modelHotWaterStorage_constProp_L2
Extends from TransiEnt.Basics.Icons.ThermalStorageBasic (Icon for thermal storage model).
Information
Purpose of model
Simple energy balance model of a hot water storage without spatial discretisation. Thermodynamic properties are not calculated in dependence on the temperature. The model consists of two heat exchangers that are connected artificially with an energy balance.
Level of detail, physical effects considered, and physical insight
- Consideration of heat losses
- Dynamic energy balance
- No pressure losses considered
- No stratification considered (no discretization)
Interfaces
fpGenIn: inlet from heat generator
fpGenOut: outlet from heat generator
fpGridIn: inlet (return) from consumer/grid
fpGridOut: outlet to consumer/grid
T_stor_out: Temperature in heat reservoir in K [K]
SoC: State of charge of the storage
Governing Equations
Q_flow_loss=k*A*(T_store-T_amb)
dE_stor/dt = Q_flow_gen - Q_flow_con - Q_flow_loss;
Q_flow_con=Q_flow_demand (Q_demand is an input)
Q_flow_gen=Q_flow_store (Q_flow_store is an input)
T_stor = E_stor/(Volume*rho*cp) + 273.15;
Validation
The model was tested in the test model:
TransiEnt.Storage.Heat.HotWaterStorage_constProp_L2.Check.Check_HotWaterStorage_constProp_L2
Version History
Created by Arne Koeppen (arne.koeppen@tuhh.de), Apr 2013
Edited and revised by Lisa Andresen (andresen@tuhh.de), Jun 2013
Modified by Anne Senkel (anne.senkel@tuhh.de), Dec 2017
Modified by Anne Hagemeier (anne.hagemeier@umsicht.fraunhofer.de), July 2021 (FluidPorts as conditional components, corrected equation for E_start).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Volume | Volume | d^2/4*Modelica.Constants.pi*height | |
| SI.Area | A | d*Modelica.Constants.pi*height + 2*d^2/4*Modelica.Constants.pi | |
| Fundamental Definitions | |||
| Boolean | useFluidPorts | true | |
| TILMedia.VLEFluidTypes.BaseVLEFluid | Medium | simCenter.fluid1 | Medium in the component |
| SI.Pressure | p_drop_nom | simCenter.p_nom[2] - simCenter.p_nom[1] | Pressure drop on supply side |
| SI.MassFlowRate | m_flow_nom | 20 | Nominal mass flow rate |
| SI.Height | height | 20 | Height of heat storage |
| SI.Diameter | d | 11.28 | Diameter of heat storage |
| SI.SurfaceCoefficientOfHeatTransfer | k | 0.08 | Coefficient of heat transfer |
| Temperatures | |||
| SI.Temperature | T_max | 383.15 | Maximum allowed temperature in storage |
| SI.Temperature | T_start | 273.15 + 90 | Initial temperature |
| SI.Temperature | T_amb | 273.15 + 15 | Assumed constant ambient temperature |
| Fluid Properties | |||
| SI.Density | rho | 1000 | Density of the storage medium |
| SI.SpecificHeatCapacity | cp | 4200 | Heating capacity of the storage medium |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| TransiEnt.Basics.Interfaces.Thermal.FluidPortIn | fpGenIn | inlet from heat generator | |
| TransiEnt.Basics.Interfaces.Thermal.FluidPortOut | fpGenOut | outlet to heat generator | |
| TransiEnt.Basics.Interfaces.Thermal.FluidPortIn | fpGridIn | inlet (return) from consumer/grid | |
| TransiEnt.Basics.Interfaces.Thermal.FluidPortOut | fpGridOut | outlet to consumer/grid | |
| TransiEnt.Basics.Interfaces.General.TemperatureOut | T_stor_out | Temperature in heat reservoir in K | |
| Modelica.Blocks.Interfaces.RealOutput | SoC | State of charge | |
| TransiEnt.Basics.Interfaces.Thermal.HeatFlowRateOut | Q_flow_gen | Generated heat flow | |
| TransiEnt.Basics.Interfaces.Thermal.HeatFlowRateOut | Q_flow_con | Consumed heat flow | |
| TransiEnt.Basics.Interfaces.Thermal.HeatFlowRateIn | Q_flow_store | Heat flow into the storage | |
| TransiEnt.Basics.Interfaces.Thermal.HeatFlowRateIn | Q_flow_demand | Heat flow from the storage |