Adam Savage's One Day Builds: Refrigerated Cooling Suit!

Adam Savage here in my cave with my friend Kipp Bradford, how are you sir? Very good. I'm excited because we're about to explore a new view of cosplay technology. If you're a regular follower, you'll know that I built it myself. a space

suit

from the alien John Hurt

suit

and I wore Don on the floor of Comic-Con in San Diego in 2012 2014 in 2014 and I almost got heatstroke wearing basically what was a quilt with armor attached to it, so The following year Chris Hadfield and I walked. the floor in a pair of spacesuits from 2001, the silver Clavia suits into which he had built an integral

cooling

system consisting of a bucket of ice water with a recirculation pump, and cool T-shirts that worked quite well, but Kip, between many other things he has done in his life as an engineer he specializes in extremely small refrigeration units and we are hoping to build one here in the cave today small enough that he can use it in cosplay so get ready we are going to get cold ok ?

Kip, where is he? We start, there are many small details in the workshop. I'm not even sure I know what this is, yeah, okay, so where do we start? Adam, this is the compressor. Okay, oh, this is the step that fulfills Boyle's law that does bring

cooling

. and it recirculates these things, yes, our gas, so what is it? You compress it when you release it from the compression, the temperature goes down, it corrects itself and you get the cooling, that's exactly it, so the compressor works like any compressor. There's a piston inside here in this. In case the piston is a rotating piston, so it rotates and by doing so it is a vane pump.

These are the palette pocket. As a vane pump, it sucks a gas into this inlet, draws it through the compressor and increases the pressure as in Boyle's law. PV equals NRT as the pressure increases, the heat also increases the temperature because we are doing mechanical work, we put electricity in here, that electricity is what makes the right magnetic field pump the rotor, the rotor, the vein, the vein squeezes the gas, we are working on the gas well, so, just like if you are pushing down on a bicycle pump, it can heat up, it heats up as you do that work, so the energy from your arms is transmitted to the pressure of that gas, then the gas heats up as we work with it and it compresses, we can push that hot gas through another heat exchanger where we blow air on it and take that heat away and when we take the heat away , we are not just eliminating it. heat, actually we are also compressing the gas or we are just removing the heat, okay, so the pressure, the pressure on this outlet side remains constant mm-hmm, the temperature is what changes, so we take that gas to constant pressure and blow the air. about it and the reason the pressure doesn't change is because even if we remove all that heat from the gas itself, there is more new gas coming in from the back, so what happens is not that the pressure changes but it changes the state from which we pass.

From gas to liquid, I see it because we are taking the temperature, we can put more gas in the same volume, we can put more gas in the same volume, okay, that becomes a liquid and that liquid then goes to the other half of the system where we boil it and what we stir it is how we lower the temperature exactly, look, I don't have a refrigerator, it works. I'm logged in my time just a little. If you are an engineer, you will notice this. like a reverse Rankine cycle, well, a thermodynamic cycle that is a completely closed circuit and we work with a piston or rotor or some type of machinery that performs that compression, so we put mechanical work into the system and we go from electricity to mechanical work for thermal and then we get rid of the thermal and then we reverse and go back to the cold side, we boil, we turn to gas and the waste sucks the gas back into the inlet and I'm surprised this is an especially small compressor, am I right? is this is this is one of the smallest this is one of the smallest compressors and this has a pretty fascinating history in the first Gulf War DARPA put out a call for a portable, portable environmental control system Oh, so exactly what We are working on exactly that and an RFP was made for small compressors, yes, and two companies, one of those RFPs and one of those companies is Aspen compressor in Marlborough, Massachusetts, these are made in Kentucky, the design of the compressor is a fascinating PhD in mechanical engineering from MIT, of course.

Of course, it makes these super small, incredibly well balanced, high efficiency compact compressors, and when you say well balanced, that means the compressor is efficient because it doesn't lose any of its energy to vibration, so when it's highly balanced you have a smooth system and everything. the energy goes exactly where you want it and it means that if you use it you won't get all that except vibration in your tears. Oh again, it won't make much noise if you ever have your tent. The compressor comes on in the middle of the night and you hear that, man, oh, I have to set a timer for the right time.

Wake up my neighbor exactly. Yes, I know normal people live upstairs and sometimes we make their lives worse. I don't know, they've never done it. I complained about the type of music. I love history. Well, the good thing about the DARPA story is that DARPA makes this call and gets a couple of companies to respond with these super compact and compressor technologies and they quickly figure out what to put people on. in space suits in the middle of the desert, trying to fight a war is a bad idea, because if you have some kind of failure in the system, they get super compromised immediately, but we got this cool technology out of this and this notion that you can make systems of very compact refrigeration and cooling using a low voltage portable DC compressor technology, so the original purpose of this was to wage wars with people in these crazy suits.

Yes, it's not the smartest idea, I think the result has been quite transformative for many doctors. applications I use them for a medical evacuation system that could stabilize the temperature of people in medical evacuation helicopters after traumatic injuries on their way to a hospital. Humbly, nothing substantial is being done. You can actually take down their doctors. Wow, so I found other uses for it. I made some. fun projects and the last system I built was the second smallest portable air conditioner in the world. I couldn't get him to be the smallest, he only got to be the second smallest and is currently in a NASA space suit simulator that is running around the world pretending. being on Mars, oh, simulation space, they're kind of like what the guys use in the high seas experiment, it was on the high seas, so it's okay.

Oh, fabulous, fabulous, what we are going to build is a replica of the high seas, basically air conditioning, oh. Oh my gosh, that's really exciting. I've followed the offshore experimentation project for years, obviously, I revere what those guys have been through and I know the complications of that program, but I also love those suits and they're great. I love reading about how. How much they love their suits, they fall in love with them, okay, so what's the point? Obviously, this is the center piece of this, but how do we start making our assemblies so that this is our center piece and there are two other pieces that we need? one heat exchanger to reject the heat mhm and we need another heat exchanger to absorb the heat.

One of those heat exchangers that rejects heat will go from the refrigerant, which is a gas in this case, to the air, okay, and we'll have a fan blowing. the air over that, the second heat exchanger will go from liquid refrigerant, as it is vaporizing, to cold water and that water will then circulate through its cold jacket. Oh, okay, so there's going to be a heat exchanger between the right, so it would take like a big aluminum. plate that is touching the water or something like that, something like that will actually use a stainless steel heat exchanger that will go directly from the boiling coolant to the water, oh, to it, oh, okay, and we will adjust the system a little bit so that the water doesn't freeze or you can also use alcohol instead of water and great, I don't have money for that even colder ah yes, let's use alcohol, so let's see, I love that idea yes, yes, Mr. purple, it will work.

Isopropyl works. Actually I usually use. alcohol with vodka oh yes, great, yes, we will send for a vodka. There is much in the mission to serve and accelerate. Why vodkas are great because they are non-toxic, depending on how much you drink, since I don't drink, that's fine. Gather the pieces here, let's light the fire. Okay, these are both versions of the same thing. These are two versions of the same thing. We have a huge changing table and then a smaller key exchanger. Now the high seating project uses this smaller heat exchanger. mhm and the offshore project is not that sensitive to noise mm-hmm, we can generate a little more noise and it won't cause you any problems, although I think we want to use a larger heat exchanger and a quieter fan. so the weight is not much different no it is quite negligible so sure yeah listen I can fit something as big as this and then we are also going to put two other heat exchangers on the table we will talk about these two as well because they are Pretty cool technologies Aspen Compressor, an American company made in the USA that has some really clever technology and it's hard to get refrigeration components in low quantities.

Most of these companies do not sell to consumers or individuals. Now he doesn't sell to consumers or individuals. but if you go to an HVAC store you won't find compressors like this, you won't find compounds like this. They sell repair parts from those HVAC stores, so it's difficult to develop the supply chain knowledge to know where to get it. things, these two components are made in the USA, this is a heat exchanger from the company called all coil which is in New York, Pennsylvania, and they make components in small quantities ideal for specialized applications like what we are doing if it were To a company, say in China or Thailand, that manufactures these for refrigerators or air conditioners, the minimum orders will be 10,000 units.

Okay, answer the phone. You have to send them a check for 10,000 units and then they will put in a good word. All coils are great because you can order one. Oh, and to be clear about the structure of this, this is just a wide, flat tube, yes, and through which the material passes, and all of this is simply an aluminum surface meant to remove heat, okay, that's super cool so this is called a Microchannel Heat Exchanger and it has little microchannels that run along each of these coils so there's maybe a hundred channels up and down here and we push the gas into this end that the gas flows through and because we're pulling so much heat the gas is a liquid at the wrong time, the other side stands up and it's incredibly cool, that's really neat and seeing all the way through this thing and The larger the heat exchanger is for a given amount of gas we are trying to cool, the more surface area we have to draw that gas and the less air we need to blow over a given surface, Scottlo, so the air flow a bulk might be the same, but if the bigger fan I make for a given amount of airflow mm-hmm, the slower and quieter the fan can get, so if I have a really small fan and I'm blowing, let's say Exner's CFM x / CFM.

I have high speed, it was noisy, of course, if I double the size, I quadruple that surface area. and I can reduce the speed proportionally and then also have quieter fan blades because they don't cut the air, which is fine, so a bigger fan means it's quieter, okay? It also means we can actually run your system if you want if you're like I need 800 watts of cooling good things to know about the body while we're here right now we're not being very active we're dissipating about 100 watts of heat I'm talking about well bulb heat up those incandescent bulbs I guess kids maybe don't know about those yeah kids yeah the brighter 100 watt bulbs and it got really hot it got really hot so that's what we're turning off. the same amount of heat throughout our body, okay, so it's room temperature, this compressor can put out a couple of thousand watts, you really turn it up to the max.

Wow, so we're not going to need to do that to keep you cool, but If you decide that you want to run through Comic-Con, not only do you turn up the dial and it's amazing, amazing, okay, I'm really excited, so We have a confessor, we have the heat exchanger that we are going to get rid of. from the heat and we're going to place this on top of the compressor. Well, we have a heat exchanger in which we will boil the coolant. I brought two options here and I think we'll use the larger option.several reasons, one is that it is called a support plate heat exchanger and is made of stainless steel.

We put coolant in these tubes, those tubes and water through those tubes. I don't know don't worry but they exchange heat between the two yeah very cool and we can put some fittings on this end that blow less water over here and then into your suit Wow MPT it's not actually a straight pipe thread British and the reason Bruce straight pipe threads are used for these is instead of a taper instead of NPT okay, so the taper thread is basically a compression stretch fiction fit, so you're literally stretching the metal and tightening it and that's great except once you have that preload you have to maintain the preload or else the adjustment fails and if your warming up and cooling down and warming up and cooling down and doing this ignition putting in a lot of movement and yeah, and it's going to go away, it comes loose and it doesn't matter how much thread lock you put on it. eventually it will come loose, it's so amazing that I did it in my book when I was writing the chapter on glue which was one of the hardest parts to write .

You have to think about what the glues will go through, yes, and it's expanding and cooling. that means it will move away from this or that material if it doesn't have exactly the same material property so we use a straight thread and then the seal is created with a gasket no, and that gasket only provides a little bit of preload and if the gasket any Maybe, you know, maybe in ten years the rubber hardens, you unscrew it, another pops another, okay, done, all good, I like it, this is cool, so we connect these components with a copper tube and There is a missing piece here. we use the compressor to put work into the system properly and then we exchange heat with this first heat exchanger.

Yes, now we have to create some way to reduce the pressure to keep the pressure on the high pressure side high. We have to lower the pressure so that the coolant will boil properly, so we have liquid coming out of the bottom of this heat exchanger, we want to expel that liquid and if you think about water in space, the vacuum of space mmm is a borrowed from pressure that the water will just boil and as it does, it will absorb heat, right, this is the same thing, we have a low enough pressure that this substance here, which is our coolant, mm-hmm boils at the pressures on the side of low system pressure and this is a new type of refrigerant that doesn't contribute to the ozone hole that closes properly like using freon yeah okay so this was developed as a replacement for freon in the early 90's and It does not destroy the ozone layer and not many people know it, but among human beings there are many crimes.

The ozone hole is about to become a former human who cried as if it were closed. It's been closing steadily for the last nine years as the industry has responded, yes, and very occasionally we see signs of ramping up at its factories in China. I think there's a recent story I heard. The Amazon and the fires also help you as a tribute to yes, but we are then, how do we create that low pressure system? So we tested that low pressure system with the copper tube equivalent to a resistor. It's basically just a resistance to flow that We can use a small nozzle to create that pressure drop, yes, so you have a high pressure behind a nozzle, you have a low pressure in front of the nozzle, yes, or we can use a long stretch of copper tubing, so any length of tubing will create resistance. and friction as the fluid flows through it and it literally operates exactly like a resistor that does it with electrons but does it exactly with fluid, so the whole analogy of electrons with water pressure actually still works, It still has clues, yeah, yeah, that's cool, the copper tube. we'll use the length that will create the pressure drop and we can change that length that will change the pressure drop and that will have an effect on the temperatures that you'll feel great at, so we'll choose something that will give us a little bit of a little bit below zero to ti on a high speed setting with a fantastic compressor.

I'm going to act to get us some vodka at the store and I also have a cool new shirt that is actually a perfect full body outfit and that's the one I want to try. I bought. It's actually a cool 1980s British RAF suit for high altitude pilots, but all those tubes feel like they're good, it still exists and it's flexible, great, great, awesome, um, well, you got two that I'm going to get those widths, right? That's excellent and the tube. It's perfect, you feel your hunger weight than you thought oh yeah, yeah, that's great, so there are some big ones running out.

I haven't pressurized it, but my cursory inspection led me to believe it's in pretty good shape, yeah, this is expensive and the tube says, you know, it's funny because this is the other question I have, there must be optimizations you can make. for flat tubes that have greater contact with the skin, yes, and therefore better heat exchange, so that's the funny thing, there is a discovery in In the early 2000s, some Stanford researchers, Dennis Gran , are one of them that get the best heat exchange through the parts of their body that do not have hair, so the palms of the hands, soles of the feet, face and can generate the most heat. exchange across those surfaces than putting on a suit around the entire body oh my goodness but I think putting the suit on all over the body creates perceived comfort in addition to the actual heat exchange and that's also very important there are a couple of water pump options, oh look at that and this has to have a water tank ha ha ha ha, that's the oh, that's the size you need, it doesn't need to be bigger, it doesn't need to be bigger than that, so this is the exact size that is on the high. sea ​​suit Wow Wow Wow and this one is different this one is different it has a built in tank and pump ooh that's a sexy thing to know I thought you might appreciate it oh my gosh this is amazing as as an engineer I appreciate it Less complexity equals to more reliability, so I'm leaning towards the pump and tank combo.

What do you think we should both try? The good thing is that we can build the cooling circuit properly and make it something independent and then you can and then play with the options, okay, cool, I have the CAD right there, there is a little pump that is here mm-hmm, this one It's this amazing $200 British water pump, really high pressure, super quiet, high quality, and I didn't. I didn't get a chance to grab it because I was running late to the airport. Oh, we'll just use the one I sent. This is great. It looks like some kind of bait pen.

Yes, we need some LEDs in there. Yes that's fine. So what is the first step for assembly? Actually, the first step to assembly is we want to set up the components so that we have two heat exchangers that we'll basically need to put together and then clamp some copper tubes together so they're nice, and if we go with the drawings that I made. I think the ideal setup will be something like this. Okay, do you need me to make a bracket so we can make a bracket or I think the process that usually is? To do this is lay out the pieces and then determine what the run of copper tubing should be and we have an offshore model that we are starting with but we will use a different heat exchange than I use with offshore so the system of offshore used this heat exchanger which I haven't talked about yet.

Well, I talked about that for a second. Well, what is different between this heat exchanger and this one? It's one thing: two different channels for different liquids to be held. opposite each other, yes, yes, and this heat exchanger is a stack of steel plates with some ridges and the steel plates are pressed together and placed in a furnace and then the furnace is raised like mounting electronic devices on surface, almost exactly right, and that stack you can see these types of channels formed by channels and the way this bottom plate is a tray, the rest of these plates have the same tray feature, okay, so store all the high mm-hmm and the trays alternate cooling water, cooling water to water, the brazing process is you could do this with a blowtorch, yes, but doing it in an oven gives you good uniformity.

This heat exchanger is also steel plates, but these are flat steel plates and they did not have the channel, they have been etched, so those plates are thin enough that we can use real processes and then they are joined together into a vacuum furnace and the bonding process involves heating it, a different metal support is placed around it and that similar support when you heat it, the steel expands more than the support. So as the steel expands the support creates a compressive force that diffusion bonds the layers of steel together, OMG with Wow we can etch microchannels using photolithography processes that are super precise, we get a much smaller unit and compact than No, it doesn't have the capacity for this, but as you can see, it's impressive.

The small heat exchanger is something that can cool a human body that has a cooling power rating of 800 watts. Some believe it has a power rating of about 1.2. kilowatts of cooling and this is very efficient because you can get high amounts of precision in the etching process and that means a lot of flow through it even though it's very tight a lot of float a lot of surface area for exchange just in the surface area is everything the surface area is everything and the difference in price on these is also pretty funny this is maybe 40 $50 to make them in a factory overseas this is about $400 so the difference in costs is 10 times bigger, okay, I see super cool technology one-time projects, those are not crazy prices, but for any commercial company that has a variant difference, they must really have the need to use something of that size, let's use this mainly because we can put threaded fittings correctly and actually do it. easy to interact directly with your suit and bomb and when you hold this here and this goes with this, I would love to know if these pipes can be there while I have plenty of space to put, say, a fake place for a spacesuit, this space will be a cousin, so I would love to keep that dimension, this X dimension, as narrow as possible.

Suppose we can cut them a little more, we're not going to cut them, but we're going to bend them. It's good, awesome. I also have some metal benders and some flame tools that we need to bend, you know, the copper tubes to create a nice flat profile. Well, we'll keep everything online and that way we can get our coolant. to our heat exchanger so we come out of the compressor and go up to the top of the heat exchanger that way we notice the gas coming and going and condensing into a liquid the liquid falls to the bottom and then the bottom comes out and then it goes to the bottom of this heat exchanger, okay, where we boil, so we end up with a gas at the top, okay, and then okay, so there's a direction to this, there's a direction, yeah, and then mount this.

For this, I assume we need a little bit of some support äj-- that's right, it will be good, we can zip tie, but the supports will be better, okay, ultimately, I have endless spacers and our little nuts and bolts. and even all the twine should be needed after we have everything laid out the way we want we'll mount it on a cool 80/20 fixture a piece of wood just so we can braise it yeah once it's braised it'll hold the Things together. so we can make sure we measure and create a bracket that holds everything to your fabulous suit, don't put any pressure when attaching them to the copper joint because copper and aluminum joints are delicate, they are very delicate, oh, that's lovely, yeah, it is.

It's smooth and I can guarantee that I'm not overloading the joint, right, right, notice that it stays straight when it comes out of here. I got most of the curvature and that's important because we don't exactly stress at all exactly because If we lose these connections, soldering copper to aluminum is one of the hardest things I've ever tried to do. I want to think about it, I don't even want to think about it. He got better people than me. Pass this on, John, okay. I'm going to go up a tube that's going to come out of the compressor and it's going to have to go in here, so if I flip it like this and then it gets to the top, I can come out and over at the top, okay, that looks cool. makes it easy, okay, and then the tube coming out of the bottom is going to go to our expansion valve, so we'll have something like this, we'll go in here, we'll have a coil of a little bit of this and like I said, the length will determine the temperature What determines the temperature is the length of this tube that gives us the pressure drop well the speed of the compressor that tells us how much gas we are moving how much mass passes from a certain correct point and then the amount ofthe superior because we want to do well. flow we want the right cold coolant to go up and we want the water to go down that way you're going to get the most effective cooling the fastest and then it comes out of me to yes to there, yes, it's pumping a lot. "No, oh, that seems about right, we should turn it up, we're going at that slow speed here, so you turn that fan on and let's go, yeah, I was thinking it didn't look like it was getting colder, but now it is, I mean , I definitely feel fresh all over.

I loved it. These cool 1975 Royal Air Force suits are still fully functional. They're fast. We can leave before you feel like the moment you did. I feel a difference. Yeah that seems to be one of the limiting factors and how cold we can get Yeah yeah I can feel the conspirators we're circulating so we definitely need a more powerful pump Yeah buddy look at me I'm getting cold this one the most elaborate way to be cold in most of the United States right now, if you just walk outside, it will also help you understand how amazing it is that NASA has incorporated us all into their space, students write something complete, everything here is in a self-contained space suit along with oxygen. and other things happening and other telemetry, oh yeah, again, I always understood how the system worked, but seeing the level of complexity of it is kind of surprising in the vacuum of space.

Dealing with temperature is really complicated because you can't eliminate temperature by having air that is cold or hot, you have solar radiation that brings a lot of energy to people and then you are giving away photons in space, so there are these flow offsets. heat, so NASA had a system that kept astronauts cool by boiling a gas and dissipating a liquid in space and basically just vaporizing it and by doing that, you can have a lot of phase changes happening here, it's changed, it absorbs energy , absorbs heat and tah-dah. Now we are controlling the temperature. I feel like I'm outside.

Oh yeah, it's a great day. I'm starting to feel very cold. Actually, I think we're going to achieve something good at some point. You can look at the thermal image. Oh yeah, that's amazing. Yes, you can see the lines on your body where FLIR collects all the cold tubes. That's spectacular. I think that's what I would call a successful test of the mini refrigerator that Kipp designed and we built here because he has me frozen and I want to. to say cut so we can wrap it I can put on normal speed clothes so the cut is really noticeable it's moving I mean it's moving to warm up yeah man and if we turn up the pump yeah that'll be pretty amazing.