Development and Validation of a Minichannel Evaporator Model under Different Dehumidifying Conditions
Minichannel Evaporator, Numerical Modeling, Heat and Mass Transfer
This paper presents a numerical model (Fin1D-MB) to predict the performance of minichannel evaporators under dehumidifying conditions. The presented model applies a segment-by-segment discretization to the evaporator, adding in each segment a novel bi-dimensional discretization to the fluids flow, fin, and tube wall. The Fin1D-MB model introduces a new approach to model the air-side heat transfer by using a composed function for the fin wall. This function is based on the fundamental one-dimensional fin theory and the technique of movable boundaries between wet and dry portions along the fin height. This modeling scheme allows capturing the heat conduction between tubes and different dehumidifying scenarios for the fin and tube. The proposed model was validated against experimental results for a minichannel evaporator operating with R134a at various test conditions. Generally, the numerical results were in good agreement with the measured data. The predicted inlet refrigerant and outlet air temperatures, refrigerant-side pressure drop, and cooling capacity were within Â±0.5 oC, Â±20%, and Â±5% error bands, respectively.