DIY Chiller Alternative Method

[steve1981]

Now I haven't seen anyone try this yet and wanted your thoughts on it. I'm far too tight to pay £500 on something I will use for a month of the year (our hot season... one month... at best) Anyway, I have seen plenty of coiled hose pipes in a fridge method which seem to be ok but I understand that a rubber hose is not a good insulator. I won't be using SS or titanium because I might as well just buy a chiller it is so dear. My theory is this...

Buy a mini table top freezer (that will fit in my cupboard) Cut an in hole and an out hole. I will then put about 50m of thin wall hose pipe in a water tight bin, fill the bin with water and freeze it making a solid ice block with a hosepipe inside and the in and out ends sticking out. This will then be plumbed into the mini fridge constantly keeping it frozen and hopefully cooling the tank water as it travels through the inside of the ice block.

Any issues that anyone can foresee?

[der_wille_zur_macht]

A mini fridge doesn't have the power to move a significant amount of heat over a long period of time. You won't see a meaningful temperature drop. The block of ice won't help in any meaningful way.

If you want to do DIY cooling on a budget, evaporation is a clear winner by a substantial margin. Do everything you can to increase evaporation and forget about ice or dorm freezers.

[swclown]

I think if you could find a mini-freezer this could work but I don't know if they make those or how big and/or expensive they are.
Like stated a mini-fridge won't have a large freezer section and won't do enough, but it largely depends on the size of your tank.

this is something I did years ago and it worked very well (5-10 degrees drop). this is an exhaust fan and so it's pretty powerful. if there is room under your stand and over your sump this could work as long as you have ventilation. the only downside is it puts a lot of humidity in the air. My basement doesn't have AC so it got a little uncomfortable but it worked.

[IMG]

[der_wille_zur_macht]

Originally Posted by swclown

I think if you could find a mini-freezer this could work but I don't know if they make those or how big and/or expensive they are.
Like stated a mini-fridge won't have a large freezer section and won't do enough, but it largely depends on the size of your tank.

A mini freezer won't work any better than a mini "fridge" - it's essentially the same thing just with a different setting on the thermostat. The challenge isn't how cold it is inside the fridge/freezer, it's the power the device has to move heat. You can set a small freezer to 30F and start pushing warm tank water through it, but if it isn't powerful enough to maintain the cold temperature, it'll just slowly warm up as it burns itself out from running 24/7. Even a full size fridge/freezer from your kitchen would barely be powerful enough to make a dent in a typically sized tank's temperature.

Again, evaporation is really the best approach here. Even on a tiny tiny tank, where the dorm fridge approach MIGHT work, evaporation will give you more bang for your buck, in terms of being simpler, cheaper, more effective, and consume less power.

[mcgyvr]

http://www.beananimal.com/articles/d...m-chiller.aspx

[sleepydoc]

Thanks, McGyvr - that's exactly the link I was going to post!

First, a mini fridge isn't designed to run like this. Second, the compressor is not big enough to pull out enough heat. Third, if you're too cheap to buy a chiller, than any tubing you're willing to pay for is not going to transmit heat well and will make the setup horribly inefficient.

I would first try fans, then focus on removing sources of heat from your system - get a more efficient pump, switch to an external pump. Look at switching your lighting, etc. if it's only for a month, you could also look at reducing your lighting time or changing the schedule to a cooler part of the day.


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[mcgyvr]

In your "hot season" what temperatures is the tank reaching?

[BigDave]

Option 2...

buy a deep freeze. Freeze gallon jugs full of rodi water (in case they leak).

When the tank starts to get too hot, put one of the gallon jugs in the sump.

I'm assuming if you're only needing a chiller for one month, that you mostly need it during the heat of the day. 3-4 gallons of ice should easily make it one day. Then the freezer can spend the next half a day refreezing the gallon jugs.

And now you have a deep freeze for storing ice cream too

[der_wille_zur_macht]

Originally Posted by BigDave

Option 2...

buy a deep freeze. Freeze gallon jugs full of rodi water (in case they leak).

When the tank starts to get too hot, put one of the gallon jugs in the sump.

I'm assuming if you're only needing a chiller for one month, that you mostly need it during the heat of the day. 3-4 gallons of ice should easily make it one day. Then the freezer can spend the next half a day refreezing the gallon jugs.

And now you have a deep freeze for storing ice cream too

That's not really a viable alternative. Melting ice requires very little energy compared to evaporating water - the difference is an order of magnitude. You'd have to melt a TON of ice in a typical reef tank to lower the temp only a few degrees. Meanwhile, evaporate a gallon and you're dropping the temperature significantly.

For reference:

http://reefcentral.com/forums/showthread.php?t=78140

[d0ughb0y]

someone can invent a poor man's chiller using the same principle as a chiller (heat exchange outside of the tank), but using an ice jug full of ice and water instead.

just like these used for post-op recovery for knee surgery.

https://www.djoglobal.com/products/a...cuff-ic-cooler

It continuously cycles ice cold water using air pressure and gravity.
I think the design of this is genius.

anyone who had knee surgery knows how well these work.

[BigDave]

Originally Posted by der_wille_zur_macht

That's not really a viable alternative. Melting ice requires very little energy compared to evaporating water - the difference is an order of magnitude. You'd have to melt a TON of ice in a typical reef tank to lower the temp only a few degrees. Meanwhile, evaporate a gallon and you're dropping the temperature significantly.

For reference:

http://reefcentral.com/forums/showthread.php?t=78140

yeah, but if you use a fan, where do you store all your ice cream?

I was just throwing out an alternative.

[der_wille_zur_macht]

Originally Posted by d0ughb0y

someone can invent a poor man's chiller using the same principle as a chiller (heat exchange outside of the tank), but using an ice jug full of ice and water instead.

just like these used for post-op recovery for knee surgery.

https://www.djoglobal.com/products/a...cuff-ic-cooler

It continuously cycles ice cold water using air pressure and gravity.
I think the design of this is genius.

anyone who had knee surgery knows how well these work.

Ice just doesn't have the power to make a difference in all but the smallest aquariums. It doesn't matter how you move the heat, the ice itself is a bottleneck.

Originally Posted by BigDave

yeah, but if you use a fan, where do you store all your ice cream?

I was just throwing out an alternative.

See, that's the thing - use the freezer to store the ice cream, what it was designed for and what it's good at! Don't fool around with aquarium water running through it.

The heat of fusion of ice (energy required to melt it) is 333.55 J/g. The heat of vaporization of water (energy required to turn it into water vapor) is 2257 J/g. Evaporating one gallon of water removes almost seven times the energy from your tank as melting one gallon of ice. You'd have to melt nearly seven gallons of ice to get the same drop in temperature as evaporating one gallon of water. To put this another way, evaporate two cups of water and you've beaten what you'd get from melting an entire gallon of ice.

Remove lids or open hoods, throw a few powerful fans on there, and evaporating a gallon or two a day is trivial. Swapping dozens of gallons of ice in and out of the tank all day seems like a lot of work in comparison. Surely it will work but it doesn't seem sustainable compared to putting a fan on the tank, increasing aeration, or other changes to raise evaporation. I'm not trying to steamroll the conversation here or kill ideas, I'm just trying to be realistic in a way that may be able to save some frustration for people who need to cool their tanks.

(Yes, there is some energy removed from the tank to heat the now-liquid water from 32f to the tank's temperature, but it's tiny compared to the either of the energy constants mentioned above - only a few percent difference compared to melting the ice, much less evaporating water).

[SFish]

I have found these.

http://www.bghydro.com/1-10-hp-water...SABEgICx_D_BwE

Obviously they are not top of the line but they maybe worth a shot.

[ericarenee]

Originally Posted by d0ughb0y

someone can invent a poor man's chiller using the same principle as a chiller (heat exchange outside of the tank), but using an ice jug full of ice and water instead.

just like these used for post-op recovery for knee surgery.

https://www.djoglobal.com/products/a...cuff-ic-cooler

It continuously cycles ice cold water using air pressure and gravity.
I think the design of this is genius.

anyone who had knee surgery knows how well these work.

when i had my shoulder/ arm surgery I had one that had a cuff that connected to a chiller that actually cooled the water in a resivour that you had to fill up and circulated it thru the cuff..It could also heat the cuff with electric and had E-Stim.. I had to use it on my shoulder / arm for about 4 months.. Awesome little machine..

As far as just using ice in gallon jugs . I have had to do this in the past..

The best way to do this is create a swamp chiller in a bucket . run vinyl tubing into a bucket with a pump in it having about 20 feet or so . as much as you can fit inside the bucket pump the water back into the tank with a slow pump.. fill the bucket with ice water.. Something insulated works best like a old cooler..

[sleepydoc]

Originally Posted by der_wille_zur_macht

Ice just doesn't have the power to make a difference in all but the smallest aquariums. It doesn't matter how you move the heat, the ice itself is a bottleneck.

The heat of fusion of ice (energy required to melt it) is 333.55 J/g. The heat of vaporization of water (energy required to turn it into water vapor) is 2257 J/g. Evaporating one gallon of water removes almost seven times the energy from your tank as melting one gallon of ice.

Completely true, but if s/he is already maximizing the evaporation and is right on the edge for a few weeks, then the ice might be enough to eek through. Otherwise, see my previous post!

[Valentini89]

I think I'll just spend the $500-600 on a chiller lol. I live in Florida and it stays hot and hotter almost year round.

[d0ughb0y]

Originally Posted by Valentini89

I think I'll just spend the $500-600 on a chiller lol. I live in Florida and it stays hot and hotter almost year round.

Do you have AC in your house or at least a room ac in the room where the tank is? A chiller will dump heat into the surroundings, hence will warm up the area around the tank even more. Compared to say a window ac, where it dumps the heat outside of the house. You can get a window ac for like $200 or less.

[Ron Reefman]

Originally Posted by Valentini89

I think I'll just spend the $500-600 on a chiller lol. I live in Florida and it stays hot and hotter almost year round.

Originally Posted by d0ughb0y

Do you have AC in your house or at least a room ac in the room where the tank is? A chiller will dump heat into the surroundings, hence will warm up the area around the tank even more. Compared to say a window ac, where it dumps the heat outside of the house. You can get a window ac for like $200 or less.

I live in SW Florida and I have 2 tank systems, each has their own chiller. Both are outside the house so the heat released is outside. Since I switched to leds and keep the house at 82F in the summer, the chillers don't really run much at all. But lose power due to a summer thunderstorm or a hurricane... After a hurricane you can have days of 95F heat and lots of sunshine. Your tank will be in SERIOUS trouble. So get a generator to run it all.

To the OP, I understand this is WAY, WAY more than you need. But that small 1/10th HP chiller for under $300 looks like a really good solution. I'd plumb it into the system with a ball valve. Shut down the chiller when it cools down and flush it with fresh water. Store it for 10 months and then before it gets hot again, hook it back up and open the valves. It shouldn't take more than 30 minutes after it's all built-in.

[BigDave]

Color me impressed.

I have a 1/3rd HP chiller on my tank. I know it needs to be recharged as it hasn't been running very efficient this year.

On a whim, I took the advice of this post and threw some fans on my tank this morning. I figured at a worst, it would slow down how long it took the tank to get warm, and at a best it might lower the temperature some.

I was very pleasantly surprised to see that for the most part, the tank temperature seems to have been steady all day. I will add that I am working at home. When I work from home, I don't mess with the downstairs AC (where the tank is), but I do lower the upstairs to a comfortable temperature (78F).

Here's a graph for the last two days of my tank temps. You can see it slowly raising up until the chiller kicks on and then it drops 1 degree. You can see how the temperature pretty much stopped rising about the same time I turned the fans on.

We'll see what this does to my evap rate. I may also have to adjust how much Kalk I put in my top-off water.

[d0ughb0y]

using chiller only, how long does it take to drop the temp by 1F?

I am using fan only, and fan turns on at 79 and off at 78, it typically takes 2 hours to do that, and up to 6 hours if ambient is warmer, based on my controller log.

[BigDave]

You can see it in the graph. During the day when the house is at 80, it can take almost 5 hours to pull the temp down one degree.

This chiller was used when I got it, and I think it's low on refrigerant. Even at night with the house at 76 it can take 1 hour to lower the temp.

Even if the temp just maintains at 80 all day, that's better than what I was getting. And I'm sure running the two fans is less electricity draw than that chiller cranking up.

[SuperSaltwater]

Buy a chiller, nothing beats it. Works fast and last years. Stop being cheap and bite the bullet. You won't regret it. Why risk expensive fish and coral. Imo

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[sleepydoc]

Yes, a chiller will undoubtedly lower your tank temp, but at the expense of increasing the room temp and dramatically increasing your power consumption. (It also requires additional plumbing to install.)

Fans, in contrast, are cheap to buy, cheap to operate, easy to install and have minimal effect on the room temp.

Unless your temps are such that you are already bordering on a catastrophic crash, there is little downside to trying the fans and potentially significant cost advantages.


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[steve1981]

Wow i forgot about this thread and haven't been following. I managed to pick up a second hand chiller for £125 and works great. Wish I hadn't of hesitated before. To be fair I wouldn't pay £500 new for it, but second hand fleebay bobbie... perfect.

[Windy2]

Melting ice gives requires about 200 btu/lb to melt. If you evaporate 1 lb of water you will generate 900 btu of cooling. Evaporation is by far cheaper than anything else. Unfortunately, high humidity makes it harder to get the evaporation you need. I live in an Oregon desert and have high temps with 15-20 humidity. Evaporation works great and actually helps keep the humidity up in my home.