Using a Heat Exchanger for BOTH Heating and Cooling a Large Aquarium

[ca1ore]

My next big tank project is to replace my army of stick heaters and 3/4HP chiller with a dual purpose heat exchanger. I know there are a few threads on this topic elsewhere on R2R, but I did not want to hijack those, so I chose to start my own thread on the topic. Also, unlike most of those, I opted to purchase a purpose-built aquarium unit from Bill Wann at Aquarium Engineering. So while there is a DiY element to this (the installation process), I also chose to start this in the equipment rather than DiY section because I am buying rather than building.

I chose to go with a heat exchange/control panel system from Bill for a few reasons. First, he's a pretty clever chap and has been using a larger version of what I bought from him on his huge system for a while for both heating and cooling. Having something I can use for cooling was really important to me because my large chiller is an energy hog (and I have access to 50 degree well water). Second, with a sizable investment in corals and fish, I was loath to rely on what appear to me to be mostly cheaply made foreign heat exchangers. OK, I know there are folks out there using them, but I chose to go with something that I trusted to be of the highest possible quality. Third, I've been wanting to buy something from Bill for a while just so I can get hands-on experience with what he makes.

Summer's are quite busy for me personally, so this will likely be a slow gestation, but here is my overall plan:

1. I will not be putting the heat exchanger into the main return loop, preferring to use a separate pump loop. Partly because I don't want to lose any flow from the main return, but mostly because it gives me an independent point of redundancy should something go awry. A heat exchanger like this will overheat a tank in an eye blink, so having the ability to turn off the heat circuit pump in an emergency is important.

2. The water heating system in my house is a bit quirky. Although the actual hot water heater is electric, it functions mainly as an insulated holding tank because the feed is from a hot water coil in my oil fired boiler. So while I will take the hot water feed for the heat exchanger from the output of the hot water tank, I'll need to tap into the cold water pipe prior to the boiler for the return. That way I can ensure that the water heating is occurring mainly in the boiler (otherwise I don't save on heating energy costs).

3. The cooling side uses the hot water return as the feed for the cold water. Since there is no practical way to return that water to the house loop, it gets sent outside as 'waste' to a cistern.

 

[Victoria M]

This is very interesting. I will be following along.

 

[User]

What’s the benefit of running the cooling loop considering you have to dump the water after it leaves the HE? Can’t you Run a bunch of pex and tie it in somewhere?

Totally on board with the heating loop. I’ve had this on my to do list for months but not gotten around to it. My tank hasn’t needed heating since March. Just not sure cooling loop makes sense considering I could just leave my fishroom door open, or run the ventilation for a few minutes.

 

[JMM744]

I almost bought the same system from him. I just didn’t have the cash at the time. I figured I could piece one together diy over the summer but you know how that goes. Nothing done. Interested in seeing what extras you need to get to get it functioning. Please include those things if time permits.
Thanks, Jim

 

[ca1ore]

What’s the benefit of running the cooling loop considering you have to dump the water after it leaves the HE? Can’t you Run a bunch of pex and tie it in somewhere?

Benefit is that I don't need a bunch of PEX in the sump. I also figure the vastly superior heat exchange from the Ti versus PEX will also mean I can run a much slower stream of cold water.

 

[User]

Benefit is that I don't need a bunch of PEX in the sump. I also figure the vastly superior heat exchange from the Ti versus PEX will also mean I can run a much slower stream of cold water.

You misunderstood. I didn’t mean put pex in the sump. Pex is a crappy heat transfer material. I’m with you on the ti heat exchanger.

I meant- why not run pex from the cold side of the heat exchanger and run that back to your supply. The same way you’re doing for the hot loop- your returning that back to the boiler, right, not dumping it down the drain? So why not return the cold loop back to supply?

 

[JLUR_]

You misunderstood. I didn’t mean put pex in the sump. Pex is a crappy heat transfer material. I’m with you on the ti heat exchanger.

I meant- why not run pex from the cold side of the heat exchanger and run that back to your supply. The same way you’re doing for the hot loop- your returning that back to the boiler, right, not dumping it down the drain? So why not return the cold loop back to supply?

He would have to pressurize it above the well water loop pressure to get it to return properly. IIRC a lot of wellwater systems have an expansion tank to account for pump surge so by sending water back to the system it would fill/overfill his expansion tank. If it does overfill the expansion tank it would backflow through his well pump potentially damaging it. Since he's not paying for city water and is really only paying for electricity to pump the well water up the smart move here is to just send it to the cistern as waste water like he's planning. If it were city water it might be possible but depending on his pressure drop through the exchanger he might need a beefy pump to do this essentially negating some of the money saved with this new setup.

I'm curious how much the shell & tube cost? I've designed a few saltwater systems that utilize a titanium plate HX with EPDM gaskets that cost about $500 for the HX. They bolt together and can be serviced pretty easily if/when they foul.

 

[ca1ore]

Oh, I see. Not sure actually how I would do that. Well pump is a beast and i don't see how I'd get the water back into the system. I'm going to use the waste water for garden uses (or even as source for my RODI).

 

[User]

Oh, I see. Not sure actually how I would do that. Well pump is a beast and i don't see how I'd get the water back into the system. I'm going to use the waste water for garden uses (or even as source for my RODI).

Got it. I wasn’t versed in the pressure requirements of well vs city water. I had no idea they pumped that hard.

Why not put it into the boiler? That’s where cold water goes after the pressure regulator anyway, right, and where the hot out is going?


I can’t find pricing info on bill wanns site for that kit. Curious how it compares price wise to an inferior Chinese version. FWIW- I’ll be running one of those, and don’t really have concerns regarding engineering. Other than being 100% confident that it’s titanium, proper safeguards can easily protect the sulpnif it were to fail. Like keeping it out of the fishroom to start so it doesn’t spray chlorinated city water into the sump if a weld seam fails

 

[User]

He would have to pressurize it above the well water loop pressure to get it to return properly. IIRC a lot of wellwater systems have an expansion tank to account for pump surge so by sending water back to the system it would fill/overfill his expansion tank. If it does overfill the expansion tank it would backflow through his well pump potentially damaging it. Since he's not paying for city water and is really only paying for electricity to pump the well water up the smart move here is to just send it to the cistern as waste water like he's planning. If it were city water it might be possible but depending on his pressure drop through the exchanger he might need a beefy pump to do this essentially negating some of the money saved with this new setup.

I'm curious how much the shell & tube cost? I've designed a few saltwater systems that utilize a titanium plate HX with EPDM gaskets that cost about $500 for the HX. They bolt together and can be serviced pretty easily if/when they foul.

That was the snippet I wasn’t versed in. Well vs city water pressure differentials.

Thanks

 

[ca1ore]

I had no idea they pumped that hard.

Makes our aquarium pumps seem like toys by comparison. Mine is a 240volt monstrosity that can deliver 50 psi at 300 feet of head pressure.

 

[ca1ore]

Why not put it into the boiler? That’s where cold water goes after the pressure regulator anyway, right, and where the hot out is going?

Because it would only flow if somebody happened to be using hot water at the same time.

 

[ca1ore]

I can’t find pricing info on bill wanns site for that kit. Curious how it compares price wise to an inferior Chinese version.

It's a custom item - not on the price list. If you have to ask …… LOL Snd me a PM if you want to know.

 

[ca1ore]

Assembling the plumbing parts. Trying to decide whether to use copper (which I have a lot of experience with) or PEX (which I have no experience with). Maybe a combination of both. I have a couple of pumps as circulation options. I wonder if I can swap the pressure volute from the panworld 100 into the panworld 50? Circulation pump will pull from the bottom if the sump and return over the rim into the return section.

 

[ca1ore]

Beginning install .....

 

[ca1ore]

Misc plumbing shots....

 

[ca1ore]

As you can see from the plumbing pictures, I ended up using a bunch of copper pipe, fittings and valves that I had on hand (approx $125 if bought new). Purchased some pex to make the curved connections. Man, that stuff is easy to use. I can see why most residential new construction uses it. Spent about another $125 on pex (needed the crimp wrench, which can be used for future projects). Dual coils of blue extension cord are the control lines that will plug into my apex, one for hot and a second for cool. As I noted at the outset, I’ll be using a separate circulation pump. I have a few options on hand - probably I will use a panworld 100PX. If that proves excessive, I can try a panworld 50, but I have the non pressure version so that may struggle against 40’ of 3/4” flex pvc.

Have a coil of 3/4” flex pvc on hand, so will use that to get water to and from the heat exchanger. That would be around $50 if bought new. The circulation pump will also function as a point of redundancy if excessive heat or cooling condition should occur, apex can shut down the pump. I will also connect the pump through a ranco controller then into apex. Should apex get stuck on, the ranco will be a second level of control. I like this better than using the ranco on the hot/cold control outlets because it is not constantly cycling on or off.

All the hard plumbing work is done, it’s just a few other bits like the pvc, a further leak test and then put it into service.

 

[Dr. Dendrostein]

My next big tank project is to replace my army of stick heaters and 3/4HP chiller with a dual purpose heat exchanger. I know there are a few threads on this topic elsewhere on R2R, but I did not want to hijack those, so I chose to start my own thread on the topic. Also, unlike most of those, I opted to purchase a purpose-built aquarium unit from Bill Wann at Aquarium Engineering. So while there is a DiY element to this (the installation process), I also chose to start this in the equipment rather than DiY section because I am buying rather than building.

I chose to go with a heat exchange/control panel system from Bill for a few reasons. First, he's a pretty clever chap and has been using a larger version of what I bought from him on his huge system for a while for both heating and cooling. Having something I can use for cooling was really important to me because my large chiller is an energy hog (and I have access to 50 degree well water). Second, with a sizable investment in corals and fish, I was loath to rely on what appear to me to be mostly cheaply made foreign heat exchangers. OK, I know there are folks out there using them, but I chose to go with something that I trusted to be of the highest possible quality. Third, I've been wanting to buy something from Bill for a while just so I can get hands-on experience with what he makes.

Summer's are quite busy for me personally, so this will likely be a slow gestation, but here is my overall plan:

1. I will not be putting the heat exchanger into the main return loop, preferring to use a separate pump loop. Partly because I don't want to lose any flow from the main return, but mostly because it gives me an independent point of redundancy should something go awry. A heat exchanger like this will overheat a tank in an eye blink, so having the ability to turn off the heat circuit pump in an emergency is important.

2. The water heating system in my house is a bit quirky. Although the actual hot water heater is electric, it functions mainly as an insulated holding tank because the feed is from a hot water coil in my oil fired boiler. So while I will take the hot water feed for the heat exchanger from the output of the hot water tank, I'll need to tap into the cold water pipe prior to the boiler for the return. That way I can ensure that the water heating is occurring mainly in the boiler (otherwise I don't save on heating energy costs).

3. The cooling side uses the hot water return as the feed for the cold water. Since there is no practical way to return that water to the house loop, it gets sent outside as 'waste' to a cistern.

Being a large investment your making for your reef, if me, I'd set up a tank less water heater, on propane, use well water, same as using it for cooling. Have well pump on 24/7 with a by pass so it loops back to well, when no heat or cool needed. You want to avoid turning devices on off continuously. Less issue down the line. Separate heating from home, don't need to turn on home boiler just for tank. My thinking

 

[Dr. Dendrostein]

I'm an HVACR contractor. 25+ yrs. Following. Thanks for sharing, comrade

 

[JMM744]

@ca1ore
So is this system running yet?