Experimental investigation on anti-condensation characteristic of desiccant coated metal cabinet

Condensation occurring on metal cabinet surface seriously affects the maintenance and operation safety. In order to prevent condensation, desiccant coating surface method is proposed and investigated in this paper. Basic operation model of desiccant coated cabinet to realize anti-condensation and regeneration is first introduced, then an experimental setup is established to investigate and compare both anti-condensation and regeneration capacities of zinc sheet samples with and without desiccant coating. Widely adopted silica gel is adopted as desiccant material in this study. Results show that silica gel coated sample can effectively extend the anti-condensation time 2 to 6 times longer. When surface temperature is between 35 °C and 50 °C under experimental conditions, the coated desiccant material can be regenerated and recycled. The corresponding longest regeneration time is 160 min. The dynamic adsorption capacity of coated silica gel is also analyzed and it is found that both adsorption rate and mass of silica gel increases under lower surface temperature, and improvement index gradually becomes less obvious with decreasing surface temperature, the corresponding saturated adsorption mass of silica gel before condensation is about 0.3 g/g. Finally a practical case study of desiccant coated cabinet is conducted at Shanghai and operation testing shows that occurrence probability of condensation for desiccant coated cabinet greatly decreases from 70% to 10% compared with conventional cabinet in plum rain season, and there is no condensation occurring within desiccant coated cabinet in early autumn. The performance of silica gel coated cabinet is tested under relatively extreme condition with simulated high humid environment (30 °C, 90%) lasting for 7-10 h, it is found that the cabinet could continuously operate for about 60 h without condensation. In conclusion, desiccant coating method is proven to be an effective way to prevent condensation.