modelPolynomialIsentropicEfficiency
Extends from PartialIsentropicEfficiency (Based model used by all models describing isentropic efficiencies).
Information
This model contains a calculation procedure for isentropic efficiency models (for more information, please check out AixLib.Fluid.Movers.Compressors.BaseClasses.PartialCompression). The calculation procedures based on a polynomial approach are presented below.
Implemented approaches
Actually, three polynomial approaches are implemented in this
package. To add further calculation procedures, just add its name in
AixLib.Fluid.Movers.Compressors.Utilities.Types
and expand the if-structure.
| Reference | Formula | Refrigerants |
Validity ncompressor
|
Validity Πpressure
|
|---|---|---|---|---|
| DarrAndCrawford1992 |
ηise = a1 + a2*n +
a3/ρinlet
|
R134a |
40 - 75
|
3 - 10
|
| Karlsson2007 |
ηise = a1 + a2*π + a3*π^2 + a4*n +
a5*n^2
|
R407c |
No information
|
No information
|
| Engelpracht2017 |
ηise = a1 + a2*n + a3*n^3 + a5*π^2
|
Generic model |
0 - 120
|
1 - 10
|
References
J.H. Darr and R.R. Crawford (1992): Modeling of an Automotive Air Conditioning Compressor Based on Experimental Data: ACRC Technical Report 14. Publisher: Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.
F. Karlsson (2007): Capacity Control of Residential Heat Pump Heating Systems. In: PhD thesis
M. Engelpracht (2017): Development of modular and scalable simulation models for heat pumps and chillers considering various refrigerants. Master Thesis
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelling approach | |||
| Types.IsentropicPolynomialModels | polyMod | Types.IsentropicPolynomialModels.Karlsson2007 | Chose predefined polynomial model for flow coefficient |
| Real[:] | a | Multiplication factors for each summand | |
| Real[:] | b | Exponents for each summand | |
| Integer | nT | size(a, 1) | Number of terms used for the calculation procedure |
| Real[:] | c | {1} | Coefficients used for correction factors if needed |
| Reference properties | |||
| Modelica.Units.SI.Frequency | rotSpeRef | 9.334 | Reference rotational speed |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Efficiency | epsRef (from PartialEfficiency) | Ratio of the real and the ideal displacement volume | |
| Modelica.Units.SI.Volume | VDis (from PartialEfficiency) | Displacement volume | |
| Real | piPre (from PartialEfficiency) | Ratio of compressor's outlet and inlet pressure | |
| Modelica.Units.SI.Frequency | rotSpe (from PartialEfficiency) | Compressor's current rotational speed | |
| Medium.ThermodynamicState | staInl (from PartialEfficiency) | Thermodynamic state at compressor's inlet | |
| Medium.ThermodynamicState | staOut (from PartialEfficiency) | Thermodynamic state at compressor's outlet | |
| Modelica.Units.SI.Temperature | TAmb (from PartialEfficiency) | Ambient temperature | |
| Modelica.Units.SI.Efficiency | etaIse (from PartialIsentropicEfficiency) | Overall isentropic efficiency | |
| Real[nT] | p | Array that contains all coefficients used for the calculation procedure | |
| Real[2] | corFac | Array of correction factors used if efficiency model proposed in literature differs from efficiency model defined in PartialCompressor model |
Revisions
- October 20, 2017, by Mirko Engelpracht:
First implementation (see issue 467).