Experiment and exergy analysis on performance of plate-fin heat exchanger with transient frosting process

In engineering applications, the plate-fin heat exchanger is selected in a preferential manner owing to its high heat transfer coefficient and compactness. When the temperature of plate-fin heat exchanger is lower than the triple point temperature, frosting process might appear on the cold surface of the heat exchanger channel. The accumulation of frost mass in the flow channel leads to higher thermal and flow resistance in the heat exchanger. To retard or alleviates the adverse effect of frost, the transient frosting process inside the flow channel of plate-fin heat exchanger are researched experimentally in this paper. The influencing extent of environmental factors on the transient frosting process of the heat exchanger are investigated. The operating conditions and influencing factors of experiments are designed by orthogonal tables. The influencing factors are evaluated by analysis of variance (ANOVA) and range analysis. The experimental and analytical results showed that the maximum frosting rate is mainly affected by the flow rate and humidity content of humidified warm nitrogen. With higher flow rate and humidity content of humidified warm nitrogen, both flow resistance and heat transfer resistance rise with frosting process. Larger frost mass enlarges the pressure difference between inlet and outlet of humidified warm nitrogen. Furthermore, exergy efficiency of plate-fin heat exchanger deteriorates significantly with the accumulation of frost mass.