A simplified explicit model for determining the performance of a chilled water cooling coil

• An explicit model was developed for the chilled water cooling coil.
• Averaged heat transfer coefficients based on known boundary conditions were employed.
• A constant sensible-to-latent load ratio was adopted for a wet coil.
• An explicit equation was derived to predict the dry portion of a partially-wet coil.
• The errors in the simulated coil total capacities were below 2.2%.

A simplified explicit model for the chilled water cooling coil was presented which could determine the performance of even a partially-wet coil without any need for iterative calculations. A quadratic correlation was derived for evaluating the dry portion of a partially-wet coil from the inlet chilled water temperature based on performance data generated from a validated numerical model for a sample coil over a range of operating conditions. By applying the present explicit model to simulate the performance of the sample coil, it was found that the errors in the calculated coil total capacities did not exceed 2.2% when compared with those based on the numerical model. The percentage errors in the simulated coil latent capacities varied widely from 100% for a just-slightly-wet coil down to 0.26% for a fully-wet coil. Nevertheless, the present model was considered an efficient and yet accurate approach for determining the performance of a chilled water cooling coil.