Question-and-Answer Resource for the Building Energy Modeling Community
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May I try first :)
Normalised parameters are: 0.5005, -1.2614, 1.7609
I've based them on an assumption that the nominal efficiency has been estimated for FC with no degradation (right part of equation you provided is 1).
Another assumption is that the nominal efficiency is estimated for the nominal power Pnom of 10000 (maximum value of x in the Curve:Quadratic object). This results in enom = 1.283458
We can also define part load ratio PLR as a ratio between Pel and Pnom which gave us following equation
e0 + e1 * Pel + e2 * Pel^2 = enom * (eA + eB * PLR + eC * PLR^2)
e0, e1 and e2 are 0.642388, -1.619E-4, 2.26007E-8 respectively.
Just for ease of creating a table the above equation can be shorten: M = enom * Q where M = e0 + e1 * Pel + e2 * Pel^2 and Q = eA + eB * PLR + eC * PLR^2
Let's add some values to table:
Pel PLR M Q = M / enom
0 0 0.642 0.501
1000 0.1 0.503 0.392
2000 0.2 0.409 0.319
3000 0.3 0.360 0.281
4000 0.4 0.356 0.278
5000 0.5 0.398 0.310
6000 0.6 0.485 0.378
7000 0.7 0.617 0.480
8000 0.8 0.794 0.618
9000 0.9 1.016 0.792
10000 1 1.283 1.000
The last step is to fit the last column to the quadratic function of PLR which ultimately gives values mentioned at the beginning of the answer. Please redo calculations just in case I made some mistake.
Cheers, IK
