Considering using a tankless water heater for the reef..

[enderg60]

Ok so I have a 300g tank, with a 100g fuge, 40g sump and 2x40g frag tanks. All but the display is in the basement where temps can drop to 55*F. Last year I was struggling to keep the temps above 70 with over 2000w of heaters(mostly 250w, and some random other ones).

Well its starting to get cold again, and I was looking at replacing my 12 heaters with 2 1000w, or 3 800w units...and well they are expensive, and so is running them. I do plan on insulating the sump and some piping, but I need a better solution.

So I came across this.
http://www.eztankless.com/products/ez101.html">http://www.eztankless.com/products/ez101.html</a>

42kbtu, or 12kw of heating for $135..not bad. And I found a few on craigslist for $80! The only downside to this unit is it has a safty timer that will shut the unit off after 15 min. I spoke with the manufaturer, and he said the unit is turned on by a flow switch so to reset it all you have to do is turn off the flow for a few seconds and turn it back on.

After a bit of searching I found this hot water pump.
[IMG]https://www.wattspremier.com/products.php?product=Instant-Hot-Water-Recirculating-System">https://www.wattspremier.com/product...ulating-System</a>

which can be found on ebay for $120. The timer seems to be what I would need to keep the unit runing. Just let the Controller turn the pump on, and have the timer on it set for 15min on and X min off(not sure what its settings are) and let the heater do the rest.

I can mount it outside under my deck, and not bother with the $3-400 in stainless vent piping. And run a CPVC closed loop to it from the tank. I was planning to run a coil in the fuge itself, but I cant decide what the coil material should be.

Ok so far as I can tell I should easily be able to set this up for under $300(once I figure out what to use for the coil in the sump), anyone see any holes in my plan?

 

[markl]

try to cover the sump or at least part of. I saved 4 degrees last year by making a 3 piece cover for my sump.

 

[smallblock]

find an old broke down chiller and use its coil?

 

[jead85]

Sounds interesting, so you will be recirculatingnhot water over and over?

 

[enderg60]

I plan to surround and cover the sump with 1/2" pink insulation anyway.

Ive been trying to find chiller coils for the ground loop for the summer...no luck. I would need 1hp worth of coils just for this, and another 1hp for the ground loop. Using a 100ft coil of pex or something would be more cost effective.

And yes it will be recirculating the same water on a closed loop.

 

[jef4y]

Personally I think you'd do better by insulating and covering the tanks, as well as getting some ambient heat in the basement.

 

[smallblock]

JeF4y;570192 wrote: Personally I think you'd do better by insulating and covering the tanks, as well as getting some ambient heat in the basement.

Good thought, may actually be more cost effective that way

 

[enderg60]

Im denfinitly going to insulate the sump, but heating the basement is not cost effective. its 1500 sqft of empty concrete underground. Plus I keep the house at 68 max in the winter and I want the tank at, at least 76 so insulation or not Im still going to need a massive heater.

 

[rizmaher]

I had a buddy with a similar situation, I helped him frame up a small room in the unfinished basement. We insulated and dry walled the room plus added a vent from the air handler in the basement. The room itself was just under $200, but he went all out and installed cabinets and a sink. It looked like a lab at the end.

 

[jead85]

Go for the thicker pink foam boards. Much better R rating

 

[puffer9375]

If it's possible I would enclose the sump area like a little room. I don't know your layout but it wouldn't cost that much to frame the area out and use waferboard for the walls. Then you could put a small space heater in the room. Just a thought for what it's worth.

 

[puffer9375]

Rizmaher was reading my mind while I was typing. LOL

 

[jead85]

I agree on the room idea, again would use the thicker foam board on the room. Maybe make it removable for summer?

 

[dwhatley]

We have an all electric 220 on demand unit for half of the house (which costs us about the same as running a normal 220 water heater on a timer according to our last test). In the winter we still have to bring the water temp above 50 so it is connected through our water heater but the standard unit is turned off most of the year and on a timer for the winter. This would seem to work similarly if you used it with the tank and could pressurize the flow but these things make HOT water (enough to cause a first degree skin burn) and I don't know that there is a way to adjust the temp without adding cold water. Even our standard water heater cannot be set below 90.

 

[schwaggs]

Interesting idea!

I would use a circulation pump that is used for hot water heat in homes like this one: http://www.google.com/products/catalog?hl=en&q=hot+water+pump&cid=14788583684004495464&ei=hQGtTMiXNYPgzQX52KmTBA&sa=title&ved=0CEUQ8wIwBTgA#p">http://www.google.com/products/catalog?hl=en&q=hot+water+pump&cid=14788583684004495464&ei=hQGtTMiXNYPgzQX52KmTBA&sa=title&ved=0CEUQ8wIwBTgA#p</a>

They are made to circulate water in homes that have radiators and hot water heat.

I have a couple questions/concerns for you:

1) If you plan on circulating hot water through a length of tubing in you fuge (I think that is what you are proposing), you need to be careful of carry-over heat. All the heat that is in the water in the tubing buried in your fuge will continue to heat your system after the call for heat ends (circulation pump stops). This may or maynot be a big deal, you won't know until you try. Potential solution is to use a separate heat exchanger like the others suggested. You would circulate hot water through the heat exchanger and tank water through it. When you don't need heat, stop circulating tank water through the heat exchanger and the heat stops.

2) Be carefull installing this under your deck. You need to make sure the carbon dioxide can escape properly so you don't poison yourself... ;)

3) Can the tankless water heater handle hot (~140 degree) water on the input?

I think building a small, insulated room in the basement and heating it might be your best bet...

 

[mojo]

Tagging along. This is an issue for my system in the winter as well (600-800 gallons total, depending on if I have my frag tank online).

I remember seeing a thread on reef central about someone who did this in California and saved a good bit of money by going with natural gas instead of electricity. He ended up with a pretty complex system, but it did work. I'm almost positive he did a closed loop + heat exchanger.

Take pictures and let us know what happens. I may be following in your footsteps if you're successful.

 

[theplatypus]

You might be able too run a closed loop off of your existing water heater's output. Basically you would T off the output of your water heater, reduce down to pvc,or stainless steel, into your sump and back into the input of your water heater.

 

[mojo]

theplatypus;570284 wrote: You might be able too run a closed loop off of your existing water heater's output. Basically you would T off the output of your water heater, reduce down to pvc,or stainless steel, into your sump and back into the input of your water heater.

I just found a thread doing exactly that - http://www.reefcentral.com/forums/showthread.php?t=1561871">see here</a>. Good pictures and explanation.

Still looking for the original thread that I was referring to.

 

[theplatypus]

mojo;570285 wrote: I just found a thread doing exactly that - http://www.reefcentral.com/forums/showthread.php?t=1561871">see here</a>. Good pictures and explanation.

Still looking for the original thread that I was referring to.[/QUOTE]

Interesting thread, but I'm pretty sure he could have gotten away with a much smaller pump. I didn't read the whole thing, but it appears that he's trying to account for head loss on a closed loop. Which if I remember correctly isn't an issue. THere would be some loss to due to friction,but none to head pressure.

 

[mojo]

I agree- he shouldn't be fighting any head issues. Not only that, but the smallest Panworld or similar external pump would be much better suited; a mag drive pump just isn't reliable in that kind of situation...