Drone with Thermal Vision

First, the good news: The solar power system that the Studierendenwerk commissioned in 2025 on the roof of the Mensa Vita is still in excellent condition. This is confirmed by a recent inspection using a thermal imaging drone – a flying specialist that detects problems you’d never see with the naked eye.

650 Images in 30 Minutes
In June, a DJI M4TD drone took off and flew over the entire solar array on the cafeteria roof. Equipped with a high-resolution thermal imaging camera, it captured over 650 images in just over 30 minutes – some in the infrared spectrum, others as standard digital photos.

Why thermal images? “Defective or dirty solar cells generate more heat than intact modules,” explains Udo Coenen-Staß from the Studierendenwerk’s building management department. “These temperature differences are invisible to the naked eye, but they show up on infrared images.”

Artificial Intelligence Analyzes the Data
The image data was then processed by AI software to create a precise 3D model of the system. Each of the 762 solar modules was automatically detected and analyzed for its temperature behavior. The result: an individual “Health Index” – a kind of health certificate for each module.

Good Results
The results are encouraging: 724 modules showed no abnormalities, while only 38 were examined more closely due to thermal anomalies. The most common cause: shadows from trees and roof structures. Since the drone flew in the morning, some objects were still casting shadows on the modules. These heat up unevenly, which is visible in the thermal images. In most cases, this is harmless because the shadow moves throughout the day.

More problematic is the permanent shadow cast by a stair railing. Several modules directly behind the railing of the roof stairs are regularly affected. Here, a structural modification or a rearrangement of the modules might be advisable. Deposits have formed on several modules, causing local “hotspots.” A temperature difference of over 20 degrees Celsius was measured on one module – this can lead to damage over the long term. Another module shows signs of an electrical defect and should be inspected by a licensed electrician.

Nevertheless, the inspection confirms that the solar system is operating reliably. Udo Coenen-Staß is satisfied: “With a few targeted measures, its performance and service life can be further ensured – so that the cafeteria will continue to be supplied with self-generated solar power in the future.”