To calculate the amount of energy required to change air from one condition to another, what must be calculated?

To calculate the amount of energy required to change air from one condition to another, one must focus on the enthalpy of the two conditions. Enthalpy is a thermodynamic property that reflects the total energy of a system, encompassing both internal energy and the energy associated with pressure and volume. When air undergoes changes in temperature and humidity, calculating the enthalpy allows for a comprehensive understanding of the energy needed for these transformations.

By examining the enthalpy of the starting and ending conditions, one can determine the net energy required to achieve the desired change. This is critical in various applications, such as in drying processes, where understanding these energy shifts can lead to more efficient operation and effective moisture removal.

In contrast, while the humidity level and temperature difference are important factors in determining how air behaves when it is heated or cooled, they do not provide a complete picture of the energy changes involved. The energy of the environment is also not sufficient for calculating the energy changes specific to the properties of the air itself. Therefore, focusing on the enthalpy gives the most accurate assessment for requiring energy calculations in changing air conditions.