Peltier cooling

Anyone done any larger scale peltier (solid state) cooling? Seems like a cheap way to go. I'm thinking about building a few thousand watt system to chill my rig.

The standardized 12710 40x40mm module sold by many Chinese (and some American) manufacturers looks to be one of the most effective, pumping 100W @12V and as much as 160W by bumping that up to 15V+. They can be purchased, including shipping for around $3.50 per unit. They get a DeltaT of about 70°C. So with good air cooling alone, in winter (average +5 to +10°C ambient), I should be able to pull a pot glycol into the -20°C range - and keep pulling a lot of heat out as it's added. With good ice water cooling, and a lot of insulation (and a lot of chips) I could see the -40 to -50°C that I'm after.

I found these little aluminum water blocks made for computer chip cooling on eBay, mass produced from China. They have 40x40mm blocks for $3.50 or 40x95mm blocks for $4.40 that could cover 2 chips, including shipping.

I figure several of these double chip blocks could be adhered to the outside of an aluminum pot full of circulating glycol. Then all of the water blocks run to a large (ice?) water reservoir or car radiator/fan with some cheap aquarium pumps (or one big pump split through many blocks) since that won't get below freezing.


I think a 50' coil submerged in this pot could work for my injection coil, and the same for my recovery coil. I've thought about strapping them right onto my material columns to keep them cold. I could possibly even set it up to switch coolant loops and the polarity of the chips and instantly switch from column chilling to column heating for recovery.


There are also some larger 62x62mm modules that can pump ~240W @ 12V or up to 550W at 17-18V, as cheap as $20 but they seem difficult to cool. Powering them would also be more difficult as they each gobble up 30+A. The smaller modules still need ~10A but that's a much cheaper power supply (a few bucks). It's still going to cost some money if I want to string together 30-100 of these chips, which I figure will get me by.

Well it's certainly a cheap project to get started with. I'm going to order 10 chips and 5 waterblocks, as well as some 12-15V power supplies. I'll also grab some heatsink/fan combos that could be used instead of water cooling, and we'll see how cold we can get with those alone. Even if this setup is only 25% efficient, a 375W countertop solid state lab chiller setup for $100 is a great bargain. I bet you could do some great small chillers for fractional distillation with these also.

It could work, but is inefficient compared to vapor compression cooling. If you can't afford a chiller, using ice made in your home freezer would be a more efficient method of cooling than peltier-style devices.

Well electricity is only a nickel a kWh here so total electrical efficiency isn't that important if I can do so much cheaper in build cost. I'm looking at around $2-3k for a decent used recirculating chiller that's only going to give me a thousand watts of cooling power or so. Anything bigger starts costing a LOT more. If I can replace that with a $300-800 system like I've described, even if it used 3000-4000W to do the same work as a 1000W compressor, it's worth it to me...especially if I can scale it up piece by piece from there. When I was just using regular ice to chill my system, I was running through about 180-200lb/day. Ice machine rentals are reasonable though. A machine that makes 200lb/day is only $50-75/month. But ice isn't going to get me to -40°C. Peltiers definitely can, if you use enough of them.

Itsgotatail said:

Well electricity is only a nickel a kWh here so total electrical efficiency isn't that important if I can do so much cheaper in build cost. I'm looking at around $2-3k for a decent used recirculating chiller that's only going to give me a thousand watts of cooling power or so. Anything bigger starts costing a LOT more. If I can replace that with a $300-800 system like I've described, even if it used 3000-4000W to do the same work as a 1000W compressor, it's worth it to me...especially if I can scale it up piece by piece from there. When I was just using regular ice to chill my system, I was running through about 180-200lb/day. Ice machine rentals are reasonable though. A machine that makes 200lb/day is only $50-75/month. But ice isn't going to get me to -40°C. Peltiers definitely can, if you use enough of them.

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good luck getting enough surface area to readily chill any significant amount of solvent to -40. If you succeed, hats off to you. I just don't want you wasting your time trying to chill from the exterior of the walls of a vessel with several, inefficient, localized cooling devices. Chillers have a coil immersed in coolant. You won't get that kind of heat transfer by attaching something to the outside of your vessel.

Yeah, perhaps I'll look at putting a water block on the cold side of the peltier also and do a fluid to fluid heat transfer.

Peltiers are not good in high load situations.

I haven't seen any setups/chillers with 1000W or more of peltier elements but there are at least a dozen companies making countertop or rackmount solid state, peltier based lab chillers in the 200-1000W range that claim -5 to -20°C coolant temperatures. I think most people's experience with peltiers is the little 5-10W "drinkwarmers". No, I wouldn't expect one of them to do much in a system like this. But the companies producing these lab chillers, like www.thermotekusa.com and www.thermoelectric.com claim their units to be as much as 80% MORE efficient than a comparably sized compressor based system. Unfortunately they're quite expensive for how small they are. Guess I'll just try and see.

One of the issues you'll face is pulling the heat out of the hot side. You'll need a water pump capable of decent pressure and a significant radiator to dump the heat to atmosphere. A heatsink and fan on the module isnt going to be effective. To get to -40 you'll need a cascade system. The cooling power drops drastically when you cascade pelltiers.
Talk with a refrigeration tech. If you buy a used condensing unit he can probably build you a chiller capable of 2k btu at minus 40 for under $4k...
All you need is a off the shelf condensing unit, heat exchanger and liquid pump capable of cont -40.

...companies producing these lab chillers, like www.thermotekusa.com and www.thermoelectric.com claim their units to be as much as 80% MORE efficient than a comparably sized compressor based system.

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I’d like to see the data on these.

Sounds a lot like the beginning LED days where bogus claims are made (& still are) in order to suck in consumers.

edit:
I could find no such claim made by the two companies linked above.
After reviewing the sites these seem like legit systems but according to one site, not a single one of these Peltier systems can get temps below -5C. I didn’t see any system capability specs on the other site.

I’m curious about your goals using these Peltier devices?
Obviously your looking for cooling but why go this route?
Peltier devices are relatively slow at reaching their set points compared to traditional methods.

Truthfully, it's just out of a liking of them from my days doing computer overclocking... And thry've dropped about 80-90% in price over the last 10-15 years. Sometimes a technique that seems really unrealistic becomes feasible because one of the variables changed.