Will This hot water heat exhange work?

[nfored]

Chopper said something in another thread about adding a heat exchanger to your hot water heater to heat the aquarium. I figure I am paying for the hot water heater to run 24/7 any way so way not try and use it to heat the aquarium. The only problem I see, is all heat exchangers use copper tubbing and I thought that was a no no for aquariums. I could probably find one thats stainless steal? The other problem is I wounder how i would keep it from over heating? Any way what do you think.

 

[nfored]

Hot water comes in from the hot water heater and fills a plastic tub. the tube has pvc coiled inside it. Hoping the water would be hot enough to transfer some heat through the pvc to warm the water in the pvc. Or i could use vinly tubing coiled up inside, that actully sounds better.

 

[Tigerdat]

You could make the heat exchanger out of stainless steel tubing, places like Summit racing sell it for fuel line. 20 foot coil is about $30 although the largest diameter is 3/8 inch which is probably a little small. I did do a quick web search and was able to find 1/2" and 5/8 thin walled tubing that would work too. I would think that anyplace that sells metal should be able to get some for you.

 

[nfored]

How do i keep the temp from getting to hot? will I need to use a temp controller and hook it up to the pump? If so I will need to change the design as I am using one pump to return the water to the aquarium through the heat exchanger and shutting this pump down would stop filtration.

 

[nfored]

Bump, how would I regulate the temperature?

 

[CHOMPERS]

Sorry for not getting back to you on that. Contrary to popular belief, copper is ok for use in an aquarium. Elemental copper is not soluble in water. It is ionic copper and aqueous copper where you run into problems (algaecidal). Elemental copper will not convert to ions without a constant source of electricity and it will not convert to aqueous copper without an ORP source. This is why tap water from homes with copper plumbing is safe to use in aquariums. (That stainless tube is cheap enough. I love anything stainless.)

To regulate the temperature, first use the thermostat on the hot water tank. Just because the tank comes from the manufacturer with the setting maxxed out, doesn't mean that it has to stay there. By turning the setting down, you will also greatly extend the life of the heater. Go to the farthest bathroom in the house and adjust the hot water setting so that it gets a comfortable temperature (way under scaulding) (may need tweaking in the winter).

When the thermostat is adjusted, you will need to adjust the length of your coil to closely match the heating needs of the tank system (this part is hit and miss). You want to get it to where the heat exchanger won't keep up with the demand of the tanks. Then tweek the hot water heater's thermostat to get the temp in the tanks adjusted.

To control fluctuations, have the heat exchanger provide the bulk of your heating needs and supplement it with an electric aquarium heater(s). The aquarium heater(s) will not have to work hard to make up the difference and its thermostat will be easier to get precise.

 

[Dr Joe]

This is all based on the assumption that the water heater (not hot water heater) is on all the time...it is not. By implementing this, you will force the water heater to be on more frequently, raising your electrical costs.

Temp at the faucet is ok @ 120*F but problems do arise when lowering the W/H tank temp. Tank temperature should not be lower than 130*F (hence the minimum thermostat setting) to prevent bacterial growth, (such as Legionnaires disease). Dishwashers need 140*F to properly clean & disinfect.

The other down side to lowering the H/W temp. is the greater use of hot water to get the same end result (and if more people are using the hot water the last one will be lacking ).

This exchanger would work...
http://www.americanroyal.net/page/page/4344238.htm
but you will still need to limit the hot water exchanged by limiting the volume passed thru the exchanger and then mix it with the tank water in a sump.

Oh, and CHOMPERS is correct about the copper and copper pipe builds up with a thin scale of calcium carbonate that further protects the pipe.

Boy, do I sound grumpy...

Dr Joe

.

 

[CHOMPERS]

Boy, do I sound grumpy...
.

The Grumpy-O-Meter barely twitched.

 

[nfored]

Thank you guys so much, I might have to weigh the cost over this. Here in Kansas City Natrual gas cost a ton. So If i will actully be using more, it may be cheaper to keep using 2 300 watt heats. During the winter both will be on almost all the time, but during the summer both will be off 80% of the time and on wil be of 90%.