there is confusion about the exergy_balance function

[legendary-zju]

Dear Francesco:
I have some confusion about your code. There is no information of the property (self.E_P and self.E_F in the exergy_balance function) in comp class. Could you teach me their meaning? In the heat exchanger class, the condition of calculating exergy is divided into 6 cases. The logic of calculating self.E_P and self.E_F under one condition seems to be distinctly different from under another condition. Could you tell me their calculating logic? I would appreciate it.

Best

Zhang

[legendary-zju]

The code that confused me:
if all([c.T.val_SI > T0 for c in self.inl + self.outl]):
self.E_P = self.outl[1].Ex_therm - self.inl[1].Ex_therm # cold side
self.E_F = self.inl[0].Ex_physical - self.outl[0].Ex_physical + (
self.inl[1].Ex_mech - self.outl[1].Ex_mech)
elif all([c.T.val_SI <= T0 for c in self.inl + self.outl]):
self.E_P = self.outl[0].Ex_therm - self.inl[0].Ex_therm # hot side
self.E_F = self.inl[1].Ex_physical - self.outl[1].Ex_physical + (
self.inl[0].Ex_mech - self.outl[0].Ex_mech)
elif (self.inl[0].T.val_SI > T0 and self.outl[1].T.val_SI > T0 and
self.outl[0].T.val_SI <= T0 and self.inl[1].T.val_SI <= T0):
self.E_P = self.outl[0].Ex_therm + self.outl[1].Ex_therm
self.E_F = self.inl[0].Ex_physical + self.inl[1].Ex_physical - (
self.outl[0].Ex_mech + self.outl[1].Ex_mech)
elif (self.inl[0].T.val_SI > T0 and self.inl[1].T.val_SI <= T0 and
self.outl[0].T.val_SI <= T0 and self.outl[1].T.val_SI <= T0):
self.E_P = self.outl[0].Ex_therm
self.E_F = self.inl[0].Ex_physical + self.inl[1].Ex_physical - (
self.outl[1].Ex_physical + self.outl[0].Ex_mech)
elif (self.inl[0].T.val_SI > T0 and self.outl[0].T.val_SI > T0 and
self.inl[1].T.val_SI <= T0 and self.outl[1].T.val_SI <= T0):
self.E_P = np.nan
self.E_F = self.inl[0].Ex_physical - self.outl[0].Ex_physical + (
self.inl[1].Ex_physical - self.outl[1].Ex_physical)
else: # only self.inl[1].T.val_SI <= T0
self.E_P = self.outl[1].Ex_therm
self.E_F = self.inl[0].Ex_physical - self.outl[0].Ex_physical + (
self.inl[1].Ex_physical - self.outl[1].Ex_mech)

[fwitte]

Hi @legendary-zju,

the fuel exergy, product exergy and exergy destruction per component depend on the purpose of the component and on the context, i.e. the ambient state and the fluid's state (specifically temperature). I would direct you to read the paper on the implementation of the feature in tespy and the references on exergy (mostly (co-)authored by Tsatsaronis) cited in it: https://www.mdpi.com/1996-1073/15/11/4087.

Best