World map of potential areas for the use of water cooling pitchers (botijos)

Abstract

A 1:80,000-scale world map of the suitable areas for botijos (a Spanish word for traditional pitchers used for cooling water by evaporation) is presented in this paper. The map has been obtained combining four variables that define the convenience of these sweating jugs, namely: dew point depression, temperature, access to drinking water and presence of local ceramic raw materials. The resulting world map shows the great potential interest of this chilling technique in every continent, especially in Africa, Asia and Australia.

Bio-inspired evaporation from shaped interfaces: an experimental study

“…Overall, results suggest that: (1) protrusion shape matters for evaporative performance, for the simple reason that curved, triangular and rectangular profiles have different length-to-width proportions; (2) there is more into evaporative design than just extending protrusions beyond the boundary layer of nearby surfaces (e.g. the wetting base, in our case).…”

“…In such stage, aspects of macrogeometry which modulate boundary layer development are more important than material structure. According to (2), the boundary layer of the cellulose sponges should be overall thicker than that adjacent to the protrusions of the paper strips, because of the wider evaporating surfaces of the sponge models (extrusion length larger than the paper protrusions w avg ). Thus, it is hypothesized that the boundary layer of the relatively large wetting base of the paper strips was an important factor for the shorter planar protrusions underperforming the sponge models.…”

“…Ancient technology would exploit the cooling effect of this phenomenon for food preservation and beverage refrigeration, in Persian ice houses and artisanal pottery (e.g. earthware jugs, pot coolers) [1,2]. Modern utilization of evaporation is broad scale, for processes as diverse as thermal management, drying, mixing and separation of chemical substances.…”

Refrigerated flowers in the torrid Mediterranean summer

“…Strong cooling effects arising from intense water evaporation in dry-hot climates have been long used by human cultures from the Mediterranean Basin, Middle East, and Africa as a chilling technique, in the form of sweating pitchers made of porous clay, which typically achieve temperature drops of 5-20 C relative to the ambient temperature ("botijos" in Spanish; Chemin et al, 2018;Martínez de Azagra & Del Río, 2015;Zubizarreta & Pinto, 1995). I propose that the large thermal deficit found inside C. corymbosa flowerheads at high ambient temperatures was achieved through a "botijo effect."…”

“…The high ambient temperature and low relative humidity faced by C. corymbosa presumably augmented the cooling efficacy of transpiration during the hottest part of the day, leading to the large thermal deficits observed. Strong cooling effects arising from intense water evaporation in dry–hot climates have been long used by human cultures from the Mediterranean Basin, Middle East, and Africa as a chilling technique, in the form of sweating pitchers made of porous clay, which typically achieve temperature drops of 5–20°C relative to the ambient temperature (“ botijos ” in Spanish; Chemin et al, 2018; Martínez de Azagra & Del Río, 2015; Zubizarreta & Pinto, 1995). I propose that the large thermal deficit found inside C. corymbosa flowerheads at high ambient temperatures was achieved through a “botijo effect.” As suggested by one reviewer (Richard Karban), support for this hypothesized mechanism might be found by comparing the cooling ability of plants differing in their access to water, for example, through experimental manipulation of water availability by differential watering.…”