remote heat exchangers

polywise

OLD SCHOOL-ish
looking for some info and a link or two

Would like hear about the pros & cons, also ould be great to see some set up pics.
 

MeuserReef

Welcome to the next level
What type of system are you looking for here? More specifically, what material (ie, freon, glycol, water, etc.) are you trying to use to carry away heat?

Im in the process of building a new heat exchanger for my R-22 based chiller system. I can take a few snap shots of what I have so far and post them later tonight if you'd like.
 

polywise

OLD SCHOOL-ish
MeuserReef,
I am looking to hook one up to my hot water heater, and use it to heat water in a remote sump, also thinking about similar application but using a burried underground plastic water tank to use for cooling. what do you think?
 

MeuserReef

Welcome to the next level
I like the idea of using your (already) hot water as a heater and the (already) cool tem of the ground to cool, however you are going to have to have a way to "call" for heat when the temp drops below a certain temp and to "call" for cooling once the temp rises past a certain point.

Because the ground is always cool and the hot water heater is always hot, I would suggest 2 independant closed systems, one for the heating, and one for the cooling. You would need a 2-Stage temperature controller (such as the <a href=http://www.rancoetc.com/ranco-etc211000000-stage-p-105.html?osCsid=c6807a027ef82b678705e4132d09d445>RANCO ETC</a>) This would turn either the Heating loop, or the Cooling loop on depending on the needs of your system.

Shyland83 is currently underway with the "Geo-Thermal cooling" option in <a href=http://www.reefcentral.com/forums/showthread.php?s=&threadid=1332850>THIS THREAD</a>

I dont have a link to any Hot Water heater type heating systems, but it wouldnt be that tough.
 

polywise

OLD SCHOOL-ish
MeuserReef,
I'll look into the thread,
I was thinking on two seperate systems
I have a Medusa three digit controller that I am planning on using.
 

MeuserReef

Welcome to the next level
I am not famaliar with the Medusa but Im sure it will work. 2 seperate, closed systems, each with a Titanium heat exchanger that is in direct contact with your tank water sounds like a good plan to me. If you need Titanium, you should PM Shyland82. He bought a bunch of 3/8" OD Titanium tubing and is selling some that he doesnt need. I believe they are 6' lengths.
 

eznet2u

New member
There is no such thing as a "Hot Water Heater".

There is no need to heat Hot water.

It's just a "Water Heater". :rolleyes:
 

MeuserReef

Welcome to the next level
<a href=showthread.php?s=&postid=12231561#post12231561 target=_blank>Originally posted</a> by eznet2u
There is no such thing as a "Hot Water Heater".

There is no need to heat Hot water.

It's just a "Water Heater". :rolleyes:

Thank you for the clarification.


Perhaps it should be called a "Liquid H2O BTU Applicator" :D
 

H20ENG

Pro builder/aquarist hack
Premium Member
"Liquid H2O BTU Applicator"
LOVE It!

Polywise,
There is a guy on ebay selling Ti exchangers for a really good price. Remote exchangers let you get the noise and heat of a chiller outside while letting you run only small refrigerant lines, rather than large plumbing lines to the remote unit. Cons; More refrigerant piping, but no worse than your household air conditioner.

That said, I also prefer chillerless cooling if possible. You still need the HX though (bigger capacity unit since geo water is maybe 60 degrees, rather than the 35 or so refrigerant).

Meuser,
Would you then use the same Ti coil for both heating and cooling?

I drew one up using a solar collector, drainback tank, geo loop, circ pump, and 2 three way valves. BUT you need 2 bladder tanks to account for the thermal expansion, and possibly a vacuum breaker on the hot side.

So the tank water is flowing through the HX all the time. The controller calls for HTG, CLG, or OFF.

A call for either HTG or CLG runs the circ pump.

HTG aligns the 3-ways to circ water through the solar drainback HX to the tank HX. Once up to setpoint, the circ pump stops. The valves stay aligned to the last called for position.

CLG runs the circ pump and aligns the valves to circ water through the geo loop and the tank HX.

One thing that has crossed my mind is whether thermosiphoning will occur by leaving the valves open to the HX during off cycles. Not sure, but it would also depend on the physical layout of the HXs and piping.

Fun stuff!!
 

MeuserReef

Welcome to the next level
:hmm3:

Meuser,
Would you then use the same Ti coil for both heating and cooling?

I was thinking that you would have 2 small pumps that would each feed their own independant closed loop. This would keep the systems seperate and would reduce the complexity of the plumbing. Since both the geothermal cooling loop and the water heater loop will only require a low flow rate, I would think that a pair of small Iwaki external pumps (dirt cheap on eBay) would be all that you would need to accomplish this. The cooling loop could even contain Propylene glycol to prevent freezing (the OP is in NY.. brrrrrrr)

Closed loops would also allow the lines to be made of non reef-safe materials that have good temperature transfer properties (ie copper, aluminum, etc). This would only really be an issue with the cooling loop as Hot water would be pumped through the heating loop. The Titanium part would only be required in the area in contact with the saltwater (in sump I would imagine).

For the Heating loop, PEX tubing would be sufficient for the run to the water heater and back as it is used in home construction all the time nowadays for both hot and cold water.

I would guess that the Heating loop would heat a bit faster than the cooling loop woudl cool if using this setup. Im definetly going to be looking into the Geothermal cooling once I have a tank on a first floor again! (and just for those readers wondering.... there's no such thing as a "crawl space" in Houston!)


Dont get me wrong, your idea is the more "engineer-approved" route and would probably be the better system. Mine is a bit more simplified I guess.
 

H20ENG

Pro builder/aquarist hack
Premium Member
True, and those pumps are cheaper than three way valves. You could use the PEX for the whole shebang if you had enough space for good exchange with the tank. I was just dreaming of the ultimate geo / solar setup:D

If you are running the domestic hot water (DHW) through an exchanger then back into the domestic system, you technically need a doubled walled heat exchanger and a big backflow preventer outside. Either dont tell the city or run it to somewhere useful after sucking the heat out of it:)

Oh, and I have a 36" crawl space. nanny nanny :lol:
 

MeuserReef

Welcome to the next level
<a href=showthread.php?s=&postid=12232652#post12232652 target=_blank>Originally posted</a> by H20ENG
Oh, and I have a 36" crawl space. nanny nanny :lol:

I have palm trees in my back yard...

nanny, nanny..! :D
 

polywise

OLD SCHOOL-ish
eznet2u,
Abit too late but -- you know how it is, what you think, is not always how it comes out.
H20ENG,MeuserReef - Up here in NY, right now trees still do not have leaves on them.

H20ENG- your statement
"If you are running the domestic hot water (DHW) through an exchanger then back into the domestic system, you technically need a doubled walled heat exchanger and a big backflow preventer outside. Either dont tell the city or run it to somewhere useful after sucking the heat out of it"

In my house, my hot water storage tank is heated via a internal heat exchanger connected to my boiler. I am planning on tapping off of the in and out of the hot water storage tank and just looping the water to a heat exchanger in my sump. If temp drops below set point on storage tank, the boiler takes over and bringsit back up to the set point.

Think this is a good idea?
 

BeanAnimal

Premium Member
It will not be cost effective to use your hot water heater to heat a remote "sump". The losses in the system will add up to quite a substantial water heating bill. Your are much better off just using a standard aquarium heater to directly heat the water.
 

denverhoss

Premium Member
Maybe you'd be better off using the "IN" side of the water heater as a chiller instead of a heater. If the water usage is sufficient, and the water coming into the house is nice and cool, you could run it through a brine bath that also contained titanium tubing coming from the tank. You'd basically be pre-heating the water headed for the water heater to cool the tank water. You could get colder water by doing this at point where the water enters the house, but then your cold water faucets might not be as nice and cool.
 

H20ENG

Pro builder/aquarist hack
Premium Member
I have palm trees in my back yard...

OK, you win.:sad1: Damn, you also have a reef out back. I have 54 degree water full of Great Whites...:rolleyes:

Polywise,
It would take a pretty detailed analysis to see which would be more cost efficient (electric heaters or gas fired loop water). If your hot water tank was pretty large, you may get by, but if its smaller than say 50g, your boiler will be short cycling and wasting gas. There are ways to limit the heat loss of your system, but you'll need to look at the whole package.

Denver,
Good point, though this only holds true while you are using the hot water.

I had an idea along the same lines for my RO/DI feed. The incoming cold water line would tee off and run through a long poly or PEX coil in my sump then back to the feed line to the RO.

A solenoid valve on the shorter straight run to the DI (between the Tees to/from the coil) would close when the tank called for cooling.

This would then route the domestic water through the coil in the sump, cooling the tank, and warming the water feeding the RO. Normally the valve would be open and the water would not flow through the coil, as the path of least resistance would be through the straight shot (12" of 1/2" pipe, vs. 50' of 1/2"PEX). This of course would only work when the RO was running.

I guess you could do this same setup to your main house feed so that whenever the water ran it would be available for cooling. (And, again would technically require a double exchanger and backflow, if you went by the book)

Obviously good controls and sequencing are a must here, but its very doable.
 

polywise

OLD SCHOOL-ish
H20ENG,
I thought about using the house supply, but came to the conclusion that if the house was not using water, but the tank was calling for cooling, it would only be a while before there could be a overheating risk.
 

H20ENG

Pro builder/aquarist hack
Premium Member
Yes, you'd definitely need an alternate plan, but the water line would be your "first stage". Then if that was not running then fans, chillers, etc would need to run. Pretty easy to control / wire.
 

ConsultantERP

New member
I did not read this entire post, but your assumption that it is not called a "Hot Water Heater" is incorrect. As a mechanical drafter the term is "Hot Water Heater", the designation within symbols is "HWH". So the old joke is on us, it is called a "Hot Water Heater". I don't have a reason for this, but I did have an arguement with an engineer, and he showed me that the standards show "Hot Water Heater". As if anyone really cares anyways.
 
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