Influencing factors of thermal performance of small-size vaccine cold storage: An experiment-based parametric study

Abstract

The temperature gradient and thermal performance of a 20-m2 small-size vaccine cold storage warehouse for a working temperature range of 2–8 °C are studied in four central cities of northern, central and southern Jiangsu Province in China. The effects of cold storage geometry, cooler layout, air curtain and vaccine load on the thermal performance of vaccine cold storage are experimentally studied. Based on the findings in experiments, evaluation metrics are proposed for vaccine cold storage with loads. The results showed that for small vaccine cold storage, the arrangement of two air coolers with appropriate cooling capacity aligned along the length direction produces a more uniform air distribution inside the cold storage. With a reduced length to width ratio of cold storage, the temperature inhomogeneity coefficient decreased. Meanwhile, an air curtain outlet wider than the door can better maintain the cold storage temperature when the door is open. Results of three extended evaluation metrics were obtained for a case with 80% load, i.e. the average temperature deviation ratio Nη = 1.38, the ratio of temperature inhomogeneity coefficient Nσ = 1.15, and the temperature range ratio NR = 1.16, showing the deviation of temperature field of the loaded vaccine cold storage from the unloaded one.