Decoupled Modeling of Chilled Water Cooling Coils Using a Finite Element Method

Chilled water cooling coils are important components in air handling unit systems. Generally the cooling coil removes both moisture and sensible heat from entering air. Since the sensible and latent heat transfer modes are coupled and the saturation humidity ratio vs. temperature curve on the psychrometric chart is non-linear, it is very difficult to solve cooling coil heat transfer differential equations across the entire coil. However, the sensible and latent heat transfer modes can be decoupled using a constant sensible heat ratio (SHR) and the saturation humidity ratio vs. temperature curve can be treated as linear in a small area corresponding to a finite element of the coil. This paper presents the decoupled cooling coil model using the finite element method with an application to the simulation of a particular cooling coil case.