chiller alternative

One word of caution on using a coil or loop for summer cooling.... during the 3 to 6 months of idle time (no flow through the coil) the anaerobic processing that will occur in the stagnant water could leave you with a very toxic dose of water when you re-start the system in the following summer...

So, it may be prudent to make some provision to flush the line when you shut it down and as part of your restart...

If you can afford the stainless steel tubing, it will have a much higher heat transfer rate between the ground contact and the circulating water than any form of plastic tubing...

When digging outside of the house last year, we consider installing 50 to 200 feet of SS tubing, buried about 6 feet below ground to use a heat sink for the display tank. Between the above concern and the cost of the tubing, purchasing and running a chiller is the better option for us...

 

going green +spending green$$$$$
your best bet would be to just shop for a energy efficient chiller and probly in 10 years it will payed for its self..(just as it needs replacing LOL..)

 

unless you live in a warm state and it will pay off real soon as we have easy $400 elec bills in fla. year round.

 

If you want the setup to be green and work, use the geothermal cooling. Have a separate cooling loop so you don't have to worry about any life fouling the line. Just run it outside and down about 3 feet. You will need to figure out the heat load you need to remove in the summer time to tell how long the pipes will need to be. Then a heat exchanger plumbed into the tank and a pump to run the ground loop is all you need. And it will work. The fridge idea will not work for much heat at all, the heat pump in a fridge is not big enough to handle the heat load of any tank over a very small size. A fridge works via insulation. It pulls the temp down and then stays cool with good insulation, if you keep a heat source in the fridge, like leaving the door slightly open it will heat up and the compressor on it will burn up pretty quickly.

Kim

 

I know you want to avoid it, but my 2cents is go with a chiller. I tried not to get one, came up with every reason not to buy on. .. then I did.. no more "special ice cubes" no more quick, get a fan and try not to drop it in the tank.

I did the Ron Popiel,.. set it and forget it.

What pushed me over the edge.. all was OK.. until I went away and the AC in the house was no longer in the 70's.. my sister came over to feel the fish and the high heat alarm was going off.. I had to ask her to dump in ice, then lower the AC in the house even though no one would be home for 2 weeks.. when I got back, I order my chiller.

 

I went down this road spent 4 to 5 months designing a system because I thought I could save myself big $$$ and be greener.

My design was based off a double closed loop system that I saw for a solar system to heat homes in the north and actually used on a home in Wisconsin. Check out "Mother Earth News", my wife got it for me I believe she saw an oppertunity to redirect my energy when she thought I would install a solar system in our home instead of attempting to cool a fish tank.

The system required stainless steel tubing for the reef tank portion of the loop, a 5 to 10 gallon heat sink, then a copper tubing for the second portion of the loop that is used to cool the heat sink. The copper tubing was connected to in-line 110v pump a copper header and then to a couple cooling loops. I found that vinyl tubing does not have as good a heating coefficient so I used PEX tubing (only comes in 250' spools) which is used in radiant heating in both concrete floors and in between the floor joists.

In order to control the cooling of the tank a system of shutoff valves was required to do this I used saltwater safe temp sensors, microcontroller (HC6811 Motorola controller had sitting around from college), food save valves with relays and actuators ($$$$). A similar design was required for the other portion of the loop to prevent the system from running all the time again more ($$$).

Finally problems with the design it did cool just not fast enough to handle a heater failure or extremely warm days. The large 10 gallon tank sitting in the basement full of a 20/80 mixture of antifreeze (provides higher coefficient of heat transfer and reduced corrosion to copper) did not fit in to a children and dog friendly home. The design also consumed more electricity than I expected and required lots of tweaking more than I wanted to spend.

So this a quick down and dirty posting of a $1,500 plus chiller that worked, by no means is this posting to discourage someone from attempting to build their own chiller. If you are looking to save money quick this is not the route. It is just like going green with heating a home, I haved headed down that road now and when the system is fully installed it will cost roughly $20,000 and will take at least 7 years before I will see the pay off.

Good lucK on your DIY Chiller