PV thermal imaging · B2B and partners

Drone thermal imaging of photovoltaics: we show differences, the diagnosis belongs to the service company.

A drop in output with no clear cause, the handover of a new installation, a warranty coming to an end - these are the moments when it is worth seeing the temperature distribution across the whole installation from the air. This page explains the method and its conditions; the scope we agree with companies, O&M services and partners.

Thermal visualisation of twelve PV modules with one locally warmer area
Thermal visualisation, not a sensor capture

The problem and the audience

The right moment, the right audience.

A·01

Companies with a PV installation

A warehouse roof or ground-mounted: output lower than the simulation, the handover of a new installation, a warranty coming to an end, damage after hail or a windstorm. A survey like this puts in order where to start the conversation with the service company - instead of guessing.

A·02

O&M and service teams

Instead of walking module by module: an index of observations with location and priority, so the crew goes to specific rows rather than "to the whole thing". Interpretation and repair remain with the service company.

A·03

Installers and roofers

Installers and service companies add aerial material to their own inspection. The client and the interpretation stay with the partner, we are responsible for the flights and the quality control of the data. The rules of the channel: Partner Program.

Installations on detached houses we serve only as a paid route pilot on scheduled routes, with no public price - the starting point is a roof inspection.

What IR can point out

Thermal observations, not verdicts.

A thermal camera records the apparent temperature of the module surface. Against the uniform background of a healthy installation, patterns stand out that are worth checking - each of them is an observation for verification, not a diagnosed fault.

O·01

Point patterns

Single cells clearly warmer than their surroundings - an image typical of, among other things, local overheating of a cell. What it means in this particular installation is settled by the service company on site.

O·02

Module and string patterns

A whole module or a string of modules whose temperature differs from the neighbouring ones - an image that is sometimes linked to the operation of a string or of the connections. The cause is decided by an electrical measurement, not by a photograph.

O·03

Surface patterns

Areas with an image typical of shading, soiling or accumulated debris. Some disappear after cleaning, some need an on-site look - which is why we pair every entry with an RGB frame.

The same thermal image can have several different causes. That is why every entry in the report has the status of an observation with a location and a level of confidence - and the recommended next step points to the appropriate expert, it does not replace them.

Conditions of the method

Quality gates, not a guarantee of the result.

PV thermography only makes sense in defined conditions. We take the thresholds from the IEA PVPS methodology for PV thermographic inspections and treat them as gates: thresholds that are not met stop the flight rather than lower the quality of the data.

G·01

Sunlight

Minimum 600 W/m2 in the plane of the modules (POA), a stable sky, no precipitation. Too little light means too little thermal contrast - the observations stop being reliable.

G·02

Wind

Up to 4 m/s. Stronger wind cools the surface of the modules and blurs the temperature differences the method is meant to reveal. We verify the forecast with a measurement on site.

G·03

Geometry and data

Native GSD up to 3 cm/px, radiometric capture (R-JPEG) and an installation working under load. Digital zoom does not replace the right distance from the plane of the modules.

If the thresholds are not met on the day of the mission, we postpone the date or change the scope to RGB documentation. A gate that has been passed makes the observations comparable - it does not promise that every defect will be found.

The RGB/IR pair

Every thermal frame has a twin in RGB.

Some of the "anomalies" on a thermal image are the shadow of a pole, a leaf or a reflection of the sky. That is why we document every observation with a pair of frames taken from a similar angle: the service company sees straight away whether it is looking at a thermal phenomenon or at ordinary soiling.

RGB frame · context

Twelve PV modules in visible light - RGB frame of the RGB/IR pair
Illustrative image

IR frame · temperature distribution

The same twelve PV modules in a thermal visualisation - IR frame of the RGB/IR pair
Thermal visualisation, not a sensor capture

The result of the work

An index of observations, not a folder of photographs.

What the material contains

  • an index of observations with locations: section, row, module
  • a pair of RGB/IR frames for every entry
  • a level of confidence and a priority for verification
  • a record of mission conditions: POA irradiance, wind, GSD, time of capture
  • a mission log together with the rules on data access and retention

The structure of every entry

The report keeps four things apart: the observation, the context of the conditions, the limit of the method and the recommended next step with its owner. The service company gets material to work with, not an opinion it has to argue with.

See how the material is laid out

Limits of the method

What this material does not settle.

We write about it openly, because material posing as an expert opinion spoils decisions. Aerfield delivers ordered data from the air - the interpretation belongs to the service company, the electrician or the surveyor, depending on the case.

A PV thermal survey

  • does not rule on an electrical cause and does not replace measurements by a licensed electrician
  • does not calculate energy losses - it points out areas to compare with production monitoring
  • does not guarantee that every defect is captured; some faults leave no thermal signature in the given conditions
  • is not an energy audit, an expert opinion or a certificate for the installation
  • does not settle a warranty claim - it is input for the conversation with a service company or a guarantor

Scope and pricing

The scope is set after the brief, not from a price list.

Every installation has a different geometry, access and decision to support - which is why the quote follows the scope, with net or gross stated unambiguously in the offer.

B2B / partner brief

  • location, type of installation (roof/ground) and approximate capacity
  • the layout of the installation and its documentation, if available
  • the decision at hand: handover, warranty, drop in output, damage
  • access to the site and health and safety requirements
  • the channel for the results: directly or under the partner's brand

Terms of cooperation

  • price threshold: from 2,200 PLN net (working floor), quoted by scope
  • a lower unit rate only on a combined route or across a series of visits
  • interpretation of the observations and repairs: the appropriate service company or partner
  • we open the thermal inspection once our internal method gate (G4) is passed, including a blind review with an O&M service
  • channel cooperation: the rules are on the Partner Program page

method gate G4  We agree the scope and the date of the pilot now; delivery of the thermal camera survey opens once the quality gate for the method is passed. Until then every demonstration material is clearly marked as a demo.

Questions about the method

The most common doubts.

Will thermal imaging find every fault in the installation?
No. The camera records temperature differences on the surface of the modules in particular conditions and at a particular moment. Some faults leave no thermal signature, others only appear under a specific load. That is why we speak of observations for verification by a service company, not of detecting faults.
Why the thresholds: minimum 600 W/m2, wind up to 4 m/s, GSD up to 3 cm/px?
These are method gates consistent with the IEA PVPS methodology for PV thermography. With weaker sunlight the contrast drops, stronger wind cools the surface of the modules, and too great a distance blurs the detail. Thresholds that are not met mean postponing the date or changing the scope to RGB - not doing the thermal work "somehow".
Will the report settle a warranty claim or calculate energy losses?
No. The report is input for the conversation with a service company or a guarantor: it points out observations with their location and a recommended next step, and the areas to compare with production monitoring. The cause and the consequences are settled by electrical measurements taken on site by the appropriate specialist.
Does the installation have to be switched off during the flight?
No, quite the opposite: a thermal inspection is carried out on an installation working under load, because only then do the temperature differences carry information. We need the manager's consent and access to the site; the operator works from the ground, within visual line of sight of the drone.

Check Feasibility

Describe the installation - we will agree the scope.

A reply within 1 business day. Scope and price after the brief; the date of the mission is always conditional: the method gate, the airspace zone, access and the weather.