Service Oriented Architecture enabling the 4th Generation of District Heating

The 4th Generation of District Heating (4GDH) is a complex agglomeration of heat providers, distributors, and consumers that must be automatically, continuously managed and coordinated. It is a complex system of systems; a definition which we align to Maier's architecting principles for systems-of-systems as collaborative systems. Wrapped in the idea of system of systems is the reality that the 4GDH systems' descriptions and specifications are not currently all known. Nonetheless, the transition into the 4GDH is actual. We propose the use of two frameworks to secure a smooth metamorphosis and assure systems' operation, maintenance, and evolution. The two frameworks are the Arrowhead Framework and the OPTi Framework. The first one enables system integration through Service Oriented Architecture (SOA) and the second one offers the overall system optimization with respect to all stakeholders. This paper uses the Model Based Systems Engineering (MBSE) tool SysML to model a district heating complex's structures and behaviors from the concept level down to the sensors and actuators within a district heating substation where we apply the SOA technology based on the open Arrowhead Framework. We focus on the Arrowhead Framework's core services, i.e. Service Registry, Authorization and Orchestration to clearly describe the interactions between the different service providers and consumers. Going back up from the sensors to the systems, it is clear that SOA is the architecture that will empower the 4GDH.