Subminiature cool pad applying sorption cooling effect

Abstract

This paper describes the conceptual development and idea verification of a subminiature portable cooler that does not necessitate any precooling nor any external energy supply during the process of cooling. The basic principle of the cooling mechanism is the vaporization of water and subsequent cooling due to the evaporative latent heat loss. In this work,, the vaporization of the water was stimulated by a desiccant material to improve the cooling effect. By using a pre-activated desiccant, considerable cooling effect can be obtained until the desiccant becomes saturated with the absorbed moisture. The evaporative cooling caused by the desiccant was modeled and analyzed with consideration given to the sorption characteristics of the desiccant. In addition, the portable cooler was fabricated in a shape of a thin pad, and its cooling characteristics were tested and compared with the analytic results. The results show that the cool pad can reduce its temperature at the cold side from its initial temperature, 30 degrees C(86 degrees F) down to 17 degrees C(62.6 degrees F) within ten minutes without any energy supply and keep the low temperature for about an hour.