Analytical study of evaporator coil in humid environment

In this paper, a distributed simulation model for predicting steady-state p erformance of a direct-expansion air-cooling coil is developed. This model uses a numerical method to calculate the partially wet and totally wet fin efficiency and takes into account the refrigerant pressure drop along the c oil. The model simulation of a test coil is validated with experimental dat a collected under different air conditions using R134a as a refrigerant. On the basis of this model, a number of parameters which reflect the characte ristics of evaporator coils are analyzed in diverse humid environments and it is found that the performance of the coil is significantly affected by a ir relative humidity. Comparison of coil performance with R134a and R12 as refrigerants, whose difference in properties is small, shows that the diffe rences in coil design for a specified cooling load and in the heat exchange characteristics for a given coil cannot be ignored. (C) 1999 Elsevier Scie nce Ltd. All rights reserved.