3719 -- Comparison of Methods of Modeling the Air-Side Heat and Mass Transfer in Chilled-Water Cooling Coils PDF

Three different methods of modelling the heat and mass transfer in chilled-water cooling coils are compared. A new model (model 3) is compared with discretised versions of the models presented in ARI Standard 410-87 (model 1) and by McQuiston (model 2) and with the ARI log-mean enthalpy method. The models differ both in the method used to determine the heat-transfer rate to the primary surface and in the method used to determine the fin efficiency. It was determined that heat-transfer rates predicted by model 1 agreed within 1% to 2% of the new model, while model 2 predicted heat-transfer rates 2% to 8% higher than did model 3. However, by modifying the assumptions used in model 2, it was possible to bring its predictions to within 2% of those of model 3. The ARI log-mean enthalpy method was also found to agree well (within 2%) with model 3.

KEYWORDS: calculating, heat flow, fluid flow, cooler batteries, air conditioning, finned tube heat exchangers, heat transfer coefficient, models, comparing.