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endless pool dehu

Bob Bona_4
Bob Bona_4 Member Posts: 2,083
Brad, I am doing a small addition about 16x20 on the first floor, 10x12-ish second (the second floor is stacked over about half the footprint of the first; the rest of the first has raised shed type ceiling.

Under that shed portion is a 8x, say, 14 endless pool. Let's say about 5500 gallons. The job has morphed from me roughing in radiant in the slab adjacent to the pool, and doing plates under the second floor (bath) to coming up with the mechancials to heat the radiant.

The endless pool outfit delivered a Raypack Versa 50K output 80% disposable boiler to be put in a mech room the size of your typical ranch bedroom closet, shared with the hydraulics for the pool wave generator and the filtration system, where my proposed A/C air handler is to go and where my radiant tubes are stubbed to. 5 lbs in a 1/2 lb..

I initially was not to be involved w/ the pool heater, the endless pool people were taking care of it.

So here we are, pre insulation. and the question comes up, how am "I" going to heat the radiant. My thoughts are something like a TT Solo, powering the radiant zones and a TT Maxi Flo 80 pool indirect. If anything, this will eliminate the need for a chimney and combustion air that the Raypack heater will require. Even thinking TT Excellence to supply the domestic to the bath above (the existing house is FHA, w/ electric HW that was told is marginal).

But, the boiler issue is secondary to the issue of dehumidification, or the lack of any. Originally, when I was asked to provide cooling to the new spaces, dehu was not a issue delivered to me, and like the boiler, I assumed the endless pool guys had that covered. (oh, that word "assumed"....what a devil :))

Load comes in conventional at 2-2.5 tons for the total new space. Toss up b/t ductless split (not so great, won't cover the second floor), and typical VS split w/ some spiral to the pool area. I have been scrambling for data re the pool usage period (does it have to be mantained at temp 24/7, or only weekend type use), water temp (80 or higher for thereuputic). Cover?

Have at it! TIA!


  • Bob D._2
    Bob D._2 Member Posts: 34
    Another Way?

    Obviously, I'm not Brad, but consider looking into something along the lines of a Dectron "Dry-O-Tron" DSV Series. Two birds with one stone? I've had good luck on University-sized Olympic complexes with similar stuff.
  • Brad White_203
    Brad White_203 Member Posts: 506
    Full Plate

    Both of us, Bob! :)

    Bob D. is right on track regarding using a heat-pump type dehumidifier. At least it will mitigate the heating load somewhat. (It will not keep up with backwash and quick recovery needs, don't let anyone tell you otherwise.)

    Now, volume aside, such systems are based on surface area. That is really it as far as evaporation and varies with the RH to be maintained. I usually figure 55% but may allow a climb to 60% on occasion. Air temperatures are usually at least two degrees above water temperature, this much you know.

    Most evaporation rates from charts are based on static pool water. Agitate this and the apparent surface area (and evaporation) go way up. This is where it gets subjective.

    When "active" this baseline "usually" doubles. When an endless pool maybe 2.5? I do not know. I did one several years ago (maybe 20 years) for a pharmaceutical company west of Boston.

    The endless pool manufacturers really OUGHT to guide you in this regard.

    One of the best resources I know is Pat Reynolds at PoolPak in York PA. Pat is a mainstay in this segment of the industry. Mention my name and your concerns. PoolPak has a wide array of system products geared to all kinds of applications. I have done several pools using their line going back 20+ years.

    Now, you mentioned the pool and boiler equipment in the same room. "Sealed Chemistry" is not. I get a certain pucker factor when I see chlorine and combustion together even in separate systems. You do too, I bet.

    The pool system should stand on it's own. It will be a 24/7 operation but a pool cover will greatly mitigate this. Your energy code may require one. I am not sure of the size limitation but our state energy code does require them for most pools worth conditioning (unless you use renewable/free pool heat such as solar that is, minor exceptions like that).

    But given the "Active" versus "dormant" loads, the system must respond to those variations. Using hot gas bypass is a mitzvah.. :)

    For the adjacent spaces, ductless split systems are hard to beat for versatility, especially the inverter driven ones.

    Hope this gets you started and that it covers your questions in some way.

  • don_185
    don_185 Member Posts: 312
    Got a fax

    Number? I can fax you a water evaporation chart along with a ventilation chart and...a calculation chart for pools and spas.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083

    is 203-327-4704 attn Barbara, Don- appreciate it.

  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083


    I think another call to Endless Pool is in order to see how concerned they are about rain forests, what their MO usually is.

    For a pool this small, do you feel that the conventional A/C will make a dent in RH, or, like I kind of think, a dedicated dehum specifically there to control things is the only way to go?

    The other endless pools I've done in the past were above slab basement installs, and it was simple tapping off existing HVAC to condition the room-but note I was a lot younger and less aware back then :). This one is new from the ground up, with the pool in ground, stepped up to floor level.
  • Brad White_203
    Brad White_203 Member Posts: 506
    Two Approaches

    First off, conventional AC does not last in a pool environment. If you get three years out of a unit so applied, you are doing really well. I have seen some go after a year or less. They really become gross...

    We use two approaches well, maybe three, in our office. (Our office meaning I am the pool guy...):

    1. Water-source heat pump systems (Pool-Pak, Desert-Aire, Dectron, Dumont, etc.). Made for application, mechanical dehumidification and some pool water heating as a bonus. Year-round control especially if you use an auxiliary outdoor condenser for heat rejection when the pool and enclosure are at temperature.

    2. Economizer Outside Air- Using OA as the dehumidification means. In winter time this can be a third of what the code requires (usually 0.50 CFM of OA per SF of all areas). Good wintertime control, 100% ventilation in summer with no real control but no condensation either. (REMARK: AC changes this dynamic- you will cause condensation but you have to control where, right?)

    3. Same as above but using a passive heat-pipe heat recovery coil and bypass dampers. This to me is the lowest energy user but you will still not have summer time temperature control.

    Short primer, but our basic approaches.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656

    Bob, I've used LifeBreath's HRV's for pool dehumidification for many years. The make a special unit for larger pools, but a 150 or 200MAX would work fine for your lap pool, and are very cost-effective. The unit does require a sidewall or rooftop intake and exhaust, as well as the supply and return ducting to the space.

    The attached pic shows an 8x14 lap pool using a 200MAX HRV with 4 supply outlets and 1 common return. We installed a 10Kw electric coil in the supply plenum for supplemental. The deck is radiant heated, but the supplemental coil was required for design temps. The pool is heated using a FPHX on a Viessmann VBC boiler and a tekmar 150 setpoint control.

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  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083

    you doing cooling in there too Paul? The pic looks almost just like this job. Good advice, thanks.

    Where did you stash the equipment?
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083

    does stuff running if the pool was using ion or other non-chlorine treatments seem to fare, Brad?
  • singh
    singh Member Posts: 866
    Vapor Barrier

    Make sure the builder of the enclosure pays attention, and uses vapor barrier for the walls, floor, and ceiling! Overlapped and seal well.

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  • don_185
    don_185 Member Posts: 312
    I tried

    but,something was wrong on your end.I'll try again on saturday.

    Take a look at thermastor HI-E Dry you may find that it will
    do the job being you're heating and cooling the room on a seperate system.

    I've used several and they are price right and has lots of capacity.
  • Brad White_191
    Brad White_191 Member Posts: 252
    Limited experience, Bob

    I have seen two smaller (residential) pools which use UV and bromine respectively and both had residential grade equipment to start. Those are the ones that lasted the longest, at least three years that I recall.

    There was occasional shock chlorine treatments when the UV was not quite up to task (I suspect the lamps were overdue for replacement). That did not help.

    In each case though, there was mold and mildew from the moisture itself. With outside air brought in for ventilation, I imagine this brought the casings (1" lined) below the dewpoint and rust formed too.

    Again, limited but definitely not "made for the purpose". Not a firm opinion but more common sense is how I see it.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656

    The equipment is in an outdoor closet, directly in back of the return grill that's visible. No A/C. The HRV exchanges and dehumidifies (and heats) the air.

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  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    ok don

    it's wife's office-I'm having fax problems...I can get email, or if you have a moment on Monday, much appreciated!
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083

    I was there yesterday trying to hash out duct runs. There were guys cutting aluminum frames for sunroom type windows, about 4-5 5x5 sections.

    I didn't look close but I wonder how "tight" they were..

  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083

    really interesting Brad. I had no idea how short a lifespan things in this set up can be. Perry ought to add this equipment in his study (JUST KIDDING, Perry) :)

    I can see I have some more research to do here. Endless hasn't got back to me from this afternoon, I'll bug them again Monday.

  • Brad White_191
    Brad White_191 Member Posts: 252
    I forgot to add

    that the bromine-treated pool had aluminum ductwork.

    Bromine is very aggressive towards aluminum. I warned the HO about this combination and he told me that he was going with UV. For some reason the system went in as bromine and the in-wall ductwork became severely pitted.

    (Bromine is touted as an "odorless" alternative to chlorine as you probably know, but to me it still has a smell.)

    As far as I know, the PCD (PVC-coated duct)buried around the perimeter, held up fine. The units in this case rotted away though and were replaced with Desert-Aire units which are probably still in operation, being about 5-6 years ago by this point.
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