs. 4–8 hours in PVsyst+CAD.

Sales acceleration. Sales teams use Helioscope reports as customer-facing proposals.

Layout optimization. Auto-stringing and shading analysis quickly compare design variants.

CAD interoperability. DXF export feeds AutoCAD for permit-ready drafting.

Team collaboration. Cloud-based access lets multiple stakeholders view and comment on the same design.

How Helioscope Works — Workflow

1. Create site. Drop a pin on the map, draw the building polygon.
2. Configure modules. Select module model from the component library; set tilt, azimuth, row spacing.
3. Place keep-outs. Mark setbacks, RTUs, vents, walkways, fire-access paths.
4. Lay out modules. Drag-and-drop or auto-fill module groups (called “Field Segments”).
5. Select inverter. Pick from the database; assign field segments to inverters and MPPTs.
6. Run auto-stringing. Helioscope routes strings respecting MPPT voltage/current constraints.
7. Review shading. Annual shading heat map identifies high-loss modules.
8. Run simulation. Helioscope computes annual energy.
9. Export. DXF + PDF + CSV.

Engineering Deep Dive

Helioscope’s simulation engine — what it does well

• Hourly time-step. Uses TMY weather (default sources: NREL TMY3, NSRDB, Solargis).
• Shading. Voxel-based 3D shading uses sun-path trace from each module position; accurate for typical commercial geometries.
• Stringing. Per-MPPT current and voltage constraints enforced; per-string mismatch loss included.
• IAM. Uses a simple cosine + Fresnel correction.
• Module model. Manufacturer Pmp, Voc, Vmp, temperature coefficients from component database.

What Helioscope’s simulation does NOT do (vs. PVsyst)

• No single-diode I-V curve simulation under partial shade.
• No detailed thermal model — fixed cell temperature derate.
• No Perez transposition (uses isotropic + cosine).
• No bifacial 2D ray-tracing (uses simple analytical formula).
• Limited soiling modeling (single annual average).
• No Volt-VAR or dynamic inverter response.

Result

Helioscope yields are typically within ±3% of PVsyst for simple geometries with light shading. Divergence grows for sites with heavy shading, mixed orientations, or unusual climates — these need PVsyst.

Design Considerations

• Use latest module/inverter models in the component library; Helioscope updates them frequently but lag from manufacturer release is 1–3 months.
• Set the right tilt and azimuth. Roof-mount field segments adopt the roof tilt; ground-mount needs explicit settings.
• Account for row spacing. GCR settings affect inter-row shading.
• Validate stringing. Auto-stringing is usually correct but check per-MPPT current sums for high-current bifacial modules.
• Run a shade analysis. Identify modules with >5% annual shade; consider removing them or splitting MPPTs.
• Confirm with the manufacturer’s string-sizing tool before final permit submission.

Permitting Implications

Helioscope’s auto-generated layout, stringing, and basic SLD can be exported as DXF and refined in AutoCAD for permit-ready PE-stamped drawings. Most commercial projects use Helioscope for the layout and an external drafter (or service like Heaven Designs) for code-compliant SLD finalization.

Utility Interconnection Impact

For mid-sized commercial projects (100 kW – 1 MW), Helioscope-generated energy estimates are sometimes accepted by smaller utilities for interconnection studies. Larger projects require PVsyst.

US Code Requirements

Helioscope flags basic NEC 690.7 voltage violations and per-MPPT current limits. It does not check NEC 705.12 (120% rule), conductor sizing, or rapid shutdown placement — those remain manual design steps.

India Regulatory Context

Helioscope is used by Indian EPCs for design iteration, but for SECI tenders, MNRE-funded projects, and CEA connectivity studies, PVsyst is required.

Software Applications — Practical Tips

Importing CAD

Upload georeferenced DXF or KML to overlay the existing site plan. Trace the building polygon on top. Match orientation to true north (Helioscope’s reference).

Field segments

Group modules with the same tilt + azimuth + module model into a “Field Segment.” Each field segment can be assigned to one or more MPPTs across inverters.

Inverter assignment

Drag inverter blocks onto the design canvas; visually assign field segments to MPPT channels. The auto-stringing respects these assignments.

Conduit routing

Helioscope supports basic conduit routing for the AC and DC sides — useful for materials estimation but not detailed enough for final installation drawings.

DXF export

Export with the “Permit Set” option to get a clean DXF layered for modules, stringing, equipment, and labels. Open in AutoCAD for cleanup.

Real-World Examples

Commercial — 487 kW carport, Phoenix

Designer used Helioscope to lay out 1,218 modules across two canopies, auto-string into 4 inverters × 9 MPPTs. Yield estimate: 815 MWh/year. Exported DXF to AutoCAD for final permit-ready SLD and structural reference.

Commercial — 1.2 MW warehouse rooftop, Texas

Helioscope identified 12% annual shading on a corner section due to adjacent water tower. Designer removed those modules, gaining 3% PR. PVsyst cross-check confirmed yield within 2% of Helioscope estimate.

Iteration — 200 kW retail rooftop

Designer evaluated 4 module orientations and 3 inverter topologies in Helioscope in one afternoon. Selected design exported to PVsyst for final bankable yield.

Common Mistakes

1. Treating Helioscope yield as bankable. It’s not. Cross-check with PVsyst.
2. Skipping shade analysis — under-counted shading inflates yield estimates.
3. Using out-of-date module .csv for new module models not yet in the library.
4. Forgetting to override defaults — Helioscope’s default soiling, mismatch, and degradation are generic.
5. Auto-stringing without per-MPPT current verification for high-current bifacial.
6. Not exporting both DXF and PDF — DXF needed for permit drafting, PDF for stakeholder review.
7. Assuming Helioscope’s SLD is permit-ready — it’s a starting point, not the final drawing.

Best Practices

• Pair Helioscope (design iteration) with PVsyst (bankable yield) and the manufacturer’s string-sizing tool (NEC compliance verification).
• Maintain a library of standard inverter and module models in Helioscope.
• Use the “Compare Designs” feature to evaluate alternatives side-by-side.
• For ground-mount projects with trackers, validate Helioscope’s GCR setting against PVsyst.
• Export PDFs with the full assumption table for transparency.

Comparison Tables

Helioscope vs. PVsyst vs. Aurora

Standards & Certifications

Helioscope itself isn’t certified, but its output references the same datasheets and standards as PVsyst (IEC 61853 modules, IEC 61724-1 PR methodology).

Key Takeaways

• Helioscope is the fast commercial solar design tool — site polygon, module layout, auto-stringing, yield estimate, DXF export in one workflow.
• Use Helioscope for design iteration; use PVsyst for the bankable yield report on commercial and utility-scale projects.
• Auto-stringing respects MPPT voltage and current constraints, but always validate per-MPPT current for bifacial high-current modules.
• DXF export accelerates permit drafting but the auto-SLD requires manual cleanup for PE-stamped drawings.
• Now owned by Aurora Solar Inc.; integration with Aurora’s residential tools is ongoing.