modelGasStorage_varXi_L2

L2: Model of a simple gas storage volume for variable composition

Extends from Base.PartialGasStorage_L2 (Partial model of a simple gas storage volume for real gases).

Information

1. Purpose of model

This model represents a compressed gas storage for real gases with variable composition. It extends Base.PartialGasStorage_L2.

2. Level of detail, physical effects considered, and physical insight

The model consists of a volume, in which the gas located. Pressure losses inside the volume and during charging and discharging are neglected. There is no discretisation of the flow field or the heat transfer. The heat transfer is modelled using a replacable heat transfer model, the default model uses a constant heat transfer coefficient. The parameter variableCompositionEntries can be used in case that not all components are freely variable, e.g. when hydrogen is fed into natural gas. This reduces the number of states.

3. Limits of validity

The model is only valid for negligible pressure losses and negligible changes of the heat transfer coefficient (other heat transfer models can be used). For high pressures there are errors due to errors in the gas models. The gas in the storage is always ideally mixed, there is only one composition in the storage.

4. Interfaces

gasPortIn and gasPortOut: Real gas input and output

heat: heat port for the heat flow into/out of the storage

p_storage: signal output of the gas pressure

5. Nomenclature

(no elements)

6. Governing Equations

Simple mass and energy balances are used. For the compositions, component mass balances are added.

7. Remarks for Usage

(no remarks)

8. Validation

This model is not validated and might produce different results depending on the energy balance equation used in the base model.

9. References

(no remarks)

10. Version History

Model created by Carsten Bode (c.bode@tuhh.de) in Apr 2017

Modeli modified by Carsten Bode (c.bode@tuhh.de) in Apr 2021 (added simplifications for composition)

Parameters

TypeNameDefaultDescription
SI.SpecificEnthalpyNCV (from PartialGasStorage)TransiEnt.Basics.Functions.GasProperties.getRealGasNCVVector(medium, medium.nc)NCV of gas components
SI.SpecificEnthalpyGCV (from PartialGasStorage)TransiEnt.Basics.Functions.GasProperties.getRealGasGCVVector(medium, medium.nc)GCV of gas component
SI.Diameterdiameter (from PartialGasStorage_L2)sqrt(4*V_geo/(pi*height))Diameter of storage
SI.AreaA_heat (from PartialGasStorage_L2)pi/2*diameter^2 + pi*diameter*heightSurface area of storage
Integer[:]dependentCompositionEntriesif variableCompositionEntries[1] == 0 then 1:medium.nc else TransiEnt.Basics.Functions.findSetDifference(1:medium.nc, variableCompositionEntries)Entries of medium vector which are supposed to be dependent on the variable entries
Fundamental Definitions
TILMedia.VLEFluidTypes.BaseVLEFluidmedium (from PartialGasStorage)simCenter.gasModel1Medium in the gas storage
BooleanincludeHeatTransfer (from PartialGasStorage)trueconsider heat transfer
Integer[:]variableCompositionEntries{0}Entries of medium vector which are supposed to be completely variable
SI.MassFraction[medium.nc - 1]xi_nommedium.xi_defaultConstant composition
Geometry
SI.VolumeV_geo (from PartialGasStorage)1geometric inner volume of the storage cylinder
SI.Heightheight (from PartialGasStorage_L2)3.779*V_geo^(1/3)Height of storage
Initialization
SI.Massm_gas_start (from PartialGasStorage)1e5Initial mass in the storage
Booleanstart_pressure (from PartialGasStorage_L2)truetrue if a start pressure is defined, false if a start mass is defined
SI.Pressurep_gas_start (from PartialGasStorage_L2)1e5pressure in storage at t=0
SI.ThermodynamicTemperatureT_gas_start (from PartialGasStorage_L2)283.15Temperature of gas in storage at t=0
SI.MassFraction[medium.nc - 1]xi_gas_startmedium.xi_defaultMass composition of gas in storage at t=0
Statistics
BooleancalculateCost (from PartialGasStorage)simCenter.calculateCosttrue if cost shall be calculated

Connectors

TypeNameDefaultDescription
TransiEnt.Basics.Interfaces.Gas.RealGasPortIngasPortIn (from PartialGasStorage)
TransiEnt.Basics.Interfaces.Gas.RealGasPortOutgasPortOut (from PartialGasStorage)
TransiEnt.Basics.Interfaces.General.PressureOutp_gas (from PartialGasStorage)
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_aheat (from PartialGasStorage)

Components

TypeNameDefaultDescription
TransiEnt.SimCentersimCenter (from PartialGasStorage)
TransiEnt.ModelStatisticsmodelStatistics (from PartialGasStorage)
SI.Massm_gas (from PartialGasStorage)Gas mass
SI.MassFraction[medium.nc - 1]xi_gas (from PartialGasStorage)Gas composition
SI.EnergyFlowRateH_flow_in_NCV (from PartialGasStorage)Inflowing enthalpy flow based on NCV
SI.EnergyFlowRateH_flow_out_NCV (from PartialGasStorage)Inflowing enthalpy flow based on NCV
SI.EnthalpyH_gas_NCV (from PartialGasStorage)Enthalpy of the gas bulk based on NCV
SI.EnergyFlowRateH_flow_in_GCV (from PartialGasStorage)Inflowing enthalpy flow based on GCV
SI.EnergyFlowRateH_flow_out_GCV (from PartialGasStorage)Inflowing enthalpy flow based on GCV
SI.EnthalpyH_gas_GCV (from PartialGasStorage)Enthalpy of the gas bulk based on GCV
HeatTransferheatTransfer (from PartialGasStorage_L2)
Summarysummary

Contents

NameDescription
Outlineprotected
Summaryprotected