Terracotta (ceramic) cooler

Evaporative cooling of water from the surface of the ceramic material known as terracotta (terracotta). Water absorption terracotta keeps the material constantly moist. This property is used to cool the rooms.

Terracotta is not an ordinary ceramics. Has its own specific properties. In addition to the world-famous chinese terracotta army is a material widely used and is still used for the production of vessels, wall materials, and necessary kitchen utensils.

Items from the terracotta is made from hrubozrného clay. As soon as the artisan will create from clay the final shape of the product, the product is either left to dry in the Sun, so slowly bakes into the final shape. Or the slow way, baked in the oven. The result is a strong and durable material with a specific porous structure.

nádoba z terakoty
Terracotta vessel from the Kurdistan filled with water up to the upper part of the ear. It is observable leak terracotta in contrast with the dry throat of the container.

The material is quite heavy, so it is suitable needs for outdoor planting plants in containers. The center of gravity is low to the ground and reduces the risk of tipping of the container. Terra cotta at the same time, will last for many years of the bad weather and can withstand allegedly -30°C....

For the use of the cooling is the most interesting feature terracotta its porosity (material contains air bubbles). This allows for the gradual penetration of water through the walls of the container. Glazed, or otherwise impregnated with (for example, staining and painting) a vessel of this ability loses.

To this day the products of the terracotta used to be in the Far east for the storage of water. Historically, the use of the ability of the gradual penetration of water through the wall of the container to the passive cooling of the air in the rooms as it is a niche Mašrabíja see. article Mashrabyia – cooling niche .

What is evaporation, evaporation

It's about the process by which a liquid changes to a gas, but only from the surface, in the case of a vessel, therefore, of the levels. Evaporation is accompanied by cooling, because the molecules leaving the liquid to shrink its total internal energy. The temperature of the evaporating liquid is therefore always somewhat lower than the ambient temperature. 

More on the website: Techmania – evaporation, condensation

Sweating container heatsink

And just the terracotta vessel has the ability to leak water the whole surface of the walls. Increased surface area for evaporation of water. The structure of the material has the characteristics of a colander, so does not pass spontaneously a large amount of water and the effect can be likened to the sweating of the container.  

It is commonly filled with the container gives to the drafts and the gradual evaporation from the surface of the container light breeze arrange the distribution of colder the more air around the room. The absence of a draft, we have no choice but to use a fan.

Another idea from the same drawer uses passive terracotta cooler in the role of the aesthetic element of household with a feature wall radiator: Nave

The idea of standing on a hollow terracotta sculpture similar, from our region well known, radiators central heating.

Terracotta in the function of the liquid-absorbing wood material

This group innovation leverages the terra cotta as a soaking material, which is able to retain shape. Terracotta acts like a sponge “sucking” the liquid. Compared to most normal to strongly absorbent materials, such as just washing sponge, the terracotta retains its shape and is not subject to deformations. 

The idea seized in India and created an outdoor cooler with a passive air flow: 

And a small digression: I normal ceramics can skillfully use. A good example is the room of the cooling container in the video:


Find in the CZECH republic suitable product from the terracotta is not as easy as it would seem at first glance. In search of terracotta products on the internet to learn that the word terra cotta today far rather does the shade of brownish-red color. Or a terra cotta to incorrectly emit products of classic, high-temperature fired clay. The traditional representative are clay pots. Maybe it remains to study the manufacturing process of terracotta and try to own the production. Or try the normal ceramics and at least try the cooler from the previous video.

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