.AixLib.Fluid.Movers.Compressors.UsersGuide.Approaches.MechanicEfficiency .AixLib.Fluid.Movers.Compressors.UsersGuide.Approaches.MechanicEfficiency
Generally, 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
|