Elco, I built a CFC, copper and clear plastic external. A turbulent wrap around wire does make a neglegable temperate drop difference, however covering the copper is near impossible, straight or curled. If you are going with stainless your heat transfer will be diminished compared to copper, however SS will be much better for longevity. That being the case you can mitigate the heat transfer variance buy adding length and increasing flow rate across the coil through the outer tube. Either a higher water pressure to increase flow rate. Or a larger diameter hose. Again this is also relative to your ground water temp. In the summer it can be as much as 30 degrees F higher here in Chicago.
Perhaps we can create a Glycol CFC with a stainless inner?
CFC are awesome (I have one, built it myself)
Why did you use expensive silicon tube for the exterior? This makes no sense at all.
If you look at the thermal conductivity of materials (W/(m K)), copper has it at 400, while stainless steel is at 17.
Unless you plan to cool boling acid, there is absolutely no need to worry about chemical resistance.
BTW, “copper is bad” myth is concocted by idiot hipsters.
Very intestesting I could be tempted to buy the 10m one as I’m not too happy with plate chiller I have and some worries about getting it properly cleaned.
Once ‘kettle in’ reaches the right temperature (20C around 19;07), you can start transfering to the fermentor. You don’t have to wait until the whole kettle is at 20C. So unless I am looking at it wrong, after 7min, you could start transferring cold enough wort to the fermentor.
Actually, yes, I do plan to offer these. I have the 18x24 silicone tubing in stock.
I think I want to design a custom part though for fitting the inner tube to the tee at the end. I don’t really like the cable gland fix. I will have to discuss this with the company that makes the coils.
Perhaps 11.5m is also overkill, because the longer coil will cool better but reduce the flow rate. Reducing the length will reduce the costs too.
Thanks @Elco, keep us posted. Reducing the length sounds like a good plan. The closeness of the CFC water and wort temperatures suggests that you could go shorter (with the current flow rate). Interestingly, the CFC water out is slightly hotter for much of the graph than the wort. I’ve always suspected this is the case with my plate chiller, but I don’t understand how that could be possible.
On a related note, the ambient tap water here in Australia can get quite warm. I’m hoping to use the brewpi spark in the future to enable automatic switching from tap to chilled water (20L stored in my fridge) once the bulk of the heat is removed from the wort.
That’s the counterflow part: the water that has warmed up the most already will touch the hottest wort that just comes in. In a perfect CFC, the water output will be at the wort in temperature and the wort out will be the water in temperature.
I too am trying to get away from my plate chiller. Here’s my counter-flow chiller that I based off of Elco’s prototype design. I used 10m of 12 mm copper tubing inside 19 mm braided PVC tubing.
I used a 3/4 inch threaded T and went with Gardena-compatible quick connects for my chilling water connections. I then reduced the wort outlets from 3/4 inch down to 1/2 inch and used compression fittings to seal the ends of the T. I also used a second pair of compression fittings to allow for 1/2 inch connecting hardware at the ends of the wort tubing. I recently upgraded my home brewery to tri-clamp and camlock fittings, so I went with camlock outlet connectors instead of 1/2 inch hose barbs. I formed the chiller by twisting it around a corny keg but it was still a bit “springy”, so I added the straps to keep everything tight together.
I also had some spare 3/4 inch threaded couplers, garden hose quick connects and threaded plugs. I used these to make end caps for the water connections since they like to drip any leftover water when not in use. I also have two 1/2 inch camlock dust covers on the way to keep any dust, dirt or critters out of the copper tubing when not in use. I’ve yet to test it, but I’m expecting impressive results.
Thanks, the PVC hose inner diameter is 19 mm. I had ordered 10 meters of hose to match the copper tubing, but as you can see I ended up cutting off about 10 - 15 centimeters on both ends fo the copper tubing. I originally planned to have a 12 mm - 1/2" copper coupler soldiered to the end of the copper tubing but a metal worker friend of mine suggested that I use something else, in case I have to take something apart in the future. Fortunately we found the compression coupler solution.
I used three of these, except the ones the chiller are 12 mm x 12 mm with 1/2" threaded ends I reduced from 3/4" - 1/2" at the “T”. I only needed the nuts with the inner compression hardware from one of the coupler to seal the “T”. At each end of the copper tubing I used only one compression nut to couple the tubing to the fitting, this freed up the other 1/2" threaded end to connect hose barbs, or in my case camlock connectors. I was able to find the couplers at a local hardware store here in Germany, in the plumbing section. If you can’t track them down, I could always send some your way.
I went with 3/4" since it was the closest size for my 19 mm PVC tubing, and I figured that it would allow ample water contact over the entire surface of the copper tubing. I suppose 1/2" would have worked as well, but I think it would have been a bit constricting for the water flow and it would reduce the heat transfer potential. The 19 mm PVC tubing is connected to the T with a brass threaded hose barb. I only ended up reducing on the wort outlet of the T on each end from 3/4" - 1/2". The hose quick connects are connected to the T via a 3/4" double nipple. I know that male versions of these exist, but the shop where I order most of my Stainless Steel plumbing hardware from only had 3/4" in the female fitting.
So inside the coupling, is it one copper tube going all the way through? or 2 separate pieces? it looks like a nice solution, better than the cable glands.
No problem. Yes it is all one piece through the entire chiller.
I actually wrote to you about the cable glans that you used a few months ago. You mentioned that you ordered them through aliexpress. I picked some up, but the compression was made with a plastic fitting and was far from leak proof, it actually made quite a mess.
