大容积卧式玻璃门风冷冷柜凝露分析

Study on Moisture Condensation in Large Volume Frost-free Chest Freezers

为了改善风冷冷柜玻璃门外表面的凝露状况,本文在某一卧式玻璃门风冷冷柜样机实测凝露数据的基础上建立了数值仿真模型,用来研究玻璃门外表面的凝露规律,并分析了三种改善凝露措施的效果。仿真结果表明,增加玻璃厚度或者采用中空玻璃可以有效改善玻璃外表面凝露情况,当采用4 mm+4 mm氩气+4 mm中空玻璃时,玻璃外表面高于露点温度的面积比为99.4%,基本没有凝露析出。增加防凝露电热丝有一定效果,但由于电热丝与冷柜玻璃门无法完全匹配,在环境相对湿度较高时效果有限。改变出风角度可以从根本上改善玻璃表面内温度,效果最突出;当出风角度倾斜45°向下时,玻璃外表面凝露区域最少,高于露点温度的面积比为97.6%。

Moisture condensation is a common issue in chest freezers with glass doors. To reduce the impact of condensation,a numerical model was established in this study to investigate the condensation characteristics on the glass doors, based on the experimental observation in a 750 L frost-free chest freezer prototype. The effect of three countermeasures were numerically compared. The first method is to use multi-layer glass doors with air gap and low-emissivity coating, which can effectively reduce the condensation phenomenon. When using the double layer glass with 4 mm thickness of glass and 4 mm thickness of void gap charged with argon, the non-condensation area can reach 99.4%. Adding anti-sweat heating tape can inhibit condensation, but the effect is limited at high ambient humidity conditions, because the anti-sweat heater cannot fit very well with the geometries of the glass door in the studied large volume freezer. By optimizing the discharge angle on the supply air duct, the surface temperature of the glass door can be fundamentally improved, thus leading to the best improvement in terms of reducing the condensation. When the discharge angle is 45° towards the bottom, the non-condensation area can reach 97.6%.