Short Stuff: Yakhchāls - Ancient Fridges | STUFF YOU SHOULD KNOW

[Music]. hey and welcome to the short stuff I'm. Josh and there's Chuck Jerry sitting in. free Dave and so this is short stuff the. how do you say this again Edition yeah. I'm going to say it's pronoun it's. spelled y a k h you know as most words. are uh c h a a l I'm going to say. yakal I'm going with the straight ahead. Yak CHS all right okay.

so you say it your way throughout I'll. say it my way and I'm sure I'll. inevitably unconsciously start saying it. your way well we'll see uh but what. we're talking about is the the promise. from our Refrigeration episode a little. bit more on these ancient um basically. ancient refrigerators or cooling systems. uh they were found across ancient uh. Persia at least as old as uh 400 BC um. this is modern day Iran and this is. these are places where uh believe it or. not the climate enables freezing of Ice.

uh when you would not think you should. be able to freeze ice yeah it's pretty. amazing and apparently still today in uh. Iran Afghanistan and. Tajikistan um tajikstan yeah I said it. right the first time they call the. refrigerators Yak CHS which is how I. would say it if I were in Iran but. that's the name for their fridge which. means that at some point someone in Iran. has gone into a store and said you got a. smag Yak Chow yeah exactly uh and these.

have been the the fascination of like um. everyone from Engineers to historians to. physicists over the years because. they're just so. um kind of confusing and how they. actually work uh and I'm still not. entirely sure how it works it seems to. be a little magic involved um one thing. I know uh goes a long way toward keeping. this ice uh and we got to say some of. this ice is is mine from the mountain.

and brought down and preserved some is. made on site we'll get to that but one. big factor is the insulation of the. structure itself which is made from uh a. mortar called uh. surge is that how you're saying it yeah. sand clay egg whites lime goat hair and. Ash M quite a mixture some of these were. several meters thick some of these Yak. chws were um but there was a study we. got some of this information from the. engineering for Max forom and they did.

an analysis from 2018 of yaks and just. how um effective they might have been. and they found that the walls of a yak. cha um had the same insulative. properties as a wall that of concrete 3. in thick surrounded by a 1ot thick. wrapping of Styrofoam insulation that's. how effective these things were sand. clay egg whites lime and goat hair and. Ash I was going to say like the secret.

is egg whites but who knows I know you. throw goat hair in there and yeah who. knows what the secret I think the secret. is the whole thing together the whole. sej um mixture yeah probably so um so I. mentioned that sometimes the ice was. brought in from the mountains and kept. there throughout the year but uh usually. what would happen is is they would make. ice they would bring in water they would. divert water from an aqueduct um through. these Underground water channels called.

uh canat and they would Channel them to. the north side of this wall uh it's. another thing we haven't mentioned yet. is they have these very very high walls. that act as shade for these channels um. to keep uh you know the wind off of it. uh because stuff isn't going to freeze. as fast if it's moving so to keep the. water still and to keep it cooler away. from that. sun yeah and this so the channel has a. little diversion into to a trench or a.

pit or like a very shallow like. rectangular Pond usually and um it. they'll divert water in there to fill it. up and then they let it freeze overnight. um over the course of a few nights it'll. continue to freeze and freeze and freeze. in layers um and the the what they're. taking advantage of you know like when. it snows and then the temperatures heat. up and all the snow melts but there's a. little pile of snow like in a shaded. corner of your yard that never gets. Direct direct sunlight and it just takes.

forever to melt they taking advantage of. the same thing they're building that big. old um that big old wall to keep it. shaded and just let this ice um grow and. grow and grow and then once it reaches I. think 50 cm which is like about a half a. meter um thick then they'll cut it into. blocks and they put it in the yak Chell. and they store it through summer like. this stuff will stay frozen for an. entire summer so in that sense these Yak.

CHS are built to store cold throughout. the course of a year even when the. summer comes around still cold yeah uh. another way that helps us out is that. Dome shape it's not domed because they. like domes even though domes are nice uh. it's conical because that optimizes. What's called the solar chimney effect. is uh that's when you create a. convection current letting that heat go. up up up and out uh through these. openings at the top and bringing in that. cool air from the bottom they also have.

um wind catchers that they call. beers um and they actually take wind and. direct it downward into the yaka Dome um. and so the the air that hits it is. cooled by that ice and the air that's. not cooled by it or cooled enough like. you said that chimney effect takes it up. along the curved sides toward the hole. in the top and it says see you later. don't come back that's right uh and that. feels like a good time for a break and. we'll come back and talk about what the. heck they're doing with all this ice. right after.

[Music]. this all right so they're making ice. they're preserving ice what are they.

doing with all this ice um one of the. things they're doing is using it as a. refrigerator um you know they'll store. food in there that they don't want to to. go bad and just using it as a as a cold. house um they will also just use the ice. to eat uh and a treat uh they have. something called uh Fuda over there it's. a Persian uh traditional dessert has. thin vermicelli noodles uh made from. cornstarch and then you mix that up with. a little semi Frozen and syrup of sugar.

and Rose Water and then serve it up with. a little lime juice and maybe some. ground pistachios and it's like a little. Persian icy that has to be better than. it sounds don't you think oh I think it. sounds great I think the pistachios are. what are throwing me off oh yeah you. don't like pistachios or I do like. pistachios it just they don't seem to go. with the rest of the ingredients but. like I said I'm sure it's delicious I. mean it's a traditional Persian dessert. it's got staying power so yeah who am I.

to question Fuda exactly I bet it's. delicious one of the cool things about. this is that yak Charles I mean and. there's some still around uh I think. there's one in uh Kerman Iran that's. about the size of a five-story building. so you would think of course obviously. this was reserved for royalty you would. be dead wrong because not only were Yak. chells open and available to the public. there are some that people just built. for their houses that were a use as well.

yeah for sure uh they would make those. um delicious Fuda they would make. sherbets and preserve. them fruit and ice and they would put. them on a donkey and go sell them at. market and stuff like that uh they would. sell ice directly from uh those places. sometimes um and you know one of the. things they're also taking advantage of. is the greenhouse effect um you know the. Earth is going to stay um fairly warm at. night because of the greenhouse effect. trapping those gases in the atmosphere.

but if it's low humidity and if it's a. really clear night that effect is going. to be weaker and that heat can uh. dissipate and disappear more readily and. so that's when they discovered like hey. we can make these little thin layers of. ice and kind of build you know day by. day night by night on these clear low. humidity nights eventually to get you. know some pretty significant ice MH and. once they figure that out someone said. go get the donkey yeah exactly it's time. to sell some some sherbet and harvest.

some goat hair one other thing I saw in. that Max forom uh analysis they figured. out that they could make about what. would be equivalent to three million ice. cubes a season wow yeah which is a lot. but they were like you'd think it be. more and I was like it seems pretty good. to me especially if in 400 BC you know. yeah depends on how big those cubes were. were they big uh fancy cocktail cubes. that's a lot more ice than a a ice. nugget that's right you're absolutely. right um I expect that they're probably.

all donkey head size so 3 million donkey. head size ice cubes that's big think. about the poor donkey that had to cart. those around I know no fun uh you got. anything else yeah I mean these went. away obviously because of uh modern. refrigeration came on the scene and also. uh one thing that was happening was they. were making this ice kind of out in the. open and a lot of it would get. contaminated with dust and it wasn't. like the healthiest ice in the world and. so that combined with um modern.

refrigeration coming along they're like. maybe we should just not have these Much. Anymore U but like you mentioned there. is one still around at least in uh kman. and there are groups there that are. trying to preserve this way of life and. at least keep it um you know not like a. chief refrigerating method but like hey. we can't lose uh our our culture and so. let's work to take some of these old. ones and restore them at least even if. only for like Museum and touring. purposes for sure but also there's a lot. to learn from them especially um when.

we're trying to advance like passive. Cooling and other things that require. less energy to cool things down Yak. challs or something to turn to and say. how do we do this and someone says go. get the goat here yeah that's right with. get some egg whites too no one likes. those right what do we do with all these. yolks yeah uh well I think uh that's it. for short stuff right Chuck I think so. well that means short stuff is that.

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