Automotive evaporator / wort chiller

[ja09]

The heat exchanger is merely a way to maximize that contact. Which way the heat is flowing isn't particularly relevant.

This is where you're completely wrong. The fins are designed to dissipate (or absorb) heat of liquid INSIDE of the heat exchanger, in which they are very effective because of the surface area of the fins. You're trying to do this the opposite way by pumping cold water through the fins which are immersed in boiling wort. You will do a very good job absorbing heat INSIDE in the exchanger, not dissipating heat OUTSIDE. The fins are too small and by the time the water hits them, it will already be 212* because you have more surface area than water.

Basically, what this comes down to is that Homebrewing has been around a long time and there are some very intelligent and ingenuitive brewers. If this was a good idea, there would be plenty of people already doing this, especially on this forum. You're seriously not concerned about cheap filler metals and compounds in a $12 chinese automotive evaporator? Not to mention they will need to be boiled in the wort to sterilize the evaporator that has plenty of nooks and crannies for bacteria to hide.

 

[Owly055]

OK, so imagine all the hops trub down inside those fins glued on with sticky wort.

I hadn't thought of the hops trub............ Perhaps the suggestion of pumping wort through the unit and submerging it in ice water does make more sense.......... the whole thing is not shaping up into one of my more brilliant ideas ;-).......

H.W.

 

[Puddlethumper]

I hadn't thought of the hops trub............ Perhaps the suggestion of pumping wort through the unit and submerging it in ice water does make more sense.......... the whole thing is not shaping up into one of my more brilliant ideas ;-).......

I actually thought it was pretty creative. That's what is neat about this forum, it gives us all a chance to talk things over with others who are involved and really understand.

Cheers!


edit: Besides all this, you can make a perfectly good immersion chiller out of copper tubing and some fittings from Home Depot for around $50.

 

[Facinerous]

Geez this thread really took off again.

I mean no disrespect, but we have all become peanuts in this gallery. Though some responses are with good merit. Owly, I'm interested to hear how your exchanger works in your heated water test. I agree with you that the exchanger does not care which direction heat is flowing.

Ja09. Of course homebrewing has been around a long time. You can say "if this were a good idea people would already be doing it everywhere" and this may have already been tried by a few people. This isn't a new concept by any means. Its just a different object. There is a thread floating around here about using a garage door opener for a mill motor. Its just another motor, just sourced from a different place.

[edit] additional

In matters of efficiency. If you were to pump water through this exchanger where the inlet water temp were 60 degrees, and the outlet temp was the same temperature as the wort is. Then you have achieved maximum efficiency for that volume of water. The circulated water has reached thermal equilibrium with the wort. That is the efficiency of the exchange though. This is not efficiency in speed of cool the wort though.

The rate of Free Convection for Water is: 20 - 100 (W/(m2K)) according to engineering toolbox.
The rate of thermal conduction for aluminum is: 205 W/(m.K) according to engineering toolbox.

You should have a fantastic transfer of heat to the liquid flowing through the exchanger.

The efficiency of cooling wort quickly would then be directly proportional to your rate of flow through the tubes in the exchanger. So your limiting factor would be your rate of flow, and the ability of the warmer wort to get to the fins.

 

[ja09]

Ja09. Of course homebrewing has been around a long time. You can say "if this were a good idea people would already be doing it everywhere" and this may have already been tried by a few people. This isn't a new concept by any means. Its just a different object. There is a thread floating around here about using a garage door opener for a mill motor. Its just another motor, just sourced from a different place.

Don't worry, I'm sure I'll give up soon

Not sure why I got involved in the first place. I would also love to hear an unbiased report of the heated water test, because all I'm working off is theory at the moment.

ps. the garage door opener mill motor is completely different. If the op can prove there's no lead or other leaching filler metals in the evaporator, this WILL WORK. I do firmly believe he needs to pump the wort through the evaporator and immerse in an ice bath, not the other way around. This would essentially create a giant plate chiller that could (potentially) chill the wort in a couple minutes or less.

 

[masonsjax]

I like the idea of trying new things. This hobby has seen massive leaps forward in recent years because people think outside the box. Please do experiment with crazy ideas, just be careful. This particular idea is similar to other ideas that have been proposed here. I think most of the previous threads ended with the OP deciding not to proceed for one reason or another, usually the uncertainty about material safety. The OP here is probably right, the limited exposure probably makes the material safety a non issue, no more than the pollutants our bodies are exposed to daily. I'm not going to do this myself though becauae there are so many unknowns, but I'm watching to see how it goes.

 

[Newsman]

This sounds disturbingly similar to "hey, I wanna cool my wort in an automobile radiator I got from the junkyard for $10" THAT is DEFINITELYnot a good idea....this idea, I will say has the potential to be a good idea, but like many others I'd be concerned about what alloy was used to manufacture this. If it were me, I'd try to use a pocket knife to shave some metal off the fins, etc and have it tested to see what it's made out of.

 

[augiedoggy]

This sounds disturbingly similar to "hey, I wanna cool my wort in an automobile radiator I got from the junkyard for $10" THAT is DEFINITELYnot a good idea....this idea, I will say has the potential to be a good idea, but like many others I'd be concerned about what alloy was used to manufacture this. If it were me, I'd try to use a pocket knife to shave some metal off the fins, etc and have it tested to see what it's made out of.

The OP has already mentioned many times that he has/is getting things tested for contaminants.

 

[augiedoggy]

While your points are good, I think we need to put this in perspective..... We are not leaving a chiller in wort more than perhaps 20 minutes to half an hour. The wort is only mildly acidic, nor is it likely that the metals used are highly reactive. The wort starts out at perhaps 180F, and quickly drops to room temp, while the metal in the chiller is relatively cooler. It isn't an environment conducive to significant reactions, nor is the time in that environment very significant. I personally don't know of anybody who leaves the chiller in the wort for a month......... do you? What metal ions might be transferred to the wort in that half hour are likely to be measurable in parts per billion.... far too low to be significant.

H.W.

Well I respectfully disagree here.
When I use my chiller I do so right after the boil.... the wort is more than 180degrees and 20 to thirty minutes is plenty of contact time for the wort to do a number on pulling contaminants out of the metal and softer solder? this is why if one has an immersion chiller thats starting to tarnish and puts it in the wort to chill a batch it will usually be nice and shiny when he pulls it out especially at these temps..... Remember many people run the hot boiling wort through the chiller for a few minutes without any coolant to sterilize the chiller internally before using it....

unless the evaporator is stamped "ROHS" its safest to assume at this point that its soldered together with leaded solder especially for $12...Honestly there is a lot of truth to the fact that in china theres little regulation to stop companies from disposing of their waste in shady ways like dumping it into the product contents... remember the chinese drywall incident and the mercury in the knockoff Colgate toothpaste from the dollar stores?.... you can cut open a cheap futon mattress or stuffed animal and sometimes find some disgusting old recycled rags/carpet you name it stuffed inside...its not always NEW waste.

All im saying is I think its foolish to ignore these past incidents as isolated cases and unrelated Peanut gallery conversation.... until things get tested this whole conversation is might as well be peanut Gallery material.

 

[illinoisbrassman]

The other problem that I see is even if this particular evaporator coil works, and is food safe. The next one may not either work or be food safe, and unless it is the exact same model it will provide different cooling results. There are hundreds of different auto evaporator coils on the market, where a 25' or 50' of copper or stainless immersion coil is pretty much all going to provide similar results. YMWV -- your mileage WILL vary

 

[Jphillips13]

This is where you're completely wrong. The fins are designed to dissipate (or absorb) heat of liquid INSIDE of the heat exchanger, in which they are very effective because of the surface area of the fins. You're trying to do this the opposite way by pumping cold water through the fins which are immersed in boiling wort.

An evaporator does in fact, absorb heat from outside the fins, and transfer it to the evaporating refrigerant flowing through the inside of the tube. The way the OP wants to move heat with this part is exactly the direction it was designed for.
A condenser coil has more fins per inch usually than an evaporator coil. To pump the wort through the inside with the coil in an ice bath, a condenser coil will work faster. At least given the same coil size.

 

[Owly055]

An evaporator does in fact, absorb heat from outside the fins, and transfer it to the evaporating refrigerant flowing through the inside of the tube. The way the OP wants to move heat with this part is exactly the direction it was designed for.
A condenser coil has more fins per inch usually than an evaporator coil. To pump the wort through the inside with the coil in an ice bath, a condenser coil will work faster. At least given the same coil size.

We'll just have to agree to disagree on this...... and I strongly disagree where we are talking about two liquids.......... These are designed for liquid and air....... It's not the direction of heat travel, it's the medium it's being transferred into that governs the design........ In an evaporator, you are spraying tiny droplets of liquid from the expansion valve that absorb vast amounts of heat, and cooling large amounts of air, which is a medium that doesn't change temp that readily. The condenser does exactly the same thing, but transfers the heat from a super heated liquid to air. They would be completely interchangeable except for dimensions..... They are exchanging exactly the same amount of thermal energy from an internal liquid to / from air. I work with this stuff all the time..... If we were air cooling wort rather than water cooling it...... running the wort through the tubing would be a significant advantage... But we aren't.


H.W.

 

[Jphillips13]

I also work with this stuff everyday. Specifically ice machines.
After I'd though about both coils more, either one will work because they will pick up heat faster than the water can carry it away.
I have a condenser coil I've been trying to find time to try out on water. It measures 12 inches by 10 inches but has enough passes it should be roughly 50ft of tube. I see no reason why this won't work as long as attention is paid to material safety.
An immersion chiller is still liquid to liquid. It's still copper, stainless or aluminum tube, it just has more surface area.


Sent from somewhere using Home Brew

 

[Hamaki]

After following this thread through from beginning to end I think this last post hit a very important point. Why are you immersing the cooler with all the fins, etc, into your wort? Why not immerse the cooling fins in cold water and run the wort through the nice smooth, easy to clean copper tubing? No need to clean out the fins, etc. and you still get cooled wort.

Oh, and for the "Nervous Nellies" out there, copper is just copper ... the metal itself doesn't pay any attention to whether we called it an automotive application or a "food safe" application. Run some hot PBW through it and it is clean.

My point was more that the heat transfer capability of my heater core was not outstanding. I don't know how the configuration of the evaporator compares but my thought on the heater core is that the former ice water between the fins warms considerably because I'm not stirring or pumping it. Since I'm not trying to cool 200+ degree wort to 65, just 78 degree water to the low 50s, it meets my needs.

If the evaporator is set up to have good flow through the fins, whether it be wort on the outside or on the inside, I think heat exchange would be much better than the 15 degree drop I'm seeing. If it were me, I think I'd rather run the wort through the smooth inside tubing rather than try to clean the trub out of the fins.

Looking forward to all your results, OP!

 

[Puddlethumper]

Lol funny you should say that.... here in the states they spray all the vitimans and minerals onto the cereal when its stripped during manufacturing.... you can stick a magnet in a bowl of total cereal floating in milk and the cereal is attracted to it from the added iron.
We put spray so much artificial vitiman minerals and other substances in our cereal you would need a doctors perscription to get it if it was sold in Canada..

Amusing post. However I think that ja09 has a point though. At least here we know that anything that gets near our food has been through a ton of government supervised tests and years of analysis. There is paper-trail behind those additives. Although it can and does happen, it is still an anomaly for anything really bad to slip through.

In China and a lot of our other trading partners overseas there is no FDA or EPA watchdogging the manufacturers. If they can make it and sell it at a profit, great. And if Americans are willing to buy junk at an inflated price, that's even better. In many of these places there simply are no rules.

His concern about the safety of the things we buy from them is a point with quite a bit of merit IMO.

 

[augiedoggy]

Amusing post. However I think that ja09 has a point though. At least here we know that anything that gets near our food has been through a ton of government supervised tests and years of analysis. There is paper-trail behind those additives. Although it can and does happen, it is still an anomaly for anything really bad to slip through.

In China and a lot of our other trading partners overseas there is no FDA or EPA watchdogging the manufacturers. If they can make it and sell it at a profit, great. And if Americans are willing to buy junk at an inflated price, that's even better. In many of these places there simply are no rules.

His concern about the safety of the things we buy from them is a point with quite a bit of merit IMO.

OK be forewarned this post is KIND OF off topic .. But since we are all waiting patiently for the OP's test results and have exhausted anything else topic related it seems...

I totally argee but.... a growing amount of boxed and frozen foods are coming from foreign countries now (along with most everything else)... They usually only say who distributes them not were they are made in most cases... that was my earlier point about Aldi supermarkets getting busted for having horsemeat in thier frozen entries.... apparently they came from europe where the meat was substituted and sold as beef...

Also we do have quite a bit of non safe crap allowed in our food as well though not as bad initially . look at NutriSweet or whatever it was called and most of the fake fat and sugar substitutes out there... They just slowly fade away and something else takes its place claiming to be healthier then later you hear about all the negatives of that right about the time something else gets launched on the market... other countries have outlawed a lot of chemicals and substances we are allowed to consume in our food and vice versa... some of that is politics... looks at the vapor cigarettes... last I knew they are totally unregulated and manufactures could be sticking anything in them at this point.

Our FDA and USDA only checks a fraction of what you might think. like most government organizations they function on the pennywise pound foolish creed.. put it this way if they checked our food manufacturing and meat industry like they treat air travel security we would likely see drastic price increases in food prices and 1/3 of production getting shut down immediately. They simply dont have the resources to be as effective as we are led to believe. Its more like a random check/inspection. or a lottery with good odds and they hope thats enough to scare the food and drug industry into being compliant.

Ground beef isnt supposed be cooked rare because of the feces found in it more often than not from poorly trained and rushed slaughterhouse people who are often illegal immigrants and poor conditions.... Its not just because of Ecoli like most choose to believe.
And as many know mad cow disease is from feeding cattle ground up cattle brain matter mixed with thier feed.... cannibals (or most any species) get the same disease if they consume brains of thier own species because of a protein found in the brain that causes it.

 

[Puddlethumper]

Also we do have quite a bit of non safe crap allowed in our food as well though not as bad initially . look at NutriSweet or whatever it was called and most of the fake fat and sugar substitutes out there...

At the risk of dropping too far off topic I felt it important to address the above point.

The NutraSweet controversy is a classic example of the real issues in food safety in this country. And that issue is not that unsafe foods are slipping through the food "safety net". The problem is how many people perceive that things are slipping through.

Aspertame has had a lengthy battle ever since it was introduced in the early 1970's. Initially the critics didn't think the studies on it were done properly. Later investigation revealed those studies were perfectly proper. Then the critics called "foul" and claimed a cover-up. Again, investigation revealed there wasn't one. Then the critics claimed health issues associated with long-term use. Further studies showed these claims to be false with the limited exception of sensitivity from extremely small group of individuals with one particular medical condition.

A great quote readily available on Wikipedia spells it out very accurately, "Potential health risks have been examined and dismissed by numerous scientific research projects. With the exception of the risk to those with phenylketonuria, aspartame is considered to be a safe food additive by governments, worldwide, and major health and food safety organizations. FDA officials describe aspartame as "one of the most thoroughly tested and studied food additives the agency has ever approved" and its safety as "clear cut". The weight of existing scientific evidence indicates that aspartame is safe as a non-nutritive sweetener"

The only problem with aspartame is that it has been embroiled in a whole bunch of controversy, all of which has been proven to be unfounded.

 

[masonsjax]

The FDA, being a govt agency, has to be paid a hefty pile of funds before they approve something for public consumption. The more you pay, the healthier your product is.

 

[augiedoggy]

sorry I edited and added more ramblings above...

 

[Puddlethumper]

The FDA, being a govt agency, has to be paid a hefty pile of funds before they approve something for public consumption. The more you pay, the healthier your product is.

I know a lot of people think that is true. I don't agree. And I hold that view based on what scientific investigation has told us.

 

[masonsjax]

Of course it's true. That's why so many innocent dietary supplements and health foods have footnotes. In order to even get reviewed by the FDA you have to come up with a pile of money. If it's not a trademarked or patented ingredient or recipe, theres no way someone can ensure they are the sole beneficiary to that investment, therefore no one coughs up the entry fee. On the other hand we have a "health food" manufacturer recalling several of it's brands of peanut products this very week for dangerous bacterial infection.

 

[VladOfTrub]

If you are tossing the coil into hot liquid it might be better to circulate the hot liquid through the fins. The liquid will cool quicker with flow created by some source, than statically. Maybe, place the coil slightly above the liquid level and design some way to continually circulate hot liquid through the fins without aerating. That way you can slow down or increase the volume of liquid through the fins, to find the sweet spot of heat transfer. Acting like the fan speed selector in a window shaker or variable drive fan. The device will act kind of like an evaporative condensor found in water towers. Without the high evaporation rate of a water tower. An auto A/C compressor is driven by an engine. The compressors can produce as much as 7.5 tons of cooling at engine RPM of 2300, 90K BTU/hr. A condensor condenses the heat laden vapor and changes it to a liquid at the refrigerant's condensing temp. Condensing temp of most refrigerant is 105F at 95F ambient across the coil. Condensing takes place in the top 1/4 of the condensor. The liquid is sub cooled as it flows through the coil. To increase sub cooling affect, coil builders use a few tubes at the bottom of the coil as a sub cooler. Sometimes, a suction to liquid heat exchanger is used to further lower liquid temp, to reduce flash gas in the expansion device. If you know the GPM of coolant flowing through the inside of the tubes, fins per inch and a couple of other numbers that you will know, since, you work with refrigeration. You can figure out the cooling capacity of the coil. Some evaps are coated with a special lacquer that keeps them from corroding. If the coil is coated, vinegar nor salt will reach the copper. Scrape a U-bend with a knife edge to see if anything peels off. It's hard to tell by looking at the coil if it is coated. Coated copper feels smoother than non coated. It will have a similar smoothness that regular copper gets after wort does it's thing to it. High temps will remove the coil coating. If the tubes are coated, so are the fins. If it is coated, find out if the coating is OK to use in something that will be poured down the throat. Brew on!

 

[augiedoggy]

I know a lot of people think that is true. I don't agree. And I hold that view based on what scientific investigation has told us.

Based on past investigations and things brought to light during them the truth actually falls in the middle.... There has been cases where lobbying and bribery have gotten things approved quicker or without proper testing but I dont believe its as general of a practice as many joke about.... Then again with the little exposure I have and the stuff I have seen some government agencies do I really cant say it would surprise me...look at how much they new about cigarettes but yet how long they delayed taking any kind of action to inform people of anything... there was certainly politics involved there...

 

[Puddlethumper]

Based on past investigations and things brought to light during them the truth actually falls in the middle.... .

I suspect you are very close to the truth in this matter. Only a Pollyanna would think that politics doesn't come into play in anything involving a bureaucracy. But I also have far more faith in the accuracy of the information I can get from a Material Safety Data Sheet than from anything fed to us by the sensationalized propaganda stream we call the 6 O'clock News.

There is a very important third party that always seems to be missed by those with an antagonistic view toward the manufacturers and the agencies that oversee them. That third party is the legal system and the extremely litigious society we have become. That third party presence impacts decisions made by everyone involved in the process. And it is that very third party that is the reason for all the extra warning labels and precautionary statements on everything we buy.

I don't think anyone believes the system we have is perfect, but it is a pretty good one, and for the most part it works reasonably well. And it is light years ahead of most of our trading partners in Asia.

 

[Hamaki]

Sorry to raise the dead (especially if results were posted & I missed it) but did this experiment ever pan out? Lab analysis for leached metals? Time needed to chill to pitching temp?

 

[Owly055]

Sorry to raise the dead (especially if results were posted & I missed it) but did this experiment ever pan out? Lab analysis for leached metals? Time needed to chill to pitching temp?

I abandoned the experiment, not because of the cost of testing, or finding toxic materials, etc, but simply because I decided that it would be a bitch to clean...... Made an ordinary immersion chiller from copper tubing. I can cool 2.5 gallons to pitch temp in about 8-10 minutes depending on what I choose my pitch temp to be.


H.W.

 

[Jphillips13]

I did try the coil I had with water. It cooled five gallons from boil to 70 or so in under 30 minutes. I ended up making a copper chiller from 3/8 tubing that has almost identical performance. The condenser coil, as owly mentioned, was a pain to clean. It also was difficult to stir with the square coil in the kettle. It's performance wasn't too close to a traditional chiller to justify testing for contamination from solder or coatings.
That's as far as I took it. It worked but would be a pain to use in a real brew. A chiller can be made for very little money and no worries of toxins.

 

[Jphillips13]

Performance WAS too close to a traditional immersion chiller to worry about testing for solder leaching.
Couldn't edit the post above for whatever reason.