add function to find second law efficiency

HP_Model.py

@@ -212,3 +212,23 @@ def getCOP(self, T_source_in: float, T_sink_out: float, Q_dot_H: float, K: int =
 
         return (Q_dot_H / self.getElectricalPower(T_source_in, T_sink_out, Q_dot_H, K))
     
+    # ==================================================================================================== 
+
+    def getEta_II(self, T_source_in: float, T_sink_out: float, Q_dot_H: float, K: int = 3) -> float:
+        """
+        Calculates the interpolated second law efficiency value at the specified coordinate point.
+
+        Args:
+            T_source_in (float): Source temerature (in).
+            T_sink_out (float): Sink temperature (out).
+            Q_dot_H (float): Heating power.
+            K (int, optional): Number of neighbors to consider. Defaults to 3.
+
+        Returns:
+            float: Interpolated second law efficiency value.
+        """
+
+        COP = self.getCOP(T_source_in, T_sink_out, Q_dot_H, K)
+        COP_Carnot = (T_sink_out + 273.15) / (T_sink_out - T_source_in)     # in Kelvin!
+
+        return (COP / COP_Carnot)