Immersion Chiller with 330 GPH Pump

[catalanotte]

I followed a lot of advice here and rather than a single pass immersion chiller opted to build out one with a standard submersible pond pump. I saw a lot of discussion on the right size pump, with a number suggesting you go as big as you can afford.

I assembled and tested the system with cold water for flow rate and here is what I got.

60ft of 3/8 OD (1/4 ID) Copper Tube
330 GPH Tetra Fountain Pump (Max 6.5 ft head)
3 ft of 3/8 ID poly tube for each conection with hose clamp.

Tested system with inlet and discharge at same level and produced a flow rate of 1/2 GPM (30 GPH). I expected about this much due to the effective head loss of 60 ft of copper tube. If I raise the discharge just 2 ft, flow drops to about .25 GPM (15 GPH).

At this slow flow rate, I am loosing a lot of cooling efficiency with a 60 ft coil. Could anyone who has solved this problem comment on the below two options I am considering.

1 - Bigger pump (about a $40 cost increase) should up flow rate through system. Not sure if the extra cost is worth it.

2 - Split coil into 2 - 30 ft coils and use a barbed tee fitting to run both coils in parallel. I assume the pump can push a lot more volume if I can cut the back pressure down. But, will 30 ft be long enough for heat exchange to get the discharge water temp up to near the wort temp?

Any suggestions from folks that have built similar systems.

 

[poptarts]

split it into 3 pieces and make a "hydra" chiller. Or return the pump buy a hose and make a counter flow. or try it and see how well it works.

 

[Sudz_Makenzie]

I just snagged a 1/6 hp pump , 1350 gph, from Harbor Freight:
http://www.harborfreight.com/16-horsepower-submersible-utility-pump-68422-8394.html
A garden hose screws directly onto the provided adapter which then feeds into a Y fitting (with turnoffs) to the wort chiller. The other connector on the Y fitting goes to a garden hose attached to the house. I begin chilling the wort with the tap water until it gets down around 100 F then switch over to the pump. The pump is in a 5 gal bucket of ice water and the return water is fed back into the bucket .... chills wort pretty quickly that way.
BTW ... the pump can also be used in a Carboy/Keg washing setup for which there are other threads here on HBT.

 

[dyqik]

If you are recirculating your water with the pump, then there's no problem with pumping water faster so that the cooling water doesn't warm all the way up to the wort temperature. It will cool faster with a bigger average difference between the cooling water and the wort temperature. You don't need to heat your discharge water up. If you aren't recirculating, and want to save water, then you can add a valve on the outlet of your IC to reduce the flow rate (I do this with my CFC).

So yes, split the 60' copper into two or three smaller parallel coils, and you'll chill faster. If you need to save water, restrict the flow with a valve on the outlet.

 

[soupfist]

I just snagged a 1/6 hp pump , 1350 gph, from Harbor Freight:
http://www.harborfreight.com/16-horsepower-submersible-utility-pump-68422-8394.html
A garden hose screws directly onto the provided adapter which then feeds into a Y fitting (with turnoffs) to the wort chiller. The other connector on the Y fitting goes to a garden hose attached to the house. I begin chilling the wort with the tap water until it gets down around 100 F then switch over to the pump. The pump is in a 5 gal bucket of ice water and the return water is fed back into the bucket .... chills wort pretty quickly that way.
BTW ... the pump can also be used in a Carboy/Keg washing setup for which there are other threads here on HBT.

Sudz, I'm thinking about buying this pump and doing exactly what you suggest here. What size coil are you using with this pump? I have a 50-ft 3/8" coil and my biggest fear with this pump would be it's too overpowered to use with a tube size that small and so I'm going to be blowing a lot of hoses off of hose barbs...but maybe I'm overthinking it? What's your experience with it been like?

 

[catalanotte]

You can buy a high GPH pump, but the back pressure through your coil will increase to a point where it limits the flow. You will not likely have a pressure problem as most submersible pumps aren't going to push more than 15-20 psi, well below the capacity of your typical fittings.

Focus on the max head of the pump, not the GPH when buying. The key is to balance the flow rate and maximum head pressure of the pump to the coil. A 60 ft 3/8" coil produces the equivalent of about 5 ft of head pressure at a .5 GPM flow rate and goes up exponentially to almost 20 ft of head pressure at 1 GPM. This makes a much larger flow rate pump only marginally more effective, unless it has a very large working head pressure.

I have a Tetra brand pond pump with a 6.5 ft max head. With a 60 ft coil of 3/8" copper, the 330 GPH pump I bought has worked great, particularly since I got the pump for $25 at Menards. I get about .6 GPM and can cool 6 gallons from a boil to 70 deg F in about 20-25 minutes. I cool to 110 with a single pass in about 10 minutes, than recirculate with ice blocks in a cooler from 120 down to 70 in another 15 minutes. Takes about 3 large tupperware bowls of ice and works like a charm. The slower flow rate ensures 100% heat transfer between the wort and cold water in the coil.

 

[Sudz_Makenzie]

Soup, I'm using a single 25' 3/8 copper coil and have had no back pressure issues whatsoever. To help with the ice, I freeze a couple of 1/2 gal milk jugs and put them in the bucket with the ice and top off with water. I'm able to get the wort down to 70f pretty quickly ... even in the hot summer.
Cheers!

 

[grathan]

Splitting the coil a great idea. Even if it doesn't pump more water, it will pump more cooler water.

 

[Sudz_Makenzie]

Here are a few pics of my wort chiller setup:

 

[Photopilot]

Sudz,
That is slick, tell me about this piece? A straight or curved piece like this might add a nice touch to my setup.

 

[logdrum]

Not the OP, but that is a dishwasher hookup, Lowes or HD. 3/8" compression x female garden hose.

 

[helterscelter]

I begin chilling the wort with the tap water until it gets down around 100 F then switch over to the pump. The pump is in a 5 gal bucket of ice water and the return water is fed back into the bucket .... chills wort pretty quickly that way.
BTW ... the pump can also be used in a Carboy/Keg washing setup for which there are other threads here on HBT.

+1 to this. Multipurpose tools are the best. :mug

 

[SeeMont]

Interesting discussion. I brew with out running water. I have to haul water to my shop in 5 gallon buckets. SO Here is what I do. I have a 20' 3/8 copper coil, (I need to go to a 50" coil) My water is in a 35 gallon plastic garbage can, I freeze water in 2 liter pop bottles, I get water down to 40 degrees. I use a 264 GPH pump http://www.harborfreight.com/264-gph-submersible-fountain-pump-68395.html This system has worked well, I can bring a 6 gallon batch to 75 degrees in 15 to 20 minutes. Hope this helps.