Coil Drink Cooler
Inspiration came from the Six Legged Groove Machine's portable rave party seen at Phreaknic, and the crazy steampunk contraptions people are building for events like DragonCon. Most of them look interesting, some even dispense liquid, but none of them seem to actually cool the contents.
Proof of Concept
Worked well. Cooled liquids as expected. One thing we may have to watch out for is acidic drinks eating at the copper and creating a metallic taste. Can be easily reworked into a MK I version. Steampunk theme will be difficult due to the size and shape of the containers. Cyberpunk/Rave theme would work excellently.
In order to enhance the party atmosphere a fluorescent material should be added to the coolant so that it glows as it circulates through the clear plastic tubing. The quinine in tonic water glows a blueish-white under a blacklight. Vodka and tonic water combined in the coolant tank with dry ice will give us a very cold vodka tonic that is constantly being recarbonated. This will bring the total number of serveable drinks to three.
After building the proof of concept, we learned that acidic drinks and copper don't mix well. The acid breaks off copper molecules into the liquid intended for drinking, and could cause heavy metal poisoning over time. We're going to shoot for stainless steel tubing next.
- 10Ft 1/4 Inch Copper Tubing (10Ft / Coil) (Home Depot, $12 for 20 ft) (DON'T DO THIS: Acids found in soft drinks are corrosive to copper.)
- Cylinder for shaping the coil (we used a can of baked beans)
- Plastic Drink Reservoir (1 per coil) (We purchased two 1 gallon Snapware containers from Target, $6/each)
- Plastic Coolant Reservoir (We purchased a square 2.5 Gallon container from Wal-Mart, $6)
- Drill and Drill Bits (For drilling holes in the plastic containers)
- Hack Saw (for cutting copper tubing)
- Fish Tank Water pump (DC pump with solar panel $20. 2.5 ft lift, 42 GPH. Also available is a 500 GPH bilge pump for $17. Way more than we need)
- 3/8 inch vinyl tubing (Home Depot, $4)
- Dry Ice (optional. Must be 18 to purchase. Wal-mart, $6/small bag)
- Alice frame (Army Surplus Store, $20-30 depending on whether you get the straps or not)
This is a redesign of the MK I based off of Phreaknic field trials. This version will let me test out new features before building the 2.0 version
- Modular drink containers for ease of cleaning (dishwasher safe)
- All systems completely separate from each other, ie. cooling pump system, drink module, coolant tank, and dispensing system all separate
- All serviceable hardware should be on the outside of the pack
- Serviceable hardware should be able to be worked on by another person without removing the pack.
- Smaller coolant tank
- Pressurized dispensing system
- Rigidly mounted cooling coils
- Smaller diameter cooling coils
- Screw-on water-tight lid for drink modules
- Improved electrical wiring layout
- Taps need a narrower spray pattern
- Drink modules need a port in the lid for quick filling
Proposed extra features:
- A heat exchanger instead of an open cooling system to prevent the pump from freezing.
- Hot swappable drink modules
- Reverseable pumps for one-man in-the-field refills
- Small portable charger for the batteries
- Status lights and master pump control panel
- Insulation (may compromise dishwasher safeness)
- Sight glass or some method of determining drink levels
- Improve battery life with larger batteries
- Come in 4mm, 3 lpm and 8.6mm, 7 lpm versions
- About half the cost of the current coolant pump
- Can be used for dispensing and cooling
- Three pumps after shipping is $41
- 1 pump for coolant, 2 pumps for drink dispensing
- Drink Modules
- 6 x 18 inch pvc pipe with a cap permanently fixed on one end and screwed onto the other (use 4" diameter instead)
- Cooling coil fixed to the screw-on lid
- Two ports for coolant in lid
- One port for dispensing on the top
- Tube goes from bottom of the interior to an interface embedded in the lid
- Dispenser pump interfaces to the interface on the exterior of the lid
- Flange with screw-on cap (2 inch diameter?) for quick mixing of refills
- Sight glass to determine drink levels
- Coolant system
- 6 inch pvc pipe tee with permanently mounted pipe caps and a screw on lid
- Pressure valve to prevent explosion from CO2 buildup
- Fixed heat exchanger coil mounted inside (maybe)
- Interface to coolant pumps
- Dispensing System
- Pony keg taps
- Interface to dispensing pumps
This will be the steampunk themed version. The clear plastic tanks will be replaced by cylindrical tanks made of clear acrylic or pvc pipe. The tanks should be 6 inches across and 18 inches long. On the coolant tank will be a vent stack shaped like a chimney for the vapors from the dry ice. The overall look will be similar to a WWII flamethrower.
- NOTE: Never built. Dropped in favor of the MK III
This design was vastly simplified over previous versions. The philosophy behind this was to make the design as simple as possible using as many locally obtained materials as possible.
- Uses compressed gas instead of pumps or gravity to dispense beverages
- Uses an ice bath instead of circulating cold water
- Much lighter than previous versions
- No moving parts
- No electricity
- Disposable modular drink containers
- Better lid/container for the ice bath.
- The size was perfect but the lid was not strong enough to keep the mostly empty bottles from popping the lid off.
- Better seal for the bottle caps.
- The caps did not always seal all the way on the bottles. Usually this was fixed by almost over torquing the cap which is not easy to do on a wet bottle.
- Holsters for the drink nozzles.
- Pressure gauge with a finer resolution
- Larger gas reservoir.
- CO2 tire inflators are too expensive to go through as quickly as I did. Possibly look into using a paintball tank and an air compressor to refill.
- Need multiple caps to cover a variety of bottles.
- Work around was pouring drink from incompatible bottle into an empty 2 liter
Parts (per module, 2 modules per backpack):
- Kitchen sink sprayer (modified)
- 1/4 inch NPT to 1/4 inch hose barb brass fitting
- ~6 inches of 1/8 inch inner diameter vinyl tubing
- #10 rubber O ring
- ~8 inches of 1/4 inch stiff plastic tubing
- 1/8 inch plastic ball valve
- 3 x air fitting tee
- 4 inches of 1/2 inch copper pipe
- Copper pipe to threaded copper pipe adapter
- 1/2 inch copper pipe end cap
- 1/2 inch brass ball valve
- 2 x 1/4 inch NPT to 1/8 inch hose barb brass fitting (to the drink modules)
- 1/8 inch vinyl tubing
- 1/4 NPT to 1/4 hose barb brass fitting (to the fill valve assembly)
- Relief valve preset to 35 PSI
Fill valve assembly
- Air fitting tee
- Pressure gauge
- Air tank fill valve (aka threaded schreder valve
- 1/4 NPT to 1/4 hose barb brass fitting
- ~12 inches of 1/4 ID clear vinyl tubing
- Army surplus Alice pack frame with straps
- 5 gallon plastic container
- 2 x 1/2 inch copper pipe bracket
- 6 x #10-32 bolts with nuts and washers
- 6 x rubber washers (for gaskets on the bolts)
- Zip ties
- Began working on this at the hackerspace meetup, 9/17 - 9/18