Trainers Shape the Way: Train-the-Trainer Workshop at the Bundesfachschule Kälte-Klima-Technik in Maintal

The Bundesfachschule Kälte-Klima-Technik is the vocational training centre of the Landesinnung Kälte-Klima-Technik Hessen-Thüringen/Baden-Württemberg, the regional refrigeration and air-conditioning trade guild. On 28 September 2026, its headquarters in Maintal opened a training week for its trainers, with more than eight trainers from various sites. Robert Heß, member of the management board and head of practical vocational training, invited the InnoVET PLUS project XR2ACH and gave us the entire first day of the week, and with it the trainers’ valuable time. Many thanks for that!

We sat in a room full of training rigs built for the new inter-company training course on heat pumps (KK7). It was a fitting place to talk about the future of training.

From didactics to a learning journey

The day began with a short overview of the project: why XR2ACH exists and where it stands today. We then turned to the didactic side: how can immersive media be integrated into training in a meaningful way?

To answer that, we introduced the types of virtual learning environments described by Weise and Zender, and mapped them to the cognitive processes and knowledge types of the revised Bloom’s taxonomy (Anderson and Krathwohl). We used the overview from the study “AR and VR Meet Boiler Suits” by Beckmann, Menke and Weber (2018), which makes exactly this mapping for AR/VR training in the HVAC trades. The trainers were already familiar with these concepts. This let them carry their own expertise straight over into virtual learning environments.

Next, we showed how the features of the XR2ACH app map onto these types:

• Expositional: the trainer guides learners through content in a fixed order, for example by explaining a compressor model to the whole group in a shared virtual room.
• Explorational: trainees explore a model or a system at their own pace and in their own order. This supports understanding and factual knowledge, for instance when freely exploring the CAD models.
• Training: procedures are practised step by step, with guidance and immediate feedback. This is procedural knowledge, as in leak detection or commissioning.
• Experimental: in simulations, parameters can be changed to understand cause and effect, for example how a fault spreads through a system.
• Constructional: trainees deepen their knowledge by creating something themselves, for example by assembling a compressor from its parts or designing a refrigeration system from a component library.

The revised Bloom’s taxonomy adds two axes: which type of knowledge is being taught (factual, conceptual, procedural and metacognitive) and which cognitive process is required, from remembering and understanding through applying and analysing to evaluating and creating. This shows which learning environment suits which learning objective. CAD visualization is best suited to understanding structure and function; the simulations suit applying and analysing. Through the learning objectives they fulfil, they come together in an overarching learning journey. This links to the concept of VR nuggets by Robin Horst and Ralf Dörner: small units of knowledge that specifically call for immersive media, used in small portions at different stages of a learning journey. The swimlane approach of the InnoVET PLUS project XR-Upskill, which plans AR and VR content along a training course, gave a practical example.

Hands-on: alone, together, in the same room

Every trainer then received a temporary login, and we started with single-player CAD visualization. Switching on passthrough was a highlight: suddenly the compressor models stood in the real room. It caught the trainers’ attention at once. Co-located CAD visualization, which we had just tested at the SCHAUFLER Academy anniversary, turned out to be a particularly popular use case.

One trainer had brought his own Meta Quest 3. Through a private release channel in Meta’s distribution system, the app was installed on his headset within minutes, with no need to share an APK file. A third trainer also put on a headset. One of them opened a multiplayer room, the others joined, and the three of them worked together on collaborative CAD visualization and leak detection in VR. They particularly enjoyed spraying as much leak detection spray as they liked without the can ever running empty, and now and then they “borrowed” each other’s measuring devices.

The guest Wi-Fi was not good enough for wireless casting. So we streamed one headset to the projector by cable through a laptop. Multiplayer on the same Wi-Fi, by contrast, ran smoothly, because the app’s networking is lightweight.

The group suggested limiting consumables in the simulation and deducting points for counter-productive behaviour. This fits well with the environment’s learning analytics system, which we also briefly presented.

Where does XR fit into inter-company training?

After lunch, a conversation among the trainers developed on its own: how can XR learning content be built into the current plans for inter-company training (ÜLU), and into their upcoming revisions? The discussion also covered cooperation between learning venues, with other inter-company training centres, companies and vocational schools, and the opportunities and challenges this brings.

Together we discussed which ÜLU courses would benefit most from which features, and where the plan offers enough flexibility to introduce something new without risk. One example is leak detection in the course on leak testing and refrigerants (KK2): practise in VR first and then on the real system, or the other way round, with VR as a repeat afterwards. Another is visualizing compressors and components in the installation course (KK3). For the trainers, one point was clear: immersive learning content should complement practical training, not replace it.

New features and scenarios were discussed as well, including:

• setting and checking controllers and pressure switches, and seeing what a wrong setting does;
• compound systems and supermarket refrigeration, including CO₂;
• further compressor types;
• assembling a complete refrigeration circuit, as in the journeyman’s examination.

The organisational side of a roll-out mattered just as much: hygiene for shared headsets, maintenance and care of the devices, and the number of headsets per site and per course.

Commissioning with roles reversed, and feedback you can feel

To close, we showed an unfinished version of the service and commissioning scenario live, with roles reversed: the facilitator was in VR, and the trainers guided him step by step by voice. This raised the question of missing haptics. We explained how we plan to design haptic feedback explicitly, both visually and through controller vibration. We also demonstrated haptic gloves (bHaptics TactGlove DK2) with a demo app. They are to be tested in the finished learning environment from the first quarter of 2027.

The day ended with a barbecue together, plenty of conversation and an optimistic outlook on what XR2ACH can make possible in training. Many thanks to Robert Heß, the Bundesfachschule Kälte-Klima-Technik and all the trainers for their time, their openness and their valuable ideas!