Overall efficiency of a radial fin assembly under dehumidifying conditions

The aim of this paper is the analysis of heat transfer in a radial fin asse mbly during the process of dehumidification An individual finned tube geome try is a reasonable representation of heat exchangers used in air condition ing. The condensation process involves both heat and mass transfer and the cooling takes place by the removal of sensible as well as latent heat. The ratio of sensible to total heat is an important quantity that defines the h eat transfer process during a dehumidifier operation. A one-dimensional mod el for heat transfer in the fin and the heat exchanger block is developed t o study the effects of condensation on the fin surface. The combined heat a nd mass transfer process is modeled by incorporating the ratio of sensible to total heat in the formulation. The augmentation of heat transfer due to fin was established by comparing the heat transfer rate with and without fi ns under the same operating conditions. Calculations were carried out to st udy the effects of relative humidity and dry? bulb temperature of the incom ing air, and cold fluid temperature inside the coil on the performance of t he heat exchanger. An analysis of the overall efficiency for the assembly w as also done. Results were compared to those under dry conditions, wherever appropriate. Comparison between present results and those published for re ctangular as well as radial fins under fully wet conditions were made. Thes e comparisons established the validity of the present model. Ir was found t hat the heat transfer rate increased with increment in both dry bulb temper ature and relative humidity of the air. The augmentation factor, however, d ecreased with increment in relative humidity and the dry bulb temperature. The fin efficiency decreased with relative humidity.