yelling at them only works for things you need hotter 
8 Likes
For those interested I posted how to estimate “tonnage” at temperature in the chiller calculation thread. Others have posted the sensible heat loads for various solvents. 10 tons (approx 120k btu/hr) at 50F gets very small at -112F (probably less than adiabatic loss in a large system for that matter). This is obviously refrigerant dependant, but there’s no magic solution.
To the OP: it seems like the big shortage in the market is something with several ton capacity at cryo temperatures; this requires multistage or cascade systems. Unfortunately, most manufacturers seem to be building these bigger custom systems with a bunch of smaller (7-15hp) compressors in tandem. It sucks. What the industry really needs is 100-400hp centrifugal process chillers that have been modified to oil properly at those temperatures in a multistage/cascade configuration. Trane/Carrier scale.
4 Likes
I noticed nobody has mentioned the onboard recirculating pump.
I have found a big difference between chillers is the type, size, and power of the recirculation pump.
I feel like its the same thing you either have a crap pump for cheap that is guaranteed to fail or u pay industry standard prices to get a better pump/chiller that u might not need all of.
Also a big difference between cheap and standard is how many different heat exchange fluids the pump is capable of circulating at what temp.
I have 2 smaller chillers with pumps and one without.
A lil AI for my 2l rotovap and a bigger neslab for a big rotovap. The AI has a junk pump. Btw so is the pump i shelled out $300 for from @usalab CRAP! It lasted 2 months. The neslab has like a super 1.5hp pump that probably could run all 3 chillers at temp
@Xander what is/are the specs of the pump(s) in your chillers? What fluids do they run @ what temperatures? And what is the flow rate of the pump @ working temperature with (each) fluid?
I need a motorized (single phase?) pump that will move 5-10 gallons/minute of denatured alcohol @ -80°C and pump this liquid up 8-10’ head thru about 100’ of 1/2" line including 2 coils and circulate it
3 Likes
7-15 hp Compressor is what’s readily available except for with Trane/Carrier units. However almost everyone (including Trane/Carrier) pipes in tandem. my units are piped individually - Single, Dual or Quadruple refrigeration circuits, yet our standard units are incapable of reaching such low temperatures. We can produce these units if we were to switch over to screw type compressors but their seems to be resistance to this type of compressor because people are not familiar or don’t like the use of one single compressor.
1 Like
I thought the reason nobody used screws anymore was that the COPs were terrible and the compression ratio limitation was bad due to excess friction heating. We actually run a 250hp trane screw for facility cooling, but only because we got it for less than $10k.
The reality is that in order to make a good cryo chiller, you need a real cryogen (N2 or He), which means you need multiple stages and refrigerants. But if you want 50 tons at -80C you’re going to need a dozen 10hp compressors or more on a skid. It’s an absolute nightmare. This is in my opinion the single largest issue with scaling QWET extraction.
What I would really like to see is someone modify a trane or carrier liquid cooled skid(s) to operate with these low temp refrigerants. They would make absolute bank compared to Huber and the like.
4 Likes
Wish more of that made sense.
2 Likes
I saw a chinese screw-compressor based chiller that boasted quite the cooling power. Not UL listed though.
1 Like
I will keep it as simple as possible
I need a chiller for lab tests. Let’s say -80c with ability to chill a minimum 120 gallons to that temp in 4 hrs or so. For this let’s say 1/2 gpm. Would take one that does double that. Cash waiting, but need it by mid May… Anyone? Educate me here, or PM me with solution
2 Likes
