CFD MODELING OF A COMPARTMENTED COOLING COIL FOR DEMAND VENTILATION TO ACHIEVE ENHANCED INDOOR AIR QUALITY

摘要

Compartmented cooling coil is a key component of a newly developed air-conditioning and air distribution system at the National University of Singapore 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 (IAQ) and achieve significant energy savings. It has been observed that the unique features of the compartmented cooling coil are fundamental to improving the heat and mass transfer performance of the coil. Whilst empirical measurements have been undertaken to evaluate the performance of such a coil, flow visualization employing CFD modeling techniques are also envisaged to provide a better insight into the fundamental characteristics of a compartmented coil which addresses both indoor air quality and energy issues according to zone-specific demand of ventilation and cooling loads. A highly refined cooling coil model is developed with distinct compartments which has finer meshing at the key surfaces. Boundary conditions obtained from experiments will include bulk air stream conditions upstream of both the compartments of the coil. Three different models (k-ε model, RNG model,Reynolds stress model) are used to compare the simulation results. This paper presents the development of the CFD model of the compartmented coil and an evaluation of the heat transfer characteristics.