Background This study introduces an innovative personnel training method for facility management and maintenance of Thermal-Energy-Storage (TES) chiller plants using a serious 3D game. Training games can improve the decision-making of personnel where they can learn to deal with management of TES chiller plants in the context of this study in an active learning approach. Intervention The research aims to investigate the effectiveness of an immersive learning experience with computerized simulation and synthetic task environments as a training game for facility managers. The serious 3D game adopts a first-person perspective, allowing players to assume the role of a facility manager and actively learn how to address maintenance issues commonly encountered in chiller plants. Methods The study implemented a first-person-based serious 3D game centered around a TES chiller plant. Participants, in the role of facility managers, engaged with the game and followed instructions to gain practical knowledge in managing maintenance issues within a controlled and simulated setting. Results The findings demonstrate increased engagement and interest among personnel when learning how to manage chiller plant issues within a serious 3D game environment. Notably, personnel experienced reduced pressure compared to real-life scenarios, as they navigated the challenges without the presence of a supervisor. Limitations The study’s limitations include a higher proportion of male participants in the qualitative content analysis, which may affect the generalizability of the findings. Additionally, the absence of a control group limits the ability to make direct comparisons with traditional training methods. Conclusion The results suggest that serious 3D games hold potential as an effective training tool for facility management and maintenance personnel. By engaging in active training within simulated and synthetic task environments, personnel can enhance their skills and decision-making capabilities. However, further research with a more diverse participant sample and a control group is warranted to fully evaluate the effectiveness of this innovative personnel training approach.