modelDirectHeatExchangerWithElectricHeat
A model for generating hot water using a district heat exchanger and supplemental electric resistance
Extends from Buildings.DHC.Loads.HotWater.BaseClasses.PartialFourPortDHW.
Information
This model implements a basic domestic hot water source for a district heating network. It includes heating by the district through a heat-exchanger and optional electric resistance to bring the temperature of produced hot water to setpoint, if the district supply water is not hot enough.
It is based on Fig. 5 in Evaluations of different domestic hot water preparing methods with ultra-low-temperature district heating by X. Yang, H. Li, and S. Svendsen at doi.org/10.1016/j.energy.2016.04.109.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Efficiency | eps | 0.8 | Heat exchanger effectiveness |
| Boolean | have_eleHea | true | True if has auxiliary electric heater |
| Modelica.Units.SI.HeatFlowRate | QMax_flow | Modelica.Constants.inf | Maximum heat flow rate for electric heater (positive) |
| Modelica.Units.SI.MassFlowRate | mDom_flow_nominal | Nominal flow rate of domestic hot water | |
| Modelica.Units.SI.MassFlowRate | mHea_flow_nominal | Nominal flow rate of heating source water | |
| Modelica.Units.SI.PressureDifference | dpDom_nominal | 0 | Pressure difference in heat exchanger on domestic water side |
| Modelica.Units.SI.PressureDifference | dpHea_nominal | 0 | Pressure difference in heat exchanger on heating water side |
| Modelica.Units.SI.PressureDifference | dpEle_nominal | 0 | Pressure difference in electric reheater for domestic water |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.HeatExchangers.Heater_T | heaEle | Supplemental electric resistance domestic hot water heater | |
| Buildings.Fluid.Sensors.TemperatureTwoPort | senTemHot | Temperature sensor for hot water supply | |
| Buildings.Fluid.HeatExchangers.ConstantEffectiveness | hex | Domestic hot water heater heat exchanger | |
| Buildings.Fluid.Sensors.TemperatureTwoPort | senTemHexOut | Temperature sensor for hot water leaving heat exchanger | |
| Modelica.Blocks.Interfaces.RealOutput | THexOut | Temperature of hot water leaving heat exchanger | |
| Modelica.Blocks.Interfaces.RealOutput | PEle | Electric power required for electric heater | |
| Modelica.Blocks.Sources.Constant | zero | Zero power if no heater |
Revisions
-
September 11, 2023 by David Blum:
Update model for release. -
June 16, 2022 by Dre Helmns:
Initial Implementation.