Middleware platforms are key technology in any Internet of Things (IoT) system, considering their role in managing the intermediary communications between devices and applications. In the energy sector, it has been shown that IoT devices enable the integration of all network assets to one large distributed system. This comes with significant benefits, such as improving energy efficiency, boosting the generation of renewable energy, reducing maintenance costs and increasing comfort. Various existing IoT middlware solutions encounter several problems that limit their performance, such as vendor locks. Hence, this paper presents a literature review and an expert survey on IoT middleware platforms in energy systems, in order to provide a set of tools and functionalities to be supported by any future efficient, flexible and interoperable IoT middleware considering the market needs. The analysis of the results shows that experts currently use the IoT middleware mainly to deploy services such as visualization, monitoring and benchmarking of energy consumption, and energy optimization is considered as a future application to target. Likewise, non-functional requirements, such as security and privacy, play vital roles in the IoT platforms’ performances.

Due to its potential benefits in data transparency, maintenance, and optimization of operation, the Internet of Things (IoT) has recently emerged in the building automation system (BAS) domain. However, while various IoT devices have been developed, the integration into BAS remains a challenging task due to the variety of conventional interfaces used in existing BAS. From an objective point of view, integrating IoT connectivity on existing devices’ printed circuit boards (PCBs) would be the most efficient option in terms of cost and resources, but requires adaptation of product lines, and vendors would often couple this with their own services and without an option for customization. By contrast, the majority of research activities focus on developing alternative or additional measurement systems, rather than connecting with legacy system components. Furthermore, most research applications cover very simple and individual use-cases with a do-it-yourself character and limited applicability in industrial applications. In this study, we present a scalable, industrial-like embedded solution to connect to common interfaces in BAS applications and share all the hardware and software design as an open-source platform for public use, customization, and further enhancement. Moreover, a thorough measurement performance analysis was conducted, suggesting an acceptable trade-off among accuracy, flexibility, and costs, e.g., achieving a performance increase by over 75% and a cost reduction by roughly 34% compared to a previous design.