FAN FPAI ontology
The Fanfpai ontology describes the resources (appliances) used in the Flexible Power Application Infrastructure (FPAI) . These resources are defined in the Resource Abstraction Interface (RAI class), which is used to express the energetic flexibility that appliances can offer and how this flexibility should be exploited. The RAI is an interface layer between:
- the Resource Abstraction Layer (RAL class) that monitors and controls the appliances and knows how much flexibility they can offer. The RAL consists of two main components: the resource manager (ResourceManager class) and the resource driver (not considered in this ontology);
- the energy apps (EnergyApp class) that are typically provided by a third party and exploit the flexibility that appliances have to offer. An energy app is only interested in exploiting energetic flexibility and not in the details of a specific appliance, such as a washing machine, for instance.
A Resource represents an appliance within a household or a building that can provide flexibility with regard to consumption, storage and production of energy. There are several type of resources defined in FPAI:
- TimeShifter resources, which are a category of appliances that produce or consume energy according to a predetermined energy profile and whose flexibility comes from their ability to shift the start time of this profile. Typical examples of time shifting appliances are WashingMachine, DishWasher, AutomaticVacuumCleaner;
- Buffer resources, which are a category of appliances that can provide electrical flexibility. With a buffer appliance one can choose to consume/produce more energy now (within certain operational constraints) so that it consumes/produces less energy later, or the other way around. Most buffers are thermal. Examples of such appliances are Refrigerator, Freezer, HeatingSystem;
- EnergyStorage, which is category of appliances similar to buffers, but with the main difference that with buffers the electrical energy only flows in one direction: it is either consumption or generation, while with a storage appliance the electrical energy flow is bidirectional. The storage category includes self-discharging batteries (e.g. Li-In/NiMH batteries), chemical storage batteries with conversion loss (e.g. flow batteries), and mobile storage in electrical vehicles;
- UncontrolledLoadOrGeneration, which is a category reserved for appliances that cannot be controlled and, as a consequence, cannot offer flexibility. It is however important to know how these appliances behave energetically to make informed decisions about the usage of flexibility in the other three categories. A SolarPanel is an example of an uncontrolled generation appliance, which generates energy that cannot be controlled since it depends on external natural conditions (i.e. the weather), whereas Lighting represents an uncontrolled load.
Important concepts in the ontology are ControlSpace, which is used to describe the energetic flexibility of a particular resource/appliance, and Allocation, which indicates how this flexibility should be used. The ResourceManager constructs and communicates a ControlSpace. In response to a ControlSpace communication, a ResourceManager can receive an Allocation, which contains a precise EnergyProfile that the ResourceManager should try to follow as closely as possible. There are several control spaces that correspond to the different categories of resources, namely TimeShifterControlSpace, BufferControlSpace, EnergyStorageControlSpace, and UncontrolledControlSpace. Each control space is characterized by specific properties. The ontology also defines the Energy, Power, Duration classes and their corresponding units of measure.