WEBVTT - How Refrigerators Work 0:00:02.520 --> 0:00:05.720 In text with Technology with text style from how Stuff, 0:00:05.760 --> 0:00:16.480 what's that coming? Hey then, everyone, and welcome to tex Stuff. 0:00:16.520 --> 0:00:19.079 I am Jonathan Strickland, one of the two hosts of 0:00:19.120 --> 0:00:21.479 the show, and I'm Lauren vocal Bon, the other of 0:00:21.480 --> 0:00:23.400 the two hosts of the show. And today we wanted 0:00:23.400 --> 0:00:27.040 to talk about something that's pretty cool. Oh no, yeah, 0:00:27.200 --> 0:00:31.280 already started. We're gonna talk about refrigerators. And and here's 0:00:31.280 --> 0:00:34.280 the interesting thing, guys, if you listen to the episode 0:00:34.320 --> 0:00:37.480 that Chris Pallette and I did quite some time ago 0:00:37.560 --> 0:00:41.080 about air conditioners, this podcast is going to sound very 0:00:41.120 --> 0:00:43.519 similar to that because the technology is used in air 0:00:43.560 --> 0:00:47.680 conditioning systems and the technologies used in refrigerators are essentially 0:00:47.760 --> 0:00:51.240 the same, just one is a more small and controlled 0:00:51.320 --> 0:00:56.600 and um not for people usually, right, No, there's some 0:00:56.680 --> 0:01:00.279 notable exceptions to that. We are not going to talk 0:01:00.320 --> 0:01:03.240 about those, guys, because that's creepy and probably belongs in 0:01:03.280 --> 0:01:06.720 another podcast. Okay, so we're not talking about people in 0:01:06.760 --> 0:01:12.080 refrigerators today, although now I can't think of anything else. Um, 0:01:12.120 --> 0:01:14.320 but no, no, no, First, let's start with what the 0:01:14.360 --> 0:01:18.480 definition of refrigeration is. So it's defined as the process 0:01:18.560 --> 0:01:22.720 of achieving and maintaining a temperature below that of the surroundings. 0:01:22.959 --> 0:01:24.920 And the aim of it is to cool some sort 0:01:25.000 --> 0:01:29.040 of space or object to a required temperature, right, because 0:01:29.080 --> 0:01:32.080 bacteria grow most rapidly in this and it's it's called 0:01:32.080 --> 0:01:37.640 the danger zone. Actually in between I now I have 0:01:37.720 --> 0:01:40.160 a new thing filling up my head. But okay, yes 0:01:41.040 --> 0:01:46.640 that I debatably better than than Archer really and so okay, 0:01:46.640 --> 0:01:49.040 well excellent, but so yeah, the danger zone is in 0:01:49.080 --> 0:01:52.280 between forty degrees fahrenheit and a hundred and forty degrees fahrenheit, 0:01:52.320 --> 0:01:55.040 which is a four point four to sixty degrees celsius. 0:01:55.280 --> 0:01:59.480 And and in that temperature range, bacteria really just groove out. 0:01:59.800 --> 0:02:02.480 They can they can more than double in in twenty minutes. 0:02:02.720 --> 0:02:07.240 That population just explodes. And and bacteria and for things 0:02:07.280 --> 0:02:11.040 like you know, food stuff that that we would consume, 0:02:11.480 --> 0:02:14.440 that's not necessarily a great mix. That can lead to 0:02:14.720 --> 0:02:18.160 u some pretty nasty contamination. Uh, it can lead to 0:02:18.360 --> 0:02:21.800 some really serious health problems. And uh, and this is 0:02:22.000 --> 0:02:24.520 why refrigeration is such a big deal. I mean, clearly, 0:02:24.560 --> 0:02:27.760 before we had any kind of refrigeration, we had to 0:02:27.760 --> 0:02:31.240 look at different ways to preserve food. Otherwise you pretty 0:02:31.280 --> 0:02:34.560 much had to get food from the source and consume 0:02:34.600 --> 0:02:37.919 it right away, immediately or as close to immediately as possible. 0:02:38.040 --> 0:02:40.560 Or you had to cook it so that it would yeah, 0:02:40.720 --> 0:02:42.720 so it wouldn't spoil as quickly. Or you had to 0:02:42.919 --> 0:02:46.200 salt it like crazy so that again the salting would 0:02:46.240 --> 0:02:51.400 would inhibit the bacteria from from uh from reproducing so quickly. 0:02:51.800 --> 0:02:55.760 And even in refrigeration, we still have that uh, that process. 0:02:55.840 --> 0:02:58.440 It's just slowed down quite a bit, which is why 0:02:58.520 --> 0:03:02.160 you cannot leave food in a refrigerator uh indefinitely. It 0:03:02.200 --> 0:03:05.440 will eventually go bad. Um. And then just like in 0:03:05.480 --> 0:03:09.080 that great Far Side cartoon, the potato salad will hold 0:03:09.160 --> 0:03:14.160 up the catchup when potato salad goes bad. So the 0:03:14.480 --> 0:03:18.880 trick here, though, is how do you create this cool environment? 0:03:19.000 --> 0:03:25.000 This this cold environment? Because adding heat two things is easy. 0:03:25.600 --> 0:03:29.720 Taking heat away not as easy, less easy. And also, 0:03:30.440 --> 0:03:34.560 before I get all my physicist friends sending in messages 0:03:34.600 --> 0:03:37.760 about the use of the word heat, I do apologize 0:03:37.760 --> 0:03:40.280 we're going to be using it in the vernacular quite 0:03:40.280 --> 0:03:43.560 a bit because that's really what everyone's familiar with. But 0:03:44.120 --> 0:03:48.960 to be clear, an object does not possess heat. It 0:03:49.040 --> 0:03:52.000 has a temperature, but it doesn't possess heat, and objecos 0:03:52.000 --> 0:03:54.720 will have internal energy as a result of molecular motion. 0:03:55.080 --> 0:03:59.480 And heat is really the description of an energy transfer process. 0:03:59.560 --> 0:04:02.920 And uh, you go from a high temperature object to 0:04:03.000 --> 0:04:08.400 a lower temperature one. That is the basic concept of heat. 0:04:08.440 --> 0:04:11.000 It's really an energy transfer. So when we say, like, 0:04:11.080 --> 0:04:13.600 this object's got a lot of heat to it, uh, 0:04:13.840 --> 0:04:16.960 that's a that's a completely colloquial way by saying it. 0:04:17.320 --> 0:04:20.400 So I do acknowledge that. I apologize. But if you 0:04:20.520 --> 0:04:23.560 really want someone who's going to be a stickler for science, 0:04:24.760 --> 0:04:27.520 go bug Robert Lamb because he loves that the stuff 0:04:27.560 --> 0:04:34.240 to blow your mind. Gay, Um, Robert's awesome. I love Robert. So, yeah, 0:04:34.279 --> 0:04:37.120 that's the way heat works. Though you have high temperature 0:04:37.160 --> 0:04:40.680 low temperature, then heat moves from the high temperature to 0:04:40.880 --> 0:04:43.679 the low temperature. It does not go the other way around, 0:04:44.240 --> 0:04:47.880 right without without some sort of external force working on 0:04:47.920 --> 0:04:51.000 the system. Uh. This is essentially one of the basic 0:04:51.080 --> 0:04:55.080 laws of thermodynamics. And so you've got this, Uh, you've 0:04:55.080 --> 0:04:56.560 got a way. You have to find a way of 0:04:56.640 --> 0:05:04.400 creating a lower temperature or environment to pull heat from 0:05:04.520 --> 0:05:08.120 or to for heat to transfer from the objects that 0:05:08.120 --> 0:05:12.599 are inside a refrigerator to make them cool. So that's 0:05:12.640 --> 0:05:15.440 the basis of refrigeration. But you know, to get to 0:05:15.480 --> 0:05:18.039 that point, we had to do a lot of stuff 0:05:18.080 --> 0:05:20.320 and we had to understand a lot about physics for 0:05:20.360 --> 0:05:23.720 this to become what we now all kind of take 0:05:23.760 --> 0:05:29.000 for granted. Yeah, So to to get started, I guess 0:05:29.160 --> 0:05:31.240 we can talk about what the predecessor was to the 0:05:31.279 --> 0:05:34.320 modern refrigerator, which was the ice box, right, or you know, 0:05:34.400 --> 0:05:36.680 going going way back in time, you had you had 0:05:36.920 --> 0:05:40.480 people not even making ice boxes, but yes, just collecting 0:05:40.480 --> 0:05:43.240 ice and putting it next to stuff. Yeah, or like 0:05:43.279 --> 0:05:45.800 maybe you know, you might have a seller that you'd 0:05:45.839 --> 0:05:47.560 put ice into, or you might just have a hole 0:05:47.560 --> 0:05:50.520 in the ground, or you may just like if you 0:05:50.560 --> 0:05:53.080 were in a part of the world where there was 0:05:53.400 --> 0:05:57.280 a significant amount of snowfall. Uh, we here in Georgia 0:05:57.480 --> 0:05:59.560 are not in that part of the world. We did 0:05:59.600 --> 0:06:02.120 have some know the other day, I could see a 0:06:02.440 --> 0:06:05.800 bare trace of it next to my steps. Some of 0:06:05.839 --> 0:06:07.520 it landed in my hair when I walked my dog. 0:06:07.640 --> 0:06:09.600 That was that was about it. But if you were 0:06:09.600 --> 0:06:11.800 in a place where they get a significant amount of 0:06:11.839 --> 0:06:14.320 snow and they're large snow banks, then one of the 0:06:14.440 --> 0:06:17.800 things you might do is store some food inside the snow. 0:06:17.839 --> 0:06:20.359 They're bury it in the snow and just hope that 0:06:20.520 --> 0:06:23.760 nothing comes along to to grab that food. Or Yeah, 0:06:23.800 --> 0:06:25.919 if if you've got an ice house, you can preserve 0:06:25.960 --> 0:06:28.120 some of the ice with a sawdust or wood shavings. 0:06:28.200 --> 0:06:31.240 Later on, cork was used to insulate it for a 0:06:31.279 --> 0:06:34.560 few months anyway, until temperatures warmed up enough. Right right, Yeah, 0:06:34.600 --> 0:06:38.120 you could. You could definitely slow the process, insulated enough 0:06:38.160 --> 0:06:41.159 from the heat of the outside environment so that it 0:06:41.200 --> 0:06:44.839 would preserve you wouldn't lose too much in melt off. 0:06:44.880 --> 0:06:47.160 It took a while before people started to figure out 0:06:47.400 --> 0:06:50.920 the best ways to keep ice from from melting too quickly. 0:06:51.279 --> 0:06:54.080 And it's interesting because just as they were really getting 0:06:54.360 --> 0:06:58.200 getting very good and making sure they kept ice uh 0:06:58.480 --> 0:07:03.000 cold for as long as pas well, even in hot environments. Uh, 0:07:03.160 --> 0:07:06.760 that's when the mechanical refrigeration technology had started to really 0:07:06.800 --> 0:07:09.880 take off and it became less important. And these were 0:07:09.880 --> 0:07:13.440 happening simultaneously, which is really fascinating to me. It was 0:07:13.480 --> 0:07:17.600 in seventive that the first refrigerating machine was produced. I 0:07:17.640 --> 0:07:20.960 believe it could make small amounts of ice in the lab. Yeah, yeah, 0:07:21.000 --> 0:07:25.080 to to really understand well, first of all, the word refrigerator, 0:07:25.240 --> 0:07:27.280 I found the I found the earliest use of it, 0:07:27.720 --> 0:07:30.080 which was or at least earliest recorded use that I 0:07:30.120 --> 0:07:32.800 could find, which was from fifteen fifty. But it was 0:07:32.800 --> 0:07:36.200 all about using chemicals in water. People were discovering that 0:07:36.240 --> 0:07:38.800 if they added certain chemicals to water for some reason, 0:07:38.800 --> 0:07:40.920 the temperature of the water would drop. So if you 0:07:40.960 --> 0:07:43.720 were to put something in a container of water that 0:07:43.760 --> 0:07:46.920 had this chemical in it, you could cool that's something. Now, 0:07:46.960 --> 0:07:50.320 if that's something was unprotected food and that chemical was poisonous, 0:07:50.480 --> 0:07:52.680 that was not necessarily a great thing. But if that's 0:07:52.720 --> 0:07:54.800 something were I don't know, a bottle of wine and 0:07:54.840 --> 0:07:56.960 you happen to be French, this was a great way 0:07:56.960 --> 0:07:59.920 to cool your wine. And in fact, in the Renaissance, 0:08:00.120 --> 0:08:03.600 these cooled drinks became very popular, to the point where 0:08:03.600 --> 0:08:06.720 if you added chemicals to water, it would drop the 0:08:06.720 --> 0:08:09.120 temperature enough that if you put something in it that 0:08:09.600 --> 0:08:12.920 that you could turn on a regular basis, you could 0:08:12.920 --> 0:08:16.280 actually make ice this way. Um. Yeah, So this was 0:08:16.320 --> 0:08:18.720 kind of an early ice maker, not efficient, not good 0:08:18.760 --> 0:08:21.680 for producing ice on any kind of large scale, but 0:08:21.800 --> 0:08:24.160 it was one of those things that the rich people 0:08:24.320 --> 0:08:26.600 really enjoyed, and really those were the only ones who 0:08:26.680 --> 0:08:29.560 had any chance of getting at it. Um. But yeah, 0:08:30.280 --> 0:08:34.960 it was just before your the refrigerator unit type thing 0:08:35.000 --> 0:08:37.720 you were talking about from the seventeen seventies. Seventeen fifty 0:08:37.720 --> 0:08:41.520 five is pretty much when we talk about the origin 0:08:41.559 --> 0:08:45.440 of the idea. That's when William Cullen made his machine 0:08:45.480 --> 0:08:50.320 with which you used a vacuum UH and UH ether 0:08:51.040 --> 0:08:55.720 to UH to create this UH environment where he would 0:08:55.720 --> 0:09:00.560 put water into a container, put a smaller amount of 0:09:00.600 --> 0:09:04.680 ether in there, put a essentially a vacuum bell jar 0:09:04.800 --> 0:09:07.679 on top, you know, with a pump on it. By 0:09:07.760 --> 0:09:10.400 creating the vacuum, the ether would start to boil off. 0:09:11.200 --> 0:09:13.640 And when the ether was boiling off, when it was vaporizing, 0:09:13.960 --> 0:09:17.640 he noticed that the temperature was going down in the 0:09:17.679 --> 0:09:21.160 water and in fact, but when the ether would continue 0:09:21.200 --> 0:09:24.559 to boil off, the water would start to turn into ice. 0:09:25.240 --> 0:09:27.880 Now we'll talk about why that is a little bit later, 0:09:28.000 --> 0:09:30.920 but this was one of those early observations that started 0:09:30.960 --> 0:09:34.360 to lead people into thinking, you know, if we harness 0:09:34.480 --> 0:09:42.280 this in some way, pretty cool. Yeah, there's no way 0:09:42.280 --> 0:09:45.679 to avoid it. Voco boumb Join us together, we will 0:09:45.760 --> 0:09:48.200 rule the galaxy. Jonathan. We need to we need to 0:09:48.240 --> 0:09:51.360 chill out, Yes we do. Okay, all right, now too fast, 0:09:51.440 --> 0:09:56.240 too fast. You gotta gotta pace yourself here. Um. So anyway, 0:09:56.280 --> 0:09:59.840 this does form the basis. This, this idea of UH 0:10:00.120 --> 0:10:05.320 vapor pulling out heat somehow, that is what was the 0:10:05.440 --> 0:10:09.040 very basis of mechanical refrigeration. It would be quite a 0:10:09.040 --> 0:10:11.840 while before the mechanical refrigerators would start to become a 0:10:11.880 --> 0:10:15.480 real thing. Uh, I have a in eighteen o three, 0:10:15.960 --> 0:10:20.200 you have a Thomas Moore obviously not that one different 0:10:20.240 --> 0:10:24.680 Thomas Moore UH of Maryland. In fact, he received a U. S. 0:10:24.720 --> 0:10:28.360 Patent for a refrigerator. Now this was not the same 0:10:28.360 --> 0:10:30.560 thing as the mechanical refrigerators that would come later. But 0:10:30.600 --> 0:10:33.720 that same year that was when the domestic ice box 0:10:33.840 --> 0:10:37.480 was invented. So three you get the domestic ice box. 0:10:37.520 --> 0:10:41.000 This was usually a wooden cabinet that you would put 0:10:41.000 --> 0:10:44.120 a block of a large block of ice into the 0:10:44.160 --> 0:10:47.559 top and then you would keep your food and and 0:10:47.559 --> 0:10:50.960 and consumables in the bottom part of this cabinet, and 0:10:51.040 --> 0:10:55.880 convection would essentially keep because because heat rises and cold sinks, 0:10:55.920 --> 0:11:01.319 that which is which we know is the generalization was generalization, yes, 0:11:01.360 --> 0:11:04.959 but but in general in this particular case, yeah, you've 0:11:04.960 --> 0:11:07.880 got you've got the dense the dense cold air going 0:11:07.920 --> 0:11:11.000 down and the and the less dense warm air moving up. 0:11:11.040 --> 0:11:14.439 Because yeah, but we we understand that is a gross 0:11:14.720 --> 0:11:18.000 over generalization. But for the purposes of this podcast, it's 0:11:18.120 --> 0:11:20.320 effective enough. Yeah, you kept that ice on top. You 0:11:20.360 --> 0:11:22.800 have a like a drip tray on underneath, because hey, 0:11:22.840 --> 0:11:25.600 that ice is melting um, and so you would collect 0:11:25.600 --> 0:11:28.440 the water which you would not just pour into the 0:11:28.480 --> 0:11:31.040 top where it would magically become ice again. Essentially, once 0:11:31.040 --> 0:11:32.600 that ice was gone, you had to go out and 0:11:32.640 --> 0:11:35.439 buy more ice. And actually the ice trade was really 0:11:35.520 --> 0:11:38.040 huge right around that time. In eighteen o six, I 0:11:38.080 --> 0:11:41.920 think Frederick Tudor began his his ice empire. He was 0:11:41.960 --> 0:11:45.439 called the Ice King. Yeah, um, when he started cutting 0:11:45.520 --> 0:11:47.920 chunks out of the Hudson River in various ponds around 0:11:47.920 --> 0:11:51.200 Massachusetts and then exporting it as far as China and Australia. 0:11:51.360 --> 0:11:55.840 In India India. Yeah. Also what's interesting is that India 0:11:56.120 --> 0:11:58.480 was the way the way they were producing ice in 0:11:58.480 --> 0:12:02.040 India at this time was through a process called nocturnal 0:12:02.320 --> 0:12:05.800 radiative cooling. Right, I was reading about this this it 0:12:05.880 --> 0:12:08.319 took me a while to grasp how that work. I 0:12:08.480 --> 0:12:09.959 still did not understand it. So, I mean what I 0:12:09.960 --> 0:12:12.199 w I understand that basically they were doing was putting 0:12:12.240 --> 0:12:16.560 water in shallow clay trays and setting it outside under 0:12:16.600 --> 0:12:19.760 the open sky overnight and then in the morning ice 0:12:19.800 --> 0:12:23.280 would be there. Yeah, what what essentially is happening is 0:12:23.320 --> 0:12:27.800 that the uh, it's there is another physical process going 0:12:27.840 --> 0:12:29.600 on here. But you've got you've got a tray of 0:12:29.640 --> 0:12:33.679 water outside. The sky needs to be clear because what's 0:12:33.679 --> 0:12:36.680 happening is the heat is radiating from the water out 0:12:36.720 --> 0:12:40.560 into the atmosphere and escaping that way. Now, if there 0:12:40.559 --> 0:12:44.520 are clouds, then the heat can radiate back down too, 0:12:44.720 --> 0:12:47.720 because it's like an insulator. It'll it'll end up insulating 0:12:47.720 --> 0:12:52.720 the earth and you end up you don't get enough. Right. 0:12:53.080 --> 0:12:56.720 But otherwise, even if the the ambient temperature outside is 0:12:56.800 --> 0:13:00.679 still right around freezing or just above freezing, you can 0:13:00.679 --> 0:13:04.000 still freeze water that way. Under a clear sky also 0:13:04.000 --> 0:13:06.640 helps if it's a very dry climate. Right, And and 0:13:06.679 --> 0:13:08.720 from what I understand that it's important that it's a 0:13:08.880 --> 0:13:11.520 it's an earthenware tray because that way you get some 0:13:11.600 --> 0:13:14.600 of the uh, well, you have to have that insulated 0:13:15.559 --> 0:13:17.720 effect there as well. It's the earthen tray and there's 0:13:17.800 --> 0:13:20.640 usually hay underneath it, Yeah, some kind of compressed Yeah. 0:13:20.679 --> 0:13:23.040 So it's it's interesting that that was the way that 0:13:23.120 --> 0:13:26.640 India was producing ice, but that was not a very 0:13:26.800 --> 0:13:29.199 again and a very efficient way of producing ice. You 0:13:29.240 --> 0:13:31.880 couldn't produce a lot of it, and uh there was 0:13:31.920 --> 0:13:36.080 a big demand. So Tutor was really raking it in 0:13:36.760 --> 0:13:40.320 by harvesting ice in the United States, just natural ice. 0:13:40.520 --> 0:13:43.280 Not he's not producing it in any mechanical means. He's 0:13:43.280 --> 0:13:46.240 actually going out and digging it up, packing it in 0:13:47.000 --> 0:13:49.480 wood shavings and that sort of stuff, cork, that kind 0:13:49.480 --> 0:13:51.440 of thing, shipping it to the other side of the world, 0:13:51.559 --> 0:13:54.439 and making huge bank off of it, huge bank. And 0:13:54.679 --> 0:13:56.600 I want to mention that also right around this time, 0:13:56.960 --> 0:14:02.240 in UH seven, ammonia was first liquefied in a laboratory, right, 0:14:02.320 --> 0:14:04.920 which will becoming point um, So just keep that in 0:14:04.960 --> 0:14:07.080 your heads for a second. And um. And then also 0:14:07.200 --> 0:14:10.160 in eighteen o five, right before Tutor began his big 0:14:10.160 --> 0:14:14.000 ice trade, UM, Oliver Evans described did not create but 0:14:14.040 --> 0:14:17.480 described a closed at their vacuum refrigeration system. Yeah. So 0:14:17.559 --> 0:14:21.480 this is the same sort of of mechanical system that 0:14:21.560 --> 0:14:26.080 would eventually become what we use in refrigerators, most refrigerators, 0:14:26.240 --> 0:14:31.840 I'm saying refrigerators in general, but there are different types. Yeah, well, 0:14:31.840 --> 0:14:35.040 we'll mention a few, but but the we're focusing on 0:14:35.080 --> 0:14:39.040 what most of us have available in like in our kitchens, uh, 0:14:39.560 --> 0:14:43.280 and maybe our basement if Okay, I'm not going to 0:14:43.360 --> 0:14:47.720 go back there. It's dark base to a dark placed 0:14:47.760 --> 0:14:50.880 voco bomb really early on, I'm very fond of that 0:14:50.960 --> 0:14:55.640 of that documentary American Psychos. Okay, that's fair. In eighteen twenty, Uh, 0:14:55.800 --> 0:15:00.520 this is interesting that the Michael Faraday was working again 0:15:00.640 --> 0:15:04.320 with liquid ammonia, and that's when he started realizing that 0:15:05.080 --> 0:15:09.400 liquid ammonia, which ammonia is naturally at room temperature, is 0:15:09.440 --> 0:15:12.160 a gas, right because it boils it at like negative 0:15:12.160 --> 0:15:15.760 twenty seven degrees fahrenheits. So, so to to liquefy it, 0:15:15.840 --> 0:15:18.160 you have to compress it, you have to pressurize it 0:15:18.240 --> 0:15:20.800 to make it a liquid. And he realized that when 0:15:20.800 --> 0:15:25.160 it went from liquid back to gas, it caused cooling 0:15:25.240 --> 0:15:30.480 and so again another important part of this mechanical refrigeration. Now, 0:15:30.600 --> 0:15:35.040 in one a German physicist by the name T. J. 0:15:35.320 --> 0:15:39.600 Cbeck discovered that if you have two junctions of dissimilar 0:15:39.640 --> 0:15:44.840 metals kept at two different temperatures, it induces electromotive force 0:15:44.960 --> 0:15:47.360 or electric currents. So what that means is that, let's 0:15:47.360 --> 0:15:49.880 say that you have a junction of a copper wire 0:15:49.960 --> 0:15:52.600 and an iron wire, all right, and then you have 0:15:52.640 --> 0:15:55.280 a second junction where the iron wire is attached to 0:15:55.400 --> 0:15:58.040 a second copper wire. And let's say you were to 0:15:58.160 --> 0:16:03.040 heat up that, uh, that first junction and cool down 0:16:03.240 --> 0:16:05.360 the second junction, perhaps put some ice on it, you 0:16:05.400 --> 0:16:09.440 would actually induce electricity to flow through that wire. Now 0:16:09.560 --> 0:16:14.800 that's important because in eighteen thirty four, uh Peltier discovers 0:16:14.880 --> 0:16:17.920 that if you do the opposite, if you put electricity 0:16:17.960 --> 0:16:21.240 through a series of wires that have these kind of junctions, 0:16:21.240 --> 0:16:23.160 one side will heat up and the other side will 0:16:23.200 --> 0:16:25.720 cool down exactly and then by up to I think 0:16:25.720 --> 0:16:28.360 forty degrees fahrenheit. It all depends on what kind of 0:16:28.400 --> 0:16:32.560 material material you're using. Uh. In fact, this sort of 0:16:33.120 --> 0:16:35.640 is called the Peltier effect. Actually, but this sort of 0:16:35.760 --> 0:16:39.240 effect is dependent upon the types of metals or or 0:16:39.320 --> 0:16:43.680 materials you're using and uh, their purity. If you're using 0:16:43.680 --> 0:16:47.480 pure metals, the effect is is pretty small, so small 0:16:47.520 --> 0:16:50.000 as to not be very useful. It's interesting in the 0:16:50.080 --> 0:16:52.720 laboratory setting, but not terribly useful. Also, if you're using 0:16:52.720 --> 0:16:56.160 pure metals, they tend to be very good thermal conductors, 0:16:56.480 --> 0:16:59.640 which means that that that difference in temperature will not 0:16:59.720 --> 0:17:03.600 mean taine itself for very long. You will eventually have 0:17:03.880 --> 0:17:06.320 the the heat will move from the high temperature to 0:17:06.359 --> 0:17:10.440 the low temperature and balance that out. Uh. Meanwhile, if 0:17:10.440 --> 0:17:12.800 you were to use an insulator, then you wouldn't get 0:17:12.800 --> 0:17:16.320 the effect, So it would take years before anyone would 0:17:16.359 --> 0:17:18.280 find a way to make that useful. But that is 0:17:18.400 --> 0:17:23.080 used that That same technique is used in some electric 0:17:23.720 --> 0:17:26.240 little portable refrigerators, things like the kind of stuff you 0:17:26.320 --> 0:17:31.040 might plug into your your car outlet. Yeah, basically, you 0:17:31.119 --> 0:17:33.199 just get a whole bunch of these junctions set up. 0:17:33.240 --> 0:17:35.080 You put the hot ones outside the unit, the cool 0:17:35.119 --> 0:17:39.560 ones inside the unit. Fridge. Yep, that's exactly it. So 0:17:39.720 --> 0:17:42.080 so spoiler alert, that's how that one works. But we 0:17:42.119 --> 0:17:44.239 thought if i'd be interesting to talk about that. But 0:17:44.320 --> 0:17:46.800 that's that was what caused was the basis of that 0:17:46.880 --> 0:17:50.200 sort of refrigerator. UM. And that same year, in thirty four, 0:17:50.520 --> 0:17:55.120 Jacob Perkins developed a vapor compression cycle refrigerator using ether. 0:17:55.640 --> 0:17:58.359 So you got a lot of people working on patent 0:17:58.440 --> 0:18:01.679 for it. Happened that year m H and UH eighteen 0:18:01.720 --> 0:18:04.280 forty four you had John Gory proposing an air cycle 0:18:04.320 --> 0:18:08.920 refrigerating machine for making ice. UH. Eighteen fifty you had 0:18:09.119 --> 0:18:12.720 Rudolph Clauseus who said heat can never pass from a 0:18:12.720 --> 0:18:15.640 colder to a warmer body without some other change connected 0:18:15.680 --> 0:18:18.119 there with occurring at the same time. This is what 0:18:18.160 --> 0:18:19.919 I was talking about at the top of the podcast. 0:18:20.240 --> 0:18:24.080 It's kind of a rewording of the second law of thermodynamics. 0:18:24.640 --> 0:18:28.160 It's related to that. So UH, that's one of the 0:18:28.160 --> 0:18:32.080 the principles that guided refrigeration as well. UH. In eighteen 0:18:32.080 --> 0:18:34.520 fifty one, our buddy John Gory from back when he 0:18:34.840 --> 0:18:38.080 had proposed that air cycle refrigerating refrigeration machine to to 0:18:38.119 --> 0:18:40.840 create ice. In eighteen fifty one, that's when he got 0:18:40.880 --> 0:18:44.560 the another patent for mechanical refrigeration. And in eighteen fifty 0:18:44.600 --> 0:18:48.960 five Alexander Twining starts his first commercial ice making plant 0:18:49.040 --> 0:18:53.199 using vapor compression refrigeration. We'll explain what that is in 0:18:53.240 --> 0:18:57.080 more detail in a little bit. Eighteen fifty six, commercial 0:18:57.119 --> 0:19:01.640 refrigeration begins in industries like brewing and meat packing. Now, 0:19:01.840 --> 0:19:06.240 commercial refrigeration did not necessarily mean they were using mechanical refrigeration. 0:19:06.680 --> 0:19:09.560 They could be using natural refrigeration, as in going out 0:19:09.560 --> 0:19:12.959 and buying lots and lots of money and packing stuff. Um. 0:19:13.000 --> 0:19:15.199 It's interesting to me that brewing picked up on this 0:19:15.240 --> 0:19:18.280 really quickly, like like the brewing companies were like, we 0:19:18.320 --> 0:19:21.520 want beer that tastes good. It's as though alcohol technology 0:19:21.560 --> 0:19:24.680 is something that drives industry in some way. Yeah. Meat 0:19:24.800 --> 0:19:29.119 the meat packers were slower to follow suit, which is disturbing. 0:19:30.160 --> 0:19:32.760 Spoiled meat was something everyone was used to write and 0:19:32.800 --> 0:19:35.879 if you're drunk enough, you don't care. Okay, got it. 0:19:36.000 --> 0:19:38.520 I understand now. As someone who does not imbube alcohol, 0:19:38.560 --> 0:19:40.360 it was just completely foreign to me. But I don't 0:19:40.359 --> 0:19:43.600 eat meat either, so what do I care? Um. Also, 0:19:43.720 --> 0:19:46.000 we're no longer in the eighteen fifties, as it turns out. 0:19:46.200 --> 0:19:48.760 But yeah, meat packing was slow to adopt this technology, 0:19:48.800 --> 0:19:51.640 but it did start it back in the eighteen fifties, 0:19:52.040 --> 0:19:55.000 and the majority of plants wouldn't switch to mechanical refrigeration 0:19:55.080 --> 0:19:57.560 until about nineteen fourteen, and by then you were getting 0:19:57.600 --> 0:20:01.159 into a really like a booming time of refrigeration. But 0:20:02.280 --> 0:20:06.000 backtracking just touch in. In eighteen fifty nine we had 0:20:06.040 --> 0:20:10.240 a Ferdinand car of France who developed an ammonious slash 0:20:10.240 --> 0:20:13.960 water refrigeration machine. Eighteen sixty eight you had Peter van 0:20:14.000 --> 0:20:19.400 der Wide. Uh. He patents thermostatically controlled refrigeration systems. That's 0:20:19.400 --> 0:20:21.600 going to be important when we get to the modern refrigerator. 0:20:22.359 --> 0:20:26.359 Eighteen seventy Carl Lynn publishes a paper called the Extraction 0:20:26.400 --> 0:20:29.600 of Heat at Low Temperature by Mechanical Means, and he 0:20:29.640 --> 0:20:33.840 designs the first practical portable compressor refrigeration machine in eighteen 0:20:33.880 --> 0:20:37.520 seventy three. Uh. In eighteen seventy seven, that was the 0:20:37.600 --> 0:20:41.280 peak of the ice trade, so in the US that 0:20:41.400 --> 0:20:44.800 it hit its peak right And the late eighteen seventies 0:20:45.200 --> 0:20:49.040 the United States was exporting almost almost a quarter of 0:20:49.040 --> 0:20:54.320 a million tons of ice to other countries. So uh, yeah, 0:20:54.359 --> 0:20:58.840 a lot of ice leaving the United States. Um and uh, 0:20:59.160 --> 0:21:02.520 it's interesting to me that at this point where the 0:21:02.560 --> 0:21:05.720 ice trade is at its peak, but mechanical refrigeration is 0:21:05.760 --> 0:21:11.120 already in its infancy. The only reason that mechanical refrigeration 0:21:11.320 --> 0:21:15.920 even started to take off, it wasn't because the technology 0:21:15.960 --> 0:21:19.560 was getting great. It's because the ice trade was starting 0:21:19.560 --> 0:21:23.280 to encounter problems. Once it gets to about the eight 0:21:23.560 --> 0:21:27.000 nineties or so, like, if the ice trade had not 0:21:27.240 --> 0:21:32.440 encountered problems, then even with the technological advances in mechanical refrigeration, 0:21:32.720 --> 0:21:35.760 we may not have seen refrigerators in the United States 0:21:36.040 --> 0:21:39.400 for another you know, I don't know four or five decades, 0:21:40.320 --> 0:21:45.400 but so, yeah, and that what happened was was that 0:21:45.880 --> 0:21:51.280 as people were essentially mining ice, you know, cutting away 0:21:51.320 --> 0:21:54.639 ice from these rivers and ponds, they were starting to 0:21:55.640 --> 0:22:01.760 uh exhaust the clean sources of water and so more 0:22:01.800 --> 0:22:05.160 and more of the ice. The demand was growing, right, 0:22:05.160 --> 0:22:08.200 and the supply was diminishing. Not that we were running 0:22:08.200 --> 0:22:10.359 out of lakes and rivers and stuff. It's just the 0:22:10.359 --> 0:22:13.480 demand was so great that there wasn't enough to go around. Yeah, 0:22:13.520 --> 0:22:16.320 there's not there's only that are frozen, and the Hudson 0:22:16.440 --> 0:22:18.399 is really big and stuff. But yeah, I mean when 0:22:18.400 --> 0:22:20.560 you're talking about a quarter of a million tons, right, 0:22:20.880 --> 0:22:23.280 so you're talking about tons of ice that might have 0:22:23.320 --> 0:22:27.760 things like sewage in Uh, not so great when you're 0:22:27.840 --> 0:22:31.119 using it in the meat packing industry as it not 0:22:31.640 --> 0:22:37.320 maybe not such a big advantage over spoiled meat. Um yeah, so. Uh. 0:22:37.920 --> 0:22:40.480 It's because the ice industry was starting to have these 0:22:40.520 --> 0:22:44.360 issues that we began to see the rise of mechanical refrigeration. 0:22:45.800 --> 0:22:48.680 Was when a trade journal called Ice and Refrigeration began 0:22:48.720 --> 0:22:52.520 to publish. Nineteen o four was when the American Society 0:22:52.600 --> 0:22:56.120 of Refrigerating Engineers was founded. By the way, the American 0:22:56.160 --> 0:23:00.400 Society of Refrigerating Engineers, I learned, was about engineers who 0:23:00.440 --> 0:23:02.879 were experts in refrigeration. It was not a society that 0:23:02.880 --> 0:23:07.119 would actually refrigerate engineers. Because the way it was worded 0:23:07.160 --> 0:23:10.760 it was confusing. I find that difficult to believe, Jonathan. 0:23:10.880 --> 0:23:13.359 I think you should check your sources. American Society of 0:23:13.359 --> 0:23:15.679 Refrigerating Engineer. It does sound like you're just shoving a 0:23:15.720 --> 0:23:17.919 guy with a hard hat into a fridge, and that 0:23:18.000 --> 0:23:22.000 brings us back to American Psycho. Nineteen eleven, General Electric 0:23:22.119 --> 0:23:27.240