Advice for "aquarium" need (cooling water / technical setup / no fish)

[vetteguy53081]

Here is My Techo unit

 

[ZombieEngineer]

With 2 chillers there are some other problems:
1) The chiller requires 500 L/h. Imaging having that flow through a 500 mL water bath. It'll all splash over.
2) The chiller is not cheap and we are not yet certain our ideas (from the chemistry side, not the setup side) will work out to justify having 2 chillers.
3) The chiller is occupying valuable space

I'll just first try the heat exchanger trick and do a small test with 2 pumps on one chiller, just to see what happens (I'm curious). Even though I almost certainly won't use that setup in the lab, I will want to know what will happen.

Is this lab at a university? If so, you could try getting in touch with some mechanical engineering students or the thermodynamics professor. They should be able to walk you through the flow/copper size to maintain temperature to see if the pump exchanger into 64L tank would even work.

They make smaller chillers that could work off lower flow that is another option for the 5L tank.

 

[niels123]

Is this lab at a university? If so, you could try getting in touch with some mechanical engineering students or the thermodynamics professor. They should be able to walk you through the flow/copper size to maintain temperature to see if the pump exchanger into 64L tank would even work.

They make smaller chillers that could work off lower flow that is another option for the 5L tank.

Not anymore. I left university with a PhD degree and now we are on our own in a tiny company with no specific knowledge on heat exchangers. My bet is to just take 5meters of 15mm diameter copper tubing and shape it into a coil.

 

[ZombieEngineer]

Not anymore. I left university with a PhD degree and now we are on our own in a tiny company with no specific knowledge on heat exchangers. My bet is to just take 5meters of 15mm diameter copper tubing and shape it into a coil.

That's the equation. In your case it would be water to water, so 4x transfer rate.

 

[MnFish1]

Thanks! Do you maybe have a link to the article?

Do you have any idea how much water flow you will loose by adding 5 or 10 meters of copper tubing? Is it in the order of 20-50% or more like 80-90%?

I had it lol. I can't find it in my history. PS - there are water baths out there with magnetic stirrers built in. Most are warm water - but there are cold water as well

 

[niels123]

I had it lol. I can't find it in my history. PS - there are water baths out there with magnetic stirrers built in. Most are warm water - but there are cold water as well

Once we know the idea works / or we know lower subzero temperatures are required we will invest in a higher-end lab chiller. There are chillers with a metal spiral that you hang in your small container filled with ethanol or acetone. The chiller cools the acetone / ethanol and you suspend your flask containing the reaction mixture in that solvent to cool it down. The lab chillers can go down all the way to -80C, but are around $8,000.

My magnetic stirrers can heat as well, so for that I won't need a water bath. They are equipped with a temperature probe so you can set them to an exact temp.

 

[MnFish1]

BTW - I might do this a little differently - after thinking about it. You have a coil of pipe in the 'big tank'. that is attached to a pump in the large tank. You have a smaller coil in the 'small tank' - that then flows back to the 'big tank' - in a big loop. You only have 1 pipe no water will exchange between the 2 tanks - only the temperature will be controlled by the copper tubing (and I believe this is the way they did it in that article I described. There is no potential for 'flooding'. You just need to make sure you have enough copper pipe in the small tank to cool it.

PS - @vetteguy53081 how cold does your chiller get the water - most of them do not go as low as 4C.

 

[MnFish1]

BTW - I might do this a little differently - after thinking about it. You have a coil of pipe in the 'big tank'. that is attached to a pump in the large tank. You have a smaller coil in the 'small tank' - that then flows back to the 'big tank' - in a big loop. You only have 1 pipe no water will exchange between the 2 tanks - only the temperature will be controlled by the copper tubing (and I believe this is the way they did it in that article I described. There is no potential for 'flooding'. You just need to make sure you have enough copper pipe in the small tank to cool it.

PS - @vetteguy53081 how cold does your chiller get the water - most of them do not go as low as 4C.

You only need to Make sure that your big tank is at 4C with whatever chiller you're using. There are also examples of this being done with small refrigerators that can be digitally controlled to a certain temperature - filled with copper pipe - there is a tank outside one side with water - that goes into the regrigerator - and is cooled - then into the other copper coil in the second vessel - and in one loop goes back to the original water source. I dont know if thats a cheaper or more expensive option for this application

 

[niels123]

BTW - I might do this a little differently - after thinking about it. You have a coil of pipe in the 'big tank'. that is attached to a pump in the large tank. You have a smaller coil in the 'small tank' - that then flows back to the 'big tank' - in a big loop. You only have 1 pipe no water will exchange between the 2 tanks - only the temperature will be controlled by the copper tubing (and I believe this is the way they did it in that article I described. There is no potential for 'flooding'. You just need to make sure you have enough copper pipe in the small tank to cool it.

PS - @vetteguy53081 how cold does your chiller get the water - most of them do not go as low as 4C.

I was thinking to use only a single copper coil in the big tank with only a single pump in that part of the setup. The "water in"-connection of the pump connects to a tube that is suspended directly in the small tank. The "water out"-connection of the pump is connected to the coil and the other end of the coil is connected to a tube that is also ends in the small tank.
Main reason: I'd like the small tank as small as possible (more practical with small flasks) and in that case there is no room for a larger copper coil. Also when I use larger flasks I can quickly change the water tank for something slighly bigger (3 L instead of 250 mL), But those two cases would require different copper coils, which makes it impractical and time-consuming to set up.

The description of the chiller says you can set it to zero Celcius. The seller (webshop) said you can get the water 4C, but not colder. Out of curiosity: for what fish (other than restaurant lobsters) would you use 4C?

Fridges have far less cooling power (in W) than the cooler I Teco have now. Also, because of safety, only special lab-grade fridges are allowed. They are around $2000 (starting price) and have no electronics on the inside to prevent the risk of explosions from flammable compounds that you keep in the fridge. The space in the lab is not an explosion hazard, but the inside of a lab fridge can be. That's why we have this rule.

 

[SteveMM62Reef]

As a HVACR Technician, with over forty years of experience, I see two problems. First I think your low water temperature is out of the range of an Aquarium Chiller, where the lower limit is around 60F. The other thing, is a liability issue on not using Lab Grade Equipment. Saw a director at the last lab I worked at, get escorted out by security, after he was fired, for a Kenmore Refrigerator being used for specimens. The Refrigerator was supposed to have two cooling circuits, so they had a back up, if one failed. They had someone else get themselves in trouble, plugging a Cascade Freezer into a non-dedicated circuit. Didn’t want to pay our on-site electrician.

 

[niels123]

As a HVACR Technician, with over forty years of experience, I see two problems. First I think your low water temperature is out of the range of an Aquarium Chiller, where the lower limit is around 60F. The other thing, is a liability issue on not using Lab Grade Equipment. Saw a director at the last lab I worked at, get escorted out by security, after he was fired, for a Kenmore Refrigerator being used for specimens. The Refrigerator was supposed to have two cooling circuits, so they had a back up, if one failed. They had someone else get themselves in trouble, plugging a Cascade Freezer into a non-dedicated circuit. Didn’t want to pay our on-site electrician.

The seller of the chiller guaranteed me the model would get to 4C.
For the fridges and freezers you are correct. However, I'm pretty certain that the chiller won't be an issue here. There are no strict rules for each and every electrical appliance other than that it needs to have a CE certification (which it has).

 

[vetteguy53081]

BTW - I might do this a little differently - after thinking about it. You have a coil of pipe in the 'big tank'. that is attached to a pump in the large tank. You have a smaller coil in the 'small tank' - that then flows back to the 'big tank' - in a big loop. You only have 1 pipe no water will exchange between the 2 tanks - only the temperature will be controlled by the copper tubing (and I believe this is the way they did it in that article I described. There is no potential for 'flooding'. You just need to make sure you have enough copper pipe in the small tank to cool it.

PS - @vetteguy53081 how cold does your chiller get the water - most of them do not go as low as 4C.

I have a thermometer from the chiller unit.

I have Three chambers in sump. section 1 gets the return line (cooler water)
Section two has a sicce pump pumping water to the chiller unit.
Section 3 has the thermo tip that senses water tempertaure that reaches the pump.
Tank is Always 78.7

 

[MnFish1]

I have a thermometer from the chiller unit.

I have Three chambers in sump. section 1 gets the return line (cooler water)
Section two has a sicce pump pumping water to the chiller unit.
Section 3 has the thermo tip that senses water tempertaure that reaches the pump.
Tank is Always 78.7

He wants the end result to be 4 degrees Centigrade - 39 Fahrenheit.

 

[niels123]

OK. Here's an update

I just wanted to try my "2 pumps on one cooler" idea so I did with 2 buckets of water. It's a total failure lol. One buckets quickly gets emptied into the other one. In the meantime I already ordered a 5 meter x 15mm copper coil, so that issue should be solved.

It's a pity that a brand new $950 chiller came with a missing hose connector attachment screw. Fortunately it's 3/4" standard thread size, so I could pick up a temporary one at a hardware store. The shop that sold me the chiller will order a replacement and send it to me.

I had the chiller running for some time with a CompactON 600 in a bucket of water, to see how it runs. To my surprise it's quite noisy when it runs (see video). The seller told me they are quieter than Blue marine chillers. For a lab it's not a big deal, but I do wonder how people do this at home? To have this sound in your house when the chiller is running would be pretty annoying to me. I could clearly hear it in the kitchen with the chiller running in the bathroom on the first floor...

Last but not least: the chiller can be set to 5 Celcius lowest temp. For me 4C or 5C is not important. If my plan doesn't work at 5C, 4C won't help either and I need (serious) subzero temperatures.

 

[MnFish1]

OK. Here's an update

I just wanted to try my "2 pumps on one cooler" idea so I did with 2 buckets of water. It's a total failure lol. One buckets quickly gets emptied into the other one. In the meantime I already ordered a 5 meter x 15mm copper coil, so that issue should be solved.

It's a pity that a brand new $950 chiller came with a missing hose connector attachment screw. Fortunately it's 3/4" standard thread size, so I could pick up a temporary one at a hardware store. The shop that sold me the chiller will order a replacement and send it to me.

I had the chiller running for some time with a CompactON 600 in a bucket of water, to see how it runs. To my surprise it's quite noisy when it runs (see video). The seller told me they are quieter than Blue marine chillers. For a lab it's not a big deal, but I do wonder how people do this at home? To have this sound in your house when the chiller is running would be pretty annoying to me. I could clearly hear it in the kitchen with the chiller running in the bathroom on the first floor...

Last but not least: the chiller can be set to 5 Celcius lowest temp. For me 4C or 5C is not important. If my plan doesn't work at 5C, 4C won't help either and I need (serious) subzero temperatures.

Ice bath??

 

[maroun.c]

Passing water by a pump in tank 1 ( larger) through copper or Maybe titanium coil pasding in tank 2 (smaller tank) then outputting back to tank one through hose shouldn't cause any floods.
For coil to cool down the water of the tank its in down to 4 degrees Celsius I'm afraid water inside the coil would have to be way colder. The fact that tank 2 is very small might make it possible to cool it that low though, tricky to have the loop in such a small volume I assume though ?

 

[niels123]

Passing water by a pump in tank 1 ( larger) through copper or Maybe titanium coil pasding in tank 2 (smaller tank) then outputting back to tank one through hose shouldn't cause any floods.
For coil to cool down the water of the tank its in down to 4 degrees Celsius I'm afraid water inside the coil would have to be way colder. The fact that tank 2 is very small might make it possible to cool it that low though, tricky to have the loop in such a small volume I assume though ?

I think it will work. May take some time to cool down, but it should get close to 5-6C, which is good enough for now. Also I will isolate the smaller bath. It's not just a thin-walled glass container.

 

[niels123]

Ice bath??

Good luck keeping an ice bath at 0C for 48 hours continuously in the lab

 

[MnFish1]

Good luck keeping an ice bath at 0C for 48 hours continuously in the lab

we did it all time time - it mostly depends on the insulation on the 'tank/box' you're using. In any case if you could figure out a way to that - it would by far be the simplest solution - if you can do it at 0C

I would think you're going to need more than 5 meters of tubing in the 'big tank' coiled - and in thinking about it - you will need a lot of coil in your 'small tank' - AND - will the coil be affected by the magnetic stirrers - I know copper is not magnetic - but copper can affect magnets.

 

[niels123]

we did it all time time - it mostly depends on the insulation on the 'tank/box' you're using. In any case if you could figure out a way to that - it would by far be the simplest solution - if you can do it at 0C

I would think you're going to need more than 5 meters of tubing in the 'big tank' coiled - and in thinking about it - you will need a lot of coil in your 'small tank' - AND - will the coil be affected by the magnetic stirrers - I know copper is not magnetic - but copper can affect magnets.

The copper coil is in the big tank only What better way to get perfect mixing then to just mix the cold water with the warm water...