Evaluation of Fin Efficiency Concept in Cooling and Dehumidifying Coils – A Monte Carlo Simulation Approach

Accurate prediction of the performance ofcooling coils is fundamental to the design of efficient ventilation and air-conditioning systems. The actual heat transfer that takes place can be considered as the performance evaluating criteria for any system and this can be expressed in terms of fin efficiency. Fin efficiency is a function of ambient conditions and fin geometry parameters. Obtaining the required fin efficiency in practice would mean that the desired heat transfer is achieved. The formulation of the concept was done by Gardner in 1945 with 10 underlying assumptions. However, it was found that the violation of these assumptions caused significant deviations from the real time results obtained. The limitation of the formulation in applying to wet fins resulted in further work by McQuiston in 1975. Wet fin efficiency was found to be 35% lower than the dry fin efficiency under high RH conditions. These formulations were based on a particular geometry and with limited empirical results. However, no comprehensive attempt was made to study the impact of such violations on both these formulations across the entire range of input variables. This paper presents Monte Carlo simulation as a tool to obtain the resulting deviations due to the violation of the underlying assumptions traditionally considered in the computation of fin efficiency based on methods proposed by Gardner and Mcquiston.