Heat exchangers require a comprehensive understanding beyond just formulas, particularly focusing on the two fluids involved. The primary equation for heat balance in a condenser involves equating the heat added to water with the heat rejected by steam. The formula is expressed as Qadded = Qrej, where Qadded equals the mass flow rate of water multiplied by its specific heat and temperature difference, and Qrej involves the mass flow rate of steam and its enthalpy. This approach emphasizes the importance of heat balance for effective thermal calculations in heat exchangers. Understanding these principles is crucial for accurate thermal analysis.