Experimental study on the effect of CO2 desublimation on heat transfer

Revealing the influence mechanism of CO2 desublimation on heat transfer is crucial for developing new liquefied natural gas heat exchangers. In this paper, an experimental platform for CO2 desublimation was built to investigate and analyze the intrinsic connection between CO2 desublimation and heat transfer, and systematically elaborated the mechanism of the influence of CO2 desublimation on heat transfer under different operating conditions based on the values of the heat transfer coefficient and CO2 thermal resistance. The results of the study show that CO2 can rapidly start condensation on the cooling surface when the gas flow rate is too fast (60 kg/h), which leads to a weakening and then strengthening of the effect of CO2 condensation on the heat transfer as the gas flow rate increases. In addition, as the cooling temperature drops, the amount of heat exchange between CO2 and the refrigerant decreases, and the magnitude of the changes in the values of the heat exchange coefficient and CO2 thermal resistance increases, with the value of the heat exchange coefficient decreasing by up to 39.9 %. Compared with the gas flow rate, the cooling temperature was the main factor affecting CO2 desublimation, and it has a more significant effect on heat transfer. This experimental study provides a theoretical basis for the design of a new type of liquefied natural gas heat exchanger and provides valuable insights into the mechanism of CO2 desublimation.