MATEC Web Conf.
Volume 324, 20203rd International Conference “Refrigeration and Cryogenic Engineering, Air Conditioning and Life Support Systems” (CRYOGEN 2019)
|Number of page(s)||10|
|Section||Refrigeration Technology and Technics|
|Published online||09 October 2020|
A mathematical modelling of frost growth dynamics on a surface of fin-and-tube air cooler
a Moscow Polytechnic University Moscow, 107023, Russia
b All-Russian Scientific Research Institute of Refrigeration Industry - branch of V.M. Gorbatov Federal Research Center for Food Systems of Russian Academy of Science Moscow, 127422, Russia
A mathematical model was developed to predict the performance characteristics of fin-and-tube air coolers with plane fins, taking into account the temperature and humidity conditions, non-uniform thickness of the frost layer along the heat exchanger core, flow-pressure characteristics of the fans and the refrigerant superheat zone. The model was verified on the experimental data of air cooler performance in frosting conditions obtained by the authors in air temperature range from minus 6 to minus 20 ° C, and experimental data from independent researchers. The presented model predicts the cooling capacity and the overall heat transfer coefficient in the evaporator with error not exceeded 15%. It was found that during dry operating conditions of the air cooler, the refrigerant boiling temperature descent by 10 °C leads to a decrease in the overall heat transfer coefficient by 35%. The main reason of that is double decrease of the refrigerant mass velocity and the refrigerant-side heat transfer coefficient by 75%. The process of frost grow leads to an increase in overall thermal resistance in the studied air cooler by 30%, more than double increase in the aerodynamic resistance and decrease in cooling capacity by 15%.
Key words: Frost / Fin-And-Tube Heat Exchanger / Air Cooler / Evaporator / Cooling Capacity
© The Authors, published by EDP Sciences, 2020
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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