[00:03] Our cooling has officially been shut off. It's going to be complicated, possibly amazing...
[00:17] Snug as a button. But this isn't your grandparents' white paint. It's high tech stuff. Where's Greg? He's better at the manual labor.
[00:33] with cheap and easy technologies? No!
[00:46] Mitchell:  The world is warming, and that excess heat optimized conditions for disease vectors,
[00:58] Unfortunately, we don't have a choice. The cooling industry is responsible which is around three times as much as shipping
[01:13] So we have two universal, potentially sustainable So there's been a trend in roofs in particular
[01:25] and to figure out how much light and heat they are actually absorbing. and paint the entire roof white and ultimately cool ourselves down.
[01:40] for thousands of years across the Mediterranean, to reflect the heat of the sun away from their homes. and quaint in the modern era, serve a practical purpose.
[01:57] which is able to reflect 98% of light, Professor, thank you so much - about white paint in particular. - It's my pleasure.
[02:13] that we came up with in seven years. Sunlight has many different wavelengths. We eventually found that using different particle sizes will help you.
[02:26] If you use them all together, a long-term practical application against climate change and global warming?
[02:42] We did an interesting analysis that you just need 1% Then that is enough to cool the Earth down back by 1 degree,
[02:54] That's wild. That's amazing. which moderates our climate. the effect is hugely reduced, which warms the Earth further.
[03:11] can make up for this and help fight climate change. I'm gonna be making an off-grid fridge. for some geothermal cooling aspects.
[03:25] which will be part of this fridge which will be powered by solar panels - I have so many questions. - They'll be answered in the video. Keep going.
[03:39] The complexity of my build means I need help I not only need his power tool skills, There are the Peltier modules.
[03:52] using solar panels. from inside the cooler and disperse it. cools the outside of the Peltier modules
[04:04] And, lastly, for some geothermal cooling, in the ground to keep it colder More about that later.
[04:17] Psych! Okay. how to bury a body. I kid. and it's actually gonna help it keep cold,
[04:32] and so essentially it's a lot harder for the Earth to lose heat. in order to keep our cooler cool. sleeping in the bunky has become unbearable.
[04:48] will help me cool the place down. We've got our scaffolding, and I've got, you know, my coverage and booties The temperature right now-- I'm gonna check it--
[05:03] is at 53 degrees Celsius, so more than halfway to boiling. Okay, let's explore what makes white paint so special. Whenever you look around you and see something colorful,
[05:18] that the object is not absorbing. because they mostly absorb the blue and red spectrum off the plant and hits your eye.
[05:32] that every color is bouncing back to your eye, white is actually all of the colors combined.
[05:44] that defines how light will interact with it. which reflects around 80 to 90% of light,
[05:56] All right, first part is always the scariest. Okay, that's very white. That's awesome.
[06:11] Now I just have to be careful I don't step backwards and die. and it's something I'm not looking forward to.
[06:26] before we build the exterior of our cooler, about the physiology of why touching foam insulation and scream and salivate and freak out, so...
[06:49] I'm strong. Okay. Aah! I hate it. I don't know, please. Oh-kay. I know I seem insane, but I'm not kidding.
[07:02] Ho! ( imitating squirting sound ) You could do this at home with a normal cooler but we've got Paul here.
[07:15] ( imitates drill whirring ) Okay, good, good. I was like, "Oh, and I'm getting sued."
[07:32] Mitch is literally watching paint dry, which is very practical, But it shows you how cool it is Like, we can all do that.
[07:46] It's hot. our bodies down right now. you not only risk heat stroke,
[08:00] So the military has developed a couple techniques One in particular is called the Arm Emersion Cooling System. Because your hands and feet have more surface area on them,
[08:15] If you can put your hands, up to your elbows, 10 degrees Celsius is the optimum, by one degree Celsius.
[08:27] It's refreshing, it's great. on a hot day can cool you down, and this is true,
[08:39] This all has to do with sweating. You see, the evaporation of water off of your body cools you down, so eating something hot actually causes you to sweat.
[08:51] and it's important that you also have some skin exposed, Also, there's receptors in your mouth, which tells your brain, "Oh, my goodness, it's hot. Time to sweat."
[09:05] So if you add that to your soup, even just to a cold soup, you can trigger those receptors, cause your body to sweat, Mm, warm soup. Refreshing.
[09:21] The answer is evaporative cooling-- from its liquid state into a gas requires energy. This energy is taken from our body, or sweat, in the form of heat.
[09:37] The resulting heat transfer leads to the desired cooling effect of sweating. you need skin exposed to the air that isn't too humid, and a shady, windy spot is ideal.
[09:50] which you may have experienced You'll feel extra cool when wet in the wind. of the liquid water from you skin's surface
[10:05] converted to vapor, thus cooling your body. 'Tis absolutely raining. Cats and dogs, as they say.
[10:17] I'm very happy that we moved away from the bunky to do this electrical circuitry. a thermoelectric cooling effect. but using a really interesting scientific principle.
[10:31] This is my favorite part, as someone who considers themselves fashionable. It's the glasses. Okay.
[10:44] which are made of semiconductors. The heat sink is gonna be on this side of the Peltier module, there's a fan here, but we're also gonna add
[11:00] and if you need to know what a Peltier module is, I'll explain it now. an electrical current through a series you create a temperature difference.
[11:16] of electricity, but they also aren't good insulators They are kinda queer and both and in-between vibes, ( chuckles )
[11:30] one with an excess of electrons if you pass an electric current through them, the movement of electrons causes heat to move in one direction,
[11:45] that is cold on one side and hot on the other. and leave the hot side outside of the fridge, we can pump the heat away,
[11:58] of the outer, hotter side of the Peltier module, I'm putting two of these units to double the power. ( imitates electric shock )
[12:15] I haven't dropped a single drop of paint anywhere, so I feel like I didn't need this suit. Let's see if the white paint is doing its job
[12:29] We've painted about a third of our roof now, Earlier, we measured this red roof So I'm gonna check it now and see what our difference is.
[12:45] Okay, we've got 39.4 on the red roof. ...30.6 on the white roof. This is a white paint that is just store bought--
[13:00] next to a red paint, so not even a black paint, The white paint experiment, it's a perfect example
[13:12] If that's real, why haven't we implemented this on a larger scale? I wonder how Greg's fridge experiment is doing?
[13:26] We're going to make a second device that has some extra help from geothermal cooling. Evaporative cooling works because liquid water molecules
[13:41] Breaking them to turn liquid to a gas takes energy, By using a sponge, a flow of water
[13:53] the heat that the water vapor is taking with it as it evaporates has a cooling effect on the surface left behind, on the ASAP fridge to help keep our drinks and veggies cool.
[14:08] With the evaporation cooler built, we now bury it. The geothermal cooling is going to help by the sun by burying it in the ground.
[14:24] when it is hot and release heat If we were able to dig five meters deep, which is a lot cooler than our current 32 degrees Celsius outside.
[14:39] We are putting the water used for evaporation underground but mostly it's to hide the water from the sun Next stop is making sure this all works.
[14:53] ( chuckles ) And hooking up to the solar panel. that I finally finished painting the roof.
[15:06] I'm so happy I did it. We got a 10-degree difference between what the roof was and what it is now, Researchers are currently developing new paint molecules
[15:21] that reflect most of the sun's energy away from our roofs, letting us have the cooling effect It not only cools our house, it can cool cities,
[15:35] That's pretty cool. The Peltier modules are hooked up. but I did ask Paul to make the cooler look cool,
[15:49] I'm obsessed! A treasure chest. You're an artiste. I mean, this is not what I expected at all. I did not make it look like a treasure chest. That was all Paul.
[16:03] Okay, so, now we just gotta hook up the electrical to the solar panels, We have all the components of the fridge completed. it will be insulated from the heat in the air.
[16:16] and ready to help cool the Peltier devices the inside of the fridge. It's the moment of truth.
[16:30] to create an off-grid fridge, so I am hoping it's gonna work. It's green. Wait.
[16:43] Ooh, that's satisfying. Yes! about all of this is just a really new We still have to hook up all of these wires
[16:57] I think we should get the solar panels back in the sun Look at this! Look how intricate this is. Arr! Shiver me timbers.
[17:12] It's so essential that we figure out because I realize how complicated it is sort of pay off a little bit.
[17:26] solar-powered, off-grid fridge! - Ooh, a treasure chest. - 'Tis a treasure chest. Greg: So the solar panels are what are charging the fans.
[17:42] This is our evaporative and geothermal cooling unit. the Peltier modules' heat sink. that we, like, use, if we're ever hot.
[17:57] And this is the temperature readings. Outside, it's 33.8, almost 34 degrees. That is, like, more than 20 degrees cooler in there.
[18:11] our veggies, our drinks, our oat milks. A normal fridge is four degrees Celsius. And we don't eat meat. So, yeah! I don't know, I'm just so happy
[18:24] So it's not as cool as an actual fridge, are affected by food spoilage. Refrigeration saves life.
[18:38] but food stored in temperatures between 4.5 where harmful bacteria double their population in as little as 20 minutes.
[18:52] of, like, thermoelectric principles and the Peltier. Is there stuff in there that we can see? - Ooh! - I'm gonna grab a drink.
[19:06] Oh, my God. Literally, there's dew all over it I feel really satisfied with our results, - Okay, let's close it so it stays cold. - Yes.
[19:20] - Let's enjoy! Eee! - Great job. is the number-one thing we need to fix in order to combat the climate crisis. there'll be three times as many air conditioning units alone
[19:36] With all this talk of heat waves and fires, and this week, I realized just how much energy it takes So, honestly, I just started thinking about my fridge at home,
[19:51] One thing I tangentially thought of is we need For me, it was interesting to realize can make such a big difference not only in your own home,
[20:07] if even just one percent of the Earth's surface on technologies and innovations So, cooling is one of the most important things we need to figure out--
[20:21] without contributing to the climate crisis. Thanks to our evaporative cooling, And thanks to our underground fridge, ahem, Gregory?
[20:34] What would you like? We got a vodka soda, aka, gay water. - Oh, thank you. - I'm gonna have a ginger beer.
[20:46] Nice and cool. All right, shall we? Greg: Yeah, we chilling, boy! We chilling, bro. ( music playing )