Solar - integrated or independent?

[Kwikee]

I'm looking at adding a solar heating system to our pool which is currently undergoing renovation by me. It will be fully drained shortly and it occurred to me that while I am drilling holes in the walls for a second suction point and light, I may as well add another 2 and make the solar heating separate from the rest of the circulation system. Does this sound sensible? I can simply core two more holes, plumb to a separate pump attached to the solar controller and it can do its thing completely free of the rest of the system.
I've looked at how I would valve an integrated system and it was getting more and more complicated and expensive, then thought of this.
Any advice? Which way would you go?

 

[Bama Rambler]

I like the idea of separate systems, and given the fact that you're already redoing the plumbing it's such a small additional expense to add a suction and return port that it would be well worth it to go ahead and add them. Since you're not adding a skimmer, I'd add two suction ports 3' apart and plumb then parallel like main drains as a safety precaution. You can plumb them outside the wall to make it easier.

 

[jblizzle]

So are you talking about having a separate pump just for the solar? If so, Seems to me that this would be the more expensive path forward.

 

[ping]

I don't see any benefit of adding a separate solar system as it would require another pump and controls. If you don't mind adding another pump and electrical costs associated with it, then you might get some benefit from buying everything to match for the best performance you can get out of the system. I don't know if you would ever see the payback though.

 

[Kwikee]

Given where the solar panels will go, I would need a decent booster pump anyway and the plumbing run would definitely be less and simpler. I would need the controller for the solar anyway, but I do away with any electric valves and the higher risk of problems associated. Maybe a bit more expensive now, but should be trouble free later.

 

[jblizzle]

Why do you think you "need" a booster pump? We have members running panels on 2 story houses with < 1HP pump with no issues.

I suppose there are advantages/disadvantages with either method.

 

[Kwikee]

From the pump to the solar panels would be close to 80' laterally, and about 18' vertically. I have a Hayward Super 2 1.5HP pump, but I think that's pushing it. By relocating a pump to the other end of the pool, closer to the roof (opposite end to the circulation system), I would have maybe 25' laterally and still 18' vertically. A 0.75-1HP pump should do that, with a simple on/off solar controller with temp sensors and timer, shouldn't it?

Otherwise as I understand it, the system would need to be tuned so that for a set run time, it's long enough to heat the pool, filter the water and produce enough Cl from the SWG. There would be no need for a controller, I guess, since it would have nothing to control.

I like the idea that it can run as it needs, for as long or as little as required. I want to be able to run the filter/SWG during the night as well for both off-peak power rates and so the Cl production is maximised with no sun. To avoid heat loss through he solar system at night, I was going to have solenoid valves operated by the controller, so it would shut itself off when it was warm enough, or when the panels were too cold.

Silly or sensible? Don't get me wrong, here, I am shooting in the dark with as much info as I can glean from the good ol' internet! If I've got it all wrong, please say so!

 

[jblizzle]

I have a good 75 feet up to a 12 foot roof with a smaller Superflo 1HP ... your Super II 1.5HP would have no issues with what you described.

Sure you have control. The filtering requires hardly any time, so you just would have to run long enough to have the SWG produce enough. Then you have an actuator on the solar loop to only turn the flow to the panels if there is heat needed and available.

My 1HP is a 2-speed. I have my controller set to run from 9-10 on high speed and 10-6 on low speed (and a short period at night). The SWG runs for all of that at 35% output. Then when solar is available, the pump automatically kicks up to high speed (if it on low) and the valve turns the solar on. At night, the temp sensors know the panels are cold so the valve is not turned. BTW, some solar controller are smart enough to even run the solar at night for cooling if the water to too warm ... my Hayward is not smart enough for that.

Since you only have the single speed, you would either need to have the pump running during the sunny part of the day and the valve turn the solar on when needed. OR I think there are some controllers that can turn the pump ON if the solar is needed (not 100% sure on this).

Anyway, cheapest route forward is to just use the pump you have. But, your alternative will work as well, just at a higher investment and running cost. There is no way to avoid the peak electric cost rates AND get solar heating.

 

[mas985]

There should be no issue at all running that solar system with a 1.5 HP Superpump. I run my solar on a 25' high roof with a 1/2 HP pump. You don't need much pump for solar especially since yours is only 18' vertical. The length of pipe doesn't add as much head loss as you think and if the pipe is at least 2" (50 mm), you should be fine.

Also, I would never ever run unfiltered water through a solar panel. You are just asking for trouble.

 

[Kwikee]

OK. So if I integrate the system, I will have two branches off the return line with a bypass in between, and I'm assuming you have an electronic 3 way valve that diverts from the bypass to the solar panels? Can you give me some suggestions of systems to look at? I had considered having two solenoid valves, one open on the bypass, one closed on the line to the solar panels. When the controller activates the panels, both valves would operate at close to the same time: the panel line opens and then the bypass closes. These valves are only $70 or $80 each, but require current to keep them activated (fairly low, a hundred mA or so). Do the usual solar controllers do this, or activate with current then switch off?

 

[jblizzle]

Have you looked at how these are usually plumbed? Check out there info and pictures at hot2sun.com ... although some are more complicated than required.

Typically all you need is a check valve after the filter, then a 3-way actuated valve to divert to the solar, then a check valve on the solar return before it tees back into the return line, then you would go into the SWG and back to the pool.

 

[mas985]

Here is a typical installation and similar to mine:

 

[Kwikee]

Excellent information! FWIW the site is http://www.h2otsun.com, the information is clear and easily understood, just what I was looking for! Looks like this setup is what I need:
[attachment=0:3fo9x80j]Solar diagram.gif[/attachment:3fo9x80j]
This will allow control of flow to the panels, while being able to control the level of flow/pressure via the bypass valve.

Now I just need to find a solar controller with the valve switching output and a reasonably priced valve! Not as easy as you would think in Australia.

Thanks for all the help!

 

[jblizzle]

Even that one is more complicated than it needs to be. No need for that many valves, but it would work fine. Although you need a check valve on the solar return still.

 

[Kwikee]

Looks like I can't stick to a decision- I'm now going back to the first idea to run a separate pump and circuit for the solar! The 3 way Jandy valve and controller is about $250 here, which will buy me a 0.75hp pump, and the solar controller was always going to be an expense anyway. The plumbing is much easier to run and I will have total control over the run time, etc. with no extra pressure load on the filtration circuit. All up the whole solar system will be around $2600, so not too bad. Just have to get it finalised and ordered and some holes cored and I'm away!

 

[jblizzle]

But the pump will cost you extra electricity every time you run it.

So instead of buying a $50 valve and $75 actuator, you are going to buy another pump ... and need the temp sensors and controller either way?

 

[peterdaly]

The 3/4HP pump I got from my pool builder was a 1000 watt pump. (I promptly did some math, said no, and ordered my variable speed pump from Amazon.)

If you have 6 hours of solar time per day, that's 6kw of power per day, in addition to your normal pump. 180kw per month. Do the math. I really have no idea about AU power costs, but you may be considering stepping over a dollar to pick up a nickel once power costs are taken into account.

Where I live, that'd be $32US per month for the life of the system...$160/year in power costs alone, taking the "open pool season" into account. $800US extra power costs over the next 5 years.

 

[SuzyAbbott]

We have four Eco solar panels that we use with. Cheap intex filter. I'm very happy with the results and having it separate from the main filter is great. Only run it when you need it and also run at night to cool down the water. Pick up a pump on eBay or during the winter. It's nice to not worry about affecting the main filter with the solar heaters and makes set up and winter break down very easy!

 

[Kwikee]

Running a separate pump is only marginally more expensive than a solar booster pump which are very common place in filter circuits anyway.
I've ordered a system that's about 115% of the pool surface area, and will set it up so I can potentially "butterfly" a second set of coils of the same area at a later stage if need be. This would allow faster heating and a longer swim season, so the pump would run less again, anyway.
@peterdaly: power prices are similar here, and $32/month seems reasonable to me. I'll see if I feel the same in 12 months time!