New wort chiller

[rifraf]

I have 2 ICs a 50' and a 25'. I use the 25' in the prechiller with ice and water, and the 50' in the wort, should I be reversing it? I've been operating under the assumption I put the exchanger with the most surface area in the wort, but is that wrong?

sorry for the barage of questions, but your post go me thinking...

Put the longer one in the wort. The longer one will slow down the flow, but the greater surface area will more than offset that. Besides, if you put the longer one in the ice then you would have slower moving water in a smaller IC which is the worst scenario.

 

[chumpsteak]

My experience with ice is that a big solid block doesn't cool for sh*t. You will get much better heat exchange in the pre-chiller if you used crushed ice. I've tried both multiple times and always end up with the crushed. More surface area equals more cooling capacity. IMO it's worth 5 bucks for the 20 lbs or so of ice it takes me to cool 10 gallons to the mid 60's. Blocks just don't cut it. In fact, when I use blocks most of the block is left when I'm finished.

 

[chessking]

My experience with ice is that a big solid block doesn't cool for sh*t. You will get much better heat exchange in the pre-chiller if you used crushed ice. I've tried both multiple times and always end up with the crushed. More surface area equals more cooling capacity. IMO it's worth 5 bucks for the 20 lbs or so of ice it takes me to cool 10 gallons to the mid 60's. Blocks just don't cut it. In fact, when I use blocks most of the block is left when I'm finished.

Your money. Me, I got a hammer.

 

[Zelbinian]

All the waste water concerned me when I did my first boil a week ago. I'm glad to find out there are ways to conserve that. Buying ice is impractical for me since I don't have a car, but I'm using old 20 oz soda bottles filled with water that I just freeze and refreeze in my poor man's swamp cooler right now. How many of those do you think I'd need to equal a 5lb bag of ice? (This way the ice is reusable!)

Did some math and answered my own question: you'd need about 4 20 oz bottles to have the same volume of ice as a 5 lb bag. Though due to the surface area issues, I'd probably add 2 more and have 2 more waiting in the wings.

 

[cosmo]

Number 3...it really only takes a minute? 20F in a minute? Maybe you weren't being literal...but you make assertions about saving water and ice, so I'm following up.

Jbaysurfer,
That's about right. Since the delta-T is very high (90F wort and 32F water) the temp drop is fast when you first switch to ice water.

Also how does more surface area in a heat exchanger NOT equal greater cooling power? How can pressure drops offset surface area? The water goes in one side and comes out the other (in my feeble mind, that's all that matters, but again, I'm no physicist). Pressure on the exit may not be as high as on the entrance, but that shouldn't really affect cooling...or what am I missing?

Yes, there is more surface area, but the longer length of the copper tubing will put more drag on the flow. With a pump, you generally don't get as much pressure as you do from the tap. A 50ft chiller will have a significantly lower flow rate (gal/hr) than a 25ft chiller. If flow rate is slow enough, it starts to dominate and you may get less cooling even with a higher surface area. Of course this depends on the pressure and flow rate that the pump can produce. It becomes a ballancing act.

This thread got me thinking though, that maybe I should put the pond pump in one bucket full of ice water, the pre-chiller in another bucket of ice water, and then maybe I can pump close to 32 degree water into the boil kettle.

Chumpsteak,
I don't think the pre-chiller will buy you anything if you are using a pump. You would already be pushing near 32F water into the chiller if you didn't have a pre-chiller. By adding the pre-chiller you are not appreciably lowering the temperature, but you are adding significant drag that can reduce the flow rate. If you are using a pre-chiller, my advice is to hook it up directly to the tap which has a higer pressure and will then cool your wort faster. Of course, this is a trade-off since you can't conserve water by recirculating and you may actually use more ice. It comes down to speed vs. ice/water usage.

 

[Justintoxicated]

So I made a chiller out of some copper coil and used crushed ice. Seems to only get the water temp down about 4-6 degrees cooler than tap water (Measured with IR thermometer). This was enough to get my beer down to 77, since my tap water was at 81/82... A pump pumping ice water would have worked better, but I would have gone through ice really fast. the 10lbs I put in the bucket didn't last very long.

I went with the coil method for simplicity, but I think I should have used a longer coil than the 20' available at home depot...

 

[cosmo]

So I made a chiller out of some copper coil and used crushed ice. Seems to only get the water temp down about 4-6 degrees cooler than tap water (Measured with IR thermometer). This was enough to get my beer down to 77, since my tap water was at 81/82... A pump pumping ice water would have worked better, but I would have gone through ice really fast. the 10lbs I put in the bucket didn't last very long.

I went with the coil method for simplicity, but I think I should have used a longer coil than the 20' available at home depot...

For a pre-chiller, if the water exiting the pre-chiller is not cold enough, you can either increase the length of the pre-chiller, or reduce the flow (or both). Personally, I prefer the pump method and recirculating.