This falls under the dumb question category. When hooking up an immersion type wort chiller does it matter if the water flows top of coil to bottom or from bottom up?
Also, I saw a youtube video where a guy said that slowing the rate of flow actually cools better than having the water speeding through the coil. Does anyone else share that opinion?
Looking at mine right now...looks like it flows bottom up. Not sure if that's correct, but that's how it was set up by the LHBS.
As for the second part, I'd agree. It's about having a happy medium...if the water's just blasting through there it's not necessarily gonna have much contact time, and won't take as much heat with it on the way out. (Also you'll waste more water.) Of course, you don't want it too slow or you'll just have hot water sitting in there.
So... your wort is going to be a little hotter at the top than at the bottom... just like the air in the room. So I'm sure a physicist could make an argument that one way was better than the other.
But the temperature in that kettle is going to be pretty close to the same throughout.
The surface area of wort-->copper-->water exposure is going to be the same. So is the rate of exchange. So the direction should not matter.
I may be wrong--but the rate of flow thing seems wrong to me. I work in a craft brewhouse, and we stop all water usage during knockout to maximize cold water flow in the heat exchanger.
That guy might think he's exchanging more heat because the water is coming out of his chiller hotter... but that actually means the surface of his chiller is hotter where it's touching the wort.
If the wort in your kettle is hotter at the top than the bottom, you're doing it all wrong. Sorry, but convection does not play ANY significant role in wort chilling. You MUST be stirring. This is the reason why direction not matter at all.
Last edited by IceFisherChris; 03-14-2010 at 05:17 AM.
That guy might think he's exchanging more heat because the water is coming out of his chiller hotter... but that actually means the surface of his chiller is hotter where it's touching the wort.
True, and its extremely hard for a person at home to find the optimum water flow rate. You could run the water for 1 minute at 0.1 GPM and the output water is equal to the wort temp. You could also run it for 1 minute at 0.5 GPM and get the same temp (hypothetically.) Same output temperature but the latter has carried out 5 times more heat.
In my opinion, everyone should turn on the water nearly full blast for the first minute. This is when you need the most water flow. I can turn on my faucet to full blast and the output water is still burning hot. Once it starts to cool down, then you can slow down the water. After 3 minutes, my flow rate is very low. Heat transfer works on temperature differential. The greater the difference in temperature, the faster the heat is transferred. Monitor the temperature of your wort as you cool it. Notice how much the temperature falls during the first minute, compared to the second, third, fourth, etc.
If the wort in your kettle is hotter at the top than the bottom, you're doing it all wrong. Sorry, but convection does not play ANY significant role in wort chilling. You MUST be stirring. This is the reason why direction not matter at all.
While convection plays no role in actually chilling , it does in how the wort sits in the kettle, so it will in fact be hotter at the top since the warmer liquid will rise. Why must he be stirring?
Because relying on convection currents is the slowest possible way to chill. If you're not stirring, it will take twice as long to chill and waste at least twice as much water. Stirring keeps the temp gradient between the chiller and wort the highest.
wort chiller flow direction
Linear Mode
