Best solar solution for 1,600 gal spa in Sacramento area?

[scrumpto]

The short version:

• I don't think we're going to be able to heat the pool enough with solar to make much difference so I'm just thinking of heating just the spa year round.
• Consideration: The spa is BIG!
• I need recommendations on which type of system would work best for our area (Lincoln, CA -- not far from Sacramento).
• Specifically, would an evacuated tube system work better than a Heliocol since we're trying to get the temps up around 100 degrees every day regardless of the outside temp?
• I understand it may not get the temps as high as I want but the higher the better.

The long version (which I think ended up being shorter!):
We've just completed a 30,000 to 35,000 pool build with a 1,600 gal spa and need some recommendations on solar. This is my third pool and I've had Heliocol (or similar) type systems on each of the previous ones so I'm very familiar with those types of systems. Due to the size of the pool, I'm thinking that all a standard solar system would do is to extend the season about two weeks on either end and provide some cooling in the summer. As such, instead of paying a small fortune for a system to heat the entire pool I'm wondering if we could find a system which would heat the spa year-round up to very high temps (e.g. 100 degrees) even on cold days? This was actually one of the reasons we built the spa so big as we knew from our last pool/spa that we would indeed use the spa year-round.

What do you guys think?

 

[mknauss]

Welcome to the forum! :handshake:

Is the spa managed as a completely separate body of water? Not sure how you can use solar heat if it is integrated with the pool system.

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[Dirk]

Is the spa managed as a completely separate body of water? Not sure how you can use solar heat if it is integrated with the pool system.

Marty, did you mean if the spa is integrated with the pool, or if the solar is integrated with the pool?

If the spa and pool are the same body of water, you heat either spa or pool with solar the same way you'd heat either with an NG heater or a heat pump. My solar is plumbed just before my NG heater, just as if it was another NG heater. Actuated valves would either pull/return water from/to the spa, just as it would the pool, and run it through the heater(s).

My controller has the capability to analyze the available heat from the solar heater, and "decide on the fly" whether to engage the solar, or the NG heater, depending on which can deliver the necessary heat at any given moment throughout the day. I can choose between "solar only" (to save money), "NG only" (to get'er'dun), or "solar preferred" to try solar first to see if it can do the job, then switch to NG if/when it can't.

That's the easy part. Getting enough heat out of the panels, year-round, is the issue. I think that could best be determined by a local solar heater installer. They can tend to exaggerate to make a sale (mine did), but if there are enough of them in your area to ask, you might get a consensus about whether there is a viable solution available or not.

I think, with a little manual intervention, or perhaps some creative automated scheduling, you could make use of both heating systems. Use NG heater to bring the spa temp up quickly (something solar would have trouble doing), then engage the solar heater to maintain the heat throughout the day. Then back to NG at night. Something like that.

 

[mknauss]

The spa. If you must circulate the spa and pool water together to chlorinate, etc., the heat in the spa is lost each day. Thus I would think the solar would be not sufficient to do much.

 

[Dirk]

Oh, that pesky sanitation, right. Good call. But couldn't you sanitize and balance the spa and pool separately? Just never run the spillover mode? Not ideal, but just like having two separate bodies, that happen to share the same filter/heater(s).

And that problem exists solar or no, right? So how do others solve for this, when their spa is integrated, but they want to use it all year. Or even in the summer? Every time they go to spill over mode, then they dump the spa heat. Maybe not as big an issue in the summer time, but still an issue.

What else did I miss?

 

[Dirk]

I did miss something. Heliocols (and similar types) have to drain each night, to keep from freezing. So that, too, would have to be managed. You don't miss that water when it's drawn out of the pool, but it might be a significant amount in a spa. Or you could try to schedule such that it drew water from the pool, heated it up in the panels, then switched to spa mode, then back to pool to dump the panel water back to the pool. I think possible, but certainly another challenge.

If the OP's spa is big enough, maybe that'll be a non-issue?

 

[mknauss]

Our integrated spa we heat up when we want to use it. It then mixes with the pool until the next time we want to use it.

I do not see a viable process to use solar for just the spa. And each time the spa wants to be used it will need to be heated.

 

[Dirk]

I do not see a viable process to use solar for just the spa. And each time the spa wants to be used it will need to be heated.

I agree, using solar exclusively. But I think a hybrid solution could work, weather permitting. Using NG to establish the temp, and then solar to maintain it. "Weather permitting" being the operative words... It would only make sense to try if the OP wanted to keep his spa heated up for long stretches, during the day, because if it could be made to work, there'd be several hoops to jump through, and it wouldn't be as convenient as just pressing the "SPA" button.

Again, I'd want to hear from a local solar installer that he actually pulled it off. Unless the OP is getting solar installed anyway, for his pool, and then can just fool around with it himself.

Of course, he's actually asking about which system to buy, and I can't help with that, sorry. I've only used Heliocol.