1997 年 63 巻 614 号 p. 3390-3395
Snow has been already used effectively as the coolant for refrigerator in some heavy snowfall area in Japan. As the surface of snow is covered with cold melting water, we can expect the gas absorption on the surface. By this mechanism, the snow is able to remove some contaminants from air such as dust or harmful gases. As in the snow cooling system, air is cooled directly by the surface of vertical snow hole drilled through snow pile, some contaminants are removed automatically and simultaneously with heat transfer process. The heat and mass transfer process are very complicated because the surface area of snow decreases and the shape of snow changes in accordance with its melting process. In this study, the authors measured the absorbability of ammonia gas as the example of contaminant of room air with a pilot plant of the snow cooling system. Experimental results show that the mass transfer rate of ammonia through the melting snow surface is depndent on air flow rate and ammonia concentration, but is not dependent on the volume of snow remaining. And it is cleared that this filter effect of the snow surface can be applied to actual use of contamination control of air conditioning.