Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
The reason for using enthalpy of water is as follows: The energy balance has two different components that cross the thermodynamic boundary of the volume: The incoming and leaving moist air, and the water.
For the moist air, water is assumed to be in vapor form. However, for the water, mWat_flow is the water mass flow rates that is drained from the components (in your case, drained from the dehumidifying coil). This drainage flow is in the form of liquid water. Hence, the leaving enthalpy flow needs to use the enthalpy of liquid water.
