recordCHPEngDataBaseRecord
Extends from Modelica.Icons.Record (Icon for records).
Information
Overview
Data base record for CHP power units. The nominal / rated operation point most likely corresponds to the given full load performance.
Requirements
These quantities must be known for reliable simulation (by value, variable relation etc.):
- Heat and Power: Q_MaxHea, etaCHP(Hi)
- Engine Geometry: hStr, dCyl, z, i
- Generator specification: p or n0, n_nominal, U_1, P_elNominal, f_1
- Lambda or xO2Exh: Required for calculation of the engine combustion, heat flow and the exhaust gas composition (Lambda = 0.21 / (0.21 - xO2Exh))
- nEngNominal
- dInn (typical values around 0.005m, important for heat transfer from engine to cooling)
Default values and variable relations
These are the default values or relations in case that there is no information available:
- nEngMax: Engine speed at full load (=nEngNominal)
- etaGen: Generator efficiency (default=0.92)
- I_elNominal (=P_elNominal/(sqrt(3)*U_1*cosPhi))
- P_mecNominal (=P_elNominal/etaGen)
- P_FueNominal (=(P_elNominal+Q_MaxHea)/etaCHP)
- VEng (default=0.25*hStr*Modelica.Constants.pi*dCyl^2*z)
- mEng (default=70389*VEng+17.913, for first appraisal of the heat capacities of engine housing, should be calibrated)
- eps (typical values around 12 (SI) and 21 (DI))
- T_ExhPowOut (default=373.15K)
- gearRatio (default=1)
- cosPhi (default=0.8)
- useGenHeat (default=false)
- Exhaust and Coolant: dExh(default=0.06m), dCoo(default=0.04m), dp_Coo(default=0.15bar), m_flowCooNominal(default=0.00003*Q_MaxHea-0.2043)
- Engine material: lambda, rhoEngWall, c (default is cast iron(most common))
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | SIEngine | true | Default:True=SI-Engine(Otto) / False=DI-Engine(Diesel) |
| String | EngMat | "CastIron" | Name of the engine material(Choices: CastIron, SpheroidalGraphiteIron, CastAluminium) |
| RotationSpeed | nEngMax | nEngNominal | Engine speed at full load (default=nEngNominal) |
| RotationSpeed | nEngNominal | Nominal engine speed at nominal operating point | |
| Real | QuoDCyl | dCyl/ref_dCyl | Comparison of cylinder diameter to the reference |
| Real | xO2Exh | 0.05 | Residual oxygen content in the exhaust gas(default value is 5%) |
| Real | Lambda | 0.21/(0.21 - xO2Exh) | Engine air ratio (default value is 1.31; min=1.01) |
| Real | z | Number of cylinders | |
| Real | eps | if SIEngine then 12 else 21 | Compression ratio (default values are 12(SI) and 21(DI)) |
| Real | i | Number of combustion for one operating cycle (1->two-stroke, 0.5->four-stroke) | |
| Modelica.Units.SI.Mass | mEng | 70389*VEng + 17.913 | Total dry weight of the engine block |
| Modelica.Units.SI.Volume | VEng | 0.25*hStr*Modelica.Constants.pi*dCyl^2*z | Engine displacement |
| Modelica.Units.SI.Length | hStr | Stroke | |
| Modelica.Units.SI.Length | dCyl | Cylinder diameter | |
| Modelica.Units.SI.Length | ref_dCyl | 0.091 | Reference cylinder diameter for friction calculation |
| Modelica.Units.SI.Pressure | ref_p_mfNominal | if SIEngine then 75000 else 110000 | Friction mean pressure of reference engine for calculation(dCyl=91mm & nEng=3000rpm & TEng=90°C) |
| Modelica.Units.SI.Pressure | p_meNominal | P_mecNominal/(i*nEngNominal*VEng) | Nominal mean effective cylinder pressure |
| Modelica.Units.SI.Efficiency | etaCHP | Nominal efficiency of the power unit referring to the fuel input | |
| Modelica.Units.SI.Efficiency | etaGen | 0.92 | Generator efficiency |
| Modelica.Units.SI.Power | P_mecNominal | P_elNominal/etaGen | Mechanical power output of the engine at nominal operating point |
| Modelica.Units.SI.Power | P_FueNominal | (P_elNominal + Q_MaxHea)/etaCHP | Nominal fuel expenses |
| Modelica.Units.SI.Power | Q_MaxHea | Maximum of usable heat | |
| Modelica.Units.SI.Temperature | T_ExhPowUniOut | 373.15 | Exhaust gas temperature after exhaust heat exchanger (default=100°C) |
| Modelica.Units.SI.Diameter | dExh | 0.0612 + (Lambda*P_FueNominal)*10^(-7) | Exhaust pipe diameter for heat transfer calculation |
| Modelica.Units.SI.Diameter | dCoo | 0.0224 + Q_MaxHea*2*10^(-7) | Coolant circle pipe diameter for heat transfer calculation |
| Modelica.Units.SI.Thickness | dInn | Thickness of the cylinder wall between combustion chamber and cooling circle (default value is 5mm) | |
| Modelica.Units.SI.MassFlowRate | m_floCooNominal | 0.00003*Q_MaxHea - 0.2043 | Nominal mass flow rate of coolant inside the engine cooling circle (default density of coolant is 1kg/l) |
| Modelica.Units.SI.Pressure | dp_Coo | 15000 | Pressure loss between coolant supply and return flow (default value is 0.15bar) |
| Real | cosPhi | 0.8 | Power factor of electric machine (default=0.8) |
| Real | p | f_1/n0 | Number of pole pairs |
| Real | gearRatio | 1 | Gear ratio: engine speed to generator speed (default=1) |
| Boolean | useHeat | false | Is the thermal loss energy of the elctric machine used? |
| Modelica.Units.SI.Frequency | n0 | f_1/p | Idling speed of the electric machine |
| Modelica.Units.SI.Frequency | n_nominal | Rated rotor speed [1/s] | |
| Modelica.Units.SI.Frequency | f_1 | Source frequency | |
| Modelica.Units.SI.Voltage | U_1 | Rated voltage | |
| Modelica.Units.SI.Current | I_elNominal | P_elNominal/(sqrt(3)*U_1*cosPhi) | Rated current |
| Modelica.Units.SI.Power | P_elNominal | Nominal electrical power of electric machine |
Contents
| Name | Description |
|---|---|
| RotationSpeed | |
| AirRatio |