BaseClasses.Carnot has wrong definition and use of evaluate_etaPL

[mwetter]

The value of evaluate_etaPL is incorrect, but it is also used incorrectly, leading to the correct results. The following change should be made

   Real etaPL(final unit = "1")=
     if evaluate_etaPL
-      then 1
-    else IBPSA.Utilities.Math.Functions.polynomial(a=a, x=yPL)
+      then IBPSA.Utilities.Math.Functions.polynomial(a=a, x=yPL)
+    else 1
     "Efficiency due to part load (etaPL(yPL=1)=1)";
 
   Real COP(min=0, final unit="1") = etaCarnot_nominal_internal * COPCar * etaPL
@@ -157,8 +157,8 @@ protected
 
   // For Carnot_y, computing etaPL = f(yPL) introduces a nonlinear equation.
   // The parameter below avoids this if a = {1}.
-  final parameter Boolean evaluate_etaPL=
-    (size(a, 1) == 1 and abs(a[1] - 1)  < Modelica.Constants.eps)
+  final parameter Boolean evaluate_etaPL=not (
+    (size(a, 1) == 1 and abs(a[1] - 1)  < Modelica.Constants.eps))
     "Flag, true if etaPL should be computed as it depends on yPL"
     annotation(Evaluate=true);