LAUSR

Abstract Cooling drinking water using earthenware pitchers, botijo in Spanish, is an ancient method used satisfactorily in hot climate regions. The evaporation process through the ceramic wall of earthenware pitchers with different shapes and filled up with water is studied in this work when the surrounding ambient conditions remain steady. Thanks to the evaporation process, the water initially cools and later, once the minimum temperature is reached, it hots until either the ambient temperature is reached or the whole water evaporates. By using different analytical functions to model the botijo’s shape and modeling mathematically the evaporation process by means of two ordinary differential equations, we have studied the behaviour of the different shapes. We have found that earthenware pitchers with small aspect ratios, large and isolated from ambient support bases, e.g. rested on a surface instead of hanged on something, are recommended to get better cooling. We also show that this can even be enhanced if their classical bulky belly is located as close to the bottom as possible.