Closed loop water wort chiller

[edmanster]

Why do people prefer to hook up to a external water source rather than using a cheap pond pump hooked to your coil in a bucket with ice or frozen 2ltr bottles like I do? I hear about people wanting to save water and this was a no brainer when I first started brewing..

 

[HoyaSaxa]

Why do people prefer to hook up to a external water source rather than using a cheap pond pump hooked to your coil in a bucket with ice or frozen 2ltr bottles like I do? I hear about people wanting to save water and this was a no brainer when I first started brewing..

The quick answer is: It's easier.

To use a closed loop recirculating pump you need a) a pump, b) a bucket large enough to hold enough thermal mass to chill 5+ gallons of 212 degree water, and c) an electrical hook up close to your chilling station.

Is it complicated... no. But it is certainly more involved than just screwing onto a tap and turning the water on.

On my last lager, I used about 15 gallons of cooling water at 45F from the tap, the same as as a 7 minute shower. I skipped a shower on brew day so I'm even:rockin:

 

[edmanster]

The quick answer is: It's easier.

To use a closed loop recirculating pump you need a) a pump, b) a bucket large enough to hold enough thermal mass to chill 5+ gallons of 212 degree water, and c) an electrical hook up close to your chilling station.

Is it complicated... no. But it is certainly more involved than just screwing onto a tap and turning the water on.

On my last lager, I used about 15 gallons of cooling water at 45F from the tap, the same as as a 7 minute shower. I skipped a shower on brew day so I'm even:rockin:

Remind me not to sit next to you on brew day...lol

 

[wolverinebrewer]

The quick answer is: It's easier.

To use a closed loop recirculating pump you need a) a pump, b) a bucket large enough to hold enough thermal mass to chill 5+ gallons of 212 degree water, and c) an electrical hook up close to your chilling station.

Is it complicated... no. But it is certainly more involved than just screwing onto a tap and turning the water on.

Exactly. How much ice water would you need to have to drop 5 or 10 gal. of wort from 212 to 65? Seems like a lot. And a lot of ice.

 

[edmanster]

Exactly. How much ice water would you need to have to drop 5 or 10 gal. of wort from 212 to 65? Seems like a lot. And a lot of ice.

I use a rubbermaid container that I store most all my brewing supplys in and 4 frozen 2ltr bottles and it brings it down fairly fast.. The pond pump is always at the bottom pulling the coldest water and the circulated water is just being poured on to the top.. We need the math pros on here to figure the equation for us..

 

[SpanishCastleAle]

Using ice at the beginning of the chill uses a lot of ice and since the wort is so hot, tap water does that first bit of chilling almost as fast as ice water.

So what many do is to use tap water at the beginning and pouring all the effluent water into their washing machine for laundry (no waste). Then switching over to a closed loop using ice water and a pond pump once the wort cools a bit.

 

[HexKrak]

I use tap water to bring the wort down to around 120 then switch to recirculating over ice water for the last bit. Even then I use almost 20lbs of ice.

 

[edmanster]

Using ice at the beginning of the chill uses a lot of ice and since the wort is so hot, tap water does that first bit of chilling almost as fast as ice water.

So what many do is to use tap water at the beginning and pouring all the effluent water into their washing machine for laundry (no waste). Then switching over to a closed loop using ice water and a pond pump once the wort cools a bit.

I think the 2ltr bottles help insulate the shock of the hot water a little bit. And most of the time with 4 of them I don't hit my temp so then I use a couple pitchers of ice and throw thoes in and repeat until I'm where I need to be.. I just don't have room in the freezer or I could do more 2ltrs and rotate them out.. Works good for me so I thought I would throw it out there since I'm new to the site..

 

[stellaontap]

I run tap water through my chiller and dump the water I use in the washing machine. Usually i do a load of towels or bedsheets and dump the hot water right in, so it soaks in hot water. By the time my wort is 75 degrees I turn the washer on, the water is not hot by then but I still didn't waste it either. It actually seems a bit cheaper to me.

Eric

 

[SpanishCastleAle]

I think the 2ltr bottles help insulate the shock of the hot water a little bit. And most of the time with 4 of them I don't hit my temp so then I use a couple pitchers of ice and throw thoes in and repeat until I'm where I need to be.. I just don't have room in the freezer or I could do more 2ltrs and rotate them out.. Works good for me so I thought I would throw it out there since I'm new to the site..

Yes but those very same insulating properties of those 2L bottles also prevents them from cooling the water very efficiently. I also use ice packs and a frozen gallon water jug, switching to wet ice a bit after that. Not trying to rain on your parade, sounds like you have a method that works. Having 75* F tap water (in summer) sucks.

 

[HoyaSaxa]

Assuming no external losses (fluid to air), you will need to remove roughly 5,925 Btu's from the wort (8.345 lbs/gallon * 5 gallons * 142F temperature drop) to get from boiling to 70F. This is conservative since the thermal capacity of wort is higher than water given the presence of dissolved solids such as sugar.

Assuming your cooling water starts at 32F, you would need 3.89 times the volume of cooling water (142/38) to get to 70F as the initial wort volume, or roughly 19.5 gallons. This assumes perfect heat transfer, and again, no gains or losses from convection. Adding ice from the freezer may lower the volume required since this ice is at 20F or so not 32F, but the volumetric requirements are still very high for a closed loop system. I'm curious, how big is the rubbermaid container you are using for cooling water?

I think the question that should be asked is what is more important to conserve, water or electricity? I think the answer will depend on where you live and which resource is more scare. Chilling water to make ice in the freezer is very energy intensive... especially when you consider that 75% of the energy in your electricity was wasted just getting the electrons to your house. Power generation also uses a tremendous amount of water for cooling (that's why they are always located on lakes or rivers). I don't have the time to run the math, but using electricity to freeze water isn't going to save a lot of water in the grand scheme of things... it may even use more overall.

Considering my tap water is 45F in the winter (and that water was chilled by the cold environment, not electricity), I'm comfortable using tap water to chill with. Besides, in the winter I use the first several gallons of hot run off to wash all my brew equip., and in the summer, I use it to water my lawn.

 

[Misplaced_Canuck]

It's not rocket science...

5-gallons @ 212F + 4-gallon of water @ 45F + 1 gallon of ice @ 25F (that's the temperature of my fridge's freezer) = well I don't feel like calculating it, you do that math.

But if we were to assume 5-gallons of near-frozen water (32F), the two would eventually equalize at 122F, so you'd need more than 5-gallons.

10-gallons of near-icy water:
10 x 32F = 320
5 x 212 = 1060

1380/15=92F

15-gallons of near-icy water:
15 x 32F = 480
5x212 = 1060

1540/20 = 77F

20-gallons of near-icy water:
20 x 32F = 640
5x212 = 1060

1700/25 = 68F

So it would take about 20 gallons... plus inefficiency, etc.

M_C

 

[SpanishCastleAle]

Don't forget the pot.

 

[edmanster]

It's a tall 7gal container I believe so it can fit my carboy brushes and canes and such.. I fill it over half way and throw in my bottles.. I start adding ice when my supply line starts becoming warm.. I think water would be cheaper than electricity for sure... Maybe it's time to get off the grid....

 

[HoyaSaxa]

It's a tall 7gal container I believe so it can fit my carboy brushes and canes and such.. I fill it over half way and throw in my bottles.. I start adding ice when my supply line starts becoming warm.. I think water would be cheaper than electricity for sure... Maybe it's time to get off the grid....

I'm pretty sure there is no way that you are chilling 5 gallons of wort to 70F with just 3.5 gallons of water. Something doesn't add up. Do you have to dump and add ice? How long does this process take? Are you sure the rubbermaid container is only 7 gallons? FWIW, one cubic foot (12"x12"x12") is 7.5 gallons.

Obviously the hot pot and wort will lose a tremendous amount of heat to the air initially, but that still doesn't explain the discrepancy. Curious...

 

[edmanster]

I'm pretty sure there is no way that you are chilling 5 gallons of wort to 70F with just 3.5 gallons of water. Something doesn't add up. Do you have to dump and add ice? How long does this process take? Are you sure the rubbermaid container is only 7 gallons? FWIW, one cubic foot (12"x12"x12") is 7.5 gallons.

Obviously the hot pot and wort will lose a tremendous amount of heat to the air initially, but that still doesn't explain the discrepancy. Curious...

Ok I'm stupid! My setup is a partial mash extract for only 2.5 to a 3 gal boil... That's where I screwed everyone up... And in the rubber made with adding ice I end up with about 5 gallons water that I clean with... Sometimes I do take out some of the warm water to prep the primary with and add more ice.. Sorry for the confusion...

 

[Bobby_M]

Ice has a lot more heat capacity than 32F water due to the state change. I'm not educated enough to explain it but The Pol found someone to crunch the numbers and IIRC it took 40lbs of ice in a completely closed system.

The reason one would want to use tap water for some of the chilling is that the temp delta is extremely high at first. It's very easy to chill from boiling to 150F even with 90F tap water. Also, it's much better to discard the first few gallons of waste water because it's going to be carrying the bulk of the heat.

In general, even home made ice is more expensive than tap water.

 

[starrfish]

I need to try this this summer, I'm fine chilling with tap temps this time of year but summer brewing in the south, when tap water runs like bath water can be a challenge.

this summer I plan on starting with tap water to get temp as low as possible (and water the garden with run off like I do now) then when I hit that "as low as possible temp with tap" flick 2 splitter valves and turn it into a closed system and use the ice water/pond pump. That way I'm not wasting too much of the ice on bringing temp down from boil.

 

[HoyaSaxa]

Ice has a lot more heat capacity than 32F water due to the state change. I'm not educated enough to explain it but The Pol found someone to crunch the numbers and IIRC it took 40lbs of ice in a completely closed system.

The reason one would want to use tap water for some of the chilling is that the temp delta is extremely high at first. It's very easy to chill from boiling to 150F even with 90F tap water. Also, it's much better to discard the first few gallons of waste water because it's going to be carrying the bulk of the heat.

In general, even home made ice is more expensive than tap water.

Good point.

The principle you are referring to is called the latent heat of liquifaction. There is more energy required to create a phase change, which is true, but there is also significantly less heat capacity in ice on a mass basis than water. In other words, it takes less energy to warm a lb of ice from 20 to 21F, than it does to cool a lb of water from 41 to 40F.

The extra energy in liquefying the ice to water is about 143 Btus/lb of ice. So basically, it takes 143 Btus to convert a lb of 32F ice to a lb of 32F water. Ten lbs of ice added to cooling water, would reduce the cooling water volume required by about 25% (1430 Btus of a required 5950). That correlates well with the 40lbs requirement you mentioned.

 

[Hex]

Looks like the pool needs some more water, I think I'll brew another batch of beer...

 

[kpr121]

Looks like the pool needs some more water, I think I'll brew another batch of beer...

Agreed! Although my pool is not open right now.

What is more wasteful/bad for the environment?

Me using 4 gallons of tap water for the first 15 minutes of chilling and dumping that water into my pool/washing machine/garden (which I would be doing anyways), or freezing multiple bottles of that same water using electricity that came from a power generation plant burning coal, cooling the towers with loads of water, having to dispose of the coal residuals in a landfill, and losing 25% of that power through the lines?

I'd rather have my beer cold and warm my pool at the same time!

 

[ACbrewer]

Since the math has been done - although I'd have used MKS not English.... I'll leave that be.

I think that using ice/snow really depends on location. First you have to use the frozen water in solution with liquid water either as a bath or as something you pump through the wort (or pump the wort through - Although the sanitation nightmares of pumping wort leave me with an ice bath )

Speaking of the ice bath, the more surface area that the water has with the ice, the better the heat transfer, so having 4 2 liters is less (time) efficent than having about 8 lb of ice cubes since you can transfer heat faster.

There is a lot of latent heat (or cold) in state change. The 143 BTU figure sounds about right for freezing/melting- I'd have to look it up . But the BTU for 1 degree up or down of either 1 pound of ice or 1 pound of water is the same. It is a matter then of heat transfer and how cold your tap water is. As has been pointed out in summer in southern climates, the tap water is warmer than acceptable ferment temp (70 deg or less).

Personally I don't have a wort chiller and only do about 3 gallon boils, so tap water and ice baths are for me. If and when I get to making larger batches I will need either a faster chill, or a style that is more tollerant of poor cold breaking [colonial beer anyone?]

 

[terrapinj]

Agreed! Although my pool is not open right now.

What is more wasteful/bad for the environment?

Me using 4 gallons of tap water for the first 15 minutes of chilling and dumping that water into my pool/washing machine/garden (which I would be doing anyways), or freezing multiple bottles of that same water using electricity that came from a power generation plant burning coal, cooling the towers with loads of water, having to dispose of the coal residuals in a landfill, and losing 25% of that power through the lines?

I'd rather have my beer cold and warm my pool at the same time!

will your freezer require more energy than it's already consuming daily to freeze some water bottles?

 

[HoyaSaxa]

will your freezer require more energy than it's already consuming daily to freeze some water bottles?

Simple answer: Yes.

If you place something warm (the water) in a space that is supposed to stay cold (the freezer), the two bodies will seek equilibrium (the freezer warms up, the water cools down). This will cause the freezer to turn on in order to maintain it's set point temperature. In other words, it will have to run more in order to remove the heat that you have added to the freezer in the form of water.

 

[HoyaSaxa]

I know it sounds counter-intuitive, but that is incorrect. The heat capacity of ice is roughly half of the heat capacity of water due to the crystalline formation. Water is about 4.2 j/g-k whereas ice is about 2.1 j/g-k. Meaning water requires 4.2 joules to heat a gram one degree kelvin (celsius) and ice only requires 2.1 joules.

 

[ExHempKnight]

My brew rig will have the chiller outlet plumbed to a 16-gallon water tank (with an overflow hose running outside, in case it requires more than 16 gallons to chill).

I'll use a pond pump in the tank to send water back to the brew kettle after all the wort is drained and chilled. Mix in a couple of tablespoons of Oxyclean, and presto. Water that would otherwise be wasted is reused for cleaning.

I figure that, after a fresh water rinse, I'll use roughly 1/3 less water. That's about all the environmental-consciousness you're gonna get from me.

 

[tchuklobrau]

Lol I was gonna use my swimming pool as a closed circuit this summer. The bottom is always 75-80 so I was gonna chill till that temp then add an inline icebath chiller. Two birds man chill the beer warm the pool 1 batch of beer at a time.

 

[tchuklobrau]

If I knew if it froze solid in the winter I would have my pool setup going now.

 

[ACbrewer]

I know it sounds counter-intuitive, but that is incorrect. The heat capacity of ice is roughly half of the heat capacity of water due to the crystalline formation. Water is about 4.2 j/g-k whereas ice is about 2.1 j/g-k. Meaning water requires 4.2 joules to heat a gram one degree kelvin (celsius) and ice only requires 2.1 joules.

Looked this one up and the physics behind it. It is both correct and makes sense once you understand why. It also means that the big advantage of ice is phase change where the latent heat in melting is huge in comparison to any given degree change. If the 143 BTU quoted on page 2 is right, then 143x more heat than a 1 degree change - 1 BTU= energy needed to heat 1 pound of water 1 degree F - or lost to cool it 1 degree F.

For those keeping score on if they should use ice and other methods, I think it gets back to 'what do you want to accomplish?' Making the wort cold as quick as possible? saving water? saving energy? Is there any improvement I could get for my end goal (quick cooling, etc).

 

[ontheuglydrumset]

This thread's kind of old, but I wanted to calculate this anyway, and thought someone else might find it useful. I'll be calculating in terms of calories (the amount of heat required to change 1 gram of water by 1 degree Celsius) as it's way easier.

Assumptions:
1) Starting with about 6 gallons of wort at 100 degrees C. I usually have slightly less than this, so this calculation will be a worst-case scenario.
2) We'll get the wort down to 80 degrees F = approx. 26.5 degrees C.
3) Specific heat of wort is approximately the same as water. For the sake of this calculation, we'll assume a specific heat of 1.05 (likely on the high side).
4) We'll brew a high gravity beer, about 1.08.
5) For cooling water, we'll use 50% water, 50% ice. The ice will start at 0 degrees C, and the water will start at 5 degrees C. We’ll call the mass of water = mass of ice = m.

Calculation:
Mass of the wort = 6 gallons * 3785 grams/gallon * 1.08 = 24,527 grams
The total heat to be removed from the wort is calculated as:
Mass * Specific Heat * Temperature Change = 24,527 grams * 1.05 calories/gram*degree * 73.5 degrees = 1,892,871 calories.

This will also equal the total heat transferred into the ice and water.
So 1,892,871 = heat to melt the ice + heat to raise the water to 26.5 degrees C + heat to raise the former ice (now water) to 26.5 degrees C = 80*m + 21.5*m + 26.5*m = 128*m
So m = 1,892,871 / 128 = 14,788 g = 3.09 gallons each of ice and water.

So 6.18 gallons total.

 

[Mikeystew]

My house uses rainwater caught off the roof stored in 2500 gallon cisterns.
When I chill, I just run the outflow hose back into the cistern to return the water. Closed system!

 

[TheBigLebrewsk1]

Why do people prefer to hook up to a external water source rather than using a cheap pond pump hooked to your coil in a bucket with ice or frozen 2ltr bottles like I do? I hear about people wanting to save water and this was a no brainer when I first started brewing..

This is exactly what I do in the summer but then in the winter use hose water and run it into my pool.