Chiller problem, tubes way too big

[JoJosReef]

I have this chiller I moved from my 83 to my 25 AIO. It is a bit overboard, but I don't have a good alternative for cooling the tank--fans don't cut it. It actually works too well--it brings the temp back to set point very fast. That is not a complaint. The problem is that the tubes are enormous and there is limited space in the AIO chambers. See for yourself:

In principle, I still have another heater and a drop-in algae scrubber that needs to go in there.

What I'd like is to use a much smaller pump with something the size of airline tubing, even if it takes longer to cool the water. But (1) I don't want to invest in another chiller because they're just ridiculously expensive, and (2) all of the chillers I've seen seem to run the same size tubing.

Is there a reducer or something I could use to safely connect to the chiller and reduce the size of the tubes feeding into it? Safety is paramount, as I don't want leaks or a connector bursting loose and spraying tank water everywhere.

Happy to get ideas from you DIYers! Thanks!

 

[JoJosReef]

I'll go ahead and call out the troops for advice: #Cheesemakers #Heathens #Cronies #SmorgasbordFamily

 

[UncommonSense]

What’s the make/model of chiller?

It should have a minimum flow rate; as long as you respect that, there’s no reason you can’t used an in-line barbed reducer, or one of several other solutions!

 

[Red_Beard]

with respect to minimum flow (otherwise you risk icing it up), and the way the tubes hook to the top of that chiller, i would also recommend an inline barb reducer. Also just sure it isn't short-cycling your chiller with it being a bit oversized, run time less than a minute or so is really hard on compressors.

 

[Fish Styx]

As @Red_Beard said, you want to make sure your flow through the chiller is sufficient to avoid it freezing. A barbed reducer would work, but I would avoid going as small as airline tubing.

 

[JoJosReef]

What’s the make/model of chiller?

It should have a minimum flow rate; as long as you respect that, there’s no reason you can’t used an in-line barbed reducer, or one of several other solutions!

This is a $250 ebay 1/3hp no-name titanium chiller. Been running a year and as far as I can tell works as desired.

It seems like I'm going to have to go back to my original DIY fridge chiller idea. This beastly chiller is just too large, too ugly and too loud. It turns on relatively frequently for less than a minute at a time. Can't imagine that is good for the compressor.

Also, for that fridge chiller idea, was thinking of getting some titanium ice cubes to throw into the reservoir during the weekend to keep water temp extra low.

 

[Fish Styx]

Also, for that fridge chiller idea, was thinking of getting some titanium ice cubes to throw into the reservoir during the weekend to keep water temp extra low.

This is a brilliant idea, JoJo. I'm putting this one in my pocket.

 

[JoJosReef]

This is a brilliant idea, JoJo. I'm putting this one in my pocket.

That's why you pay me the big bucks, Jefe.

Speaking of which, your last invoice payment and all prior payments never went through. Do you mind checking in on that?

 

[Fish Styx]

That's why you pay me the big bucks, Jefe.

Speaking of which, your last invoice payment and all prior payments never went through. Do you mind checking in on that?

They're in the mail with your Jersey.

 

[JoJosReef]

They're in the mail with your Jersey.

Oh good. I put in that order for the custom 12x3x3 foot tank and construction crew for the new fish room add-on, and the bookies have been on my back about it!

 

[UncommonSense]

This is a $250 ebay 1/3hp no-name titanium chiller.

If it was a 1/3hp from JBJ, the minimum flow rate would be 1,800LPH, or ~465GPH… it more or less needs 3/4” tubing, as the ID of a 3/4” barbed fitting is closer to 5/8”…

It seems like I'm going to have to go back to my original DIY fridge chiller idea.

This will definitely work! Bonus points if you remote mount it so it isn’t dumping that heat back into the same room as the tank!

 

[BeanAnimal]

I don’t get paid the big bucks. If anything, USD is middle of the road. Pounds are “big,” Swiss francs are “small.”

Anyway, I digress

There is an article for that

Dorm Fridge Chillers? | BeanAnimal's Reef

Can a dorm fridge be used as an aquarium chiller? This must read article sorts out the science from the internet lore, once and for all.

beananimal.com

It may work for your small tank. You need to know your heat gain and the capacity of the fridge.

 

[JoJosReef]

I don't get paid the big bucks.. but there is an article for that

Dorm Fridge Chillers? | BeanAnimal's Reef

Can a dorm fridge be used as an aquarium chiller? This must read article sorts out the science from the internet lore, once and for all.

beananimal.com

It may work for your small tank. You need to know your heat gain and the capacity of the fridge.

Very nice article. I was even close to understanding most of it.

Are compressor capacities commonly published? For instance, looking at this Danby "Beverage Center" 17x20x33" model. Here is the replacement part (poor quality zoom):

Nothing really on the "energy guide" either:

Question: in your article, what is the mechanism of cooling the tank water? I.e., how are you moving heat?

 

[BeanAnimal]

That appears to be a Toshiba compressor.

The raw compressor capacity from the datasheet is about 232 BTU/hr.

The usable capacity available for the tank is lower, because the refrigerator still has to maintain its own interior temperature.

Backing into it from the Energy Guide rating, the fridge averages about 70 BTU/hr under normal door openings and cycling. So roughly 150–175 BTU/hr is available for tank cooling (under ideal conditions).

Let's call it 150 BTU/hr to account for other losses.

That works out to about 0.71°F per hour of theoretical pulldown at 100% duty cycle on your 25 gallon tank.

You asked about the heat exchanger. This is where added thermal mass can help. It does not increase the system’s cooling capacity, but it can shift when the cooling occurs.

Back of napkin math example: If the tank gains 1 F per hour during the hottest 6 hours of the day, and the chiller can only remove about 0.71 F per hour, then it falls short by about 0.29 F per hour. With enough thermal mass, that shortfall can be buffered temporarily, and the remaining 18 hours can be used to pull the stored heat back out of the system. Does that make sense?

Even though the actual math is rather complex, we can look at the whole cycle linearly to get close enough.
Given the above. Over that 6 hour shortfall the is 1.7 F of extra heat stored in the fridges thermal mass.

To recover that, the chiller must run additional time outside the hot period. So at ~0.71 F per hour...
That is roughly 2.4 hours, or a total of maybe 9 continuous hours of runtime per day + the runtime (that 70 BTU/hr) to maintain its own internal temperature. So that stretches things out a bit and the deficit is more like 7 hours and the recovery more like 4 hours.

All in an ideal world