Looking for guidance on a chiller purchase

Hash and Stuff Extraction
, , ,
1

So I have a 3x36" jacketed column that I am unsure of the volume of, I’m estimating 10l, so I would need a 20l chiller, don’t have the funds for the cryo chillers (-86) but looking to hopefully get into a -40, would -20 be enough for dewaxing purposes? I’ve always heard colder the better, but unsure if -20 is adequate.

You guys are the best here, so here I am. I also had heard of a website selling used lab equipment at significant discounts, with the equipment having a chance of failure. I am rather handy, and could most likely asses and fix a potential problem if it saves me thousands.

can 1 chiller operate two different columns with a t split? if the volume of the chiller was enough.

any advice is appreciated , & I thank everyone for their time,

edit: I bought a 1 lb rack mounted inline dewaxing unit, ill post pictures shortly, on a new computer, no images. but like previously stated, the chiller is to chill an inline dewaxing column (3x36) with no heat load.

1 Like
2

One chiller can operate multiple locations with a t split, thought I’d warn that if you don’t have a way to match/adjust flow you’ll want to make sure hose lengths and other things which impact flow & resistance are as close to perfectly matched as you can get them.

I’d also caution that -40 is better because if you don’t have enough chiller to maintain right at -20, it’ll give additional hedge against warming up and allowing waxes/lipids into the collection pot

1 Like
3

Ya -20 works for a material column if the tank is on dry ice. But dewaxing should be -60 or lower

2 Likes
4

With hydrocarbons dewaxing is a fallacy, if you want truly dewaxed material you will need to winterize in etoh .While cold temps are beneficial to locking up water solubles, -20 -40c seems to be the sweet spot any lower you are wasting energy. Especially if you are barking up the tree of dewaxing in a non polar.

10 Likes
5

The key is keeping it at -20°c. You will have a hard time not raising the temp in the process. But if you have a the heat capacity -20 is enough.

1 Like
6

So to be safe I’d be looking at a -30 to try and maintain an minimum of -20? Thank you for the information, I do understand winterizing, and I’m glad its still applicable, i guess my next question is who’s got a chiller for sale! I don’t have the 4k budget for a new one right now.

7

Do you have a friend in the hvac industry? If so you could probably make one.

2 Likes
8

I’d love a link or a bit more info from you before I google. But I do understand that much like an AC blows air over a compressor-chilled coil, we seek to pump liquid coolant over a similar heat transfer surface. I’m just not clear on practical design of these critical interfaces when a liquid is involved, other specific hardware stuff…

1 Like
9

Thats where the friend with hvac experience comes in.
The basic components of refrigeration system are the compressor, the evaporator and the expansion valve/ capillary tube.
image

it is possible to achieve -30c with a single stage system, if you want to go lower than that you will need to construct a cascade type system. A cascade system used two separate refrigerants and two compressors to achieve this, the low stage transfers its heat energy to the high stage.

For cooling solvent, a plate style heat exchanger can be used in conjunction with direct expansion refrigeration.

image
image1200×1359 212 KB

Think of the project like a water chiller.

3 Likes
10

This can be done with parts from misc hvac systems? I know I’ve seen a thread here on diy chillers, hre ya go

11

Hi,
You could use existing parts, although there is no guarantee how it will work once modified.
I have seen people open up window ac units and relocate the evaporator inside a container full of fluid to chill and circulate. Like this:

The unit will be limited by the boiling point of the refrigerant used and the amount of heat the system can pump.

You could also cobble together a system from more basic components like these.

https://www.partstown.com/continental-refrigeration/compressors/parts

https://www.partstown.com/continental-refrigeration/condenser-evaporator-coils/parts
image

Read this, it has alot of good info.

2 Likes
12

The biggest issues with building low temp units out of generic HVAC/R components are compression ratio (see my write up in the chiller calculation thread) and oiling issues. A decent HVAC tech who works with refrigeration systems should be able to figure out both of these problems. Plate heat exchangers are great for evaporators and even better for condensers if you have a cool liquid source available.

2 Likes
13

I do have friends in the industry, I have also found this constant temperature chiller (-34c) through polyscience, it looks funky, I wish I knew more, but it appears that this could work. for only 2500$ also.

14

by the way, I love where this thread is going with home made chillers, I’ll have to talk to my people now…

1 Like
15

You may want to figure out how many btu’s per hour you need to remove, a little math now can prevent bigger headaches down the road.

2 Likes
16

Theres no heat load. Just dewaxing an in line column

17

Hi,
While there might not be any heat your adding to the column, you will still have to figure on how much energy you need to maintain that temp against ambient temps, as well as chill the solvent in the column. Everything takes energy, while your task may not demand much energy transfer it still pays to see if it will work before buying it.

3 Likes