Heat Transfer (boiler to energy plant)

State functions for water/steam calculations:
IAPWS Industrial Formulation 1997 (IAPWS-IF97)

ENERGY BALANCE OF THE SYSTEM
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DEFINITION OF TOTAL ENERGY

1. Def. 1: Enthalpy minus enthalpy by environmental
   conditions (water as LIQUID) plus HIGHER heating value
   
2. Def. 2: Enthalpy minus enthalpy by environmental
   conditions (water as VAPOUR) plus LOWER heating value