modelHeatMeter
Measures thermal energy provided between supply and return pipes
Extends from BaseClasses.PartialDynamicFlowSensor (Partial component to model sensors that measure flow properties using a dynamic model), Modelica.Icons.RoundSensor (Icon representing a round measurement device).
Information
This model measures thermal energy provided between a supply and return pipe.
It measures the capacity flow rate of the heat transfer fluid and the change in its
temperature compared to an external temperature measurement that is input into the port
TExt. The sensor does not influence the fluid.
The rate of heat flow is calculated as Q̇ = ṁ cp (T - TExt).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Time | tau (from PartialDynamicFlowSensor) | 1 | Time constant at nominal flow rate (use tau=0 for steady-state sensor, but see user guide for potential problems) |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialTwoPort) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal (from PartialFlowSensor) | Nominal mass flow rate, used for regularization near zero flow | |
| Advanced | |||
| Modelica.Units.SI.MassFlowRate | m_flow_small (from PartialFlowSensor) | 1E-4*m_flow_nominal | For bi-directional flow, temperature is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required) |
| Initialization | |||
| Modelica.Blocks.Types.Init | initType (from PartialDynamicFlowSensor) | Modelica.Blocks.Types.Init.InitialState | Type of initialization (InitialState and InitialOutput are identical) |
| Modelica.Units.SI.Temperature | T_start | Medium.T_default | Initial or guess value of temperature |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a (from PartialTwoPort) | Fluid connector a (positive design flow direction is from port_a to port_b) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b (from PartialTwoPort) | Fluid connector b (positive design flow direction is from port_a to port_b) | |
| Modelica.Blocks.Interfaces.RealInput | TExt | External temperature measurement to calculate temperature difference | |
| Modelica.Blocks.Interfaces.RealOutput | Q_flow | Heat flow rate |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.Temperature | T | Temperature of the passing fluid |
Revisions
-
February 1, 2024, by Michael Wetter:
Revised implementation.
This is for IBPSA, #1831. -
February 1, 2024, by Jan Gall:
First implementation.
This is for IBPSA, #1831.