Refrigeration / Heat Exchangers for six, 15 BBL - HDPE Fermentation Tanks

[Swags]

I have read the posts regarding the pros and cons of using plastic fermenters and at this stage I feel like the economics are too favorable to ignore - at least while budgeting capital for a startup. I posted this request for comment in refrigeration in hopes of keeping the discussion to the cooling methods and heat exchangers outlined below. thanks in advance for any input.

Six, 15 BBL, 45 degree cone bottom single wall plastic tanks would be used for primary fermentation and cooled by a glycol system running 27 degree glycol. Dimensions on the 15 BBL tank are 52”W x 81”H.

The options I have in mind for heat exchange with glycol loop include external and internal heat exchangers. The crashing and cold conditioning schedule would be to drop the beer temperature from 70 degrees to 33 degrees over 72 hours up to 96 hours in case of the internal immersion exchangers. Please comment on your preference of either external or internal heat exchanger and best choice for heat exchanger design. Thanks for any input.

External - Use a high quality, stainless steel heat exchanger with separate pump for each fermenter. Mount small pump to each fermenter to push beer at low flow rate (5 GPM?) to avoid turbulence in FV. This is more expensive and more complicated, but would cool quickly and ensure the beer gets down to 33 degrees.

- Placement - Inlet and outlet would be high/low on opposite sides
Heat exchanger type
- "Free-Flow" Plate Heat Exchanger - gap is 2/10”
- Tube and shell with inner tubes that are 1/4”

2. Internal - stainless steel immersion cooling coils for glycol loop. Depending on size and mounting position, the coils would be either fixed or easily removable for cleaning. This option is less expensive, but would take longer to cool and the beer may not get down to 33 degrees if ambient temperature is too high.

- Placement: the coils or U-tube would be attached / suspended from top of fermenter or mounted through tank walls with inlet and outlet on opposite sides of tank

- Heat exchanger type / design
- buy and retrofit a U-tube bundle from tube and shell manufacturer
- bend up a helical coil - approximately 4’ long coil inside a coil made from two 1/2” x 50’ coils
- bend up a U tube assembly approximately 4’ long from 1/2” stainless tubing

[Ray Hodge]

internal coil

I did internal coils on 1 bbl pilot ferms before, better exchange efficency than external, suggest top connections with a long drop to get down low enough in ferms to cool the bottom layers. Internal coils might lend themselves to CIP cleaning better than external, which would be a real cleaning mess with buildup inside exchanger. We bent the coils by hand, very carefully, around a cyllinder which keep deformation of the tubing to a minimum. Use a large CO2 cyllinder or equivalent, to get a tall and tight coil. 1/2" at 50' would net about 6.5 sq ft of exchange area and may be enough to cool 15 bbls. We wrapped the fermenters with closed cell foam insulation and it really did the trick. Hope this helps. PM me if you want to further discuss.

[Swags]

Thanks

Ray,

Thanks for your response. A few others have also said they used internal coils. I just threw out the other options to get opinions and consensus vote.

Thanks

[v2comp]

I would go with the coils as well, primarily because thats what I have done and because I know it works. (but also on just 120 gallon plastic conical tanks, nothing like 15 barrels)