Sweating manikin helps ASU researchers learn how to make working in the heat safer

Anyone who’s spent any time outside in Phoenix during the summer knows what it means to sweat. Sweating can be difficult, though, to replicate that during scientific research.

That’s where ANDI comes in. ANDI is a human-shaped thermal manikin that mimics the human body’s thermal regulation. That means ANDI sweats and shivers, for example.

And ANDI can go outside, which allows researchers to get a better sense of how we react to heat and cooling efforts in the real world.

Konrad Rykaczewski is an associate professor of mechanical engineering and a senior Global Futures scientist at Arizona State University, where he works closely with ANDI. Rykaczewski joined The Show to talk more about that work.

Erika Gronek/ASU

Full conversation

MARK BRODIE: Konrad, among all the things you’re able to test and measure with ANDI, are you also able to measure the effects of being in direct sunlight compared to being in shade?

KONRAD RYKACZEWSKI: Yeah, absolutely. So when you look at Arizona in the summer, actually the radiation, and this is both solar and also the infrared emitted by the surfaces that can be very hot, is actually one of the main ways that our bodies get heated.

So we spend a lot of time trying to understand this radiative pathway of heat exchange between the ANDI body and the surroundings.

BRODIE: Do you notice any kind of difference between different types of shade in terms of how ANDI responds, as far as like natural shade versus man made shade, partial, full, anything like that?

RYKACZEWSKI: Yes, there is a lot to it. We have one of my colleagues, Ariane Middel, spends a lot of time with ANDI’s best friend, MaRTy.

BRODIE: Yes. 

RYKACZEWSKI: Who is this biometeorological cart looking at, let's say, you know, how should you plan the native tree that has small leaves? Or should you have a tree that might have, you know, it's not native, but has large leaves? What, what's a better shape?

And there's, there's some nuances to it, but the main message is, any shade is better than no shade. And we found that with ANDI’s responses, too.

BRODIE: So any shade is better than no shade. But I would imagine that in the world of shade is some better than others?

RYKACZEWSKI: It really depends, all depends on the context. Naturally, you know, and going off the tree, a non-native tree will give you better shade, but it also will require more water. So there, I would say there's no single answer for that. It really depends on the context. You know, how much money can you invest and what is the shade for?

BRODIE: How big of a difference can shade make like on a day where it's, maybe 105, 110 or more degrees. How much can it help our bodies to be able to find shade, as opposed to being in direct sunlight?

RYKACZEWSKI: It's, as you may know from personal experience, it's a lot. The way we like to characterize, right, as engineers, we might talk about watts per meter square heat fluxes, which are kind of hard to relate to.

So instead, we define a metric called the mean radiant temperature, which translates that radiation that you absorb from these different sources – might be direct, reflected, diffuse, solar, infrared. And it's a temperature.

When you're in the sun here in the summer, it is not uncommon to have the mean radiant temperature be about 75 degrees Celsius. And what that means, it sort of feels equivalent to being inside of an oven whose walls are at 75 degrees Celsius, which for reference, right, at 100 Celsius, water boils.

And if you go into the shade, the radiation then the mean radiant temperature reduces very close to air temperature, so close to 40 degrees Celsius. That gives you a number to kind of quantify that experience of shade versus the sun.

BRODIE: That seems like a pretty significant difference. 

RYKACZEWSKI: It's enormous. But what's important to understand is that in this calculation, we assume a sort of average number for the absorptivity of your clothing and skin, both for the solar and the infrared radiation.

And this is where you can make a difference by adjusting what you wear.

BRODIE: Yeah, I want to ask you about that, because there are obviously a lot of companies that market moisture wicking clothing, or, you know, cool clothing as you reference. Do those things actually work? 

And I know we're sort of generalizing about a very large component of the clothing industry, and I'm sure there's a lot of variation between what different manufacturers with different brands and companies do, but by and large, do those things work?

RYKACZEWSKI: It depends, right? So this is a question that I am very interested in answering well, because, as you mentioned, there's advertising and it's advertising, they can say whatever you want they want, right? But there is very little cross comparison and comparison in realistic conditions.

So you know, if you have these different pigments you might use or approaches to reduce the solar absorptivity, they might be tested indoors. And with ANDI, what we develop is this protocol to rapidly test multiple shirts in the same conditions, right. When you're outside, it’s, you have to do things fast, because, let's say the sun changes its elevation angle.

BRODIE: What are you hoping to learn this year, this summer with ANDI?

RYKACZEWSKI: We have several different studies planned out for an entire summer. One is collecting this data in different contexts for different reasons people are outside here in the summer, and trying to understand what the changes in their core temperature and skin temperature look like in different conditions. So we're going to do ANDI construction work, landscaper or policeman or ANDI in transit.

We're looking at different ways people get heated, exposed to the heat in the summer here, and trying to understand how hot they might get, right? Is it, does it just become uncomfortable, or can it become dangerous, and when, and sort of what changes can we make to their schedule to make them safer?

So that's one part of the study, and then the other part, which we sort of talked about, is really starting to look at what kind of clothing is best to wear here in the summer.