Speaker 1: Welcome to Invention, a production of I Heart Radio. Hey,
Speaker 1: welcome to Invention. My name is Robert Lamp and I'm
Speaker 1: Joe Mccormickin Today, we're gonna be beginning and exploration of
Speaker 1: the invention of air conditioning. This is going to be
Speaker 1: a multi part series. And for the purpose of this conversation,
Speaker 1: we're not going to be talking about all cooling, refrigeration,
Speaker 1: all making stuff colder technology that has ever existed. We're
Speaker 1: going to be focusing on the invention of systems primarily
Speaker 1: for cooling and removing humidity from interior spaces, primarily, but
Speaker 1: not exclusively, for the comfort of humans and other animals.
Speaker 1: Right that. Now that being said, we are going to
Speaker 1: mention some some some various cooling technologies and air circulation
Speaker 1: technologies on the path to modern air conditioning exactly. So,
Speaker 1: I will say that I can speak from pre recent
Speaker 1: personal experience, actual actually multiple experiences, to say that if
Speaker 1: you are lucky enough who have air conditioning in your home,
Speaker 1: in your workplace, and the places that you dwell, especially
Speaker 1: in the hottest months of the year, especially if you
Speaker 1: live somewhere hot like in the American South or anywhere
Speaker 1: near the equator, I guess, or Atlanta or Hotlanta, as
Speaker 1: they know that they do not call it. If you
Speaker 1: are one of these lucky people who has this technology,
Speaker 1: you should not take this blessing for granted. You should
Speaker 1: remember every sweltering day to be thankful for this luxury.
Speaker 1: I once lived in an upper floor apartment in an
Speaker 1: old house in North Carolina, as though there was an
Speaker 1: apartment below me, and I went the better part of
Speaker 1: a blistering summer there with no air conditioning. And you know,
Speaker 1: I don't want to over dramatize my my own struggles,
Speaker 1: but I just remember, like my brain didn't work. I
Speaker 1: remember standing at the refrigerator with the freezer door open
Speaker 1: and my head stuck in it, which don't do that, folks.
Speaker 1: I mean, that's not energy efficient, but you know, it
Speaker 1: just short circuited all my rationality to be in this
Speaker 1: hundred degree apartment. I remember I would lie on top
Speaker 1: of my bed and try to sleep at night, just
Speaker 1: making like a human sweat angel, like a you know,
Speaker 1: a human shaped sweat imprint on the top blanket. It
Speaker 1: was disgusting and and more recently actually just last year,
Speaker 1: our home air conditioning and it completely broke down. In
Speaker 1: the middle of summer, and it was several weeks before
Speaker 1: we get the problem fixed. And again, maybe I'm just
Speaker 1: a whimp, but I found that in a house that's
Speaker 1: like ninety degrees plus are close to a hundred degrees
Speaker 1: with high humidity, my brain just broke. I remember sitting
Speaker 1: at a desk trying to do work with like a
Speaker 1: wet towel around my neck and a box fan propped
Speaker 1: up pointing at my head, and it just it never
Speaker 1: felt like enough. The hot, swampy summers down here can
Speaker 1: be brutal, and it really makes you appreciate again how
Speaker 1: lucky you are if you have access to this modern convenience,
Speaker 1: especially in Hotlanta or swamp Planta. We can call it that,
Speaker 1: I guess, but I got to give a shout out
Speaker 1: to my A C guy, Mike, who Robert here referred
Speaker 1: me to. Yes, my Mike is great. Effects fixed mine
Speaker 1: up as well. And indeed, air conditioning is one of
Speaker 1: those things when when it's working properly, you you hardly
Speaker 1: notice it at all and you just take it for granted.
Speaker 1: When something goes wrong, that's when you start sweating, and
Speaker 1: in all possible ways. Uh, sweating at night getting the
Speaker 1: proper terrifying night sweats on. And you know, one of
Speaker 1: the things is, is I get older, I do find
Speaker 1: that I enjoy the heat. Like I I love to
Speaker 1: read and write on my front porch, and I'll generally
Speaker 1: like push that as far as humanly possible in either direction.
Speaker 1: Like when it's colder, I'll bundle up as much as possible,
Speaker 1: but I can't quite bundle my fingers. And then at
Speaker 1: that point I'm driven inside and I have to come
Speaker 1: out when you know the warmer person portion of the day,
Speaker 1: and then what is it gets hotter and hotter. Uh,
Speaker 1: you know, I'll do whatever I need to do to
Speaker 1: try and keep the mosquitoes away, you know, burning like um,
Speaker 1: you know, ritual citronella candles, and wearing more clothing than
Speaker 1: it's perhaps temperature appropriate, just to keep them from biting
Speaker 1: that sort of feasting of my blood, that sort of thing.
Speaker 1: But but but you know, I don't mind sweating out there.
Speaker 1: I can also, you know, bring out a fan if
Speaker 1: I need to to keep the air moving. And of course,
Speaker 1: as is common with with a lot of you know,
Speaker 1: front porch scenarios, if you have a porch swing or
Speaker 1: a hammock on hand, like, that's ideal because you're able
Speaker 1: to keep the air circulating by keeping yourself in more
Speaker 1: or less continuous motion. Um. But then eventually you reach
Speaker 1: the point or I reached the point where I I
Speaker 1: have to come inside because it will just get too hot.
Speaker 1: And I enjoy having the choice, the privilege of being
Speaker 1: able to come inside and enjoy the you know, the
Speaker 1: cooler air. And you know, it's not only a privilege
Speaker 1: of our modern age, it is a privilege in our
Speaker 1: modern age. Yeah, there are millions of people around the
Speaker 1: world in hot climates these days without air conditioning, and
Speaker 1: air conditioning does not come without costs, that's right. I
Speaker 1: should also say that on my front porch, having uh,
Speaker 1: you know, a readily refillable supply of ice water is
Speaker 1: a must. And of course that's that the history of
Speaker 1: refrigeration is is right up there with the history of
Speaker 1: keeping spaces cool. Uh. So you know, both of these
Speaker 1: are technologies that we take completely for granted. So many
Speaker 1: of us that are listening to this podcast you have
Speaker 1: not only um uh you know, cool air inside your home,
Speaker 1: but you have a miraculous machine that can turn liquid
Speaker 1: water into ice, perhaps automatically, and even if not automatically,
Speaker 1: like still very passively, you're not having to actually crank
Speaker 1: it out. All right. Well, before we start talking about
Speaker 1: air conditioning systems or pre air conditioning systems for enclosed spaces,
Speaker 1: we always like to ask the question what came before?
Speaker 1: I guess the deepest you can go on what came
Speaker 1: before for air conditioning technology is biological cooling systems and
Speaker 1: thermoregulation in the body, right, and for us that means
Speaker 1: sweat and and this is going to be key to
Speaker 1: the methodology of all these various air conditioning and temperature
Speaker 1: control UH technologies that we're going to discuss in these episodes. So,
Speaker 1: your body produces sweat and UH with the in sweat
Speaker 1: evaporates from the skin to cool the body. That's essential
Speaker 1: is the evaporation, right. It's kind of how in fact
Speaker 1: it works for anybody of water. Right. You can take
Speaker 1: a just a bucket full of water, and the evaporation
Speaker 1: off the surface of that water will cool the water
Speaker 1: in the rest of the bucket because that evaporation is
Speaker 1: an energy hungry phase transfer, and it as to suck
Speaker 1: energy out of the heat from the rest of the water. Yeah, basically,
Speaker 1: liquid water evaporates into vapor using the thermal energy in
Speaker 1: the air, resulting in a lower air temperature. The water
Speaker 1: in sweat absorbs your body's heat energy and then evaporates,
Speaker 1: lowering your temperature in the process. That is evaporateate of cooling. Yeah,
Speaker 1: evaporate of cooling is one of the really cool things
Speaker 1: about chemistry when you really think about it. Here's the
Speaker 1: questions kind of similar. Um, how come when you boil
Speaker 1: a pot of water on the stove and it reaches
Speaker 1: the boiling point, the entire pot of water doesn't transform
Speaker 1: into steam all at once? Do you even think about that? Yeah?
Speaker 1: I was wondering about this one time, one one contemplates
Speaker 1: while watching the pot of water boil. Right, one of
Speaker 1: the most entertaining of activities. But yeah, it can. It
Speaker 1: can raise some interesting questions in your mind. And I
Speaker 1: think the way this works is that as water boils,
Speaker 1: some of that liquid water is turning into steam. That's
Speaker 1: a phase transition. It's the same thing that's happening on
Speaker 1: your skin. Liquid water in your skin is turning into water,
Speaker 1: vapor into steam and coming off of your skin. But
Speaker 1: as that happens in the pot, as that water is
Speaker 1: turned into steam. The pot of water loses energy in
Speaker 1: that process because it's a massively energy hungry process to
Speaker 1: turn water into steam. And so as the water is
Speaker 1: turning into steam, the water is constantly cooling back down
Speaker 1: and you have to keep putting more energy into the
Speaker 1: bottom of it to keep it boiling. And because it's
Speaker 1: largely a good thing, because I'm thinking about scenarios in
Speaker 1: which in which like large portions of water um are
Speaker 1: turned to steam instantly, and you're generally talking about an
Speaker 1: explosive situation. You're talking about an expansion of steam that
Speaker 1: can you can have, you know, catastrophic effects. You wouldn't
Speaker 1: want the pot of water you're boiling for spaghetti to
Speaker 1: suddenly become steam all at once, No, I mean you
Speaker 1: need massive energy inputs for that kind of thing to happen,
Speaker 1: just because it takes so much energy to turn water
Speaker 1: into steam. And again that's a good thing for your body.
Speaker 1: Taking that energy from the body cools the body off. Now,
Speaker 1: when we turn to technological solutions for cooling a space,
Speaker 1: there were actually tons of brilliant inventions or little innovations
Speaker 1: and tweaks in the design of homes and buildings, UH
Speaker 1: for this purpose before the invention of modern like electrical
Speaker 1: air conditioning using heat pumps or refrigeration or anything like that. Yes,
Speaker 1: the accumulation of all these little tweaks, all these little
Speaker 1: advantages that all add up to make hot temperature environments
Speaker 1: more bearable. It reminds me of like, you know, the
Speaker 1: the argument that you you you win a battle of
Speaker 1: all the small, little advantages to your side, you know,
Speaker 1: and it's very much that the case with you know,
Speaker 1: waging war against a hot climate. Let's talk about some
Speaker 1: of these little innovations throughout history. The first is I
Speaker 1: would say the absolute most dirt simple probably doesn't even
Speaker 1: need to be mentioned, but won't mention it anyway. How
Speaker 1: about a roof that's having having a top level covering
Speaker 1: provides shade and that blocks the radiation heating from the sun.
Speaker 1: So that's one of the most important innovations in designing
Speaker 1: a cooler space. Yeah, in the same way you would
Speaker 1: take you might take comfort beneath the tree or you know,
Speaker 1: by the side of a cliff, some naturally occurring shade. Uh,
Speaker 1: we are able to construct our own shade as well.
Speaker 1: But of course, by having a house that has a
Speaker 1: roof on top if all else fails for keeping the
Speaker 1: house cool at night, one option you would sometimes have
Speaker 1: in the ancient world as you could go out and
Speaker 1: you could sleep up on your roof. This seems to
Speaker 1: have been common, for example, in ancient Egypt, where a
Speaker 1: significant amount of living and sleeping happened on people's rooftops.
Speaker 1: That's right. In in past episodes of No I honestly
Speaker 1: can't remember it was this show or stuff to blow
Speaker 1: your mind, we talked about some of the ancient cities.
Speaker 1: I think this was in our toilets episodes. We're talking
Speaker 1: about the archaeological remains of cities in which you know
Speaker 1: there were entrances on all the roofs um. But also
Speaker 1: we can look to ancient accounts, say Herodotus writing of
Speaker 1: the hanging gardens of Babylon, or in Jewish lore, King
Speaker 1: David glimpsing Bathsheba bathing uh while resting on the roof
Speaker 1: of the palace. Yeah, I guess the idea is probably
Speaker 1: that it was like nice and cool out in the
Speaker 1: open air on the roof and where also you're going
Speaker 1: to be. But there are tons of other little ways
Speaker 1: that once you go beyond just having a structure with
Speaker 1: a roof to block the sun. And you start building
Speaker 1: houses with openings and windows and different hallways and rooms,
Speaker 1: there is uh, there's all this investment in the architecture
Speaker 1: of a house to help aid in cooling. And this
Speaker 1: would include the positioning of windows or other openings, the
Speaker 1: shape of rooms and floors that allow ventilation of the
Speaker 1: inside and encourage cross breeze is to pass through. Also,
Speaker 1: something that I feel like is is less uh is
Speaker 1: thought about less in modern home design is the positioning
Speaker 1: of windows away from direct sun or in the shade.
Speaker 1: I think because houses are designed with the idea of
Speaker 1: air conditioning in the mind often these days that there's
Speaker 1: less planning put into Okay, where where are the windows,
Speaker 1: What kind of light are they going to get? Is
Speaker 1: there a tree to shade the window? And so forth. Yeah,
Speaker 1: we'll definitely come back to this in the future. But
Speaker 1: we we we see this, uh, this this trend where
Speaker 1: all these tiny advantages were discussing in the With the
Speaker 1: advent of modern air conditioning, so many of them were
Speaker 1: just abandoned because they weren't seen as useful anymore as
Speaker 1: necessary to keep a cool uh you know, habitat, and
Speaker 1: part of the problem then, is when the air conditioning
Speaker 1: goes away, or when the electricity goes away, whatever is
Speaker 1: disrupting things, you have to fall back on a habitat
Speaker 1: or building that is not built with any of these
Speaker 1: advantages in place, or even if you're not talking about
Speaker 1: using your air conditioning, if you're just considering energy efficiency.
Speaker 1: I mean, I think that there are some houses that
Speaker 1: are designed without proper thought about energy efficiency for heating
Speaker 1: and cooling in the house, even if you have modern
Speaker 1: heating and cooling devices. Yeah. I mean when you're when
Speaker 1: you're a kid and you're around air can I remember
Speaker 1: just loving it. I was like, I just love the
Speaker 1: smell of the air conditioning and just wanted on all
Speaker 1: the time. You know, when you're adult and you're actually
Speaker 1: paying the bills, you don't necessarily want the air conditioning
Speaker 1: all the time. It would be nice if it went
Speaker 1: off a few times during the month of August. Uh So, yeah,
Speaker 1: you know, it would be nice to have so many
Speaker 1: of these other little, um, you know, design advantages in
Speaker 1: place as well to just reduce you the necessity of
Speaker 1: running the a C. Here's another design advantage that predates
Speaker 1: modern air conditioning. How about construction that takes advantage of
Speaker 1: the fact that warm air rises, also known as the
Speaker 1: chimney effect. So one example of this might be high ceilings.
Speaker 1: Another is top side ventilation including passive roof vents or
Speaker 1: more recently, an attic fan, and so that this can
Speaker 1: be paired with windows to create this ideal airflow situation
Speaker 1: where cool air flows in through open windows on the
Speaker 1: lower floors and then is drawn up through the house
Speaker 1: in a sort of air column that goes up towards
Speaker 1: the attic and towards the roof, creating pressure that pushes
Speaker 1: the warm rising air out through vents in the upper
Speaker 1: floors or in the ceiling of roof. Yeah, well, I
Speaker 1: have one of these attic fans in my house, and
Speaker 1: it's it's it's like being a spaceship, you know, because
Speaker 1: you can just especially if you have only like one
Speaker 1: window open, you can just create this terrific flow of
Speaker 1: air through the house, which can make a huge difference
Speaker 1: of you know, you get kind of like it's gotten
Speaker 1: a little warm, it's got a little hot inside the house,
Speaker 1: and you have a like a nice comfortable temperature drop
Speaker 1: outside of the house. You can easily equalize things like
Speaker 1: that a couple of other things would just be what
Speaker 1: do you make the house out of, Is it insulated
Speaker 1: in the proper way, something that's not going to heat
Speaker 1: up and pass heat from the outside to the inside.
Speaker 1: And then another thing would be the outside color ration
Speaker 1: of the house that can affect how it absorbs heat.
Speaker 1: Do you live in a like a black obelisk or
Speaker 1: do you live in uh, you know, some sort of
Speaker 1: a white reflective uh domicile, And it's gonna make a
Speaker 1: huge difference. And back to your point about a heat
Speaker 1: rising uh you know this also you see this in
Speaker 1: designs of you know, older houses with high ceilings. Obviously
Speaker 1: it's not the heat is going to rise out of
Speaker 1: the area in which you were living. But also you
Speaker 1: look at a lot of modern houses and the reliance
Speaker 1: on a c and where do you see the master bedroom.
Speaker 1: You see it on an upper floor, right like it
Speaker 1: becomes more of a selling point of you're you know, saying, okay,
Speaker 1: it actually has a master on the main floor. And
Speaker 1: a lot of that has to do with, you know,
Speaker 1: individuals get older. It's nicer to not have to go
Speaker 1: up a flight of stairs in order to get to
Speaker 1: your bedroom. But but also you have to to realize
Speaker 1: it's going to take more to keep that cool up
Speaker 1: there like it's it's it's ultimately from a temperature standpoint,
Speaker 1: perhaps it's better to have the master bedroom on the
Speaker 1: main floor. Yeah. Absolutely. The one thing I think we
Speaker 1: shouldn't forget is how common I mean we mentioned people
Speaker 1: sleep being on the roofs. You shouldn't forget that in
Speaker 1: hot climates, it used to be extremely common for people
Speaker 1: to sleep outside. Oh yes, I was reading about this,
Speaker 1: and in times before air conditioning, and in places where
Speaker 1: there's no air conditioning. Now it's just very common for
Speaker 1: people to sleep on porches in front of their home,
Speaker 1: or on the deck behind their home, or in or
Speaker 1: just up on the roof for somewhere out in the yard.
Speaker 1: I mean, this remains a way to stay cool at night.
Speaker 1: So we've talked to you about a number of examples
Speaker 1: of passive cooling design, uh, you know, far different from
Speaker 1: the active cooling system that you may have in your
Speaker 1: home or your apartment window. But we also have to
Speaker 1: just consider that many of humanities, the oldest civilizations, they
Speaker 1: resided in some pretty sweltering places. And while perhaps you know,
Speaker 1: such people's were less coddled by temperature control technology. Uh,
Speaker 1: you know, they still had to do what they could
Speaker 1: to keep things chill. So I ran across a very
Speaker 1: insightful article. This was This was an in g conservation
Speaker 1: and management in two thousand and eight and it was
Speaker 1: a paper by um Hatamapur and A. Betty and it
Speaker 1: considers it concerns the town of the city of Bosher
Speaker 1: in southern Iran. This is a region where today you
Speaker 1: see more than of total annual power consumption going to
Speaker 1: power a c window units. But people have been living
Speaker 1: in this region for at least five thousand years. And
Speaker 1: in this paper the authors point out the various strategies
Speaker 1: that were utilized to keep things cool. Some of these
Speaker 1: we've already discussed, but but just to you know, tie
Speaker 1: them to a specific location in a very long habited
Speaker 1: habitat region of the Earth. They pointed out that the
Speaker 1: buildings were constructed closely together but with spaces for circulation
Speaker 1: around each and they were built in the direction of
Speaker 1: seasonal fresh and cold winds. The lanes were narrow for
Speaker 1: the generation of circulation, and they employed ventilation shafts, balconies, terraces.
Speaker 1: The separation of heat generating spaces such as kitchens. Uh,
Speaker 1: that's another key one, you know, I think about because
Speaker 1: I think a number of us have probably noted, especially
Speaker 1: during the summer, just how hot it gets in the
Speaker 1: kitchen when you're just doing something like cooking, you know,
Speaker 1: frozen pizza. You could keep things a lot cooler if
Speaker 1: you made sure that your your kitchen was somewhere else,
Speaker 1: was located in an adjacent building. I mean, I think
Speaker 1: it's one of the appeals of grilling in the summer,
Speaker 1: like it's nice to be out in the in the
Speaker 1: nice weather while you're cooking, but also the thing that
Speaker 1: gets hot is not inside your house. Yeah, I think
Speaker 1: it's a great point. Um Also balconies, coverings for direct sunshine,
Speaker 1: windows and walls, trees planted for shading, colored glasses in
Speaker 1: the windows, and wooden screens outside the windows, high roofed buildings,
Speaker 1: light roof colors, and low conductivity materials like gypsum for
Speaker 1: shell walls. So so yeah, I found that, you know,
Speaker 1: again insightful considering that you know, this is a region
Speaker 1: that uh, people have been living in for at least
Speaker 1: five five thousand years, and throughout that five thousand history,
Speaker 1: most of it has been without the aid of a
Speaker 1: modern a C unit, but instead of having modern electrical
Speaker 1: air conditioning, they had this sort of army of other
Speaker 1: little ingenious design solutions to help keep things cool. Yeah,
Speaker 1: every little advantage. And later in the episode we're going
Speaker 1: to talk about one really ingenious system that you see
Speaker 1: especially in ancient Persia. This this city was in ancient Persia.
Speaker 1: But maybe we should take a break now and then
Speaker 1: when we come back we can talk about ancient Egyptians
Speaker 1: and ancient Romans. All right, we're back. So the ancient
Speaker 1: Egyptians were known to have employed a simple but really
Speaker 1: kind of ingenious system for for cooling their interior habitats,
Speaker 1: and that was they utilized wet mats of reeds that
Speaker 1: they hung in windows. Water evaporated from the wet mats,
Speaker 1: reducing air temperature in the process, and then a breeze
Speaker 1: is blowing through the window and uh and moving through
Speaker 1: these mats, lowering the indoor temperature. This is the same
Speaker 1: principle that we see later in stuff like the swamp cooler,
Speaker 1: right that uses like evaporation in a window in order
Speaker 1: to do this, And that there are places where this
Speaker 1: is still a pretty common way of cooling your house.
Speaker 1: Actually just like hanging a wet towel and a window,
Speaker 1: maybe in conjunction with a fan. Yeah. I've also read
Speaker 1: that it has been common if you're if you have
Speaker 1: laundry that you're drying, you hang them in the window,
Speaker 1: and then you're killing two birds with one stone. Yeah.
Speaker 1: Of course the ancient Romans got in on the act
Speaker 1: in large part thanks to you know, the aqueducts. Uh.
Speaker 1: They had many advances in plumbing, which we've covered on
Speaker 1: the show before and regards more to sewers, but it
Speaker 1: also meant the Romans had the ability to channel water
Speaker 1: through indoor pipes in certain homes, cooling them in the process. Yeah,
Speaker 1: it seems like they had a few strategies that were
Speaker 1: based on water and evaporation of water. Uh. This next thing,
Speaker 1: it's hard to confirm that this story is true, but
Speaker 1: it's reported it in ancient sources, including the Latin text
Speaker 1: known as the Historia Augusta or the Augustine History, that
Speaker 1: the third century Roman emperor Ella Gabalus had snow carried
Speaker 1: down from the mountains to his palace so that it
Speaker 1: could be piled up in a in a mountain of
Speaker 1: snow in his orchard to help keep it cool in
Speaker 1: the summer. Now, I do have to say that that
Speaker 1: this sounds like just an ethically Roman emperor thing to do.
Speaker 1: But but I do want to point out that in
Speaker 1: the seventy grade Inventions of the Ancient World, Brian and
Speaker 1: Fagin points out that in az Tech markets you would
Speaker 1: have found mountain ice brought down from the mountains and
Speaker 1: it would have just been available to purchase, at least
Speaker 1: if you were Aztec nobility. Uh, you could purchase it.
Speaker 1: But you know, that's got another like non Roman example
Speaker 1: of of ice as a regional commodity. Oh yeah, and
Speaker 1: this does appear to be in smaller quantities, something that
Speaker 1: did definitely go on in the Roman world. Now, as
Speaker 1: for having the snow brought down from the mountain to
Speaker 1: make a mountain of snow in his garden, you know,
Speaker 1: as with many allegations about the decadent behaviors of particular
Speaker 1: Roman emperors, I think sometimes it's hard to know if
Speaker 1: you're reading something that's based in fact, or if it's
Speaker 1: just libel against an unpopular figure or a historical adversary
Speaker 1: of the author. I think there are a lot of
Speaker 1: Roman histories that are full of allegations like this that
Speaker 1: may or may not be true, right, and it also
Speaker 1: had it has an air of the unsensible to it,
Speaker 1: you know, like they're going to be extremely diminishing returns
Speaker 1: from trying to produce a pile of snow, uh you know,
Speaker 1: in your palace or wherever. Whereas having a small amount
Speaker 1: of ice, a small amount of snow, uh you know,
Speaker 1: certainly what whatever would be able to survive the journey
Speaker 1: could be utilized in an intelligent manner. Potentially. Well, it
Speaker 1: does appear to be totally true that in smaller quantities,
Speaker 1: ice and snow transported down from the mountains were stored
Speaker 1: in special cold cellars and sold as a luxury item
Speaker 1: or just used as a luxury item in ancient Rome,
Speaker 1: though most of the other references I was reading two
Speaker 1: imported snow seemed to be about people eating it, not
Speaker 1: making a mountain out of it in their pleasure garden.
Speaker 1: So some wealthy ancient Romans, including the Emperor Nero, are
Speaker 1: said to have eaten snow, sometimes allegedly sweetened with honey
Speaker 1: or with fruit juice or other flavors, of making snow cones. Yeah.
Speaker 1: This this has turned up in preliminary research for a
Speaker 1: potential episode on ice cream. Oh, we gotta do ice cream,
Speaker 1: So yeah, we'll come back to that. But I've also
Speaker 1: seen references to snow being a luxury ittem for Romans
Speaker 1: just to be melted down and drunk like water because
Speaker 1: they believed it was very pure and cold or used
Speaker 1: to chill wine. So yeah, if you you know, you
Speaker 1: were rich and you could shell out for some fresh
Speaker 1: snow from somebody's seller that they had imported down from
Speaker 1: the mountaintop, you know, go for it. Well, yeah, it
Speaker 1: would have been exotic, it would have So much of
Speaker 1: our appreciation of various beverages has to do with the
Speaker 1: story of it, right, And it's like a it's like
Speaker 1: a fine bottle of wine. It's the lore of the
Speaker 1: wine to a large extent that you're drinking and tasting
Speaker 1: and contemplating. And if you're adding that with the you know,
Speaker 1: the properties of watching the snow melt in the in
Speaker 1: the glass, certainly in this era or in a later era,
Speaker 1: potentially having like a piece of an iceberg, you know,
Speaker 1: in your beverage. You know that kind of thing. It
Speaker 1: has bizzas. You can't blame them for being into the idea.
Speaker 1: I think I was reading somewhere that the philosopher Seneca
Speaker 1: wrote with disdain about youths when they're snow eating, as
Speaker 1: if he was talking about always on their iPhones, always
Speaker 1: eating snow. Either way, carrying snow down a mountain I think,
Speaker 1: and dumping it in a pile in your house is
Speaker 1: not a super efficient way to stay cool overall, considering
Speaker 1: all the work needed to hauld the snow down. But
Speaker 1: I was wondering, well, would making a big pile of
Speaker 1: snow actually be effective at cooling your palace. I think
Speaker 1: the answer is potentially yes. Having a large, massive snow
Speaker 1: or ice in a room can actually cool the room
Speaker 1: as the snow melts and then eventually evaporates those phase
Speaker 1: transitions like we were talking about before, or will suck
Speaker 1: energy out of the surrounding air, which will cool the
Speaker 1: air in the process. I'm not sure this would do
Speaker 1: much good just sitting there in an open air orchard.
Speaker 1: But if you were to pair snow or ice with
Speaker 1: moving air, especially so maybe you've have people constantly flapping
Speaker 1: big fans at the pile of snow, especially in an
Speaker 1: indoor space, I think you could actually get significant cooling effects.
Speaker 1: Even if if you don't have air conditioning in your house,
Speaker 1: you can probably somewhat cool room several degrees by like
Speaker 1: setting up a fan and putting a bottle of frozen
Speaker 1: water in front of it. This sounds kind of crude,
Speaker 1: but it actually does work to to circulate colder air,
Speaker 1: and in fact, there are even many large facilities these days,
Speaker 1: such as large office buildings, that have in recent years
Speaker 1: replace their traditional electric air conditioning systems with ice based
Speaker 1: cooling systems. I mean on on. On the surface, it
Speaker 1: can seem completely backwards, right, like you're stepping back into
Speaker 1: a more primal, sort of pre a c means of
Speaker 1: cooling your place. But this is actually, in some cases
Speaker 1: a more energy efficient and more cost effective way to
Speaker 1: cool a large building. So how on earth would this
Speaker 1: work well? The ice based cooling system takes advantage of
Speaker 1: a principle known as load shifting, because energy cost from
Speaker 1: an electrical grid isn't just about the amount of energy
Speaker 1: you use, it's about when you use it. So during
Speaker 1: the daytime on a hot summer, there are these periods
Speaker 1: of peak demand on power grids when too many people
Speaker 1: are all trying to draw lots of electricity at the
Speaker 1: same time to power their energy hungry building cooling needs,
Speaker 1: and it's going to result in what like rolling brownouts,
Speaker 1: right or yeah, I mean it's in any case, it's
Speaker 1: like it's putting more demand on the system, and so
Speaker 1: at these times of day there's more energy and efficiency
Speaker 1: and higher costs instead. Now, many large buildings use this
Speaker 1: ice cooling method, which switches it's the building's maximum energy
Speaker 1: consumption for cooling purposes to night time off hours, and
Speaker 1: the buildings what they do is they have giant water
Speaker 1: tanks that can hold thousands of gallons of water, and
Speaker 1: at night, when electricity demands are low, when power is
Speaker 1: the cheapest, they use that power to freeze the water
Speaker 1: into ice. Then in the daytime they use that ice
Speaker 1: that they made in the night time to chill air
Speaker 1: that is blown throughout the building's ventilation system. The ice
Speaker 1: melts gradually throughout the day turns into water. Then the
Speaker 1: melted water is frozen again the next night when power
Speaker 1: is cheap again. That is impressive. Yeah, I would, I
Speaker 1: would love to. I mean, of course, one of the
Speaker 1: issues isn't you know we made very well then in
Speaker 1: buildings they use this and just was not aware. Yeah,
Speaker 1: we might not know, uh, And and it works because
Speaker 1: what water is actually an extremely powerful thermal energy storage medium.
Speaker 1: You can think of these giant tanks full of ice
Speaker 1: as kind of like a thermal battery which can be
Speaker 1: charged whenever energy and puts their cheapest and you charge
Speaker 1: it by freezing it. But of course these ice based
Speaker 1: methods need to be paired with like fans to circulate
Speaker 1: the chilled air. So we should mention general fan based
Speaker 1: cooling effects, which also go way back into history. Yeah.
Speaker 1: I mean the simplest version of a fan, of course,
Speaker 1: as if you have any kind of like suitable fan
Speaker 1: shaped object that you can just flutter with your hand,
Speaker 1: big leaf or something. Yeah. And and I think that
Speaker 1: that's one of those things where it's at some point
Speaker 1: to humans figure that out just basic tool use. Some
Speaker 1: of the more one of the more elaborate, but still
Speaker 1: simple and elegant in its simplicity. Uh. One of the
Speaker 1: devices that certainly comes to mind is the punka fans
Speaker 1: used in India uh from about five b C onward
Speaker 1: it seems. And these are large sales that are hung
Speaker 1: from the ceiling and they're flapped manually to circulate air. Um.
Speaker 1: I imagine most of you have seen like some version
Speaker 1: of this, if not like an image of one used
Speaker 1: in India or in a depiction of say British occupied India,
Speaker 1: then then you also see them in other historical settings
Speaker 1: as well, you know, particularly hanging above like a din
Speaker 1: or table is of a prime example of what you
Speaker 1: might see one. Yeah, fans can be a fantastically useful
Speaker 1: and very energy efficient way to make a room feel cooler.
Speaker 1: I mean, there's a reason you see fans all throughout
Speaker 1: the world and all throughout history. But the interesting thing
Speaker 1: about fans is I sometimes even forget this myself. Fans
Speaker 1: And let's well, so, if a fan is moving air
Speaker 1: in or out of a room, it can change the
Speaker 1: temperature in a room, right, if you're exchanging with an
Speaker 1: outside system. If you have like a fan, uh, you know,
Speaker 1: positioned in a window. Yeah, and the and the temperature
Speaker 1: in the outside is different from the inside, that can
Speaker 1: actually change the temperature in the room. But fans inside
Speaker 1: a closed room do not change the temperature of the room.
Speaker 1: They don't actually cool the room. In fact, and in
Speaker 1: most cases they probably slightly increase the temperature in the
Speaker 1: room because you're running an electrical device from the room,
Speaker 1: and that's heating up somewhat, and so it's probably emitting
Speaker 1: some heat, so it's moving the air around, but it's
Speaker 1: not actually making the or any cooler. So why are fans,
Speaker 1: even in a closed room, so good at cooling us
Speaker 1: down if they don't actually lower the temperature in the room.
Speaker 1: This is like a fun little if you want to
Speaker 1: pause and try to figure this out yourself, if you
Speaker 1: don't already know the answer. I don't know if it's
Speaker 1: too didactic, but I had fun trying to figure this
Speaker 1: last night while I was thinking about it. It's because
Speaker 1: speeding up airflow increases the rate of evaporation from a
Speaker 1: body of liquid like water, and essentially you're a water bag.
Speaker 1: Your body is a bag of water, and your body,
Speaker 1: as we were talking about earlier, cools by evaporation of sweat.
Speaker 1: So in order for a fan to cool something, that
Speaker 1: thing actually probably needs to be wet. And I did
Speaker 1: an experiment like this in my house just last night,
Speaker 1: using a desk fan and a high accuracy instant read
Speaker 1: kitchen thermometer. So I set the desk fan going on
Speaker 1: the kitchen counter, and I held the thermometer out in
Speaker 1: front of the fan. And even though standing in front
Speaker 1: of a fan makes us feel cooler, holding a thermometer
Speaker 1: in front of a fan does not really change aange
Speaker 1: the temperature that the thermometer registers. For me, the naked
Speaker 1: thermometer probe just hovered around room temperature. Even though I
Speaker 1: held it there for a long time. It didn't do anything.
Speaker 1: But then I wrapped the thermometer probe in a wet
Speaker 1: paper towel. Now this naturally dropped the temperature of the
Speaker 1: thermometer already just because the water is cooler, right, and
Speaker 1: so the water contact drops it down. Then it's stabilized.
Speaker 1: And when you put the wet paper towel thermometer in
Speaker 1: front of a fan, the temperature plummets. It drops down
Speaker 1: as the circulation created by the fast moving air of
Speaker 1: the fan speeds up the evaporation of water from that
Speaker 1: wet paper towel, And the faster the water evaporates, the
Speaker 1: colder the paper towel gets because it's stealing the energy
Speaker 1: from the rest of that water. This rapid air flow
Speaker 1: robbed the water of energy, made it cooler, and thus
Speaker 1: you get a nice, icy cold paper towel. So when
Speaker 1: you've got a fan running on you in a room.
Speaker 1: Your body is that paper towel. You're that wet paper towel,
Speaker 1: accelerating evaporation off the top of your skin. Now the
Speaker 1: scenario you're again, you're using a desk fan, you using
Speaker 1: a rotary fan. Uh So it's interesting to dive into
Speaker 1: just you know, briefly the history of the rotary fan,
Speaker 1: and it seems that the earliest example of this goes
Speaker 1: all the way back to the Han dynasty in China.
Speaker 1: Han dynasty engineer Ding Juan created a manually operated rotary
Speaker 1: fan with seven wheels around one a d c uh
Speaker 1: and then later on during the Tang dynasty of the
Speaker 1: eighth century, hydraulic power was apparently added to this innovation
Speaker 1: as a way of uh basically for use in blast
Speaker 1: furnaces for industrial you know, um air movement circulation. So
Speaker 1: flowing water powered the spinning of a fan to circulate air, yeah,
Speaker 1: into a blast furnace. Now, but in Ding Juan's original idea,
Speaker 1: it would have required, uh, you know, a little human power,
Speaker 1: like somebody would have been turning a crank or or
Speaker 1: something in order to manually operate all of these rotary fans. Uh.
Speaker 1: So Juan's initial invention here was reported in the text
Speaker 1: Mental Miscellaneous Records of the Western Capital and excavations from
Speaker 1: a former Han tomb in seems to show the necessary
Speaker 1: parts to carry this out. So the seven fans, so
Speaker 1: there have been ten feet or three meters in diameter,
Speaker 1: were connected so that one person could power them all. Uh.
Speaker 1: And this is, of course, UH is another more elaborate
Speaker 1: means of just circulating airflow, which can can make all
Speaker 1: the difference in a stuffy room. Right. Uh. Now, it's
Speaker 1: not evaporative cooling, though I've seen at least one wiki
Speaker 1: lit listing that says Ding Juan had an evaporative cooling system. Uh.
Speaker 1: Decided sources that I ran across on those wikis did
Speaker 1: not support it. Uh, that they were just talking about
Speaker 1: what I'm talking about, just air circulation. Uh. So there's
Speaker 1: no evaporation beyond what's happening on your skin. Correct. And
Speaker 1: I didn't see it mentioned in um Ian Inkster's The
Speaker 1: History of Technology, which discusses this. But of course it's
Speaker 1: entirely within the room of possibility that he can bind
Speaker 1: a fan system with something like the Egyptian read Matt
Speaker 1: scenario that we discussed earlier. Having some sort of you know,
Speaker 1: wet fabric in front of it, but I could not
Speaker 1: find direct reference to that myself. By the way, Ding
Speaker 1: Juan also allegedly invented something like a zoo trope. According
Speaker 1: to Lance Day and Ian McNeil in Biographical Dictionary of
Speaker 1: the History of Technology, it was a quote zootrope lamp
Speaker 1: which had a thin canopy bearing veins at the top
Speaker 1: that were caused to rotate by an ascending current of
Speaker 1: warm air from the lamp. The canopy bore images which
Speaker 1: if the canopy were rotated fast enough, gave the impression
Speaker 1: of movement. Wow, it's like a it's like a fan
Speaker 1: for your eyes. Yeah. Uh, you know. It also shows
Speaker 1: that like this is an individual who was clearly interested in, uh,
Speaker 1: you know, the combination of of rotary machinery and the
Speaker 1: movements of air. Uh. And also then just throughout Chinese,
Speaker 1: ancient Chinese technology, you also see some other interesting advancements
Speaker 1: in refrigeration, which maybe we'll come back to later on.
Speaker 1: All right, we're gonna take a quick break, but when
Speaker 1: we come back, we shall return to Persia. All right,
Speaker 1: we're back. One genre of ancient cooling technology for buildings
Speaker 1: is i think a really deeply ingenious solution, and we
Speaker 1: find some great examples in ancient and medieval Persia, which
Speaker 1: would be in modern day Iran. So this is going
Speaker 1: to be the idea of wind catchers and a paired
Speaker 1: technology known as connots. And we can start with a
Speaker 1: simple version of the wind catcher that's just focused on
Speaker 1: air flow. So I want you to picture a building
Speaker 1: with towers reaching up above the roof on each side,
Speaker 1: and each of these towers has four ports that can
Speaker 1: be opened and closed, and each of these towers is
Speaker 1: hollow and it connects down to the occupied space within
Speaker 1: the building. So if the wind is blowing from the west,
Speaker 1: you would open the west facing ports on the west
Speaker 1: side of the building to accept the incoming air flow
Speaker 1: into the towers, and then on the other side, you
Speaker 1: would open only the east facing ports on the east
Speaker 1: side of the building, so that would be the ports
Speaker 1: facing away from the wind. Now, due to a couple
Speaker 1: of quirks of fluid dynamics, if you have a shaft
Speaker 1: like this that's only open on the side facing away
Speaker 1: from the wind, air will naturally be pulled up from
Speaker 1: inside the house through that shaft to flow out in
Speaker 1: the same direction as the prevailing wind. I've seen this
Speaker 1: attributed to both the Quanda effect and the Bernoulli effect.
Speaker 1: I have to admit my fluid dynamics knowledge is not
Speaker 1: sharp enough to evaluate whether these characterizations are correct, but
Speaker 1: at least several have definitely attributed it to what's known
Speaker 1: as the Kwanda effect, which just describes a property of
Speaker 1: air flow and certain scenarios. But anyway, if you've got
Speaker 1: towers on each side of a building, with towers on
Speaker 1: one side accepting the prevailing wind and and routing it
Speaker 1: down into the house, and then towers on the other
Speaker 1: side with a negative pressure allowing wind to be sucked
Speaker 1: up from the inside to blow out with the prevailing wind,
Speaker 1: it creates a complete circuit of air flow where air
Speaker 1: is sucked down into the house on one side and
Speaker 1: sucked up out of the house on the other side.
Speaker 1: And you can use this method to help drive hot
Speaker 1: air out through the roof for the highest level of
Speaker 1: the house, taking advantage of this chimney principle we discussed
Speaker 1: earlier in the episode. Now, of course, at this stage
Speaker 1: what I've described so far, this would still just be
Speaker 1: circulation of hot air from outside. Right now, we know
Speaker 1: that even if airflow doesn't actually cool a room, it
Speaker 1: can help cool your body if just you you keep
Speaker 1: the air moving because it replaces the air around your
Speaker 1: skin and helps you evaporate faster. But you can also
Speaker 1: greatly improve on the wind catcher design and generate a
Speaker 1: true space cooling effect by pairing it with an underground
Speaker 1: reservoir or subterranean water channel called a cannot. Oh wow,
Speaker 1: So this it's it's almost like we're getting into the
Speaker 1: like the creation of an artificial cave system kind of
Speaker 1: to cool the air. So cannot is a chamber of
Speaker 1: underground water resting or flowing deep in the earth, surrounded
Speaker 1: by dense layers of rocks, so the water stays cool
Speaker 1: even on the hottest days, and it can be used
Speaker 1: for several things. I think from what I've seen, it
Speaker 1: seems like it's most often used to sort of help
Speaker 1: channel water down underground from from higher level water tables
Speaker 1: up in higher elevations so that the water can be
Speaker 1: brought down for irrigation in lower lying areas. But in
Speaker 1: any case, it's underground water. It's a channel of underground water,
Speaker 1: and the water stays very cool because it's deep underground,
Speaker 1: so like even when the sun heats up the top
Speaker 1: of the Earth's surface, it's not heating up that deep
Speaker 1: bedrock below. Now picture this. You've got one shaft leading
Speaker 1: down from the surface down into the cannot that looks
Speaker 1: like it works like an intake shaft, and this can
Speaker 1: be outside the house, drawing in dry air from the desert.
Speaker 1: And then there's another shaft leading up from the same
Speaker 1: cannot into the house, into the inside of the house
Speaker 1: or whatever space you want to cool. And this is
Speaker 1: paired with an outflow wind catcher facing away from the wind,
Speaker 1: which naturally sucks air up from the inside of the house.
Speaker 1: So the circuit created here pulls air from the outside
Speaker 1: down through the first shaft through the cannot to flow
Speaker 1: over and around the cold water down there in the
Speaker 1: deep earth, and then up the second shaft into the house,
Speaker 1: and the dry air passing through the cold humid environment
Speaker 1: of the cannot becomes much cooler as it travels, and
Speaker 1: the result is that you have cold air pulled up
Speaker 1: into the house and flowing, which I think it's just brilliant. Yeah,
Speaker 1: I mean, it's a it's it's one of these systems
Speaker 1: that is um it's it. It's at once kind of
Speaker 1: simple when you when you have it all explained to you,
Speaker 1: but it is especially considering, you know, ancient buildings we
Speaker 1: were talking about it, but pretty elaborate system here. And
Speaker 1: you know, I've actually, I don't know if you ran
Speaker 1: across any modern uses of this, but I read a
Speaker 1: couple of references to UH designs for like large sports
Speaker 1: facilities that utilize at least some version of this to
Speaker 1: try and keep air circulating through um, you know, through
Speaker 1: through the uh the sports arena. Oh okay, well, because
Speaker 1: right if you've got like a sports arena, it sounds
Speaker 1: crazy to try to like air condition that with like
Speaker 1: with just electric air condition so just the sheer scale
Speaker 1: if the building might require you know, a more you know,
Speaker 1: less you know, electricity dependent method, and perhaps I don't know,
Speaker 1: it seems like the kind of thing that that could
Speaker 1: potentially be utilized in large industrial spaces as well, But
Speaker 1: I didn't run across any examples of that. Well, I
Speaker 1: don't know about the scalability of this kind of technology,
Speaker 1: but maybe, yeah, I I just don't know, but I
Speaker 1: do know they're they're ancient examples where things like this
Speaker 1: were used pretty effectively to keep some sellers and basements
Speaker 1: and and dwellings very very cool, and even to the
Speaker 1: point where they could be used to store ice in
Speaker 1: hot places like in Persia. Now we mentioned India earlier
Speaker 1: on the subject of fans uh, but I want to
Speaker 1: return to India once more, particularly to the use of
Speaker 1: step wells and also step ponds. So as Morna Livingstone
Speaker 1: and Milo Beach point out in the book Steps to Water,
Speaker 1: the Ancient step Wells of India quote, the alternating absence
Speaker 1: and abundance of water is crucial to Indian life, and
Speaker 1: the step wells and stepped ponds generated by the use
Speaker 1: of water are especially imaginative. So basically what they're saying
Speaker 1: is that much of the subcontinent is subject to intense months,
Speaker 1: soon seasons and intense dry spells, and during the dry
Speaker 1: spells people need communal access to water UH. And during
Speaker 1: the wet spells, the places they would go for unal access,
Speaker 1: of course they're going to be likely to flood and
Speaker 1: UH and greatly. And so this communal UH connection with
Speaker 1: water is an important aspect of Indian life. A prime
Speaker 1: example of this is it would be there the stepped
Speaker 1: access that you see to the Ganges River in urban
Speaker 1: areas U and think everyone's probably seen images of that,
Speaker 1: you know, especially with religious rights and so forth taking
Speaker 1: place close to the water. But a far less famous,
Speaker 1: less visited and even less preserved example would be the
Speaker 1: step ponds and the step wells. Uh. These are beautiful,
Speaker 1: by the way, if you've never looked up images of them,
Speaker 1: it is some of the most just sort of like
Speaker 1: eye rending architecture I've ever seen, and it's actually not
Speaker 1: all that complicated, is just like geometrically dazzling. Yeah. I
Speaker 1: like to think of it this way. A mountain is
Speaker 1: to a canyon as a ziggurat or a Mesoamerican pyramid
Speaker 1: is to an Indian step. Well, it looks like there's
Speaker 1: a hole in the ground and someone like took a
Speaker 1: zigaratt out of it and left a ziggarat shape in
Speaker 1: the earth descending into the earth inverted zigaratte. Yeah. So
Speaker 1: like imagine these many lattices or steps going down, uh
Speaker 1: to a ridiculous degree. Yeah. Yeah, they're essentially deep holes
Speaker 1: in the earth, dug down to the water table and
Speaker 1: then built out. So there's you know, generally a tear
Speaker 1: there's terrorist access with stairs leading down to it um.
Speaker 1: And one of the points that the author's made in
Speaker 1: this book is that while generally you think of like
Speaker 1: a journey into the deep earth, you know, like it
Speaker 1: would be it would be claustrophobic, it would be frightening.
Speaker 1: But that's not the sense you get when you look
Speaker 1: at the photographs of stepwells, like it is. It is open,
Speaker 1: it is inviting, it is It's not a sense of
Speaker 1: the earth closing around you, but instead one of opening
Speaker 1: up like a flower. They're yeah, they're beautiful, and why
Speaker 1: do I get kind of an m C. S sure
Speaker 1: sense from them? Yeah, there is kind that I think
Speaker 1: part of it is that sort of inversion scenario you get.
Speaker 1: It is like an inverted ziggarat when you look at it,
Speaker 1: and yet you're you're you're sort of climbing up, but
Speaker 1: you're climbing down. Um. So. The main distinction though, between
Speaker 1: step ponds and step wells, according to Livingston and Beach,
Speaker 1: is that step ponds were used for bathing and step
Speaker 1: wells were use more for daily water use. Now, many
Speaker 1: of these have fallen into disrepair or have been abandoned
Speaker 1: in in recent years, in part because of falling water table.
Speaker 1: You know, which renders them dry and useless, but also
Speaker 1: due to the period of British colonial rule in which
Speaker 1: the British condemned them as being you know, potential disease
Speaker 1: of vectors and so forth. But there has been increased
Speaker 1: interest in them in recent years to preserve their cultural importance,
Speaker 1: but also, you know, to preserve them as potential water
Speaker 1: sources and a changing climate. Now, obviously these things are
Speaker 1: architecturally beautiful and you can see their importance as a
Speaker 1: commune a water source, but how do they relate to
Speaker 1: the idea of air conditioning or cooling of spaces. Well,
Speaker 1: you know, some of them are more out in the open,
Speaker 1: you know, get kind of a sense of almost like
Speaker 1: a you know, it's like a you could easily mistake
Speaker 1: them for some sort of ornate swimming pool sort of
Speaker 1: you know, construction. But others are other step wells are
Speaker 1: part of temple palace or other urban complexes. So they're
Speaker 1: part of this other, this, this larger structure. And here
Speaker 1: you know, they were, of course a means of access
Speaker 1: in cool water, which in and of itself is a
Speaker 1: cooling resource. Livingstone and Beach point out that splashing one's
Speaker 1: face with cool water is a standard Indian means of
Speaker 1: coping with the heat. A step well affords this cooling method.
Speaker 1: It also affords one the ability to enjoy the shade
Speaker 1: via the terraces. Or if you've got like hot dry air,
Speaker 1: you could also have evaporative cooling there. Yeah. Yeah, Also
Speaker 1: you can rest against the cool stone. That was That
Speaker 1: was one example they brought up that I didn't think
Speaker 1: of in the early portion of the podcast. Is it
Speaker 1: It's You can also just like if you find some
Speaker 1: cool rock to lay upon, that can be used as
Speaker 1: a very primitive form of air conditioning. But they have
Speaker 1: they have a wonderful quote in the book about uh
Speaker 1: evaporative cooling via the step well quote. In dry weather,
Speaker 1: the step wells pool provides some evaporative cooling, but in
Speaker 1: high humidity, cooling happens only through contact with water. Unlike
Speaker 1: a running fountain, still water and step wells evaporates little.
Speaker 1: A moisture saturated layer forms over the water surface, and
Speaker 1: if it is not ruffled by a breeze or broken
Speaker 1: by splashing, it acts as a vapor barrier. Thus, in
Speaker 1: hot humid weather, the body does not get cooled as
Speaker 1: quickly in a step well as it does in air conditioning. Indeed,
Speaker 1: step well air feels breathlessly still. Okay, so if it's
Speaker 1: humid outside and the air isn't moving, the step well
Speaker 1: isn't gonna have much of a cooling effect. But if
Speaker 1: you had like hot, dry air and a breeze blowing
Speaker 1: through moving the air along the surface of the step all,
Speaker 1: if it was moved by humans somehow, then it sounds
Speaker 1: like you're in business right. However, the humidity is gonna
Speaker 1: also serve to conserve the water, so it has that
Speaker 1: going forth at any rate. These are again we do
Speaker 1: encourage you to do a Google image search on uh
Speaker 1: Indian step wells and take a look at something. There's
Speaker 1: also some wonderful like top ten step well images. Uh there.
Speaker 1: It makes for some just wonderful architectural photography. We'd love
Speaker 1: to also hear from anyone who has had the chance
Speaker 1: to visit. These are some of the resources I was
Speaker 1: I was looking at pointed out that you know these
Speaker 1: are these have at least in recent years. I don't
Speaker 1: know if it's changed, but in the past it's been
Speaker 1: a situation where these places, despite just how beautiful they are,
Speaker 1: they haven't been a sought out by tourists uh and
Speaker 1: and and sightseers in India. But perhaps that is changing
Speaker 1: again as as more conservation has been directed at them
Speaker 1: and perhaps just more just sort of appreciation for what
Speaker 1: they are. Yeah, all right, well, I think that probably
Speaker 1: does it for today. But the next episode, in part
Speaker 1: two of our exploration of air conditioning, we're gonna get
Speaker 1: more into the modern air conditioner that's based on refrigeration chemistry. Right,
Speaker 1: but we've hopefully we've we've laid the groundwork for those innovations,
Speaker 1: Like like we've shown you what was possible in the
Speaker 1: age before these new technological advancements, and it's pretty impressive,
Speaker 1: you know. I think I think a lot of us
Speaker 1: are going to be surprised because we have we are
Speaker 1: so coddled by modern air conditioning. We think that the
Speaker 1: different that there's basically a distinction between having a C
Speaker 1: and just sweltering, and we don't realize that there are
Speaker 1: all these uh these smaller things that can and have
Speaker 1: been done to help ensure a less sweltering environment. Yeah.
Speaker 1: So so many people now live in an a C
Speaker 1: tamed world. If the a C is cut off, they
Speaker 1: don't have all of the normal coping mechanisms that you
Speaker 1: would have to to get around that heat. It's a
Speaker 1: fundamental softening of our defenses against the evil sun. We
Speaker 1: will return to air conditioning in the next episode of Invention.
Speaker 1: In the meantime, check out past episodes at invention pod
Speaker 1: dot com and indeed let us know you know what,
Speaker 1: what is your relationship with air conditioning and particularly what
Speaker 1: is your relationship with some of these these alternative methods
Speaker 1: of dealing with the heat. Do you still employ some
Speaker 1: of them today? Uh? Perhaps you have. You know, older
Speaker 1: members of your family have told you about how they
Speaker 1: used to do things before air conditioning. We would love
Speaker 1: to hear about any of that. Huge thanks, as always
Speaker 1: to our excellent audio producer Seth Nicholas Johnson. If you
Speaker 1: would like to get in touch with us to send
Speaker 1: feedback on this episode or any other, to suggest a
Speaker 1: topic for the future, to join the Committee to Extinguish
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