CanCooler 4000

[Data]

World's Fastest Can Cooler Chiller

Way back in the 1980s when I was just a kid, I made my first Peltier powered can cooler. It did not work well and I had to accept defeat for a few decades.

We had an enormous good time putting together this Video to show the CanCooler 4000 in action. There is a lot of information in this video, I hope you all enjoy. My kids created the fun skit in the the intro. They wanted it to fit in with the modern edgy YouTube culture. No kids were hurt in the making of this video.




======== the technology ========================

There are two really important aspects that enable the CanCooler 4000 to do what it does. They both have to do with direct thermal conductivity and high thermal mass. And together they get the Delta temperature in the system small enough so that the Peltier chip can actually be used to cool a can.

The typical mistake for the hot side of the chip is to put a fan cooled heat sink on it. They are incapable of holding the room temperature. By their very nature they have to heat up in order to dissipate heat into the air. In contrast, the CanCooler 4000 Peltier chip is directly touching an enormous copper mass. Because of this, the hot side temperature does not rise by more than a few degrees above room temperature.

The typical mistake for the cold side is that the Peltier chip is trying to cool static liquid in the can where the liquid is not being stirred. Water has high thermal density which means you have to pull a lot of BTUs out of it. But water has low thermal conductivity. The cold goes into the wall of the can and starts to reach into the liquid but it can't reach all of the volume of the liquid. The water insulates itself if you will. You end up with ice, a considerable thermal gradient and a delta-T that is too great. The can cooler 4000 gets around this by constantly mixing the liquid. This makes sure that the absolute warmest liquid possible is always directly touching the cold side of the Peltier chip during the entire cooling cycle.

These two things make the delta T the smallest that it can be. And guess what? It amazingly just so happens to be enough.

So the can cooler 4000 does what no other Peltier powered electric machine in the world has ever done. And that is chill a beverage can in 150 seconds.

========== about this thread ========================


Though the conclusion videos and results are posted in this first post in this thread, all the other posts are a time progression of the events as it was being developed. Throughout this thread there are lots of videos and pics of the build progress. We started off thinking that powered mecanum wheels would agitate the can but later realized it would not have been enough and so half way through we redesigned.

NOTICE: If you are new to this thread and before you read the reply posts from last year, I want to prepare you for their nature.

Many of the earlier posts in this thread that were made after I introduced this project over a year ago, to use Peltier chips to cool a can, are very negative. You will find several stating that this project is likely to fail, or that my science is suspect, or that there is a much better way, etc.

I understand why they doubted the possibility of making this work. Peltier chips have limitations. Behind the scenes, I was advised by some people that I should not be letting them trash the thread. But everybody is welcome here on my forum. I do not tolerate trolls, but these guys were not trolls, they were just trying to add to the discussion.





========= Below here is the original first post that started this thread =============

With all the people that run through my cave bar every week you would think one of them would put another case of soda in the refrigerator when they take the last cold can. But no, invariably, I am stuck with a warm can of diet coke. . . Kids!

So, just for fun, we are working on an all electric machine that can very quickly cool a beer or coke beverage right in the can. The "CanCooler 4000" will, we hope, be able to take a room temperature canned beverage to a very cold temperature in just a few minutes. It will consume up to 4000 watts of power, stand just over 4 feet tall, and weigh close to 300lbs with 8 peltier cooling chips and 8 500W power supplies. Here is a video of a peltier chip in action.



Stay tuned and stay thirsty my friends. :tinfoil:


Cheers
Dave

 

[parametrek]

Re: Can Cooler 4000

I hope you'll reconsider the use of peltiers.

Cooling 500ml of water from 23C to 1C requires 46k joules of cooling or about 13 watthours of energy to be moved. Doing so in 3 minutes means moving 260 watts of heat from the can for those 3 minutes. Peltiers are only maybe 5% efficient in cooling so it'll require pumping at least 1300 watts into the Peltier. And of course providing a huge amount of heat sinks and cooling and fans to dissipate that 1300 watts. Of course you've already done this math.

A conventional compressor based cooler is more like 300% efficient. If you are scratching your head at how "over 100%" is possible: refrigeration isn't about making heat or making cold. It is about moving heat. A gasoline tank trunk can move thousands of gallons of fuel while only consuming a few gallons itself. Air conditioners and refrigerators and heat pumps all work by this principle. Side note: If you use electric base board heating and replace that with a heat pump you can expect your heating bills to go down by like 70%.

Back to the beer cooler. In practice it gets worse because the peltier is only 5% efficient when both sides of the plate are at the same temperature. Efficiency drops to 0% as the temperature difference increases. As the can cools the Peltier can't cool as efficiently and so you need to pump even more power into it.

A conventional cooler could move those 260 watts with under 100W of power. Well within the range of a cheap mini fridge. The main difference is that the fridge's cooling coils would be spiral wrapped around a tube that the can drops into. Much cheaper to build and to operate. Dramatically quieter and won't pump out as much heat as a hair drier. Possibly faster since it can get colder than the peltier.

I think the planned can cooler design will solve the problem just because people are going to be so terrified of the giant box that sounds like an angry jet engine that they'll keep the fridge stocked to avoid having to use the machine.

 

[FRITZHID]

Re: Can Cooler 4000

Hell, you'll have to be careful not to freeze the soda on the outside edge of the can with a small refrigerant based device, a TEC capable of that would be ridiculously large and obnoxious, let alone inefficient.

 

[Data]

Re: Can Cooler 4000

paramettrek, FRITZHID,

Thanks for your input, I appreciate your perspective and as for efficiency, I agree with you. At first glance, your math looks correct to me too. I was hoping there would be some interest in this crazy project and it sounds like you guys have some experience with this stuff.

I know enough about heat pumps and the refrigeration cycle to get myself into trouble, LOL. I just recharged my 5 ton cave unit yesterday because it was the first warm enough day here for me to use the subcooling method. I installed that unit myself a few years ago and I now know it has a small leak. My equipment is simple, just a set of analog yellow jacket gauges and a temp probe. Do either of you do HVAC work?

The purpose of this Can Cooler build project is to make a fun toy, so to speak, it is not practical in any way. It will end up setting in my bar next to my refrigerator. The goal is to see just how fast I can cool a can with peltier chips, just one can in one shot.

BTW, my rig will not make any noise except for the switching power supply fans and they are almost silent setting inside the base in my tests. I will post a pic of the base ASAP. And yes it is large and obnoxious. :naughty:

Cheers
Dave

 

[Data]

Re: Can Cooler 4000

This is a rendered computer model image of what we think the final project will look like. Also below that is, a photo of the base with me holding onto it.

Cheers
Dave

 

[mattheww50]

Re: Can Cooler 4000

My experience with Peltier devices used in coolers is they typically have a Coefficient of Performance of about .1 in a complete system, in other words for each calorie of heat transferred, 10 calories of energy will be required/consumed. Cooling a 300ml can of a water based liquid from 25 C to 5 C will then require the transfer of 6000 calories, and doing so will require 60,000 calories or roughly 200,000 joules! Doing so in 3 minutes doesn't alter the energy requirements, but merely says the devices must consume about 65,000 joules per minute or 1.1 kilowatts of power for 3 minutes. This is an absurd amount of heat to be dissipated . A mechanical refrigerator typically has a Coefficient of Performance of about 3. I gave up on Peltier refrigerators and bought an small Engel refrigerator. Because Peltier Devices have great difficulty pumping energy across a temperature gradient of more than about 20 C, they cannot make ice in a room at 25 C. A 20 liter Engel refrigerator can actually make ice easily and can easily achieve a 45 C temperature differential.

 

[Data]

Re: Can Cooler 4000

My experience with Peltier devices used in coolers is they typically have a Coefficient of Performance of about .1 in a complete system, in other words for each calorie of heat transferred, 10 calories of energy will be required/consumed. Cooling a 300ml can of a water based liquid from 25 C to 5 C will then require the transfer of 6000 calories, and doing so will require 60,000 calories or roughly 200,000 joules! Doing so in 3 minutes doesn't alter the energy requirements, but merely says the devices must consume about 65,000 joules per minute or 1.1 kilowatts of power for 3 minutes. This is an absurd amount of heat to be dissipated . A mechanical refrigerator typically has a Coefficient of Performance of about 3. I gave up on Peltier refrigerators and bought an small Engel refrigerator. Because Peltier Devices have great difficulty pumping energy across a temperature gradient of more than about 20 C, they cannot make ice in a room at 25 C. A 20 liter Engel refrigerator can actually make ice easily and can easily achieve a 45 C temperature differential.

I agree, it will not work as well if it is out in the sun on a hot day.

The starting conditions that I care about for my device are the temperatures typical of my cave. That is usually about 67 degrees F ( 20 deg C ). There are lots of details surrounding the thermodynamics of the temperature difference between the hot and cold side of the Peltier chip, the thermal conductivity of the hole system including the water/ice and lastly but not least the specific heat of the hot side.

As you will see very shortly, my machine does not need to dissipate this "absurd" amount of power during the 4 minute cooling run. :tinfoil: I will post a video of the cooling engine assembly later today so you all can see how the chips are mounted.


Cheers
Dave

 

[parametrek]

Re: Can Cooler 4000

BTW, my rig will not make any noise except for the switching power supply fans .... As you will see very shortly, my machine does not need to dissipate this "absurd" amount of power during the 4 minute cooling run.

You're skipping all of the active cooling and using a thermal sink? So 30k joules from the can and another 300k joules from the peltier. Those 330k joules if pumped into 10 kg of aluminum would raise the temperature of the sink by 29C. Since the peltier can't handle a gradient that large it would end up heating the can by around 10C.

 

[Data]

Re: Can Cooler 4000

Can Cooler 4000 engine parts video and build video condensed to 3 minutes.








Cheers
Dave

 

[Data]

Re: Can Cooler 4000

You're skipping all of the active cooling and using a thermal sink? So 30k joules from the can and another 300k joules from the peltier. Those 330k joules if pumped into 10 kg of aluminum would raise the temperature of the sink by 29C. Since the peltier can't handle a gradient that large it would end up heating the can by around 10C.

You are zeroing in, but the sink is almost 60Kg of copper. :sick2:

 

[Data]

Re: Can Cooler 4000

The eight power supplies mounted in a rail that slides into the base and all the fan holes, displays and control knob holes line up.

 

[parametrek]

Re: Can Cooler 4000

the sink is almost 60Kg of copper.

Copper has a pretty terrible specific heat though. Aluminum is more than twice as good. 330kJ would still raise that sink by 14C and that eats most of the thermal gradient. So the can will probably be all of 6C cooler.

And it will only be able to do that trick once. The 2nd can through would heat up unless the machine was given a while to cool off. This is why everyone thought there would be fans. You need active cooling to be able to cool more than one can. Though next you're probably going to say that the copper sinks are removable and replaceable.

edit: Your plates could use some more work. There really shouldn't be any visible machining on the junctions and that much thermal paste should be unnecessary. I'm also surprised you didn't opt for the latest and greatest carbon nanotube thermal material.

very late edit: The big noisy DC power supplies could be eliminated. A $1 bridge rectifier could feed the peltiers from the wall directly if they are put into a series/parallel combination totaling 170V. This will require 30% more peltiers for the same cooling but that is probably a worthwhile tradeoff given their relative prices.

 

[spaceminions]

Re: Can Cooler 4000

Seems like a shame to do stuff this way, since the power supplies still have moving parts, and this thing will make so much heat I'd need another drink to cool off. And another shame to use metal as a heat reservoir instead of something like water. An absorption cycle would be cool.

 

[KITROBASKIN]

Re: Can Cooler 4000

Well, there are those here who are amazed and interested in this project. Bold and offbeat. Thanks for sharing it and hoping to learn more. Thanks!

 

[karlthev]

Re: Can Cooler 4000

Nothing less than an incredible Coolfall creation! Congrats for the hard development and machining work Dave. I, as one of many, am waiting for the utilization of the Coolfall Can Cooler 4000! I'll take one!!:twothumbs



Karl

 

[Data]

Re: Can Cooler 4000

Thanks for the kind words guys.

Here is a pic of the saw cutting 8" aluminum for the wheel hub. :tinfoil:

Cheers
Dave

 

[Data]

Re: Can Cooler 4000

Copper has a pretty terrible specific heat though. Aluminum is more than twice as good. 330kJ would still raise that sink by 14C and that eats most of the thermal gradient. So the can will probably be all of 6C cooler.

And it will only be able to do that trick once. The 2nd can through would heat up unless the machine was given a while to cool off. This is why everyone thought there would be fans. You need active cooling to be able to cool more than one can. Though next you're probably going to say that the copper sinks are removable and replaceable.

edit: Your plates could use some more work. There really shouldn't be any visible machining on the junctions and that much thermal paste should be unnecessary. I'm also surprised you didn't opt for the latest and greatest carbon nanotube thermal material.

very late edit: The big noisy DC power supplies could be eliminated. A $1 bridge rectifier could feed the peltiers from the wall directly if they are put into a series/parallel combination totaling 170V. This will require 30% more peltiers for the same cooling but that is probably a worthwhile tradeoff given their relative prices.

The specific heat of copper is a function of its mass. I wanted the unit to be as compact as possible. For the same size of block (2" x 4" x 12") the copper can hold more heat than aluminum. But that is only half the story as copper has a very high conductivity too. As a heat sink for high end CPU coolers and flashlight emitters, it is the king. I use it as a heat sink on both my emitter and my Texas Instruments STFu power IC in my SPY flashlights.

It is a one trick pony. It will take hours to cool off before it can be run again. This is part of my design and it is necessary for it to be quiet and compact. This is not the kind of toy you would want to run several times when there is a fridge setting next to it.

The cold plates show machining marks but they have a very smooth flat surface. It just looks that way because that is how an end-mill marks a part when it is end-on machining. I did not measure the surface finish but when you have been CNC machining as long as I have, you know from experience what feed, speed and step-over is needed to get a particular finish. You are right, I later took most of that silver paste back off of it. The thermal conductivity is very good between the two with the silver. Where do you purchase a small quantity of nanotube material? Arctic Silver does not have it.

The power supplies are big but they make almost no noise. Keep in mind, I picked power supplies with variable speed automatic fans and with the short runs, the fans never ramp up. They stay so low that you really can not hear much at all. A bridge rectifier would not give me the ability to tune the output of the system. These power supplies are variable output voltage with voltage displays that show through the windows on the base. The voltage*amp power through the Peltier chips is critical to maximize the cooling of the system. If it is set too high it will actually have an adverse effect on cooling.

I need to dig in the attic and find my first Peltier can cooler, I built it back in the 80's or 90's, I do not remember exactly when. It kind of worked but it was very low power and only intended to keep a can cool. I remember having it in my 75 Impala! :wave:

Cheers
Dave

 

[Data]

Re: Can Cooler 4000

Seems like a shame to do stuff this way, since the power supplies still have moving parts, and this thing will make so much heat I'd need another drink to cool off. And another shame to use metal as a heat reservoir instead of something like water. An absorption cycle would be cool.

Water is very good at storing heat but it is not good for thermal conductivity. You have to mix it or agitate it during the process. This is actually part of the Can Cooler 4000 design. Hang in there, more details are coming.


Cheers
Dave

 

[spaceminions]

Re: Can Cooler 4000

With CPU coolers, where there's also a demand for low thermal delta, heatsink faces are often polished to a near-mirror finish with as flat a surface as possible, so that even on a microscopic level the amount of space the thermal paste occupies is minimized. Then some people use gallium based liquid metals, though of course that's only with some metals. Visible markings may feel smooth but everything adds up, esp with multiple interfaces in a row. It might be a way to gain a little performance, maybe not. I think there's a small 40mx40mm thermal pad that's carbon based; IC graphite or something. I'd just use the paste.

 

[parametrek]

Re: Can Cooler 4000

Sorry I misspoke about the details. It is a graphite cooling pad that was only released in April. Here are the specs on it:

https://www.innovationcooling.com/products/ic-graphite-thermal-pad/

There have been several reviews that confirm it does work better than thermal paste. A 3cm x 3cm chunk is $15 on Amazon. Expensive but it is zero mess and reusable.

I was talking about this with some buddies who are wiser than me and they pointed out 2 things that I wasn't aware of. The fastest COTS way to cool a can (1 minute) goes to the $25 "Chill-O-Matic." It required being loaded with ice and agitates the can for faster cooling. The least expensive and quietest would be to keep a bucket of salt water in the freezer. Plonk the can in the bucket and it will cool extremely quickly. Have to be careful because leaving it in too long might freeze the can.