WEBVTT - Rerun: Super Soakers and Rocket Science 0:00:04.040 --> 0:00:12.200 Welcome to tech Stuff, a production from iHeartRadio. Hey there, 0:00:12.320 --> 0:00:16.000 and welcome to tech Stuff. I'm your host, Jonathan Strickland. 0:00:16.000 --> 0:00:19.319 I'm an executive producer with iHeart Podcasts and how the 0:00:19.440 --> 0:00:24.120 tech are you. So it's a holiday here over at iHeart. 0:00:24.320 --> 0:00:27.920 It's Juneteenth, so we have the day off, but I 0:00:27.960 --> 0:00:31.000 wanted to bring you an episode, and this is an 0:00:31.040 --> 0:00:37.160 episode that originally published back on August tenth, twenty twenty two. 0:00:37.320 --> 0:00:41.640 It is an episode about a really remarkable engineer and inventor, 0:00:42.080 --> 0:00:44.879 and I think it's one of those things that I 0:00:44.920 --> 0:00:49.360 really enjoyed learning about, and I certainly have enjoyed one 0:00:49.400 --> 0:00:52.959 of the inventions, that being the super soaker, something that 0:00:53.040 --> 0:00:57.480 has brought me great joy, especially in the very very 0:00:57.560 --> 0:01:01.760 hot summers of Georgia and the United States. Much of 0:01:01.800 --> 0:01:07.160 it has experienced some pretty record breaking heat waves recently. 0:01:07.280 --> 0:01:10.160 So you know, the idea of an episode about a 0:01:10.280 --> 0:01:14.480 nice way to cool down that's fun and competitive, I 0:01:14.520 --> 0:01:19.200 thought would be a welcome change. So please enjoy this 0:01:19.319 --> 0:01:23.640 episode from August tenth, twenty twenty two, called super Soakers 0:01:24.000 --> 0:01:31.840 and Rocket Science. Since it's summertime when the weather is 0:01:31.920 --> 0:01:34.800 high and you can retright up and touch the sky. 0:01:35.000 --> 0:01:38.560 I figure I can talk about a fun story about 0:01:38.760 --> 0:01:43.240 invention and innovation, something that's near and dear to my heart, 0:01:43.920 --> 0:01:47.920 because these things came out right when I was in 0:01:48.000 --> 0:01:51.280 high school and I thought they were amazing. I want 0:01:51.280 --> 0:01:55.080 to talk about the super Soaker line of water guns, 0:01:55.520 --> 0:01:59.200 and not just because that's a toy that has a 0:01:59.200 --> 0:02:01.760 special place in my mind heart, because I loved these 0:02:01.800 --> 0:02:05.040 things when I was a kid, but also because it 0:02:05.120 --> 0:02:09.000 comes from one heck of a pedigree, because that technology 0:02:09.080 --> 0:02:14.680 was the brainchild of a rocket scientist, a NASA engineer. 0:02:15.280 --> 0:02:18.320 That engineer would be Lonnie Johnson, a man who is 0:02:18.880 --> 0:02:21.680 countless incredible achievements to his name. He's got more than 0:02:21.680 --> 0:02:26.400 one hundred patents to his name. Admittedly, the super Soaker 0:02:26.440 --> 0:02:30.240 bit frequently grabs attention first, although when you look at 0:02:30.280 --> 0:02:33.520 his resume, you think, how did this? How was this 0:02:33.639 --> 0:02:37.120 the lead? How was that the headline? Lonnie Johnson was 0:02:37.120 --> 0:02:41.040 born in Mobile, Alabama in nineteen forty nine, and I 0:02:41.080 --> 0:02:43.919 want to mention this right off the bat, Lennie Johnson's black. 0:02:44.200 --> 0:02:46.160 And I say that because we have to take into 0:02:46.240 --> 0:02:52.040 account that along the way he was facing massive challenges 0:02:52.080 --> 0:02:57.840 in the form of systemic racism. So his achievements are incredible, 0:02:58.480 --> 0:03:00.679 and you on top of that, you have to put 0:03:00.720 --> 0:03:05.200 into a take into account rather this issue of racism. 0:03:05.880 --> 0:03:11.280 You know, he was really facing some enormous obstacles. Well. 0:03:11.360 --> 0:03:14.560 Lonnie's father was a veteran of World War Two and 0:03:14.680 --> 0:03:17.600 worked as a civilian driver at an Air Force base 0:03:17.600 --> 0:03:21.160 in Mobile, Alabama, and his mother worked in a laundry 0:03:21.240 --> 0:03:23.919 and as a nurse's aide. So when he was a kid, 0:03:24.000 --> 0:03:27.560 Lonnie became interested in learning how stuff works. I can 0:03:27.639 --> 0:03:31.400 identify with that. His father, on top of being a driver, 0:03:31.680 --> 0:03:34.480 was also kind of a DIY kind of fella. It 0:03:34.600 --> 0:03:38.320 was mostly out of necessity, learning how to fix things 0:03:38.560 --> 0:03:42.160 and occasionally you know, doing odd jobs and stuff. And 0:03:42.200 --> 0:03:48.280 he passed down this DIY you know, philosophy to his children, 0:03:48.680 --> 0:03:51.840 and Lonnie really took that to heart, and sometimes his 0:03:51.920 --> 0:03:55.160 heart would overrule his head, like the time he was 0:03:55.240 --> 0:03:57.880 thirteen and decided to take an engine out of a 0:03:57.920 --> 0:04:01.720 lawnmower and connect it to a go kart he had 0:04:01.760 --> 0:04:05.200 made out of scraps and then went joy riding down 0:04:05.280 --> 0:04:09.360 the highway. Police had to ask him to pull over. 0:04:09.760 --> 0:04:12.520 Probably not the safest activity for a thirteen year old 0:04:12.520 --> 0:04:17.799 to pursue, but it was a demonstration of his love 0:04:17.920 --> 0:04:21.720 of engineering, and his family told lots of stories of 0:04:21.800 --> 0:04:26.120 Lonnie taking stuff apart to learn how it worked, and 0:04:26.320 --> 0:04:28.400 of course, you know, it was the classic story that 0:04:28.440 --> 0:04:31.440 he wasn't always able to put it back together again. 0:04:31.640 --> 0:04:34.640 So sometimes when Lonnie got his hands on something, that 0:04:34.720 --> 0:04:36.800 was the last time that something was gonna work, but 0:04:36.960 --> 0:04:40.400 he would learn in the process. They also told stories 0:04:40.400 --> 0:04:43.000 about the time he tried to make homemade rocket fuel 0:04:43.240 --> 0:04:47.719 and nearly set his family's house on fire. He would 0:04:47.720 --> 0:04:51.040 go to Williamson High School and that was an all 0:04:51.080 --> 0:04:54.200 black high school because this was still in the days 0:04:54.200 --> 0:04:58.359 of segregation here in the South. You know, you had 0:04:59.160 --> 0:05:02.080 schools that were whites only, in schools that were blacks only, 0:05:02.480 --> 0:05:04.480 and so he went to an all black high school. 0:05:04.920 --> 0:05:08.120 In nineteen sixty eight, he in his school entered a 0:05:08.160 --> 0:05:11.120 science fair competition that was held at the University of 0:05:11.160 --> 0:05:15.080 Alabama at Tuscaloosa, and his school was the only black 0:05:15.160 --> 0:05:19.120 school that was in attendance at the fair. And he 0:05:19.720 --> 0:05:23.159 Johnson had created a kind of robot. He called it 0:05:23.279 --> 0:05:27.559 the Linux, and it was an air powered device, again 0:05:27.960 --> 0:05:31.120 made out of scrap materials like he had rated junkyards 0:05:31.120 --> 0:05:34.159 and stuff and grabbed things that would be helpful and 0:05:34.320 --> 0:05:39.159 made this robot and it took home first prize. Now, reportedly, 0:05:39.200 --> 0:05:41.920 many at the university were not thrilled that the top 0:05:42.000 --> 0:05:45.960 prize was going to a black student. Johnson earned a 0:05:46.040 --> 0:05:49.839 scholarship to attend the Tuskegee University and there he earned 0:05:50.120 --> 0:05:54.039 a bachelor's degree in mechanical engineering. He got that degree 0:05:54.040 --> 0:05:58.680 in nineteen seventy three. Then he pursued postgraduate studies at 0:05:58.760 --> 0:06:04.039 Tuskegee and he earned a master's degree in nuclear engineering 0:06:04.160 --> 0:06:08.039 in nineteen seventy five. So the guy who created the 0:06:08.080 --> 0:06:12.640 super soaker has a master's in nuclear engineering. That's a 0:06:12.640 --> 0:06:14.760 big old whiles up for you, right, Like you wouldn't 0:06:14.760 --> 0:06:17.360 expect that when you pick up a toy that this 0:06:17.520 --> 0:06:20.880 was created by a nuclear engineer. Now, for a short 0:06:20.960 --> 0:06:26.800 while after he graduated from his master's degree, Lonnie Johnson 0:06:26.839 --> 0:06:31.200 worked as a research engineer at Oakridge National Laboratory. That 0:06:31.920 --> 0:06:34.560 was one of the facilities that was involved during the 0:06:34.600 --> 0:06:38.679 Manhattan Project. It was established as part of the Manhattan Project. 0:06:38.720 --> 0:06:41.120 In fact, this was when the United States was first 0:06:41.160 --> 0:06:44.960 developing the atomic bomb. During World War two. Of course, 0:06:45.560 --> 0:06:48.200 that would be ancient history by the time Lonnie Johnson 0:06:48.240 --> 0:06:51.240 had joined the team, but Oakridge continues to pioneer research 0:06:51.640 --> 0:06:55.360 in things like nuclear physics, including nuclear fusion and an 0:06:55.400 --> 0:06:59.880 attempt to build a working nuclear fusion reactor, which if 0:06:59.880 --> 0:07:02.120 we do, you ever managed to do one that actually 0:07:02.680 --> 0:07:08.080 creates a sustainable fusion reaction that would be transformative for 0:07:08.240 --> 0:07:11.120 our energy needs, but you know, we have to get 0:07:11.160 --> 0:07:14.520 there first. Well. Johnson would then join the Air Force 0:07:14.760 --> 0:07:17.840 after that, and he was assigned to head the Space 0:07:18.040 --> 0:07:22.760 Nuclear Power Safety Section at the Air Force Weapons Laboratory. 0:07:23.360 --> 0:07:26.280 He stayed there until nineteen seventy nine, and at that 0:07:26.360 --> 0:07:31.000 point he joined NASA's Jet Propulsion Laboratory and served as 0:07:31.000 --> 0:07:36.520 a senior system's engineer. He began work on the Galileo project, 0:07:36.680 --> 0:07:40.760 so he was part of the Galileo Project team. Galileo 0:07:41.320 --> 0:07:43.880 was a probe that we sent to study Jupiter and 0:07:43.960 --> 0:07:48.760 its moons. That project would ultimately be monumentally successful from 0:07:48.760 --> 0:07:52.960 a scientific perspective. Now, Johnson worked on this early on 0:07:53.040 --> 0:07:56.000 in the program. He would not be part of that 0:07:56.120 --> 0:08:00.520 team when the probe would ultimately launch later in the 0:08:00.600 --> 0:08:03.920 nineteen eighties, but he did work on it early on 0:08:04.680 --> 0:08:08.240 in nineteen eighty two, Lonney Johnson would actually leave NASA 0:08:08.360 --> 0:08:11.440 and return to the Air Force and he was now 0:08:11.560 --> 0:08:16.600 an Advanced Space Systems Requirements Officer at the Strategic Air 0:08:16.720 --> 0:08:20.160 Command Headquarters. He would also serve as the chief of 0:08:20.200 --> 0:08:24.280 the Data Management Branch of Strategic Air Command Test and 0:08:24.320 --> 0:08:28.440 Evaluation Squadron at Edward's Air Force Base. He was one 0:08:28.480 --> 0:08:31.000 of the engineers who would also work on the development 0:08:31.200 --> 0:08:34.920 of the Stealth Bomber, which was a super secret project 0:08:34.920 --> 0:08:38.319 at the time. Johnson actually talked about how he wouldn't 0:08:38.320 --> 0:08:40.800 even be able to tell his wife what he was 0:08:40.840 --> 0:08:44.040 working on at the time because it was classified as 0:08:44.160 --> 0:08:47.160 top secret. He would pop back over to NASA's Jet 0:08:47.160 --> 0:08:50.600 Propulsion Laboratory in nineteen eighty seven to work on the 0:08:50.640 --> 0:08:54.280 Cassini project. Cassini was a probe that we sent to 0:08:54.320 --> 0:08:57.440 study Saturn, and he was also at work on a 0:08:57.480 --> 0:09:01.400 project that would unexpectedly evolve in to the super Soaker. Now, 0:09:01.880 --> 0:09:05.080 that was something that he had been kind of working 0:09:05.080 --> 0:09:09.960 on on and off for several years. You see, Lonnie 0:09:10.040 --> 0:09:13.720 Johnson did not set out to make a new kind 0:09:13.840 --> 0:09:17.280 of water gun, you know, a water gun that would 0:09:17.360 --> 0:09:20.640 leave those little old squirt guns far behind. He wasn't 0:09:20.679 --> 0:09:25.000 trying to create a weapon of mass saturation. It was 0:09:25.080 --> 0:09:28.439 not his dream to grant battlefield superiority to the kid 0:09:28.440 --> 0:09:31.040 who could go out and buy a water gun capable 0:09:31.080 --> 0:09:33.840 of shooting streams of water further than any other on 0:09:33.880 --> 0:09:38.040 the market. Lannie Johnson was trying to do something else entirely. 0:09:38.679 --> 0:09:42.280 He was trying to solve a very tricky problem. He 0:09:42.360 --> 0:09:46.880 wanted to create a heat pump that used water instead 0:09:46.920 --> 0:09:50.040 of free on as a refrigerant, and he started on 0:09:50.080 --> 0:09:52.880 this work way back in the early nineteen eighties. So 0:09:52.920 --> 0:09:55.000 he did this while he was at the Air Force 0:09:55.040 --> 0:09:57.880 working on the Stealth Bomber. So he couldn't talk about 0:09:58.000 --> 0:10:00.560 the stealth bomber work, but he could talk about his 0:10:00.679 --> 0:10:04.240 sort of personal project, which was trying to suss out 0:10:04.240 --> 0:10:06.440 if there would be a way to make a working 0:10:06.520 --> 0:10:10.760 heat pump, an effective heat pump using water. So we're 0:10:10.800 --> 0:10:15.079 going to talk about heat pumps and how they work 0:10:15.559 --> 0:10:18.360 and why it was important to try and find an 0:10:18.400 --> 0:10:21.360 alternative to free on, so that we can have an 0:10:21.440 --> 0:10:25.839 understanding of what it was that was fueling his innovation 0:10:26.440 --> 0:10:30.080 and ultimately would spawn the super soaker. But Before we 0:10:30.160 --> 0:10:42.760 get to all of that, let's take a quick break. Okay, 0:10:43.559 --> 0:10:48.000 let's talk about heat pumps. Now. The heat pumps I'm 0:10:48.040 --> 0:10:50.760 talking about here, they work in a way that's similar 0:10:50.800 --> 0:10:54.240 to an air conditioner. In fact, there are several elements 0:10:54.240 --> 0:10:57.840 in heat pumps that are identical to things you would 0:10:57.840 --> 0:11:01.319 find in an air conditioner, except a heat pump can 0:11:01.440 --> 0:11:06.400 potentially transfer heat inside a building or outside a building. 0:11:06.440 --> 0:11:10.600 Thus it can either heat or cool a building using 0:11:10.840 --> 0:11:15.959 one system. Air Conditioners are not like that. They are 0:11:16.040 --> 0:11:19.120 a one way thing, right. They pull heat out of 0:11:19.160 --> 0:11:22.840 a building and they bring cool air in. But that's it. 0:11:22.920 --> 0:11:25.640 You can't heat a building with an air conditioner. You 0:11:25.679 --> 0:11:28.680 need a separate system. You need a furnace. So a 0:11:28.760 --> 0:11:33.120 heat bump can do both. And technically a heat pump 0:11:33.120 --> 0:11:35.440 can also be a one way type of deal. It 0:11:35.440 --> 0:11:38.240 could also be like an air conditioner, or it could 0:11:38.280 --> 0:11:41.839 be like a furnace. If you wanted where it could 0:11:41.840 --> 0:11:46.240 not reverse. The reverse is only made possible by using 0:11:46.280 --> 0:11:49.720 a reversing valve. But that's the thing is that a 0:11:49.760 --> 0:11:52.520 heat pump can do that. You can have a reversing 0:11:52.640 --> 0:11:56.400 valve installed within the system and you change where the 0:11:56.440 --> 0:11:59.360 heat is being pumped. Really, that's all it is. It's 0:11:59.440 --> 0:12:03.200 all a heat transfer system. It transfers heat from one 0:12:03.240 --> 0:12:06.760 location to another. When you're heating a building, it means 0:12:06.760 --> 0:12:09.760 you're taking heat from outside and bringing it inside. And 0:12:09.840 --> 0:12:12.200 when you're cooling a building, you're taking the heat from 0:12:12.200 --> 0:12:15.520 inside and you're putting it outside. That's really all there 0:12:15.600 --> 0:12:20.319 is to it. But how does it do that well? 0:12:20.520 --> 0:12:23.400 I could technically do a full episode about this, but 0:12:23.720 --> 0:12:26.440 I'll try and keep it short. It's also a little 0:12:26.480 --> 0:12:29.840 tricky to talk about when you don't have visual aids, 0:12:29.920 --> 0:12:33.680 but we're gonna do our best. So your typical air 0:12:33.720 --> 0:12:35.959 to air heat pump solution, there are a lot of 0:12:36.000 --> 0:12:38.120 different types of heat pumps. We'll talk about air to 0:12:38.160 --> 0:12:40.880 air because one they're the most common and two they're 0:12:40.880 --> 0:12:44.760 really simple. But your basic air to air heat bump 0:12:44.800 --> 0:12:48.800 solution consists of a pair of heat exchangers. You have 0:12:48.880 --> 0:12:52.360 one heat exchanger that's outdoors and you have one heat 0:12:52.400 --> 0:12:56.560 exchanger that's indoors. These are connected via pipes and a 0:12:56.640 --> 0:13:00.600 reversing valve that allows the flow to reverse directions, and 0:13:00.679 --> 0:13:05.240 there's a compressor and there's also some other valves, expansion valves, 0:13:05.280 --> 0:13:08.560 that control the flow of refrigerant in the system and 0:13:08.679 --> 0:13:13.520 bypasses for those expansion valves. That's also important. So I'll 0:13:13.559 --> 0:13:17.160 talk about expansion valve one and two for the sake 0:13:17.240 --> 0:13:20.880 of this description so that you can understand why they exist. 0:13:21.360 --> 0:13:24.000 And really you only need two if you do have 0:13:24.040 --> 0:13:27.080 a reversing heat pump system. If it's just going in 0:13:27.120 --> 0:13:29.960 one direction, you just need one expansion pump and that's it. 0:13:30.000 --> 0:13:32.600 You don't even have to have a bypass. It's only 0:13:32.600 --> 0:13:35.319 if you want to both heat and cool a building 0:13:35.360 --> 0:13:37.360 with a heat pump that you would need two of them. 0:13:37.720 --> 0:13:40.760 So let's start with the compressor, because really that's where 0:13:41.360 --> 0:13:45.640 the journey begins. And the compressor's job is to compress 0:13:45.840 --> 0:13:49.600 the refrigerant that's flowing through this system. Now, compressing a 0:13:49.640 --> 0:13:54.960 fluid in this case, it's essentially a vapor, it causes 0:13:55.400 --> 0:13:58.600 not just the pressure to increase, but it also causes 0:13:58.640 --> 0:14:02.280 the temperature of that fluid to increase. So what you 0:14:02.400 --> 0:14:06.400 end up with is a super heated vapor under very 0:14:06.480 --> 0:14:09.640 high pressure, and you allow that to travel through the 0:14:09.679 --> 0:14:13.960 lines out from the compressor. And let's say in this case, 0:14:14.000 --> 0:14:17.080 it's the winter and we want to heat the inside 0:14:17.080 --> 0:14:21.240 of our house. So we would have a system set 0:14:21.280 --> 0:14:24.640 so that the hot, high pressure vapor travels to the 0:14:24.800 --> 0:14:31.160 indoor heat exchanger. Now, this is essentially coils of tubeing 0:14:31.200 --> 0:14:35.120 made out of a material that conducts heat efficiently, like copper. Right, 0:14:35.480 --> 0:14:41.440 So this super high pressure, very hot vapor goes through 0:14:41.480 --> 0:14:45.880 these coils of tubing. Behind the coil of tubing, you 0:14:45.920 --> 0:14:50.720 have a fan. The fan blows cooler air across these 0:14:51.400 --> 0:14:56.160 hot coils, and that carries some of that thermal energy, 0:14:56.280 --> 0:14:59.480 some of that heat away from the coils. That's what's 0:14:59.520 --> 0:15:03.360 providing heat to the house. That's where the warm air 0:15:03.400 --> 0:15:05.720 is coming out of the vents. It's because that air 0:15:05.960 --> 0:15:09.080 was blown across these very hot coils and some of 0:15:09.120 --> 0:15:12.160 that heat transferred to the air and thus is warming 0:15:12.200 --> 0:15:15.920 your house. So the cool air starts to pull away 0:15:15.960 --> 0:15:19.680 some of that thermal energy. Well. As the thermal energy 0:15:19.760 --> 0:15:25.680 goes down inside this fluid, then the fluid itself begins 0:15:25.680 --> 0:15:29.120 to condense, it begins to convert from gas to liquid. 0:15:29.720 --> 0:15:32.520 And it's still hot, it's still had a high pressure, 0:15:32.720 --> 0:15:35.000 it's just not quite as high pressure as it was 0:15:35.000 --> 0:15:36.880 when it entered into the heat exchanger, and it's not 0:15:36.960 --> 0:15:40.800 quite as hot as it was. But this heated liquid 0:15:41.360 --> 0:15:45.520 will bypass expansion valve number one, So it goes around 0:15:45.600 --> 0:15:48.640 this valve, it doesn't go through it. The expansion valve. 0:15:48.680 --> 0:15:50.960 If you can think of it as pointing in a direction, 0:15:51.240 --> 0:15:54.840 it's pointing back the way this liquid has come. So 0:15:55.400 --> 0:15:59.120 it bypasses this valve. Then it goes through expansion valve 0:15:59.200 --> 0:16:01.960 number two. That's point in the opposite way. Now, an 0:16:01.960 --> 0:16:07.760 expansion valve allows this pressurized liquid to expand, for its 0:16:07.880 --> 0:16:11.760 volume to expand. Well, that means that the pressure of 0:16:11.800 --> 0:16:17.240 the liquid drops suddenly, as does its temperature. That's the 0:16:17.360 --> 0:16:20.760 relationship here. When you've got high pressure, you've got high temperature. 0:16:20.760 --> 0:16:24.000 When you've got low pressure, you've got low temperature. So 0:16:24.160 --> 0:16:27.520 this expansion valve allows for the rapid expansion of this 0:16:27.640 --> 0:16:30.640 liquid into a kind of a mixture of liquid and 0:16:30.720 --> 0:16:35.200 vapor that is much cooler in temperature. This mixture then 0:16:35.320 --> 0:16:39.880 passes through the coils in the outdoor heat exchanger. That's 0:16:39.920 --> 0:16:45.440 just blowing ambient air across the coils. Well, the temperature 0:16:45.440 --> 0:16:49.160 of the refrigerant has now dropped so low that even 0:16:49.200 --> 0:16:53.040 in the winter time, the air outside is typically warmer 0:16:53.080 --> 0:16:57.200 than the refrigerant is so it can be very cold 0:16:57.200 --> 0:16:59.520 outside and still be warm enough to warm up the 0:16:59.560 --> 0:17:03.320 refriger quite a bit, and so a little bit of 0:17:03.360 --> 0:17:08.320 thermal energy gets transferred into this fluid. The refrigerant then 0:17:09.359 --> 0:17:11.640 brings along some of that thermal energy, and it gets 0:17:11.680 --> 0:17:15.000 pumped back through the reversing valve to go back into 0:17:15.040 --> 0:17:18.600 the compressor, and then the whole thing starts up again. Right, 0:17:19.000 --> 0:17:23.840 the compressor compresses this mixture of vapor and liquid that's 0:17:23.880 --> 0:17:27.840 cooler into a high pressure vapor that is very high 0:17:27.880 --> 0:17:31.679 temperature and puts it back through the system again. Now, 0:17:31.840 --> 0:17:35.719 if you wanted to cool your house, this whole system 0:17:35.760 --> 0:17:40.159 moves in reverse. So the compressor still compresses the refrigerant, 0:17:40.160 --> 0:17:42.639 still makes it very hot, but now it goes to 0:17:42.720 --> 0:17:45.800 the outdoor heat exchanger, which takes away some of that 0:17:45.800 --> 0:17:49.439 thermal energy and allows the superheated high pressure vapor to 0:17:49.480 --> 0:17:54.440 condense into hot, slightly less hot, and slightly less pressurized 0:17:54.480 --> 0:17:59.080 liquid that then bypasses expansion valve too. It goes to 0:17:59.280 --> 0:18:03.360 expansion valve of one, expands into the very low pressure, 0:18:03.400 --> 0:18:07.879 low temperature mixture of vapor and liquid, moves through the 0:18:07.920 --> 0:18:11.840 indoor heat exchanger, which is blowing warm air across these coils. 0:18:12.240 --> 0:18:14.920 The coils are very very cold, so then you get 0:18:15.040 --> 0:18:19.760 cool air blowing into your house, and then the fluid 0:18:19.880 --> 0:18:24.919 continues on back to the compressor. Now, the reason I 0:18:24.960 --> 0:18:27.560 give all that is because you know you have to 0:18:27.640 --> 0:18:33.760 understand those basic pieces. But why was Johnson working on 0:18:33.960 --> 0:18:38.320 an improvement or attempting to create an improved heat bump. Well, 0:18:38.359 --> 0:18:41.840 it's because the typical heat bump was using free on 0:18:42.320 --> 0:18:49.240 as the refrigerant. Now freeon is technically called dichlora diflora methane, 0:18:49.880 --> 0:18:53.399 and this stuff has the useful trait of having a 0:18:53.440 --> 0:18:56.200 boiling point that's all the way down to minus twenty 0:18:56.280 --> 0:18:59.880 nine point eight celsius or minus twenty one point six 0:19:00.119 --> 0:19:03.560 for fahrenheit. Now, remember, like water's got a boiling point 0:19:03.600 --> 0:19:06.720 of one hundred degrees celsius or two hundred and twelve fahrenheit. 0:19:07.160 --> 0:19:11.000 That's pretty hot, But free on it'll boil off into 0:19:11.040 --> 0:19:14.760 a gas at negative twenty nine point eight celsius. So 0:19:15.160 --> 0:19:18.600 you see that even in cold winters, there's still enough 0:19:18.600 --> 0:19:22.080 heat in the ambient air to boil off the refrigerant 0:19:22.119 --> 0:19:24.959 in the heat exchanger, unless you're in like a super 0:19:25.119 --> 0:19:27.760 duper cold environment where you would be kind of stuck. 0:19:28.200 --> 0:19:31.199 The heat pump would not be a big help. However, 0:19:31.280 --> 0:19:34.960 freeon has some drawbacks. Now, a big drawback is that 0:19:35.080 --> 0:19:40.000 it contributes to environmental damage. It can it is a 0:19:40.119 --> 0:19:45.120 chemical that, when released into the atmosphere, can do massive 0:19:45.160 --> 0:19:47.960 damage to the ozone layer. Now, this was such a 0:19:48.000 --> 0:19:52.880 concern in the nineteen nineties that countries agreed to ban 0:19:53.040 --> 0:19:57.280 the manufacture of free on. First developed nations all agreed 0:19:57.320 --> 0:20:01.679 to stop manufacturing free on in the mid nineties, but 0:20:02.000 --> 0:20:05.000 for developing countries it was considered to be kind of 0:20:05.400 --> 0:20:08.680 I mean, it's looked on as a complicated situation. Right. 0:20:08.800 --> 0:20:12.280 You have a country that's on its way toward development 0:20:12.920 --> 0:20:15.800 telling it, hey, you can't benefit from the same stuff 0:20:15.840 --> 0:20:18.760 that we benefited from because it turns out that's harmful. 0:20:19.280 --> 0:20:22.000 That's a complicated thing. So those countries actually had until 0:20:22.000 --> 0:20:26.399 twenty ten to stop making free on. These days, we 0:20:26.440 --> 0:20:30.640 still use free on, but only in very specific use cases, 0:20:30.680 --> 0:20:34.080 like as a fire retardant in like submarines or aircraft. 0:20:34.640 --> 0:20:38.880 So Lonnie Johnson wanted to create a new kind of 0:20:39.040 --> 0:20:42.240 heat pump that would just use plain old water as 0:20:42.240 --> 0:20:45.000 a refrigerant instead of free on. So there was this 0:20:45.040 --> 0:20:48.360 growing concern about free on and similar chemicals and their 0:20:48.520 --> 0:20:53.320 environmental impact. But this was before countries had decided to 0:20:53.400 --> 0:20:56.640 ban the stuff, and so really Johnson was just trying 0:20:56.640 --> 0:21:02.919 to think of an alternative that would be and you know, 0:21:03.359 --> 0:21:06.600 have less of an environmental impact, and water would definitely 0:21:06.640 --> 0:21:09.119 fit the bill if you could make it work. So 0:21:09.280 --> 0:21:13.600 he's kind of thinking this through and creating a system, 0:21:14.160 --> 0:21:18.359 and part of that meant that he machined his own nozzles. 0:21:18.800 --> 0:21:21.879 So he used machining equipment to make nozzles for his 0:21:22.160 --> 0:21:26.800 heat pump design, and one day, while testing out his 0:21:26.960 --> 0:21:29.919 nozzles in his bathroom, he shot a tight stream of 0:21:29.960 --> 0:21:33.199 water clear across the bathroom in a very focused stream, 0:21:34.280 --> 0:21:38.520 and then got in to thinking about water guns. Okay, 0:21:38.760 --> 0:21:41.240 I'm going to talk more about water guns and their design, 0:21:41.760 --> 0:21:53.200 but first let's take another quick break. Okay, we're back. 0:21:53.320 --> 0:21:57.000 Let's talk about your classic water gun. So this is 0:21:57.119 --> 0:22:00.639 pre super soaker, the little squirt toy version of water guns, 0:22:00.680 --> 0:22:02.600 the kinds of that you might find in like a 0:22:02.640 --> 0:22:05.960 dollar store or something. Now, your typical water gun has 0:22:05.960 --> 0:22:09.520 a spring loaded trigger, and that trigger activates a lever. 0:22:09.920 --> 0:22:13.920 That lever in turn activates a very small pump inside 0:22:14.400 --> 0:22:17.639 the water gun, and the pump's job is to pump 0:22:17.720 --> 0:22:21.199 water from a reservoir and the gun. Often with these 0:22:21.200 --> 0:22:24.040 squirt guns, the entire interior of the gun acts as 0:22:24.040 --> 0:22:27.240 a reservoir and it pumps the water through a plastic 0:22:27.320 --> 0:22:29.760 tube and out a narrow path at the end of 0:22:29.800 --> 0:22:32.600 the gun's barrel, where a nozzle focuses the escaping water 0:22:32.680 --> 0:22:35.160 into a stream. So let's take that step by step 0:22:35.200 --> 0:22:39.040 to understand exactly what's working from a mechanical perspective. So 0:22:39.760 --> 0:22:43.240 you've got your plastic tube that extends into the water reservoir. 0:22:44.080 --> 0:22:47.000 If you follow that plastic tube from the reservoir up, 0:22:47.040 --> 0:22:48.919 you'll see that it leads to a pump. And the 0:22:48.960 --> 0:22:52.000 pump is a very simple thing. It's a cylinder and 0:22:52.040 --> 0:22:55.000 it's a piston. And the piston, when you pull the trigger, 0:22:55.040 --> 0:22:58.080 will move into the cylinder. Now, when the piston moves 0:22:58.160 --> 0:23:01.800 into the cylinder, it forces water or air or whatever 0:23:02.280 --> 0:23:04.840 out of the cylinder. Right, it can't be in the 0:23:04.880 --> 0:23:09.920 cylinder the piston's there. Also, inside the cylinder is a spring, 0:23:10.119 --> 0:23:14.960 So when the piston enters the cylinder, it compresses the spring, 0:23:15.480 --> 0:23:18.240 and when you release the trigger, it allows the spring 0:23:18.320 --> 0:23:21.280 to expand to full size. That forces the piston back 0:23:21.400 --> 0:23:24.840 out of the cylinder again, and when that happens, there's 0:23:24.840 --> 0:23:27.959 a vacuum, and nature abhors a vacuum, so water and 0:23:28.160 --> 0:23:31.520 or air flows back into the cylinder because it's been 0:23:31.600 --> 0:23:35.600 left empty by the piston's movement. Right. So when you 0:23:35.680 --> 0:23:38.560 pair this with a couple of one way valves in 0:23:38.640 --> 0:23:42.480 those tubes, you have yourself an effective pump. So one 0:23:42.520 --> 0:23:45.919 of those valves will allow water to move from the 0:23:46.040 --> 0:23:49.600 reservoir into the cylinder. So when you let go of 0:23:49.640 --> 0:23:52.960 the trigger and the piston is moving out of the cylinder, 0:23:53.400 --> 0:23:57.800 the pump sucks water up from the tube, but the 0:23:57.800 --> 0:23:59.960 water cannot flow back in the opposite direction. This is 0:24:00.119 --> 0:24:03.880 also why you sometimes have to prime the old water pistols. 0:24:03.920 --> 0:24:05.800 You have to pull the trigger a few times because 0:24:06.200 --> 0:24:09.840 you actually have to use that piston to suction water 0:24:10.000 --> 0:24:13.159 up from the reservoir to go into the pump in 0:24:13.280 --> 0:24:16.640 order to have it ready to push the water out 0:24:16.680 --> 0:24:20.480 of the gun. Now, the other one way valve leads 0:24:20.800 --> 0:24:24.240 from the pump to the nozzle in the gun's barrel. 0:24:24.840 --> 0:24:28.320 So when you pull the trigger. It pushes the piston 0:24:28.560 --> 0:24:31.560 through the cylinder, forces water out of the pump, and 0:24:31.640 --> 0:24:35.119 the only place the water can go is through this tube, 0:24:35.359 --> 0:24:38.120 through that one way valve, and out through the nozzle 0:24:38.400 --> 0:24:40.880 because the other one way valve blocks the water from 0:24:40.920 --> 0:24:44.119 going back into the reservoir. Now, because there is a 0:24:44.160 --> 0:24:48.119 one way valve right there heading to the barrel of 0:24:48.160 --> 0:24:50.720 the gun, that means when you let go of the 0:24:50.720 --> 0:24:55.200 trigger and you have the suctioning action happening again, when 0:24:55.240 --> 0:24:57.920 the piston is moving out of the cylinder, that one 0:24:57.920 --> 0:25:01.600 way valve seals shut, so air cannot come back in 0:25:02.119 --> 0:25:05.720 through the gun barrel. The only place where the suction 0:25:05.920 --> 0:25:10.000 can pull anything through is through the reservoir because that 0:25:10.240 --> 0:25:12.800 one way valve allows water to go from the reservoir 0:25:12.880 --> 0:25:15.040 back into the pump. You have to have those one 0:25:15.080 --> 0:25:18.119 way valves or else if you were to lego of 0:25:18.160 --> 0:25:20.520 the trigger and it could just pull air from the barrel, 0:25:20.600 --> 0:25:24.399 then you wouldn't suction air up out of the reservoir anymore. 0:25:24.400 --> 0:25:26.840 You could have a full water gun and keep pulling 0:25:26.880 --> 0:25:29.080