So, I thought that I would create a thread to document my experiments on a budget DIY recirculating chiller that uses a dry ice/ethanol/propylene glycol slurry with an external magnetic drive pump. My target temps will be in -50C to -60C range, but I have no idea how the pump will handle it over the short or long term. This is a couple hundred dollars compared to the lab versions at MANY thousand dollars, which most only get to -30C. Yes, it takes dry ice, but not that much to justify the difference.
Here is the pump that I am using:
https://www.amazon.com/CHUGGER-PUMP-CPSS-CI-1-Transferring-Compliant/dp/B01N9HERFS/
HOME BREWING PUMP - The CHUGGER PUMP can be used to ease transfers between kettles, cool wort via a counterflow chiller, or recirculate ice water for quicker chilling!
HIGH QUALITY MATERIALS - Stainless steel pump head, Magnetic Drive w/ base, Teflon thrust washer, Clear Silicone O-ring, Ryton/Teflon Impeller, 55" cord with plug.
PREMIUM PERFORMANCE - Featuring a max flow rate of 7 GPM and 18 Feet of head to handle back-pressure. Capable of handling liquids up to 250 degrees F.
The CHUGGER PUMP is the only home brew pump with ETL certification and USFDA food compliant materials tested for safety and performance standards.
3/4" MPT inlet and 1/2" MPT, allowing easy configuration for any application!
I choose 2x (6L and 15L) relatively thin stainless stock pots as the system reservoir. I used 8lb density 2-part Liquid Urethane foam kit (2 quarts total) to create a thermal barrier, which varies from 2 1/2 inches at bottom to ~ 1 1/2 inches at the top. The 8lb cured absolutely rock hard and was quite difficult to cut by hand. I used every drop of the 2 quarts for this outer shell. 8lb density (4lb actual weight kit) yields roughly 1/2 cubic feet, but varies depending on room temperature. I think mine had a little less expansion resulting in an even denser foam.
After the foam set (and cooled), I cut off the top to make smooth surface for lid. Using a set of cobalt and titanium step bits, drilled 2 separate holes for pump inlet and return line from condensers. The outer hole is just big enough to squeeze the outer washer for the bulkhead thru. The inner hole is slightly larger than the 1/2" NPT male bulkhead fittings. I had to use a drill bit to clean up the inside of the foam to make sure there was a flush surface for silicone o-rings.
Most of this equipment is for beer brewing, so I used lots of stainless 1/2" NPT to 3/8" barb adapters. Just as with my heated nitrogen backfill, I am using stainless/nylon braided ptfe lined tubing in -8AN size, which is slightly larger than 3/8", but secures very tightly when 3/8" barbs are sufficiently wrapped in ptfe tape and fastened with hose clamps.
I created a lid out of ~2" thick foam and notched the edges to drop into the inner pot. Foam bottom is covered with aluminum foil, and radiant barrier material was used to create a layered border insulation system. The outer pot lid is secured to foam and RB material with foil tape.
This has many applications depending on temp range, but I will be using this at these very low (-58F to -76F) temperatures for terpene extraction.
I am still waiting on a few things (stainless mash tun to filter dry ice from entering pump) and will post a final parts list once tested, but here a few pics of the work in progress:
Here is the pump that I am using:
https://www.amazon.com/CHUGGER-PUMP-CPSS-CI-1-Transferring-Compliant/dp/B01N9HERFS/
HOME BREWING PUMP - The CHUGGER PUMP can be used to ease transfers between kettles, cool wort via a counterflow chiller, or recirculate ice water for quicker chilling!
HIGH QUALITY MATERIALS - Stainless steel pump head, Magnetic Drive w/ base, Teflon thrust washer, Clear Silicone O-ring, Ryton/Teflon Impeller, 55" cord with plug.
PREMIUM PERFORMANCE - Featuring a max flow rate of 7 GPM and 18 Feet of head to handle back-pressure. Capable of handling liquids up to 250 degrees F.
The CHUGGER PUMP is the only home brew pump with ETL certification and USFDA food compliant materials tested for safety and performance standards.
3/4" MPT inlet and 1/2" MPT, allowing easy configuration for any application!
I choose 2x (6L and 15L) relatively thin stainless stock pots as the system reservoir. I used 8lb density 2-part Liquid Urethane foam kit (2 quarts total) to create a thermal barrier, which varies from 2 1/2 inches at bottom to ~ 1 1/2 inches at the top. The 8lb cured absolutely rock hard and was quite difficult to cut by hand. I used every drop of the 2 quarts for this outer shell. 8lb density (4lb actual weight kit) yields roughly 1/2 cubic feet, but varies depending on room temperature. I think mine had a little less expansion resulting in an even denser foam.
After the foam set (and cooled), I cut off the top to make smooth surface for lid. Using a set of cobalt and titanium step bits, drilled 2 separate holes for pump inlet and return line from condensers. The outer hole is just big enough to squeeze the outer washer for the bulkhead thru. The inner hole is slightly larger than the 1/2" NPT male bulkhead fittings. I had to use a drill bit to clean up the inside of the foam to make sure there was a flush surface for silicone o-rings.
Most of this equipment is for beer brewing, so I used lots of stainless 1/2" NPT to 3/8" barb adapters. Just as with my heated nitrogen backfill, I am using stainless/nylon braided ptfe lined tubing in -8AN size, which is slightly larger than 3/8", but secures very tightly when 3/8" barbs are sufficiently wrapped in ptfe tape and fastened with hose clamps.
I created a lid out of ~2" thick foam and notched the edges to drop into the inner pot. Foam bottom is covered with aluminum foil, and radiant barrier material was used to create a layered border insulation system. The outer pot lid is secured to foam and RB material with foil tape.
This has many applications depending on temp range, but I will be using this at these very low (-58F to -76F) temperatures for terpene extraction.
I am still waiting on a few things (stainless mash tun to filter dry ice from entering pump) and will post a final parts list once tested, but here a few pics of the work in progress: