Terracotta Cooling

[GeraldTheBonzai]

https://www.yankodesign.com/2026/07/25/ ... power/amp/

Ok this looks really interesting.

However, don't think it would be efficient in the UK, due to humidity levels.

[GillyBee]

That is a pretty toy. Evaporative cooling does work in the UK but not well enough in my opinion to work as a fridge. We use wet towels round the neck to cool during heatwaves and a wet tea towel or two over the cool box in hot weather to help it last longer while camping.

[GeraldTheBonzai]

As a kid we had a pantry (anyone remember pantries?). It has a terracotta type bread bin that you could put stuff in then put a sort of wet tea cozy thing over it.

Just thought it interesting that "old tech" is now being branded as "new"(ish) tech.

[ForgeCorvus]

Old style dairies were on the north side of the house, vents or windows on opposite walls and had brick floors you could wet down to cool the whole room.

I have a couple of (I think) traditional Greek water pots, they're unglazed and "sweat" when they've water in them, I did a quick experiment a few days back. I filled both pots and a roughly similar sized glass bottle with water then left them outside in the breeze.
The water in the pots was cool (not fridge cold, there are limits ), the bottle was unpleasantly warm.

Air movement is important to make evaporative cooling work as is shade

[Frnc]

Old style dairies were on the north side of the house, vents or windows on opposite walls and had brick floors you could wet down to cool the whole room.

I have a couple of (I think) traditional Greek water pots, they're unglazed and "sweat" when they've water in them, I did a quick experiment a few days back. I filled both pots and a roughly similar sized glass bottle with water then left them outside in the breeze.
The water in the pots was cool (not fridge cold, there are limits ), the bottle was unpleasantly warm.

Air movement is important to make evaporative cooling work as is shade

Yeah you have three things going on.

Shade keeps the sun off, which prevents the worst heat. A dark object in the sun can reach 70°C.

Wind aids evaporative cooling because it removes the humid air immediately above a wet/damp surface. If there was no wind, evaporation would make the air next to the surface too humid to allow much more evaporation. Wind puts new drier air there which can accept more water vapour, so more evaporation happens.

Of course evaporation cools because water requires energy to evaporate.

There is also a secondary effect with wind - convection, but this is usually smaller.

[rik_uk3]

We did the Terracotta pot cooling idea as a little experiment at school back in the 60s, it worked...a bit.