Dont buy a chiller ... use a heat exchenger

[RuGlu6]

With temperatures are as high as 30C today my tank temp jumped from 24C up to 26.5C.
So i thought its a good time to put my DIY heat exchanger to use again.

All it is , is a plastic tubing line from Home Depot "T-ed" of off cold water RODI supply tap water inside plastic tubing line going from the "T" to my reef tank sump. Then its coiled up in a small coil (about 25 feet of tubing) that plastic tubing coil is submerged it in the sump water. The plastic tubing line then continues from the sump coil back to under the sink and to the drain.


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heat exchanger coil, i have another "vessel" inside the sump then water overflows down to the sump.


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flow control valve. Sorry, the picture is sideways. You can also see yellow line going back to the "P-Trap" drain.

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I am using RODI "waste" water line to discharge heat exchanger water to the sink drain. If you dont have RODI you can go straight to the "P-Trap"

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So the cooling is achieved by heat being transferred from sump warmer water to colder water inside the heat exchanger coil.

Tap water is about 12C tank water is 26C (now down to 24) This trick works and there is enough heat transfer with that temp. difference to keep 65 Gal + 20 gal sump at constant 24C.
I even have to have a heater on and to slow down the water flow inside heat exchanger plastic tubing coil down to the steady slow drip to prevent from cooling too much.

If you have a large tank, double or triple the coil size or get Stainless Steel coil to get enough cooling capacity.

Not sure about prices today but few years ago Home Depot was selling plastic tubing in 25 feet increments for about $6. The whole project cost was less then $60.
This obviously will depend on how close your tank is to the sink.
When its really hot outside the line going from the cold water tap will sweat a little.

It took 25 min for me to type this, and my my tank temp went down from 26.5C to 25.5C.
This DIY heat exchanger works !

Pros:
cheep to make (providing you tank is close to the sink)
Easy to operate and with any heater in the sump it is somewhat automated and protected from over-cooling.
Way more cost efficient than buying a chiller
No electricity involved when house power is out it will still work.

Cons:
Wasting water.
Slight condensation on the tubing
Tripping hazard if tubing running across the room (mine is going along the walls, hot glued to the floor moldings so not an issue)
Will not work if you tank is far away from the sink.

Hope some one will benefit from this

[StirCrazy]

not the best way to do it for a few reasons, the first being it only works when you are running your ro unit, the second is that it is a pretty expensive way to cool water if you pay for your drinking water, also rather environmentally irresponsible waisting that much of a resource that is becoming limited in most of the world but that people in BC seam to take advantage of.

when I first moved to Kamloops there was a fixed charge of 20 bucks a month for water and I can't tell you how many people would run a almost empty dish washer, or water there lawn for 3 hours every second day. now that we have meters and pay for the volume we use over a base amount you don't see this happening very much.

now if you want to keep it cheep, then buy a bunch more of that plastic line and put another coil in a bar fridge then add a small pump to cirulate the water between the coil in the fridge and the coil in the sump. cheeper to set up than a real chiller but still not as good.

Steve

[Reef Pilot]

I am not sure you really have to waste that much water, as you can slow the flow just enough to cool the sump water. The reason I say that is that in a past house, we had a solarium off the deck that could get quite warm in the summer sun. So I installed a DIY air conditioner using a similar principle.

I got an old car rad from the scrap yard, and built a window like frame, complete with shutters (no ghetto look) to house the rad on one side of the solarium. On the other side, I installed a good sized exhaust fan (also found at a scrap yard), to draw outside air flow through the rad. I modified the rad ports to fit a garden hose, which I would connect outside. The output of the rad then went to a sprinkler for the lawn.

I controlled the flow with the outside water tap, and was surprised how low a flow was needed to provide very good cooling from the rad. We also opened the patio doors to the house, and it would be cooled down as well. I usually had the flow higher than needed for cooling, just to get enough water to make the lawn sprinkler work.

Anyway, the DIY air conditioner worked great, and the bonus was having my lawn watered, which was also needed during prolonged warm spells.

BTW, temps hit 31 C today here in Langley.

[mark]

I had tried similar to warm the source water for the ro unit. Thought higher temperature better rejection rate, don't think it did anything so removed, plastic not being the best for heat transfer. Did get lot of tubing out of it for other projects.

[Vancouver Reefer]

I used to live in Langley, now I've still got snow in my yard! Where did I go wrong!!??

[SmallFry]

Just a thought but why not use the waste water/brine from the RODI unit as your cold reservoir? Direct this to a large insulated container (trash can, tote, old tank) and you have quite a large heat sink that would probably stay cold enough for quite some time if the system is only used when required.
I get drinking water from mine too, but I'd think that given the typical waste ratio on an RODI unit there'd be plenty to maintain an effective heat sink.
If you are using tap water as the heat sink, I'd adjust the flow so that your waste flow from your heat exchanger is the same temperature as the sump water, that way you know you've pumped as much heat into it as possible..

[RuGlu6]

Originally Posted by StirCrazy

not the best way to do it for a few reasons, the first being it only works when you are running your ro unit, the second is that it is a pretty expensive way to cool water if you pay for your drinking water, also rather environmentally irresponsible waisting that much of a resource that is becoming limited in most of the world but that people in BC seam to take advantage of.



Steve

All good points and you are correct, accept one thing; it is not dependent on RODI in any way, i just used existing RODI tubing for easy hookups.
This can be used independently, just run water from cold tap through the heat exchange coil and drip back to the drain. No moving parts, one manual control valve for the flow and that's it. Simplicity = dependability and reliability

As for water wasting yes, it drips to the drain. However when it rains 20 days out of 30 and you don't have a water meter ... i am not that much concerned, and below are the reasons.

Have another look at this at a different angle:
No need for electric power to run this unit, but to produce power to run chiller it will take river water to turn the turbines , or burn coal, or get it from Nuclear plant and we all know how wonderfully "safe" the Nuclear power is, plus environmental impact of making aluminum, copper, plastics are highly toxic and this definitely will pollute the planet eventually. With that in mind my unit may be even more environmentally clean and friendly then buying running and scrapping a chiller.

jmtcw

[RuGlu6]

Originally Posted by mark

I had tried similar to warm the source water for the ro unit. Thought higher temperature better rejection rate, don't think it did anything so removed, plastic not being the best for heat transfer. Did get lot of tubing out of it for other projects.

Plastic is definitely Not the best material for heat transfer. But it works on small water volume like mine (65 Gal +sump).
My tank is 23.5 C rock solid even when its hot outside. And that is on slow drip rate.

If you search for NEU you will find that they use heat exchange principle as well.


they use same principal but they extract heat from sewer and storm water via heat pump and thrugh heat exchangers heat up water for Olympic village and SE False Creek. They make tons of money and are being able to keep heat and hot water rates below what BC Hydro charges to do the same with electricity.

If you ever get to go to any of the mechanical rooms of the building that is hooked up to NEU and look at the size of the heat exchanger that serves 4 or so story building you would be surprised how small it is. Its approximately 3 feet high by 2 feet wide !. This is not a joke. Obviously its not made out of plastic, and its thermally insulated, my point is, its very efficient.

[mike31154]

While this might work well for you without a water meter & all the rain, it wouldn't be cost effective or environmentally friendly in areas where water is a bit more precious, like where I live. When things get too warm in the summer, I simply try to keep the room the fish tank is in cooler by running a portable air conditioner. Don't need a chiller since my lights are LED & don't add much heat to the tank.

As for your reasoning that it takes power, turbines etc. to produce electricity for a chiller, we are fortunate in BC to have mostly hydro electric power stations run by dams, not much coal burning or nuclear going on here. Still, it's never a good thing to waste power, you don't know what you got until you lose it. In any case, the water you're using to run your heat ex-changer is delivered to your house using some big honkin' pumps that the city runs using electric power.

Still, it's great that it works for you, but in my area, with the city cranking up the water rates & a meter in the basement, I think I'll keep running the air conditioner for the week or two during the summer when it's really hot.

[rynoe]

Could also reverse the process. Fill a cooler with ice and place your coil in the cooler. Then pump tank water through it. Works well for the few days a year we need to cool our tanks.