Addressing data confidentiality and interconnectivity in digital twins: A case study on the hot water cycle of a heat pump test bench

Industry 4.0 has transformed industrial environments. Among its technologies, the Digital Twin (DT) has become prominent for enhancing efficiency and monitoring. However, the adoption of DTs remains limited due to challenges such as secure data exchange and interconnectivity among heterogeneous industrial assets, which are critical to realising DT’s potential. This paper introduces a vendor-independent platform that supports reproducible experiments with Digital Twins and enables interoperability with heterogeneous equipment. It integrates layered mechanisms for authenticated access and data confidentiality during transmission and storage. OPC UA provides certificate authentication and encrypted communication, while authenticated access and MariaDB/InnoDB encryption secure the DT’s services and data, respectively. Based on the Six-Step DT Design Framework and aligned with ISO 23247-1, a Digital Twin of the hot water cycle of a heat pump test bench (DT-HP-HWPrototype) is developed as a case study. The cloud-hosted DT preserves bidirectional communication while generating a knowledge graph from the Node-RED flow to provide foundational element of an equipement’s virtual replica. Experimental evaluation demonstrated successful operation and synchronisation between the physical system and its DT, achieving an average secure RTT_CC of 851 ms over 4G (LTE), with statistical measures characterising its variability. These results provide an assessment of the DT prototype’s secure communication performance in the specified operating conditions of this case study. Further research is needed to define network requirements and improve the granularity of process representation in the DT-HP-HW prototype.