modelDHWHeatExchanger
Counterflow heat exchanger
Extends from AixLib.Obsolete.BaseClasses.ObsoleteModel (Icon for classes that are obsolete and will be removed in later versions).
Information
Overview
Model for a counterflow heat exchanger for two circuits. In the first instance this heat exchanger is used to warm domestic hot water.
Concept
The heat transfer between the two circuits is based on the model ThermalConductor. The fluid inside the heat exchanger (each side separately) is represented by the model HeatCapacitor.
The heat exchanger is discretized in n single layers (min. 3 layers) towards the flow direction at the heater side.Example Results
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| FastHVAC.Media.BaseClasses.MediumSimple | medium | FastHVAC.Media.WaterSimple() | Standard charastics for water (heat capacity, density, thermal conductivity) |
| Modelica.Units.SI.Area | A_HE | 2 | Area of the heat exchanger |
| Modelica.Units.SI.CoefficientOfHeatTransfer | k_HE | 1500 | Thermal transmission coefficient |
| Modelica.Units.SI.Temperature | T_inlet_DHW | 283.15 | DHW Temperature at inlet |
| Modelica.Units.SI.Temperature | T_set_DHW_ideal | 333.15 | DHW set temperature |
| Integer | n | 5 | Number of segments the heat exchanger is separated to |
| Modelica.Units.SI.Mass | m_heater | 10 | How much fluid is inside the heat exchanger at the side of the heater |
| Modelica.Units.SI.Mass | m_DHW | 10 | How much fluid is inside the heat exchanger at the side of the DHW |
| Modelica.Units.SI.Temperature | T0 | Modelica.Units.Conversions.from_degC(20) | Initial temperature, in degrees Celsius |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealOutput | T_DHW | output temperature of domestic hot water | |
| Modelica.Blocks.Interfaces.RealOutput | T_return | ||
| Interfaces.EnthalpyPort_a | enthalpyPort_heaterIn | flow | |
| Interfaces.EnthalpyPort_b | enthalpyPort_heaterOut | return | |
| Interfaces.EnthalpyPort_a | enthalpyPort_dHWIn | DHW input | |
| Interfaces.EnthalpyPort_b | enthalpyPort_dHWOut | DHW output |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.HeatFlowRate | dotQ | ||
| FastHVAC.BaseClasses.WorkingFluid[n] | layer_heater | ||
| Modelica.Thermal.HeatTransfer.Components.ThermalConductor[n] | heat_transfer | ||
| FastHVAC.BaseClasses.WorkingFluid[n] | layer_dHW | ||
| Modelica.Blocks.Math.UnitConversions.To_degC | to_degC | ||
| Modelica.Blocks.Math.UnitConversions.To_degC | to_degC1 |
Revisions
-
April 13, 2017 Tobias Blacha:
Moved into AixLib -
January 12, 2015 by Konstantin Finkbeiner:
Formatted documentation appropriately -
December 16, 2014 by Sebastian Stinner:
Implemented