modelStratifiedTankWithCommand
Stratified buffer tank model
Information
This is a four-port tank model based on Buildings.Fluid.Storage.Stratified which includes the following features.
-
The two fluid ports suffixed with
Topare connected to the fluid volume at the top of the tank. -
The two fluid ports suffixed with
Botare connected to the fluid volume at the bottom of the tank. - A unique heat port is exposed as an external connector. It is meant to provide a uniform temperature boundary condition at the external surface of the tank (outside insulation).
- The model outputs the temperature of the fluid volumes at the top and at the bottom of the tank.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Volume | VTan | Tank volume | |
| Modelica.Units.SI.Length | hTan | Height of tank (without insulation) | |
| Modelica.Units.SI.Length | dIns | Thickness of insulation | |
| Modelica.Units.SI.ThermalConductivity | kIns | 0.04 | Specific heat conductivity of insulation |
| Integer | nSeg | 3 | Number of volume segments |
| Boolean | isHotWat | True if the tank supplies hot water, false for chilled water | |
| Modelica.Units.SI.TemperatureDifference | dTOffSet | if tanCha.isHotWat then +1 else -1 | Offset for set point to have a slightly higher (or lower) temperature than the required supply from the load |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | Nominal mass flow rate | |
| Initialization | |||
| Medium.Temperature | T_start | Medium.T_default | Temperature start value |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_genTop | Tank top port on generation side | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_genBot | Tank bottom port on generation side | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_loaBot | Tank bottom port on load side | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_loaTop | Tank top port on load side | |
| Modelica.Blocks.Interfaces.RealOutput | Ql_flow | Heat loss of tank (positive if heat flows from tank to ambient) | |
| Modelica.Blocks.Interfaces.RealOutput | TTop | Fluid temperature at tank top | |
| Modelica.Blocks.Interfaces.RealOutput | TBot | Fluid temperature at tank bottom | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heaPorAmb | Heat port at interface with ambient (outside insulation) | |
| Modelica.Blocks.Interfaces.RealInput | TTanSet | Tank temperature set point, top for hot tank and bottom for cold tank | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput | charge | Outputs true if tank should be charged |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.Storage.Stratified | tan | Stratified tank | |
| Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor | senTBot | Tank bottom temperature | |
| Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor | senTTop | Tank top temperature | |
| Buildings.DHC.ETS.Combined.Controls.TankChargingController | tanCha | Tank charging command | |
| Buildings.Fluid.FixedResistances.Junction | junTop | Fluid junction at top of tank | |
| Buildings.Fluid.FixedResistances.Junction | junBot | Fluid junction at bottom of tank |
Contents
| Name | Description |
|---|---|
 Medium | Medium model |
Revisions
-
November 14, 2025, by Michael Wetter:
Added output for tank charge signal which is used in the ETS supervisory control.
This is for #4354. -
July 31, 2020, by Antoine Gautier:
First implementation.