What is "Hydraulic Design"?

[South_Texas_Sun]

We just broke ground for our pool here in San Marcos, Tx. and I'm trying to educate myself a little to keep an eye on the PB and avoid problems.

I've read that good "hydraulic design" in a pool cuts energy costs (by making the pump work less) and I'm wondering where I can find out more about it.

You see, the PB has said that "although most builders route the plumbing the shortest distance, we (the PB) route it AROUND the pool and use 90 degree angles so that if leaks occur, they're easier to fix."

Is this just sales talk, and should I be concerned about "hydraulic design" that includes multiple 90 degree bends?

Thanks

[CarlD]

Since I'm an A/G guy not an I/G guy, I can only guess. I suspect that they are not running much, if any plumbing under the pool itself. But I could be wrong. The longer the runs, the more back-pressure is generated--and 90 deg bends add to that. That's when 2" pipe is preferable to 1.5". If the plumbing is exposed, well, it depends on what the straight run is versus the longer run.

Pressure and water flow through the pipes and in the pool matters--so location of the skimmer(s), low drain(s) and returns are all important.

Is he shining you on or serious? I don't know...I'll let the pros here answer that.

I do know that for repairs (I use a lot of 1.5 PVC and 1.5 TigerFlex on my pool), I prefer lots of ball valves in strategic locations to isolate drains or returns, and a lot of quick-release connectors as well.

He should absolutely NOT use TigerFlex underground--it's strictly for exposed plumbing.

[South_Texas_Sun]

Hi Carl, thanks for the reply.

You said, "Pressure and water flow through the pipes and in the pool matters--so location of the skimmer(s), low drain(s) and returns are all important."

We have a slightly sloped hill behind the house and they're building a freeform 12 to 20' foot by 40' foot pool with the hottub at the top of the slope and a "cold tub" grotto feature next to the hottub/waterfall area.

The PB admitted that the grotto feature tends to get dirtier than the rest of the pool, so he plans to put in a second drain at the bottom of the grotto. (There's spa jets in the grotto/"cold tub")

Do you think this is going to present any special problems for pumping that I should ask about?

The reason I'm asking all these questions is that I tried "Googling" for this kind of info and came up pretty much empty handed. The PB is a smaller company and I'm not sure how many pools like this he's actually built because there's not a lot of pool co's that offer this design unless you ask for it. Our fellow seems talented and anxious to please, but is learning as he goes and admits that, so I'm hoping to shorten his learning curve BEFORE he finishes our pool. lol

Thanks again.

[Poconos]

My guess on 'hydraulic design'? As Carl said flow both thru the pipes and in the pool itself is important. I suspect the term is used to indicate that the pipes are sized and routed to minimize flow resistance. ex: swept bends vs. sharp 90's etc. The builder is right about 90's making it easier to fix a problem. However, by oversizing the pipes the bends and routing become less significant. The difference in cost between pipe sizes is small so once you dig, put in the largest reasonable size.
Al

[South_Texas_Sun]

Hi Poconos, thanks for the reply.

Like you, I come from the "bigger is better" school for most things, and when asked, our Pool Builder said that he used 2 1/2" pipe.

Now, if you've ever siphoned gas out of a car, you probably realized that "too big" is much worse than "not big enough" unless you can get enough suction........ (insert veiled double-entendre here....lol)

Is there a book on pool hydraulics or some way to get a little smarter on the subject without building a few hundred pools?

Since our pool project is slightly UPhill from the house, I'm pretty anxious to get it right the first time on drainage and plumbing issues.

Thanks again.

[Poconos]

Siphoning gas is a lot different than the suction line on a pump. You have limited lung volume capacity. If you're thinking of the pump priming sequence, the pump pulls a slight vacuum (self-priming) so the size of the pipe won't matter. It still pulls the same vacuum independant of suction line size.
Al
BTW: Know of no books on the subject other than technical fluid dynamics stuff. Perhaps some of the plumbing books get into this without going into the 'why' but I don't know.