245: ELASTOCALORICS! What? Solid State Cooling

On today’s episode of Still to be Determined, we’re talking about shape changing alloys, their current uses, and what might be headed our way in the future. That’s right. Elastocalorics. Welcome back to Still to be Determined. This of course is the follow up podcast to Undecided with Matt Ferrell. And I can hear some of you saying it with me.

I’m not Matt Ferrell. That’s right. I’m Sean Ferrell. I’m Matt’s older brother. I’m a writer. I write some sci fi. I write some stuff for kids. And I’m just generally curious about technology. Luckily for me, my brother is that Matt behind Undecided with Matt Ferrell, which of course takes a look at emerging tech and its impact on our lives.

And Matt, how are you today?

I’m doing great, but I’m also getting ready to go to Germany. Right. What part of Germany are you going to be in? You’re going to be in? I’m going to be in Germany. Munich. I’m going to be going to Munich. I’m visiting a, uh, car manufacturer. And going inside their plants, seeing what they’re doing.

And I’m very excited to be in Munich. I’ve never been there. I always wanted to go. Very cool. I just do not like the act of traveling, Sean. The idea of being trapped in a metal tube flying through the sky at 30, 000 feet for like nine hours is something that I don’t find appealing.

You say that as if that’s not something we’re genetically programmed to want to do.

No, I don’t get it. Having just made travel arrangements for myself and my partner in January, we have decided to take a trip to a warm location. That’s right. We’re going to sunny Puerto Rico. Oh, nice. Yes, very nice. And we were selecting our Seats aboard the airplane, or as you like to call it, and I often do too, the giant metal tube that takes us high up into the sky and shoots us through the air at speeds man was never meant to fly at.

That’s right. We were selecting our seats and really enjoying the process of like, oh, the ticket price is not that bad. Oh, they want to charge us extra for a little bit more legroom. Oh, they want to charge us extra to sit on the aisle. Oh, they want to charge us extra if we want to actually bring luggage. Oh, they want to charge us extra.

I get it now. Yes. I was this close to believing that any moment there were, any moment they were going to be like, and there’s an extra fee if you want the plane to have wings. Do you want the plane to have wings? Are you talking about Boeing, Sean? Oh, dark humor. Yeah. Oh. Oh. It makes my little heart beat fast.

So here we are about to conversate about, well, more than just the most recent episode, we are going to kind of loop back a little bit because we had a special long form interview recently. And so we’re going deeper into the mailbag. We’re going back a couple of weeks to discuss first matt’s video about heat pumps, and then we’ll follow up with a brief conversation about his most recent, which is about a shape changing metal that could lend itself to, well, replacing heat pumps.

Weird. Yeah. It’s a little bit like BattleBots this week on Still to be Determined. We’re setting up heat pumps versus Elastocalorics. My fear, of course, as always, when Matt and I talk about all of these, and I usually don’t try, I try not to share this information in the podcast because I don’t want to sow distrust or panic.

But what if these two technologies combine and turn against us? Dark days, dark days, very dark days. But anyway, on to our mailbag from episode 243, the genius of heat pumps. And Matt, there were people who were asking for more. More, more, more. David jumped into the comments to say, when discussing heat pumps, let’s hear more about those that use CO2 as a refrigerant and attain A COP as high as five.

And that raises the question, Matt, heat pumps. Yes. How many different styles of heat pumps are there with different types of refrigerant? And when we use the term refrigerant, we don’t just mean getting cold. We mean it’s the chemical that allows for the change in temperature. So we’re not talking about just a chilling effect.

We’re talking about the heating as well. So what are some of the alternatives to the typical

refrigerants? Yeah, well, that commenter was spot on. It’s like, there’s, there’s some that use CO2. I actually did a video on that on Undecided. It was like a year ago, I think, about CO2 heat pumps and they’ve got really good, uh, You know, performance and all that kind of stuff.

Propane is becoming a very common refrigerant in newer models because less greenhouse gas implications, all that kind of stuff. There are so many different kinds of fluids that could be used in the heat pump. It really just comes down to you pick the fluid based on the performance you’re looking for in the heat pump because that determines what temperature ranges it works well in.

Does it work down to, like, cold climate heat pumps? Does it work down to negative 20 degrees Fahrenheit all the way up to, you know, 100 degrees Fahrenheit? Depends on what fluid you’re putting inside the heat pump system. So the heat pump itself, technology is not different. It’s still a compressor and all that kind of stuff that’s inside of a heat pump.

You’re just picking different fluids that give you different operating ranges because of when the, it’s the temperature at which the fluid turns into a vapor. You know, it’s like you’re, you’re adjusting, you know, What that is by what fluid you’re putting inside of it. So CO2 is a fluid where you don’t think of it as a fluid, but I know I know gases.

I try not to gas. Yeah. But you CO2 in these heat pumps, uh, works quite well. Um, so it’s, it’s really interesting to think of like, you know, if you’re concerned about climate change, Oh, CO2 is bad. Well, put it in the heat pump and it works really, really well. So it kind of breaks your brain a little bit, but it’s a pretty cool tech.

And is there another one that you can think of off the top of your head that would be Another option to avoid some of this. Well, it’s a greenhouse gas or it’s a

toxic, well, the, the two big ones are CO2 and propane. Um, and they have names like R 4 32. They have like these weird names they give them. Um, there are a bunch, but the two that are I see the most often are propane and CO2 as the fluids.

There was also this comment from Daniel who asked. Matt, could you do research to see if these in window heat pumps come in an in wall version? I live in a townhouse with in wall AC units that I would like to switch over to in wall inverter heat pumps. This would be a boon to me and many people who live in smaller units.

Thank you. So like the tech that you were talking about in the video was specifically designed for the New York City Housing Authority with the goal being, we’ve got these city run housing units. We can’t, nobody is going to want to put in a new type of tech to improve heating and cooling on a scale that would cost

millions upon millions upon millions of dollars to convert existing buildings that have what is going to always be aging tech in its heating and cooling. And so these wall units or these window units that were developed are effectively, I keep, yeah, I’ve, I don’t know if anybody but me says this, but they’re the flip phone design.

That’s how I think of them. It just opens up and sits like an inverted U in the window and really kind of a brilliant, brilliant and stoic. There are, I imagine, already existing in wall units that would do the same thing. Because the design here, the breakthrough that Matt was talking about was the flip phone design, not heat pumps themselves.

So there must be in wall units. Do you want to talk a little bit about that?

Well, yeah, it’s what Daniel’s basically asking for is basically like a mini split. So the reason you just hit on it, the reason mini splits are not necessarily the path forward for a city like New York is because it takes construction.

You’re having to knock a hole through a wall that doesn’t exist. You’re having to get electricians that come in and can wire them up for the, the electricity that’s needed because it’s not a standard you know, 120 volt outlet, it’s, it might be 240 volts or whatever it is. So it takes electricians and construction and you have to get permitting to put this stuff in.

And all this stuff just suddenly just ratchets the cost up where the window units are like, ah, you can have your super come up, he can drop it in and you plug it into an existing outlet. And Hey, look, it’s done very straightforward to put in. Versus all that construction and permitting and stuff that you have to do for everything else.

Right. If you’re in a, if you’re in a townhouse right now that has an in wall unit of some kind, you should be able to find a heat pump that will fit that size and shape that you’re trying to replace. They come in so many different sizes and shapes. You’re basically looking for a mini split. One of the big brands that you’d probably want to be looking at is something like Mitsubishi.

They make in wall units that are really, really good, variable speed inverters, so they’re highly efficient. They’re fantastic. But you can also, if you want to be a little risky, just go to Amazon and just find some random no name brand you’ve never heard of for a fraction of the cost, but then you’re kind of taking, you know, if it breaks, are you going to get warranty or not?

Uh, so depends on how much money you can spend or are willing to spend, but these systems for in wall are just all over the place. So you can absolutely find them.

And then it would be a matter of, and I’m going to ask you a question you probably don’t know the answer to. A smart manufacturer would spec these things so they would be the same size as a variety of air conditioning units that would be potentially already in people’s walls.

So a company that was wise would be saying like, Oh, let’s copy the dimensions of these things. So we have products that if somebody says, Oh, I no longer want an AC, I want a heat pump. We have something that just slide right into the same space. But this might be the kind of thing where Daniel would make a purchase and then have to hire a contractor to effectively install and seal it properly.

Potentially. So that’s kind of where it’s like, depending on what your dimensions are, you should be able to find something that gets close, but it’s not exact. So maybe it’s slightly smaller. So you have to fill in maybe on the sides or the top and bottom, like you might have to fill in a little bit of a gap, that’s going to be far easier than cutting a larger or different shaped hole.

So one path you might be able to do it by yourself, another path you might want to hire a contractor that does it for you. But yeah, sadly there is no like, hey, these are the standard sizes and dimensions that they typically come in. It varies manufacturer to manufacturer.

Yeah, I also think it would be a word to the wise, measure carefully or hire a contractor before you order anything to know that the dimensions of the entry that you’re looking for are going to match what you’re actually buying, because I would be sorely upset to order something and discover.

I mean, it would almost be worse to find that what you ordered was too small. Cause then what are you going to do? Like, yeah. All right. Anybody got any Silly Putty?

On now to our conversation about Matt’s most recent. This is how solid state cooling could change everything. And I couldn’t get enough of you using a little mini blowtorch, which you probably use on your creme brulee, if I know you. Yes. So you make a kinky piece of metal go sprink and become a straight piece of metal, which my favorite part of that was when you first hold the metal in front of the camera, it’s not straight.

It is already looped. So clearly at the manufacturer, the original state was Straight. And then they curled it into a spool and then you, in showing, look, it doesn’t stay all kinky after I twist it up. It’s going back to the way it was at the factory, whoever knows how long ago. So first question to you, you went and ordered this metal and somebody was just like, yep, we got that metal.

We’ll put it in this envelope. We’ll send it to Matt and Matt can do whatever he wants with it. Who’s doing things with this? Well, what is it being used for? Who is ordering these

things? The nitinol I ordered, I ordered an Amazon and it cost me like seven bucks or something like that. It was super cheap.

Uh, I can’t tell you what people are doing with this wire like that you buy an Amazon, it’s a very low temperature when it switches like, from Austenite to Martensite, when it changes its shape, it’s a very low temperature. You don’t have to warm it very much to get it to do that. And you mentioned how like it went straight because that’s the way it was programmed from the factory.

You can reprogram it by basically superheating it. So you could turn it like my team was saying, Hey, you should bend it into the shape of your logo and get it and program it in the shape of the logo and then kink it up and then heat it and have it go back into the shape of your logo. And I was like, that’s awesome.

And I tried to do it. It didn’t work very well because the logo is very intricate. Yeah, I couldn’t get it to do it specifically, but the way you do it is you just bend it in the shape you want, superheat it, let it cool, and then next time you do the low temperature heating, yeah, it will remember that shape you programmed it in.

So you had asked where, what are people doing with this? With the Amazon stuff, I actually have no clue. But nitinol is used extensively in medical uses. It’s used in, um, stints. So like, they can get the stint super tiny, go through the vein, where the, the artery where they need to go, and then they basically, it remembers its shape and gets big again to create a kind of structure that keeps the artery open.

It’s used a lot, but the nitinol that’s in that situation has a different temperature range were it changes shape. It’s of course medical grade. It’s got different, it’s a different kind of, the alloys different than what I bought in Amazon. In essence, it’s the same thing. For the stuff I got, I have no clue what people typically use it for, but for the higher end stuff, medical uses is where it’s used a lot.

Interesting. I couldn’t help but think as you were talking, an analogy for this would be tempering chocolate. Where you take the chocolate up to a certain temperature because you’re getting the molecules into the right position through temperature. And then when it cools, it cools to a certain, you know, quality of chocolate, um, with a certain sheen.

And that’s just about, like, The molecule arrangement and it seems like this is the same thing just in a metal. And I was also envisioning things like using electricity as a means of heating it could allow you to have a thing that could be a programmed shape such as a pup tent. Or you could have a thing that was like a little cube and then push a button and then it would turn into a pup tent.

And then to get it out of that shape, you would just literally physically force it back into the box.

Or, or Sean, Christopher Nolan’s Batman movies, his cape. Oh yeah. Oh yeah.

Oh my God. Yeah. But he’s not wearing hockey gear. No, he’s not. Ah, sci fi. Sci fi doesn’t exist anymore. It’s just sci. That’s right.

Ibram Ba jumped into the comments with this one. I remember as a kid, noticing the rubber bands got hot when you stretch them and cold when they relax. I saw a crazy project someone built that put masses of rubber bands on a rotating rack and That constantly stretched and released them while blowing air across them.

It did manage to cool and heat air, but it wasn’t what you call efficient. I can’t imagine it would be, but it is fun to watch. It is a rudimentary. Yeah. It would be fun to watch. Uh, I like the idea of like a tinker toy. Who’s he, what’s he just like rubber bands going all over the place. And you’re like, what is that doing?

I’m not sure, but it does seem to be getting warmer in here. There was this from VD. What about fatigue? How many circles will it last before breaking? Will it last for 25 years? That is a metal fatigue.

That’s a really good question. When I talked to Dr. Takeuchi about it, he brought this up and he was talking about like in my demonstration of where I was bending it.

And then straightening it, that has a very short lifespan. So it’s like the more you’re bending a metal and putting it back, it’s gonna fatigue, crack, and just break. And so he talked about how like you can bend it, you can kind of like pull it, stretch it, and then you can compress it. So imagine putting that wire and compressing it horizontally.

What they’ve landed on is compressing it. I think he said, uh, the compression, he said, lasts way longer for fatigue. It’s less fatiguing on the metal than trying to, to bend it. So stretching is better, compression is better, and it will last way, way, way longer. We came across papers when we were pulling this together that talked about the longevity, how many cycles that you can put it through before it starts to really fatigue and crack.

And this is a big question because you’d want something that would literally be able to take millions of cycles. Yeah. And there, there is research that’s showing that there is a pathway to get there. Um, it’s just a matter of doing it. And in my interview with the doctor, he, he mentioned this of like, you know, they’re trying to fine tune exactly what the alloy is made of like treatments you can do to it, coatings you can put on it.

There’s different things that you can do to it. There’s a material science at play here to really improve the performance, get it to last a long time. But this is, to me, it is a giant question mark. How long will it actually last? Because if it, if they can’t get it to last the life of the entire unit, you know, it’s not going to go anywhere.

But he was very confident in the way he talked about it. It sounds like they can crack this nut. Maybe I should

patent this, but I’m thinking a device where your metal is on some kind of spool that moves a Tiny amount for each compression and then you are feeding fresh metal into the compression area and just over time.

Yeah. Yeah. Change what metal is being used off the spool to increase longevity.

I wonder if it’s not even going to be wires. It might just be like a brick plate of the metal, like a, like plates that you’re crushing the plates. So it might be something more along

those lines. Hmm. This one from RNMSC. Two points that were raised by RN in their comment.

First, without knowing more about the specifics of the options, that really small space that includes a can or bottle of a soft drink really isn’t necessarily a negative. There’s a fairly huge need in the medical community for small refrigerators that have about that much space in them. Think insulin pens for diabetics and other medicines.

I thought that was a very good potential use case for, oh, they can only make it and it’s only this big. And yet when I go to the doctor’s office, I see small refrigerators being used all the time. And that’s, especially in a lab setting, I can imagine having a small unit that would not be requiring a lot of energy would be a benefit.

There was also this from RN, the problem I see with the elastocaloric refrigerator would be that it may not require a fluid to transfer, but I’d be concerned about the noise involved. That is going to depend on how the system works for doing the heat transfer through the material. Was there any part of your discussion around this about what this technology brings to like the sound of it.

Do you have, instead of your refrigerator compressor starting up a similar sound, but it’s now a compressor as opposed to a compressor? Huh?

Well, as when I was talking to Dr. Takeuchi about this, he mentioned how it is a solid state form of heating and cooling, but that doesn’t mean that the entire system is solid state because you most likely will have some kind of fluid.

So imagine water, just cycling across the plate of metal and you’re then blowing air across like a radiator to get the cool air so it’s like you’re you’re probably still gonna have some kind of like just water fluid that’s just helping to transfer the heating and cooling to where it needs to go but as far as noise He kind of alluded to this, instead of a compressor, you’re going to have something like an actuator.

So something that’s like a tongue, actually pushing, so it’s like there is going to be things that will still make noise. Pumps that pump the fluid can be very, very quiet. So it’s like, I wouldn’t worry about that. But you’re basically trading a compressor sound for potentially an actuator. And how loud is that actuator?

And based on what they’re doing in the labs, I’m assuming they don’t care about the noise at this point. I can’t imagine they would. So I’m assuming that the stuff they’ve got is probably kind of loud. Uh, but you’d have to, of course, shrink that stuff down, design it for being quiet. My hunch Is just that you could probably make this on the same noise level or slightly quieter, maybe, but your guess is as good as mine because I have no idea.

I think that’s something that as this technology continues to be worked on, we’ll see the answers to these questions in the future. But in the meantime, I invite all of our viewers and listeners jump into the comments. Let us know what you thought about all of this. We really appreciate the comments. It helps drive the podcast and it helps inform and shape the

mothership, which is of course Undecided with Matt Ferrell. Thank you so much, everybody, for taking the time to watch or listen. Jump into the comments, like, subscribe, share it with your friends. Those are very easy ways for you to support the podcast. And if you’d like to more directly support us, i. e.

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