Numerical Algorithm Studies of CFD Modeling for a Compartmented Cooling Coil Under Dehumidifying Conditions

Abstract

The compartmented cooling coil is the core component of the newly developed air conditioning and air distributing system called the Single Coil Twin Fan (SCTF) system. In prototype experiments, the SCTF system has clearly demonstrated its ability to provide enhanced indoor air quality and achieve significant energy savings (12%). However, the geometric parameters of the compartmented coil were chosen based on approximate estimates and intuitive reasoning, which makes parametric optimization studies necessary. Computational fluid dynamics (CFD) simulation is more feasible than experimental methods because of its flexibility and economic considerations, especially for the compartmented coil. A newly developed numerical algorithm for simulating latent heat transfer is coupled to the coil model, which is created on the platform of commercial software FLUENT. A simple two-dimensional case which has an analytical solution is utilized to validate the accuracy of the new algorithm. The accuracy of the three-dimensional model based on the prototype of the compartmented coil is validated by experimental data and can be utilized for further parametric optimization studies. This simulation model based on the new algorithm, which was developed particularly for the compartmented coil, can be generalized and paves the way for the development of numerical tools for compact heat exchangers operating under dehumidifying conditions.

The financial support of the National University of Singapore through a research grant, R-296-000-076-112, is gratefully acknowledged. Acknowledgment is due to engineer Sreenivas Viyyuri, the technical support representative of FLUENT India Company, for his aid in writing the UDF used in this study. Recognition also goes to G. Comini and S. Savino of the Department of Energy and Machines, University of Udine, Italy, for their introduction of the new algorithm.