DE

Parhelion

The digital twin of your solar plant.

Explore Parhelion

From records to a model.
From the model to numbers.

  1. Records

    Documents, a roof image, or just the production record.

  2. Geometry

    Surfaces, tilt, orientation and string layout.

  3. Sun and weather

    Sun position and irradiance for every hour.

  4. Calculation

    What each string should produce.

What Parhelion watches.
Without a sensor on the roof.

Aerial photo of a logistics park near Jirny with buildings and rooftop solar
100 m© ČÚZK
Location and geometry29°tilt derived from data
200900 W/m²
Irradiance612W/m²
Wind4.2m/s · NW
832 °C
Temperature19°C · cells 41 °C
Cloud cover34%
06 mm/h
Rain and snow0.4mm/h
Inverters14strings
Module440 Wp · mono PERC
Inverters4 × 110 kW
Layout14 strings · 26 modules
Commissioned2019
Last servicecleaning 04/2025
Documents and service1source of truth

From photon to kilowatt-hour.
Six steps, every hour.

01Sun path and irradiance
02Shade and its footprint
03Cell temperature
04Electrical panel model
05Inverter and cabling
06Expected output

The gap is the diagnosis.
One plant, one week.

Model agreement with reality98.4%last 30 fault-free days
Deviation since Thursday 09:40−6.1%string B2 · 3 days so far
Loss since the deviation began€50443 kWh at €0.11/kWh
Proposed actionCheck string B2pays back within 2 months
Plant output, 7 daysActualModelLoss
Deviation from the model

Sample data.

Every fault leaves a fingerprint.

Soiling

A slow decline that rain wipes away.

String outage

A drop, then a flat line.

New shading

A dip at the same hour every day.

Accelerated degradation

Faster decline than the manufacturer promises.

Snow

Zero, then a gradual return.

Inverter clipping

A clipped peak. Not a fault.

Faulty connector

Short dips that keep getting worse.

Module defect

The loss grows with temperature.

A neural network that looks ahead.
It forecasts output and where a loss is heading.

Production history and weather forecast
Forecast
  • Output tomorrow1,310 kWh
  • Loss in 30 days0.1%
  • Loss in 90 days0.2%
  • Loss in 180 days0.3%
Next-day forecast error, lower is better
  • Parhelion11.2%
  • Going by yesterday23.7%

An illustration of three sample situations: a clear day, panels slowly getting dirtier and a cloudy tomorrow. The forecast error was measured on the first real plant.

It finds the fault.
And doesn’t report ones that aren’t there.

91.3%of faults found1,085 of 1,189 plants with a fault
98.6%of findings point to the right stringthe technician knows where to go
4.8%false alarms15 of 311 healthy plants
2×more accurate next-day forecastan 11.2% error against 23.7% going by yesterday
Faults foundHigher is better.
  • Parhelion91.3%
  • String against neighbours89.6%
  • Plant against model2.7%
False alarmsLower is better.
  • Parhelion4.8%
  • String against neighbours100%
  • Plant against model9.0%
The first real plant

No documents. No history. Not a single false alarm.

0
false findings
371 of 400
injected faults found
96 of 96
step losses of 2% or more
7 days
median time to find a step fault
29° · 206°
tilt and azimuth from the record alone
87 °C
the inverter throttled itself. Not reported as a fault.

Blind-tested on 1,500 simulated plants under real measured skies (47,914 plant-years) and on one real 10 kW GoodWe plant with 400 injected faults. We are now confirming real faults on real plants in the pilot programme.

A model you can work with.
Move the sun. Hover over a panel.

Drag to rotate · hold the wheel or right button to pan · scroll to zoom
Panels in the model
1,558
Installed capacity
686 kWp
Production forecast
24 h
Skylights and obstacles
15

Don’t take our word for it.
Run the numbers.

Sample 250 kWp plant

A factory roof, 5 years in service, one faulty string and dirty panels.

Annual output
Gain per year
Investment
Payback
Cumulative net gain against today over 10 years:

A simplified illustration with sample prices: 1,050 kWh per kWp a year, energy worth €0.11/kWh, panels €760/kWp, storage €440/kWh. In the portal, the simulation runs on the digital twin of your own plant.

Three steps.
No new hardware.

  1. Week 1

    We connect the data

    Read access to the inverter portal.

  2. Weeks 2 to 4

    Parhelion builds the twin

    It learns how your plant runs.

  3. Then ongoing

    You get decisions

    Findings, losses in money, forecasts.

Parhelion and ordinary monitoring.

Monitoring is a thermometer. Parhelion is a diagnosis.

What you learnOrdinary monitoringParhelion
What the plant producedYesYes
What it should have producedNoYes
The loss in moneyNoYes
Cause and location of the faultOutages onlyYes
Cost and payback of the fixNoYes
How the loss will growNoYes
Verification after the fixNoYes
Arranging repairs and claimsNoSunalytiq team

What people ask us.

Do we need to install anything for Parhelion?

No. Parhelion works with the data your plant already collects and with public weather data. An on-site sensor is not required. If data is missing or too coarse, we tell you up front and suggest what to add.

How accurate is the model?

Blind-tested on 1,500 simulated plants under real measured skies, Parhelion found 91% of faults with 4.8% false alarms, and 98.6% of its findings pointed to the right string. On the first real plant it reported not a single false finding, and its next-day forecast error was 11% of installed capacity, half that of going by yesterday. We are now confirming real faults on real plants in the pilot programme.

Does it work with our inverter?

Parhelion works with production records from manufacturer portals and data loggers. Our GoodWe connection is proven on a real plant; other brands connect through their portal or an export. We confirm the exact route in the first demo.

We have no technical documents. Is that a problem?

No. Parhelion works out the tilt, orientation and size of the plant from the production record. On the first real plant that was a 29° tilt, 206° azimuth and 10.4 kWp, without a single document. Documents make the model more precise, but you can start without them.

Who will see our data?

Only authorised people on the Sunalytiq team and those you give access to. We never sell data, and a contractor receives only the description and location of the fault. Details are in our privacy policy.

What does it cost?

In the pilot programme you pay nothing for Parhelion or for our work. We propose a price for working together afterwards, based on the results on your plant, and you are free to stop.

Parhelion

See the twin of your own plant

In the pilot programme we build the Parhelion of your plant and walk you through the first findings.

  • No new hardware
  • Free pilot
  • Stop any time