I Made a $4000 Water Cooled Bed 

The first 500 people to use my link skl.sh/nikodembartnik08241 will get a 1 month free trial of Skillshare premium!

I don’t understand why eight sleep company You need to have a subscription for even using the bed when you already pay $4000.

monthly subscription for a bed. wow late stage capitalism is WILD

Peltier cells just aren't the right tool for the job IMO. It's too inefficient and burns insane amounts of energy. Better to use an old fridge compressor/heat sink.

I wouldn't say this failed. It just seem to underperform. One quick thing to try is reduce the amount of bed you are trying to cover. Maybe just half the bed or just the area around your torso. As for tube placement, what about taking two sheets and sewing channels to hold the tube in place? Anyway, great idea. Looking forward to how it keeps you warm in the winter months.

It would be cool to see you keep working on this. I think the truly hard part will be making a comfortable matress topper that has enough tubing, but one can't feel the tubing through it, nor should one laying on it squeeze the tubing shut. I would definitely love to see you continue to develop this, I would be interested in building such a system myself if it reaches some level of maturity

My suggestion would be to drop the peltier modules and to use a geothermal loop - A good excuse to rent a digger and bury some tubing in your garden.

faliure is just a step toward success i am looking forward towards this project great job

Bed sheet - get a piece of soft foam - like 50x50cm, use your CNC and cut channels in it in a shape of the tubing. Then just put the tube in, cover it with another foam and voila - you have a DIY soft matrace with water line :)

Skip the active cooling, you 100% don't need it. Your air temperature is already low enough to feel a cool effect, how does it feel to get into a 75° bathtub? You can use a real radiator, which has low resistance and can dump a lot more heat (100s of watts, vs the 5W? maybe?) than your peltier. Of course the real problem here is that electric motors have a sweet spot for output power. You need to put more of the tubes in parallel to reduce the resistance to flow; this is effectively ohm's law all over again. Your single long tube has way too much resistance.

I have chilipad bed cooler for my bedridden family member. It's been 5 years since I bought one. When I disassemble the main unit for cleaning and maintenance, I am surprised that the main unit is relatively simple and neat (and also affordable). One of best investment for bedridden homecare .

Great video, I love the fact that you posted it even though you didn't fully achieve what you wanted. You're definitely on to something good here!

maybe something like a flat inflatable water bed that you circulate the cold water under where you sleep as a heat exchanger might work instead of tubes

-20C is nuts. Just starting to watch the video but this is an awesome idea!

A monthly subscription to sleep? It looks like rent to me

Maybe you can find a cheap refrigerator where you can coil the tubing inside and then back out in a closed loop, maybe keeping it in the room next door

This was a well made, informative video. I appreciate the work you put in and even though it wasn't a success in cooling, it's good to see what you were able to learn through the process.

Very cool attempt! At the beginning of the video I immediately thought "you're probably gonna have problems with cooling capacity" and was bummed to see that happen... I think one of the problems is that cooling a long loop of water is difficult to do uniformly because ambient heat will suck all the cold temperature away. You can maybe try to do something like multiple loops to get the same effect (or have only cold water go one direction of the bed, then loop back to the reservoir) For the second problem of cooling capacity, radiators (like some other suggestions) are a good start to bring the water back to room temperature. Ideally you want to lower the temperature disparity so that the Peltier can more efficiently make the water cold...

Imagine paying a subscription for your BED! This society is doomed...

If you're after a lot of 12V current and not a lot of noise, you can get used HP modular server PSUs, the ones that according to E-number appear to be made by Liteon, their cooling is temperature regulated and generally pretty silent. Which is a bit of a change from say old Delta server PSUs which just ran their cooling full tilt. They're efficient as well and come in at power between maybe 600W and 1.2kW, that range, if i remember right. Honestly by the principle of operation the commercial product is necessarily going to have the same problem of heating the room a fair bit more than it cools down the mattress. In summer you can just yeet the heat exhaust outdoors right?

$4000 plus monthly subscription!!? I bought the competition for under $300. It doesn't connect to the Internet, but uses a high efficiency compression refrigeration cycle to cool the water. Definitely should have researched available products. Though would we have gone on this interesting adventure?

You can make the printer style power supply much more near silent by swaping the fan it's built with, with a nactua fan. Several files available online to do so

1. Use ice maker to have real air compressor, and lower power consumption 2. Sow a sock 6mm in diameter and route a tube in that, sow that to the diy matress 3. Add padding to the diy matress to prevent feeling the tubes. 4. Use silicone tubing.

2:20 If you watch professionals like Linus tech tips you'll see that they just slap a blob on and that's it, tightening the cooler on top squishes the thermal paste spreading it just fine.

That's a really cool project! I highly recommend watching LTT's attempt at making a water-cooled bed - their version was quite different and they came up with multiple interesting ideas (as well as unsolved problems) in conclusion. Hope to see a Water-cooled Bed V2!

I did a similar thing and found that water cooling works better as I cooled the hot side and had 4 100 watt modules instead of one and had a pc radiator with fans and pvc tubing that I would put on my windowsill to not heat my bedroom and achieve better cooling and only used 20 meters of 10mm tubing on a pvc mat this worked extremely well and I powered it with a pc power supply so it was silent and bought most parts on ebay and used submersible pumps so they're silent and just used plastic containers as resovoiurs and it only cost a couple hundred pounds I use it every summer and have it on a timer to not be to cold and I also used air quick connectors so that different attachments can be put on for instance a larger radiator for cooling tent also I just sandwiched the peltier modules between two 40x160mm water cooling blocks as water has a higher heat capacity it cools so much better although I will try use conventional refrigeration cooling in future as it is way more efficient.

Please do a video on the mini arcade! I loved this project. I think the tubing was a big choke point as well. I can't think of another option, but changing out the tubing to something with a higher thermal conductivity would help alot. I also wonder if, when testing it at night, your weight significantly inhibited the flow, limiting efficiency. The small fountain pump provides so little back pressure that your natural movement during sleep could have some amount of peristaltic effect on the tubing, also limiting efficiency.

Hey Nikodem, I’ve also been thinking in this direction and wanted to share a few ideas that might inspire you: 1.Cooling through water evaporation: One approach could be using an ultrasonic mister to atomize water and boost the cooler. Alternatively, you could consider wicking water through felt material and passing air over it to achieve passive evaporative cooling. 2.Hose routing: For the hose layout, you might find inspiration in the cooling systems of NASA spacesuits.

AC for the room just works. Nice workshop youve got there.

Peltier module just creates more heat than cold, you are also dumping all the generated heat next to you warming you up even more. You need to have a way to pump the heat away from your room, preferably outside. Basically you need to attach air heat pump (not sure if thats the correct term) to the bed.

Run the tubing off the side of the bed before you bend it and heat bend it so it’s a tighter radius. Use a heated roller to flatten the tube or buy flat tubing. Use a fluid that conducts heat better… idk alcohol or something. Perhaps cover the tubes with a cheap “cooling gel” bed topper to hep dissipate the thermal gradient. Bldc powered turbine pump… Some of my thoughts on how to improve the design

I built one (but no temp control) I live in the tropics so summers get to 35+C easy. I used two water cooling loops. One loop for the hot side so the peltier and pumps sit on the side table, hoses go to the window with a 120mm fan and radiator to directly dump waste heat outside. The other loop goes to the bed. My first tests used silicone food grade tubing which are far more comfortable than vinyl tubing which felt like you're sleeping on iron bars. Now, I'm using a mat (similar material as air beds) but made specifically for this kind but the cooler was just a radiator and fan. I did not purchase the cooler kit, the mat alone cost me about 40usd. I didn't put any temp control yet but one 60w peltier is enough I just turn it off when it gets too cold in the early morning. I also tried the reverse polarity heating mode during typhoon season and it was nice

@Nikodem Bartnik You can try the compressor (e.g. fridge compressor). Their COP is really good so you shouldn't have problem with the heat. Alternatively - adopting some air conditioner. The noise is not important at the prototype stage, as both are quite silent and in next versions you could work around making them more silent.

Crazy idea but I think I know what you could do to get it to work. Right now your tube setup is so all the water runs from the bottom of the bed to the top. Instead you could have lots of small loops throughout the bed. Kind of like how resistors (the tubing) have more resistance in series than in parallel.

You didn't fail, you documented a way that doesn't work so that others won't try it.

You can use more peltier modules and put the system outside? But if not, you can use an led/lighting power supply, which is passively cooled and completely mute and those psus can go up to 300-400w at 12v. This is a very cool idea and if you do more research on how to run the tubes in your bed, or how to transfer the cold to your bed (maybe copy the original product), it will be very nice, and maybe better than the original!

another idea would be to put the mattress on a sealed frame that has a blower creating a overpressure in it to force air trough the mattress to you, this should cause evaporative cooling assuming the mattress is permeable enough or the pressure is high enough.

It is better to use constant current regulation with peltiers instead of simple on-off, they are a lot more efficient at lower currents. So ideally more modules running at lower power. There are also used eight sleep covers available online (i think when you return the unit they leave the cover so some people sell them).

I made one of these without an actual cooler, it just ran water under me and cooled the water through a 120mm radiator. Can never go subambient but it didn’t need it to cool me quite well. I was sleeping comfortably in a 29C room. In a 25C room I’d wake up freezing. I just used a mattress cooling pad I bought off Amazon and old pc water cooling hardware I had laying around. It started leaking right as weather was getting cooler so I never got around to fixing it.

I wanted to make this during the summer, but I didn't want to experiment. I would love to see a follow up of this project. My idea was to use a minifridge to cool the water. Also, the cooling bit should no be in the same room as the bed. I would route the tubing in another room, or outside. My biggest fear was that I would feel every bit of the hose. I wanted to router out a path out of a matters cover (5cm foam), and hide the tubing in there, but I think that may insulate the hose a bit to much.

Having tried making a little fridge for at work, I started to profusely sweat when you mentioned peltiers... Either way, here are some more pointers to ponder over: - Your peltier only draws 60W, so it moves about 18W of energy (peltiers are generally around 30% efficient). They have 4x80W (320W) worth of peltiers, so they move around 96W of energy. Evidently, that is a big difference in capacity alone. - Water has a huge specific heat capacity, so that single peltier needs to do a lot of work. The more water, the more energy the peltier needs to move, which is why the 8sleep doesn't really use the reservoir directly (it just means more energy needs to be transferred by the peltiers). More water does keep the temperature more stable when you do finally get it there though. - You can modify a PC power-supply (or just make an adapter) to get a fairly silent 12V PSU. Most decent PC PSU's can handle 40A through the 12V lines (for CPUs and GPUs) without becoming noisy at all.

I have always wanted to make this project for my parents. I guess you just need more peltier modules and use noctua fans. Get a higher capacity PSU and change its fan to noctua too.

Nice project, i haven't watched the whole video yet, so correct me if i missed something but the VCC pin on the Arduino is typically not controlled by the 5V regulator. It is simply connected to the input voltage( in this case 12v ?). So if you need 5V you should use the designated "5V" pin on the Arduino. Btw i also learned this the hard way xd

I've been thinking about a project like this for a long time so it's very interesting to see you tackle it. One thought I've had is that air flow feels cool to your skin because you heat the air and that heated air moves away due to convection, so you could maybe attach something like a vacuum cleaner (but more dispersed) to keep the air under the covers circulating so you feel cool.

Cool experiment! Like you said, you really had all the principles as the mfgr so kudos for that.

You can use a refrigerator compressor instead of the small pump. They are cheap and designed to be really powerful at minimum loudness. You have to aim for maximum efficiency for a system like this. Maybe a different cooling liquid and a more efficient way to transfer the energy to the matress would be better approaches.

Don't use a pelier just throw an array of car radiators into a mini fridge and let it cook overnight or modify a fridge compressor to accept a heat exchanger.

If you were successful at cooling the bed significantly, you would likely be confronted by the problem of moisture condensing from the air on or near the cold tubing. Think of the constant stream of water generated by an air conditioner. It would be interesting to examine the store bought version to see if they had any feature to control that. Your micro-controller might be able to factor in the relative humidity to keep the water temperature below the dew point? Cutting grooves in foam insulation (a router would work but would be very messy) could both help route your tubing and also avoid having to lay on the tubing. Most in-floor radiant heating systems install the tubing so the hottest tubing runs adjacent to the cooler return lines to spread the heat more evenly. The relative inefficiency of peltier modules and difficulty transporting the heat outside might suggest making your own refrigeration system or adapting something like a dehumidifier which contains the necessary compressors and evaporation equipment though you would have to do some plumbing (and recharging) to extend the heat radiator outside.

Would be keen to see it with a heat pump instead of peltier. Also you could have more than one loop of pipe. You’d lower your flow rate but you’d get a more distributed change in temp across the bed. Oh I wonder if you could build a peristaltic pump. Then as long as your motor has enough torque you could drive all the loops at once

Maybe start small, like water cooling the pillow! also for warming up the room maybe use ceramic heater lamp..

Thank you for testing this idea! I am making a vest with the same principle to wear it when going out in the heat as in the astronaut suit

I've dreamed about doing this myself for years and just lack the workshop space to give it a try. I would recommend looking at fish tank water pumps, they're usually very silent while moving a lot of volume and maybe add a small radiator before the cooler to help drain heat from the water before it reaches the cooler and increase the temperature differential as much as possible.

I think on most Arduinos the VCC pin is directly connected to the input voltage for example the barrel plug connector. If you connect it to USB it will be 5v but with a external supply it will be connected to this voltage, in your case probably 12v. Only the pins labeled 5v are behind the regulator and will stay 5v.

Take 2 sheets, sew parallel seams spaced 2 inches apart from one end or side to the other giving you uniform channels to feed the tubing.

I think that even with the extra peltiers you're not going to feel much of a temperature drop because of the spacing. What you need is something like a thin air/water mattress so that you're effectively lying on a layer of water. Putting an insulating/reflective blanket under that will also keep the system from sucking heat from the underlying bed, instead of you. keep up the good work

I was thinking about doing the same thing at home. I sleep next to an aquarium so the noise part with the pump is very relatable already. I was also checking the pictures of the teardown a couple weeks ago :D I think that the thermal barrier between you and the water is also something you should consider. If you look online it is almost like an ultra thin air matress filled with water and made with the same material as a water bed. They also use one output/input per side which allows for a lot of flow which will help a lot with the cooling. I would love to try something like this in the future when money and time are right :D

water beds have existed for a hundred years without pumps and they work great.

Not sure how noisy it'd get but I feel like if you just used one of those 1/8 or 1/4 hp hydroponics/aquarium chillers people use for ice baths along with a pump in an aquarium tank you could use basically the same tubing setup with a built in temperature controller with more power and accuracy. Definitely more expensive than the peltier ones but still like 1/20th the price of the actual product and probably gives more temperature control than the original. You might need a two pump setup to keep the whole tank cold depending on the setup but I think this would solve most problems other than the noise (which might just have to be spun as a free white noise machine "feature")

Looks to me like you need to double everything and then you'd have the same as the eight sleep system. The system is meant to take heat out of your mattress and put into the air. The air is then supposed to be cooled by the central AC. If you decide to make a more powerful system, I suggest having the box outside your room or even outside the window. In the end, the eight sleep system is a luxury for the rich, not a substitute for air conditioning. Cheers

you could also insulate the water in the container, so it doesn`t get heated by the surrounding air

i thought about this, if you just pump room temp water through the mattress your body would still cool down, cause your body is warmer than room temp. but for that to work i think you would need alot more volume

You can try to use a big plastic bag that cover the entire bed but it doesn’t have to be thick and use a small fridge instead of Peltier module

You can buy pumps for fish tanks with active cooling, I wonder if you could just get one of those and connect it into the bed.

Hi, that was a fun experiment ! To improve your heat transfer, maybe you could add a material that conducts heat better (such as thin metal sheets). That way, the cold water going through the pipe could cool the whole bed area. You can mount the system underneath the matress so that you dont feel the system with your back when you lay on the bed.

generally best practice with thermal paste is to put a blob of it in the middle and then press down on it with the heat sink with quite a bit of pressure so it squeezes out to cover the whole thing by itself, this way you dont trap any air pockets. but the way you did it is also totally fine and the difference will be insignificant but tbh I think using a peltier cooler is more effort than its worth when you could just be cooling the water directly using a radiator. Ambient air temperature is already much colder than body temperature so you dont need to cool the water any colder than ambient, you just need a denser network of pipes in the matress to make them more efficient at transferring heat out of your body. then your challenge is how much heat you can extract from the water per second, and its a lot easier to do that by using a large surface area cooled by ambient air than using a small surface area cooled to sub ambient. get yourself a couple of decent PC water cooling radiators and you'll get MUCH better energy transfer than using a peltier. plus it will use a lot less power, and you wont be heating up the air in your room like adding more peltier modules would do. if you really want to go sub ambient perhaps a better method would be to have the cooling unit actually mounted outside of your house. so that the radiators could be cooled with outside air, which presumably will be cooler than the air in your room. but then you have to figure out a decent way to run the tubes out a window and to make everything rain-proof

You could get a water chiller used for aquarium. If using TE modules you need to decrease the voltage quite a bit to make them efficient. A 12v module needs to be 3 or 4v to match compressor based systems which means you will need more modules to regain the pumping capacity lost by lowering the voltage. Reason is they have internal resistance that generates heat like any resistor when you give it voltage. The higher the voltage the more heat they make and then your module much remove the very heat it just created instead of just removing the targeted heat. I would at least have 8 modules if I were powering that low. Liquid exchanger or water block on both sides. One goes to bed the other a cpu radiator with fan. Radiator size will make a difference also of course. For the water pad that goes in the bed you could get some aquarium tubing the silicone type and run it back forth directly against itself leaving a loop on the ends big enough so it don’t pinch the tubing. You will have a limit with such small tubing on water flow as in after a certain amount you would have almost no flow at all. To negate this you could have flow going in split up between multiple points and exit from multiple points also. So instead of 1 line in traveling 100ft of tubing you have 4 in traveling 25ft each if that makes sense. I may stick one together to see how wrong I am..ha anyways good luck and enjoyed your video.

I was thinking of a similar project and thought for the bed I would have to use some kind of aluminized cloth and a sewing machine to create good thermal transfer

The matress/good tubing sounds like biggest problem, something elegant Honestly a heat exchange with a fridge/heater shouldnt be hard, just noisy and big....

A different solution could be changig your mattress and bedsheets Idk which material they are made of, but ive experienced that polymer based materials trap more heat and moistur than cotton and feathers. Also better for warming in winter. Do some research on that, could be a big difference.

Wow you're so close! Try making a spiral pattern (outside in) with the hose and use the whole 50 meters. A cheap three way valve could be use to switch from the resivor to the closed loop after the air bubbles are out. Using two pumps could keep the noise down and add additional pressure. Keep up the great work!

i would definitly recomend for the tubes to change them for a big water mat i think it will help better with the heat distribucion

PVC isn't great for thermal transfer, maybe there is some kind of tubing out there for exactly that application that isn't super rigid and uncomfortable. Or maybe just use thin-walled tubing considering you don't have to run the loop with that high of a pressure

You should try using a PC AIO to cool the peltier. It would be much cooler, and those can easily disipate a few hundred watts of heat with minimal noise.

Always DIY it first 🥇😊

I love those Peltier. You really have to have a good heat sink though and they take a lot of current. You can actually stack them to get lower temperatures. If you put an array of those between two vessels of water you have a hot side and a cold side that you can tune very easily The gel foam mattress toppers work great for something like this

Tech ingredients did a great video on thermal pastes and foils.

Subscribing to your bed company is wild

monthly subscribtion for a 4k bed heater/cooler is CRAZY

Thanks for SkillShare :)

Hello, I think your main problem comes from the use of a pelletier module and its low efficiency. The simplest would be to use a source of cold water already present in your environment such as a rainwater tank in the ground or to use a solar thermal panel oriented towards the sky (radiative effect at night). If none of these solutions is possible, the use of a compressor refrigerator will be the most efficient, at low cost, by placing a container of water in contact with the cold wall. The adjustment of the temperature of the water on the mattress is done by the use of mixing taps adding a proportion of cold water (taken at the bottom of the container) with part of the water already present in the loop. The excess water returning from the bed returns to the top of the container in the refrigerator. For the noise problem, the simplest would be to place the device outside and to let only the water tubes enter in an insulating sheath. This would also dissipate heat to the outside. Have a nice day AT

A coil of copper tubing could be buried in the ground. The pump flows between the bed coil and the ground coil... Sometimes for heating, they use black plastic tubing and put it on the roof. You are creating a heat exchanger. The more efficient units just use different fluids.

I love your creativity! To stay cool at night, have you tried a hammock? It’s pretty surprising.

I wonder if you could convert an old mini fridge to a more efficient bed cooling system.🤔 I see those at my local landfill all the time, so they should be quite easy to get. Maybe you could place it outside and just run some tubes inside, like an actual AC System, to avoid noise and heat generation. Would definitely be interesting to see.🤔😊

For that 4K bed + subscription just hang a split airco for half the price and its a lot better

Nice Video Bro, keep going with this content! I just stumbeld across it and it really catched me and is a really good piece of work!

Routing grooves for the tubing in foam insulation would provide some benefits: 1) reduce heat/cold loss into the mattress, 2) make it easier to route the tubing, 3) smooth out the surface you are sleeping on. I was thinking of that flexible closed cell foam often used as protective packing. I foresee problems when you are in cooling mode with moisture from condensation accumulating on and near the tubing. It might be possible to use your micro-controller to monitor the relative humidity and keep the water/tubing temperatures below the dew point. Here in Minnesota USA, high temperatures usually include high humidity. Wet bedding could get ugly quickly. Were there any indications that the $4,000 system addressed condensation situations? More peltier modules would work but the inefficiency and difficulty transferring the heat outside would become even more of a problem. Ultimately a refrigeration system might be more effective for moving heat outside the living space. Finding a small efficient compressor could be a problem. It might be possible to adapt a de-humidifier refrigeration compressor. That would likely involve some plumbing and recharging the system .......and a few more videos. Using peltier modules to heat might be less efficient than just using an electric blanket or pad. My experiences with peltier modules usually involved the cold side frosting up but I was not using water to transfer the heat. If your pump was to fail and the peltier module wasn't shut off, you might have issues with water freezing. I really enjoy your projects. Thank you for your creative approach to probems.

Cool project. the eight sleep one is way to expensive thou. Bed jet solution seem better, as the cooling is not directly cooling, just air over your body, so to not to cool too much, just using your natural sweating/colling systems, and not to generate any extra heat in the room.

Look at the nasa cooling suits. I would think that smaller tubing would be better at transferring the heat, maybe multiple zones. But ya loose the tube, to much of a temp loss. I have been thinking of this too. I will be watching.

Nice! Well, putting the unit itself outside will work better, making it a more local cooling-system (like airco but more specialized). And then ofcourse as a more efficient bed-heater then a normal heat-blanket as we normally use (just electric heaters). If you are using it in the same room, well you mainly move heat and at the same time heat (or cool) the room + extra electric heating. Actually, peltiers work more optimized if you keep them cool on the 'hot side' too, thus a vat of water could help already to make a buffer. For more optimized cooling, you can also use the system from a normal refrigerator/ freezer which is far more efficient (and therefore more quiet) then Peltiers, still working as heatpumps. About the cooling... you need to insulate below the cooling or you will need to cool down the whole heat that is stored in the bed itself since that will keep moving upwards all the time. For example an airmatras below it. That is besides the spread of the tubes. Probably needing also to cover the bed before going to bed with the cooler/heater on for a longer time.

I think you should try to reduce area, but pack tubes closer to eachother. Also you should try to sleep on it. If it keep 24C when you sleep it would be quite chill. The problem with bed in hot nights is it's getting warm from your body heat. Also during night air temp drop. Your system might actually be enough.

just use regular bed with springs without individual coating on spring. cut in and out hole and pump ac air through it

But for cooling the water doesn't need to be sub-ambient just cooler than you. So I would ditch the peltier and just have a big radiator and pump both temperature controlled

the insulation in the expensive system is not only for thermal insulation, but also to prevent condensation i guess

That plastic tubing aint goanna do much heat transfer, maybe an oversized flexible and thin waterblock of sorts?

It seems like the primary issue is getting enough heat to transfer between the tubes and the bed. Id make a metal tubing system thatd be placed underneath the bed. To make sure the bed is comfy id inlay the tubing in a sheet of foam. Lastly id attach rolls of metal to the pipes to further disapate heat. Also id be carful with how thick the mattress is. I dont know how insulative they are

Get a mesh material and weave the tubing through, like they do on old space suits (the blue one when you google it). Also the closed loop pump is called a peristaltic pump.

Peltier is super inefficient as you know. I’d be looking in to aquarium chillers.

I would be interested if using flattened thin plastic tubes could be good. Get max surface area, "flat tube rolls" might be hard to get watertight and durable.

big bucket (25L) with bags of ice or freezer packs would work!

I feel like it's an engineering student's rite of passage To try to cool something with Peltier plates. I haven't watched this yet, but I suspect you learn how inefficient they are and swap to a radiant heat exchanger...