Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
ASHRAE 90.1's IP version is definitely NOT applicable for use with E+. All E+ curves must use SI units (and the coefficients will differ for IP and SI).
I'm not sure whether the PNNL Reference Guide has any "Authority" to define Baseline curves - and thus can be considered authoritative "suggestions". In part that's because most certification bodies are not using 90.1-2016 and in part because the "Reference Manual" is not actually part of any code - it's a supporting document. (I was not aware of the PNNL document previously - thanks for making it known to me.)
The PNNL document has curve coefficients for both EIR f(T) and EIR f(PLR) on p.261, so there are three curves in total shown in that document. For each of the curves, all coefficients act in concert to produce a characteristic performance. For a Quadratic curve, that is also true, so you can change any of them, but should do so with an eye toward the overall impact.
One aspect of these curves is that they need to produce a "normalized" result of exactly 1.0 at the AHRI design conditions. I normally calculate the result at AHRI conditions, then adjust it proportionally to achieve 1.0.
