Most of the current air-to-refrigerant heat exchanger models use the classic ε-NTU approach. These models do not account for longitudinal conduction neither in the fin nor in the tube, transverse conduction in the tube, and for the heat conduction between different tubes, which is a consequence of the employed adiabatic fin tip assumption. This paper presents a more detailed numerical approach to heat exchanger modeling with the goal to capture heat conduction effects within the heat exchanger structure and detailed representation of air properties. The new model uses a segment-by-segment approach and applies a 2-D discretization for each segment. The paper includes a presentation of the numerical scheme, validation, and a parametric study which tests the impact of the traditional heat exchanger model assumptions. The study revealed large errors in capacity prediction of individual tubes due to the adiabatic fin tip assumption, when the neighboring tubes are of different temperature.
Proceedings Title: 13th International Refrigeration and Air Conditioning Conference at Purdue
Conference Dates: July 12-15, 2010
Conference Location: West Lafayette , IN
Pub Type: Conferences
heat exchanger, modeling, simulation, microchannel fins