How Did Ancient Persians Use Ice Pools to Produce Ice in the Desert?

[askingask]

So basically I've seen that in Persia as well as in other areas, people have been using ice pools and other means to produce ice in the desert.
Specifically ice pools used the fact that deserts have low humidity, as this would mean higher evaporative cooling efficiency as well as radiative cooling efficiency. At day time a wall would ensure that the pool is kept under a shadow for the majority of the day. At night the water filled pool would radiate the heat into space bringing temperatures of the water bellow zero degrees C.

Would it be possible to reproduce these effects in a city with temperatures of let's say 20 degrees Celsius? What about 10⁰C? Especially considering the fact that humidity is relatively average to an European country.

Could the efficiency be increased by insulating the "pool" like let's say an insulated tray can?

 

[DaveC426913]

How much research have you done?

Donning my Googles for a moment indicates that the effect is highly dependent on the frigid temperatures of desert nights, brought on by the highly-transparent sky, which is, in turn, due to extremely dry desert air.
Are these conditions you can expect to replicate in a city, and with temperatures as high as 20C?

 

[askingask]

How much research have you done?

Donning my Googles for a moment indicates that the effect is highly dependent on the frigid temperatures of desert nights, brought on by the highly-transparent sky, which is, in turn, due to extremely dry desert air.
Are these conditions you can expect to replicate in a city, and with temperatures as high as 20C?

Is that a rhetorical question . I guess it's definitely harder.

 

[sophiecentaur]

Would it be possible to reproduce these effects in a city with temperatures of let's say 20 degrees Celsius? What about 10⁰C?

Not 10C but a bit lower - say 4C - can often produce frost on car roofs and windscreens. In that example, the source of water is condensation which involves a lot more energy in addition to the freezing so a scale model on a night with very low humidity I see no reason why a very shallow water-filled tray wouldn't work.

Cities are often less cold than the surrounding countryside and picking a suitable site would be worth while. A very basic wireless weather station could be modified for data recording and you could stay inside in the warm, to emerge for observations when the conditions are right.

 

[Swamp Thing]

This may interest you, it is probably the state of the art for the advanced DIYer. It is more about room cooling, but might work for ice production if the ambient is low enough.

 

[askingask]

This may interest you, it is probably the state of the art for the advanced DIYer. It is more about room cooling, but might work for ice production if the ambient is low enough.

Man I love this guy. He also made a video about using dessicant based air conditioner to cool a house, which I really recommend.
I'll definitely look into it thank you.

 

[sophiecentaur]

Man I love this guy.

Me too. I'm bingeing on Breaking Bad at the moment and the two guys have something of that (getting things just right) - without the moral problems, of course. It could have been edited imo. And I would have been wearing a mask.

 

[russ_watters]

So, he got 3C below ambient. Not much.

 

[sophiecentaur]

So, he got 3C below ambient. Not much.

True but he claims it could be better in the day when AC , rather than ice-making would be useful.

 

[russ_watters]

True but he claims it could be better in the day when AC , rather than ice-making would be useful.

That seems unlikely. In the day you are radiating against a brighter sky and often clouds.

 

[sophiecentaur]

Where's a Maxwell's demon when you want one?