Condensing Boilers as Pool Heaters? (Steamhead)

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I've heard Dave Davis of HTP has a condensor directly piped to his pool. It's been at least 5 years since I've heard that story.

Ti stabilized stainlewss would be ideal.

I wonder that filters and plate HXers are Ti or stablized.

Flat Plate uses a "special marine grade" stainless for their pool application HXers.

I wonder how copper tube boilers last so long on pool applications. i have seen them last 15 byears or more. As`far as I know it is not a special grade of copper?

hot rod

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Steamhead (in transit)

Was talking to my brother-in-law

who is in the swimming pool business, he mentioned his company uses Raypak pool heaters with heat exchangers to keep the chlorine out of them. It struck me that the sub-140° water temps in a pool would be a perfect fit for a condensing boiler. He'd never heard of this being done.

So I thought I'd throw the question onto the Wall: Has anyone ever used a condensing boiler this way? How well did it work? Any problems?

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[Deleted User]

Gotta use a HXer...

And it will probably have to be made out of Titanium, because the chlorides typically found in pool water play havoc with the typical stainless steel plate heat exchanger. Don't ask me how I know this, because I would probably defame a particular manufacturers rep and his product line "Oh, all ya gotta do is put an anode in front of it...and it will be JUST FINE").

Titanium is NOT a cheap element, nor is it easy to work with. Requires very special knowledge and rods to make it fool proof.

I see no reason why a person couldn't do it, so long as he uses all the right components, but keeping the heat source in the condensing mode will require a rather LARGE flat plate heat exchanger made of some fairly expensive stuff...

ME

ALH_4

Condensing pool heating

The low temperature and seasonal use of outdoor pools also makes them ideal candidates for solar heating. This can be done with a closed solar system and a heat exchanger, or with solar collectors made specifically for swimming pools that have a portion of the pool filtration flow diverted through the collectors.

A combination system of a Raypak or Lochinvar pool heater and pool solar collectors is a good compromise. The use of high efficiency boilers is a relatively large cost up front compared to either solar or a standard pool boiler. Though, the payback may be there if the pool is heated for much of the season. A little efficiency goes a long way on 150,000 gallons of water with 3500sf surface area in a 25M short course. So does a good pool blanket.

ALH_4

copper

Are you aware of anyone who has used a copper heat exchanger for pool heating? The pool projects I am involved with currently are public, so I can't experiment much. I assume Dave Davis has the boiler below the water surface elevation of the pool? Also, I am concerned about winter drainage of the coil-type heat exchangers in many stainless condensing boilers.

Guy Woollard

pool Heater

A mod/Con pool heater is a great idea, but the chlorine/bromine/salt levels of pools differ so much by bot design and user contribution that it would be difficult to design a competetive (boiler) heat exchanger. There is also the issue of the abrasiveness of certain pool chemicals. I have been pushing the idea of a mod/con on heating duty for the winter, then with a maxi-flo pool heater for the spring/summer/fall months. Yes, you do lose a bit with the heat exchanger, but at least it is designed for pool water. For a slight bit more..(salesman speak) there is a titanium model Maxi Flo.

Guy Woollard
N.E. Regional Sales Mgr
Triangle Tube Corp.

brucewo1b

yes Andrew

it was a Therma-Flow lt I knew it was going on twenty years and still kicking, it was however installed in the boiler romm so freezing was a non-issue

Phil Burkhart

Raypak has a system for 400-2340 MBH with 98% efficiency. The boiler and condensing heat exchanger have cupro-nickel tubes and bronze headers.
See the link for the details.

L'town radiant

Cupro-nickel

I know that normal copper will not stand up pool chemcicals for long, but what about cupro-nickel? cheaper than stainless...?

Unknown

done it

using a Triangle Tube pool heat exchanger to seperate the boiler fromthe chlorinated water.

wheels

Brad White_9

CuNi

I agree, that would be my second choice compared to 316 Ti or 316L stainless. Keep in mind that the chlorides, nasty as they are, are worse when combusted, so this is not the same reaction as taking your combustion air from the exhaust of a laundry or dry cleaners. Still, Cupro-Nickel is an excellent choice. The base composition is 90/10 copper/nickel but goes as high as 70/30; the more nickel the harder it is.

It also goes by the name "Admiralty Metal" but the term I cannot define if it has a particular composition. I used to think that the 70/30 defined it but am no longer sure.

Tombig_2

No Problem

The Raypak in the basement for an indoor pool had combustion air issues. The atmospheric W-M CI boiler doing pool room baseboard duty was old but working in a closet off the pool. They shared a B-vent flue. Thanks to some engineering advice from one of our resident ME's (thanks Brad) regarding combustion air requirements we gave the customer a two for one. The pool guy wanted me to bring combustion air to the equipment room in a finished basement while he just changed out the Raypak. Cooler heads prevailed. The Knight boiler and TT Maxi-Flo pool heat exchanger married the existing baseboards quite nicely. Sorry for the fuzzy pics.

Tom G

Mike Thomas_2

History of Pool Heaters

Pool heaters were all made of copper at one time, and they lasted for years. Chlorine is not as hard on them as you think. The worst thing was letting the ph get low. If it gets too low it can ruin one in 30 days or less. Copper nickle and titanium are manufacturers latest tricks to sell new heaters. Sure they are better, but it is no substitute for good water chemistry. The other thing most people forget in their quest for the most efficient heating system is usage time. Outdoor pools really only heat about 30 days in the spring and maybe 30 days in the fall. Doesn't make a lot of sense to spend all that extra money on something you only use 2 months out of the year. And then if you consider the run time during the month, they may not run 300 hours a year.

Glenn Sossin_2

Doing 2 of them this summer

Will have some 1st hand experience shortly. Two jobs, each with 2 Prestige 250's and the Triangle Tube heat exchnagers. Problem, you need a larger model, MF400 not large enough.

Metro Man

Better life through chemistry

I agree with Mike. Anything metal can be destroyed by letting PH get out of control. Once looked at a job that had copper lines for solar pool heat. Nothing wrong except homeowner had no concept of how and when to add chemicals. I was able to squeeze the 1" copper injection line together with my fingers. Replaced with CPVC which was more expensive at that time than copper.

Also it's where these chemical feeders are added. If you stick these in front of heaters and exchangers the life of these will be short. Ozonators are excellent for reduces chemical dependency. You need to set these up for as long of a contact time as possible. If you can smell ozone your not letting it do it's job.

Perry_3

Copper Alloys & Suitability of SS Alloys: Boiler longevity?

90/10 CuNi is essentially 90 % copper 10% nickle.

There is a standard range of alloys (85/15; 80/20; 70/30) that is commonly produced in the CuNi product line - and others available by order.

To flip it arround get Monel which is commonly in the 90% Nickle 10% Copper to 70% Nickle 30% Copper range. Monel tubes would really work great in this application.... If you got the money (and you thought titanium was expensive).

Admiralty is a Brass (Copper/Zinc) alloy. You cannot get good quality Admiralty anymore short of a Mill Run from only 2 of the mills in the world with an independent inspector there who knows what to look for. Most Admiralty sold today is real junk. Too bad, as it was such a great alloy. It was designed for the British Admiralty for condenser and other seawater HX tubes which is why it is called Admiralty Brass; and was a truely phenominal compared to the previous steel or pure copper tubes.

Concerning pool applications: I would stay away from the 300 series SS entirely - they are not a good fit (and certainly not ideal. Titanium stabilization does not buy you that much protection).

Use of a SuperFerritic Stainless (SeaCure or AL 29-C4) would be ideal. All the needed chemical resistance, lower cost than Titanium, and slightly less galvanic issues than Titanium. AL6XN may also work well; but I am not a fan of the alloy as there has been too many production problems with it (and not annealed correctly and it bombs big time).

While Titanium would work very well, along with the SuperFerritics.... you need to have the HX designed by someone who understands the galvanic issues involved. Putting Titanium tubes into a carbon steel tubesheet may not have a long life (same with the superferritics). Done right is is not a real problem.

Note: I would only match a Titanium or Superferritic HX with a SS boiler HX on the same system due to the galvanic issues involved. Trust me on that.

A big issue with pool heaters and boilers is the combustion air. If it is drawn from the pool area where you can easily smell the pool chemicals.... it will likely eat up any boiler HX relatively fast. Here is a case where we really need a boiler HX made from SeaCure or AL 29-4C. Viessmann with its Titanium stabilized SS may last a bit longer than other SS HX's; but is not immune from the possible problems here.

Be very sure that you have clean fresh air for boiler air supply.

Perry

Unknown

looks nice!!

Tom,

NO reason not to use that bouler year around. Job looks great!

My latest using your tyoe f system was to incorperate snow melt. The pool needed so much BTU that the house could not carry the load. The the customer asked about snow melt. Wow! Heat exchanger for the pool, a tekmar control, som3 5/8 pex, circulator and controls and presto, a pool heater that does snow melt in the winter!!!

Mad Dog!!!!!!!!

\"admiralty Brass\"????? Huh?

Any different from "naval brass"? or just local vernacular? Mad Dog

JohnNY

An old story.

Years ago, one of the I=B=R teachers told us a story about some famous race car driver that had a snow melt system installed in his long blacktopped driveway.
In the summer, the water in the tubing got so warm he set up an arrangement of changover valves and a heat exchanger to have the snowmelt system heat his pool water.
Free heat.
I loved that story.

That's the kind of experimenting I'll never get to do in NYC.

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Lunatic Fringe

try this unit...

Perry_3

It is different from Naval Brass

There are 3 or 4 common forms of brass currently in production. They all have slightly different alloy compositions which make each alloy really good at some specific application.

Admiralty Brass is its own unique alloy, and I have never heard of it being used for anything other than tubes; although I am sure that it would work well for other things.

Perry

Unknown

Local Students

did the figuring, 126BtuH/Sq Ft. Free engineering with a famous guy.

It was a misnomer that the tube got to hot, ot had never even seen service prior to the dual hook up.

The tube was in the sections of driveway on a 30% incline facing south, perfect for summer gain at the Latitude the house is at.

Anyway, the system worked great. Sorry to say the homeowner and GC lost all respect from all the subcontractors and suppliers. In fact, if I was called to work at the house tomorrow I would tell them to pull their racing tires over their heads.

steve

Tombig_2

Free (?) Pool Heat

Years back a friend ran some copper coil in the sand bed under his above ground pool and used them as a condensing coil for his central air unit. Not sure how much output he got out of it but the condenser fan didn't run much.

JohnNY

Lunatic Fringe

it looks great, doesn't it?

Steamhead (in transit)

Thanks for the help

I just e-mailed him the link to this thread. Those guys do a lot of commercial work- swim clubs, hotels etc. where the heaters are expected to run much of the time, so the savings from the use of condensing heaters would probably be substantial.

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