Lets Talk About On Demand Heating Tubes

[Brewmoor]

I have been looking through posts about RIMS tubes and the possibility of using it for on Demand Sparging. Who has used a rims tube for this function?

I would like to design and build a tube for this function. Here are the questions I have about this:

1.What size heating element(s)
2.Should it be controlled some way or just full on? PID PWM
3.In my case 3/4 input and output what kind of flow could I expect to get?

I am not worried about scorching. I will not be using it for recirculation just for heating sparge water. It seems like this topic comes up alot in RIMS threads but I have not found one that is specific to this task. I think this solution would work perfect for a 4 vessel double batch system I am designing.

 

[Sawdustguy]

I have been looking through posts about RIMS tubes and the possibility of using it for on Demand Sparging. Who has used a rims tube for this function?

I would like to design and build a tube for this function. Here are the questions I have about this:

1.What size heating element(s)
2.Should it be controlled some way or just full on? PID PWM
3.In my case 3/4 input and output what kind of flow could I expect to get?

I am not worried about scorching. I will not be using it for recirculation just for heating sparge water. It seems like this topic comes up alot in RIMS threads but I have not found one that is specific to this task. I think this solution would work perfect for a 4 vessel double batch system I am designing.

Have a look at this thread: https://www.homebrewtalk.com/f51/rims-build-129646/

Sizz as I remember, was pretty successful doing exactly this. You may want to read the thread and PM him if necessary. He was able to use the RIMS tube as an on demand hot water source for strike and sparge water and RIMS. I was skeptical at first. I was sure he would scortch the wort but he pulled it off and made it work. He proved me and a bunch of other skeptical members wrong and I am very happy he did!

 

[kladue]

Why not spend a bit of money and look at one of these http://www.eemax.com/SeriesTwo, when used like the diagram shows after a water heater you could have a safe source for strike and sparge water.

 

[ScubaSteve]

I've been following these discussions for some time.....there's lot of ways to look at it. I'm personally going to make one out of 1.5" triclovers, they have approx 1.3" ID. I'll primarily use it for on demand strike/sparge...but I'll also have a 5500w element in my single vessel brew in a basket setup. I will essentially be doing a direct fired mashtun, only with an element instead of flames. I think this will distribute the energy across a much greater volume of wort, eliminating the scorching issues. So, essentially...1 element for REALLY high power to heat water....1 element to maintain mash temps and keep it boiling.

 

[WPStrassburg]

I was planning on using my RIMS tube for strike and sparge water as shown below where my pump is running full flow through the tube with valve to the MLT only open enough to give me the flow rate I need. The rest of the water will go back to the pump inlet via the other valve and get recirced through the RIMS again.

With plain water you have no scorching potential so for strike/sparge watt density of the element is a moot point.

What you need to figure out your element size is the required temp increase from tap water temp to sparge temp and what your sparge rate is.

using the formula
q=r w c delta T

where
q=time rate of heat transfrr (Btu/hour)
r= flow rate (gallons per hour)
w= weight of heated water (pounds)
c= specific heat of water (Btu/lb/Degree Farenheit)
delta T= change in heated water temp (Degree Farenheit)

c is a constant for water and = 1 Btu/lb/Degree Farenheit
w is also a constant for water and = 8.33lb/gallon

So with my 6kW (20478 btu/h)element with a flow of 1 quart (15 gph) I could get a 164 degree temp rise. Or if i wanted to take my 50 degree tap water to 170 (delta T =120) I could flow ~20 gph or ~44 oz/min.


kW to btu/h converter
http://www.unitconversion.org/power/kilowatts-to-btus-th--per-hour-conversion.html

******This assumes 100% efficency and no heat loss through the RIMS or tubing*******

 

[Brewmoor]

So I wonder what "The Pol" (WillyNilly) got from his tube. He had 2 4500w elements in a horseshoe shape. I was thinking of going with two elements 5500w. My system will have 3/4" tubing and I will be sparging 100 pounds of grain. My thoughts on this is that I will be able to use a faster flow rate going with two elements. Is that a valid thought?

 

[WPStrassburg]

So I wonder what "The Pol" (WillyNilly) got from his tube. He had 2 4500w elements in a horseshoe shape. I was thinking of going with two elements 5500w. My system will have 3/4" tubing and I will be sparging 100 pounds of grain. My thoughts on this is that I will be able to use a faster flow rate going with two elements. Is that a valid thought?

Correct, more watts with the same required temp rise will allow for a faster flow rate.

What sparge rate are you expecting to require?

 

[pickles]

I did a test on my system a few days ago. I have a 4500w element in my HLT and 3500w element in a 4" dia x 12" long RIMS. Filled HLT with 5.5 gal of tap water, Brewtroller read temp at 75F. I began recirculating full throttle through RIMS back to HLT; applied full power to HLT element for 10 min and raised water to 105F. Then applied full power to both elements and raised temp from 105 to 160 in 10 min. I was suprised that I didn't double my heat output in the same amount of time. My pump is big (capable of 11.4 gpm), I'm not sure exactly what my flowrate was but it was wide open. Ambient temperature was 90F. Brewtroller was only reading temperature, not controlling elements via PID. I have the capability to turn elements on manually at full power. If I were to slow the flow rate would I see a greater temperature rise over the same amount of time? Does it matter that my water wasn't the same temperature at the beginning of both experiments?

 

[Brewmoor]

I have not figured out my flow rates yet. I am just figuring that my pumps will be 3/4 in and out, as well as all my tubing will be 3/4. If I could at least get a faster flow then I am getting with my march pump I could save some time brewing big batches. I actually have not put much thought into it yet. I have a few other parts of the brewery that are occupying my brain cells at the moment. I just know I want to eliminate an HLT I can heat strike water in the boil kettles but I will need a source other then the boil kettles for sparging.

 

[ScubaSteve]

Oh damn, I didn't know ThePol was WillyNilly......diabolical.....

 

[pickles]

Actually I just remembered that a while back I swapped the 4500W element in the RIMS for a 3500W (I'll verify tonight) because I was afraid of over loading 50A circuit.

 

[Bobby_M]

Does it matter that my water wasn't the same temperature at the beginning of both experiments?

Yup, the heat gained is limited by heat in - heat out and the heat loss will be increase the higher the temp is over ambient. I found the same results when testing effective BTU of my nat gas burners. I was testing in 40F ambient so I started seeing a slowed temp rise even at the 100F point.

 

[pickles]

Hmm that's interesting. I need to try again with water at the same starting temp in both instances.