Thermal-Fluid Characteristics of an Automotive Radiator Used as the External Heat Exchanger in an Auto Air Conditioning System

The thermal-fluid characteristics of an automotive radiator, used as the external heat exchanger in an auto air conditioning system, are experimentally analyzed and discussed in this article. The radiator in this study is a compact heat exchanger with parallel rectangular minichannels and louvered thin-plate fins. A 50% glycol-water mixture flows through the minichannels with staggered surface enhancements on the walls. On the other side, air flows through the radiator openings with the louvered thin-plate fins sandwiched between the minichannels. Single-phase heat transfer and pressure drop correlations for glycol-water flow within the minichannels and for air flow through the louvered fins are obtained and presented. The Wilson plot technique is applied to find the heat transfer coefficients on both the glycol-water and air sides. The frictional pressure drop for the glycol-water flow within the minichannels is also obtained using the Fanning equation. The uncertainty estimates for both measured and calculated parameters are then presented, and finally the results are plotted, discussed and compared with the relevant previous studies. These results show that the heat transfer rate is increased in the glycol-water side due to the surface enhancements in comparison with smooth rectangular channels. The heat transfer is enhanced on the air side as well, as compared with the flat smooth surfaces, due to the use of louvered fins.