Description: "User's Guide"

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## Buildings.Fluid.Interfaces.UsersGuide

User's Guide

### Information

The package `Buildings.Fluid.Interface` consists of basic classes that can be used by developers to create new component models.

The classes whose name contains `TwoPort` or `FourPort` can be used for components with two or four fluid ports, respectively. If a class name contains `Static`, then it can only be used for a steady-state model. Otherwise, it may be used for a steady-state or a dynamic model.

The most basic classes are the records Buildings.Fluid.Interfaces.TwoPortFlowResistanceParameters, Buildings.Fluid.Interfaces.FourPortFlowResistanceParameters and Buildings.Fluid.Interfaces.LumpedVolumeDeclarations. These define parameters that are needed by many fluid flow components.

Next, we describe the basic classes. For a more detailed description, see the info section of the class.

Buildings.Fluid.Interfaces.ConservationEquation | This is a basic model for an ideally mixed fluid volume. It implements conservation equations for mass and energy. The conservation equations can be dynamic or steady-state. The model can have an arbitrary number of fluid ports. Models that instanciate this model need to define the input `fluidVolume`, which is the actual volume occupied by the fluid. For most components, this can be set to a parameter. However, for components such as expansion vessels, the fluid volume can change in time. The model has the following input connectors: `Q_flow`, which is the sensible plus latent heat flow rate added to the medium, and `mXi_flow`, which is the species mass flow rate added to the medium. Models that instanciate this model can used these connectors to interface with the conservation equations.
Buildings.Fluid.Interfaces.StaticTwoPortConservationEquation | This is a basic model for steady-state conservation equations for mass and energy of a component with two fluid ports. The model has the following input connectors: `Q_flow`, which is the sensible plus latent heat flow rate added to the medium, and `mXi_flow`, which is the species mass flow rate added to the medium. Models that instanciate this model can used these connectors to interface with the conservation equations. Compared to Buildings.Fluid.Interfaces.ConservationEquation this model provides a more efficient implementation of the steady-state conservation equations for models with two fluid ports.
Buildings.Fluid.Interfaces.FourPort | This model defines an interface for components with four ports. Only parameters and fluid definitions are provided, but no equations. The model is identical to Modelica.Fluid.Interfaces.PartialTwoPort, except that it has four ports.
Buildings.Fluid.Interfaces.TemperatureControlledHeatFlow | This model calculates a prescribed heat flow (e.g. for an ideal heater or cooler), depending on a set temperature TSet.
Buildings.Fluid.Interfaces.PartialTwoPortInterface | This model defines the interface for component models that transport fluid, and that can exchange heat and mass. It also defines the port pressure difference as Δp = pa-pb. However, no equation is implemented to compute Δp(⋅) as a function of the mass flow rate. The model also implements equations to obtain the thermodynamic state at the ports.
Buildings.Fluid.Interfaces.PartialFourPortInterface | This model is identical to Buildings.Fluid.Interfaces.PartialTwoPortInterface but it can be used for components with four fluid ports.
Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger | This model implements the pressure drop as a function of the mass flow rate. It also implements the steady-state energy and mass conservation equations. However, it does not implement an equation that computes `Q_flow`, the sensible and latent heat transfer to the medium flow, nor does it implement an equation for `mXi_flow`, the species mass flow rate added to or removed from the medium. Models that extend this model need to provide equations for `Q_flow` and `mXi_flow`.
Buildings.Fluid.Interfaces.StaticFourPortHeatMassExchanger | This model is identical to Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger except that it has four ports.
Buildings.Fluid.Interfaces.TwoPortHeatMassExchanger | This model implements the pressure drop as a function of the mass flow rate. It also implements the energy and mass conservation equations, which may be configured as steady-state or dynamic balances based on a parameter.
Buildings.Fluid.Interfaces.FourPortHeatMassExchanger | This model is identical to Buildings.Fluid.Interfaces.TwoPortHeatMassExchanger except that it has four ports.

Extends from Modelica.Icons.Information (Icon for general information packages).