Detailed Chilled Water Cooling and Dehumidifying Coil
By S. Gabel
Revised for TRNSYS by N. Blair and R. Schwarz
This model was adapted strictly for use with the TRNSYS Program by
the Solar Energy Laboratory.
The algorithm describes the operation a chilled water cooling coil for
the purpose of cooling and dehumidifying the airstream. The algorithm accounts
for the heat and mass transfer associated with moisture condensation on the
finned air-side surface of the coil in accordance with ASHRAE methods. It
determines whether the finned surface is completely dry, completely wet, or
partially wet and partially dry. The extended surface can be comprised of
either individual circular fins or continuous plate fins. The algorithms used
to determine coil performance under dry, wet, or part wet conditions are
described in detail in subsequent sections for DRYCOIL, WETCOIL, and DRYWETCOIL.
Each algorithm assumes waterflow in a counterflow crossflow heat exchanger
configuration and models the coil using equations for a counterflow heat
exchanger. The model is appropriate for coils with four or more rows. The
heat transfer characteristics of the coil, such as fin efficiencies and
convection heat transfer coefficient, are determined from detailed information
about the coil geometry. The algorithm calculates thermal resistances between
the liquid and air streams from detailed geometric characteristics of the heat
exchanger. Sample input and output are included in the source code.
REF: A Toolkit for Secondary HVAC System Energy Calculations May 25, 1992
Joint Center for Energy Management University of Colorado at Boulder