.AixLib.Fluid.Movers.Compressors.UsersGuide.Approaches.MechanicEfficiency .AixLib.Fluid.Movers.Compressors.UsersGuide.Approaches.MechanicEfficiencyGenerally, two kinds of calculation approaches can be
identified: A polynomial and a power approach. A generic polynomial
approach is presented below:
ηeng = corFact * sum(a[i]*P[i]^b[i] for i in
1:nT)
A generic power approach is presented below:
ηeng = corFact * a * product(P[i]^b[i] for i in
1:nT)
All engine efficiency models presented in this library are based on
a literature review. Therefore, the variable corFact
allows a correction of the engine efficiency if the general
modelling approach presented in the litarature differs from
ηeng = Q̇ref / Pel or
from ηeng = Q̇refIse /
Pel, respectively.
Calculation procedures presented in the litarture have some
variables in commen and these variables are presented
below:
| Type | Name | Comment |
|---|---|---|
| input | epsRef |
Ratio of the real and the ideal displacement volume |
| input | VDis |
Displacement volume |
| input | piPre |
Pressure ratio |
| input | rotSpe |
Rotational speed |
| input | staInl |
Thermodynamic state at compressor's inlet conditions |
| input | staOut |
Thermodynamic state at compressor's out conditions |
| input | TAmb |
Ambient temperature |
Actually, four 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 defined in
AixLib.Fluid.Movers.Compressors.Utilities.EngineEfficiency.PolynomialEngineEfficiency.
| Reference | Formula | Refrigerants | Validity ncompressor |
Validity Πpressure |
|---|---|---|---|---|
| JahningEtAl2000 | ηeng = a1 +
a2*exp(pInl)^b2 |
Generic model | Generic model |
Generic model |
| DurprezEtAl2007 | ηeng = a1 + a2*π + a3*π^2 + a4*π^3 + a5*π^4 +
a6*π^5 + a7*π^6 |
Generic model | Generic model |
Generic model |
| KinarbEtAl2010 | ηeng = a1 + a2*π + a3*π^2 |
Generic model | Generic model |
Generic model |
| Engelpracht2017 | ηeng = a1 + a2*π + a3*π^2 + a4*n*π + a5*n^2 +
a6*π^2*n + a7*π*n^2 + a8*n^3 + a9*π^2n^2 + a10*π*π^3 +
a11*n^4 |
Generic model | 0 - 120 |
1 - 10 |
Actually, one power approache is 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 defined in
AixLib.Fluid.Movers.Compressors.Utilities.EngineEfficiency.PowerEngineEfficiency.
| Reference | Formula | Refrigerants | Validity ncompressor |
Validity Πpressure |
|---|---|---|---|---|
| MendozaMirandaEtAl2016 | ηeng = a1 * π^b1 * (nref/n)^b2 *
(1/((TInl+TOutIse)/2-TOut))^b3 *
(Mref/M)^b4 |
R134a,R450a,R1324yf,R1234ze(E) | 0 - 50 |
1 - 6 |