Link posted to indicate that authoritative(?) thermal engineers were noting the importance of the coolant's exit temperatures.
Think, I still prefer a device to be characterized by (C/W)inlets or (C/W)wo-ai at given flow-rates(Q)
Where
C= dTwi -ai or C= dTwo-ai (Not LMTD or part LMTD)
W is the change in SENSIBLE Heat of the coolant= Bill's "Heat Dissipated" = My
"Ww" = dT(wi-wo)*Cw*Q
Think "Sensible Heat"of coolant maybe prefereable to Energy of coolant.