Are there some non-linear data relationship in input and output of Object in EnergyPlus?

Question

I'm simulating an air conditioner system by using EnergyPlus. Are there the non-linear data relationship in input and output of Object in EnergyPlus? And Why? I cannot find the mathematical model of the Object (e.g. AirloopHVAC:UnitarySystem) in EnergyPlus. So is this model nonlinear? In addition, are there some other factors which can result in the nonlinear relationship of data during simulation?

I want to know if there is a nonlinear relationship between the data during the simulation process.