Lorentz solar pumps

[Lou Erickson]

Hello, everyone.

I've got a pool, and all the mechanicals are in good working order. Yay!

The pump and booster pump are both from the mid-1990s. They run at 3,300 watts each. Given the time we run them and the highish electric costs here, that's about $275 a month, just for the pumps. It's more than half our electric bill.

Our pool guy, a highly regarded local pool repair company, and local pool store all suggest a Pentair variable speed pump. I don't have as solid a set of numbers for this, but the estimates given to me by the pool repair guy (he had the best numbers) would be significantly lower, probably around a third of what we pay now. That would be a significant improvement!

However, I bumped into the Lorentz solar pumps on the 'net. They look great - almost too good to be true, which is what worries me.

With our current electric rates, a Lorentz pump will be paid for in 18 months. That's way better than a lot of the numbers others quote. If I adjust the electric rate in my spreadsheet to the $0.20/kwh others use to estimate, I get a similar five-year break even.

My next task, I guess, is to call the local Lorentz distributor - which I found, finally - and talk to them about costs and see if it really applies.

Have any of you used the Lorentz pumps? Any gotchas?

What do I about the booster pump? (One thought; Get rid of it. If the Polaris is too slow, replace it with an electric robot.)

Is this a crazy thing to do?

Thoughts, suggestions, gotchas?

 

[Isaac-1]

This topic comes up from time to time, and a few people here have bought them, most seem happy, but we just don't have enough long term feedback to know how they hold up over time.

 

[duraleigh]

By far, the best way to conserve energy is pump run time. Sounds like you might be running them way too much. Many can get by with 4-6 hours daily.....what is yours?

 

[JohnT]

3300W? Is that measured or from the nameplate?

3300W is almost 4.5HP, and I can't imagine any residential pool using a pump that large, especially an 18,000 gallon pool.

 

[tlevy]

I have and use a Lorentz pump - we have the Ps600 pump connected through a Cs 17.1 controller, tied to 1,500 W of solar PV.


68,000litre, IG vinyl, LorentzPS 600 Solar Pump & 1/2 HP Tristar, Sandfilter, Aquarite T-15 SWG

 

[Lou Erickson]

By far, the best way to conserve energy is pump run time. Sounds like you might be running them way too much. Many can get by with 4-6 hours daily.....what is yours?

Our pump is set to run for six hours a day, with the booster running for two in the middle of that time. Any less and we have more algae problems than usual. The chemistry is a separate discussion which will wait until my test kit arrives.

3300W? Is that measured or from the nameplate?

3300W is almost 4.5HP, and I can't imagine any residential pool using a pump that large, especially an 18,000 gallon pool.

That's from the nameplate, and from checking the Kw/h used on the electric meter. 15A at 220v. It's a big, noisy motor. The pool isa full story below the pump, and the solar is a full story above the pump. Yay for houses on hills. The booster pump is not labelled as well, but as far as I can tell is the same size.

The main pump runs the filter and there's plenty of pressure at the outlets and drainage at the skimmer, but the Polaris crawler only barely moves. When the booster is running, the Polaris is quite sprightly and will climb the walls and reach almost the entire pool.

Considering the recovery time will be less than the warranty on the pump, I'm leaning towards the Lorentz. My inefficent motor and high power costs put me in the sweet spot for solar, along with having a roof in a good place.

I still need to call the local distributor during the day and talk to them.

 

[JohnT]

Your pumps are way oversized. Even with the lifts you have, you don't need those large pumps for such a small pool. Your problem is suction head. The lift to the panels is no problem. Make sure that the solar pump is able to lift water that high on its inlet.

Appropriately sized pumps might be a better option. Your flow with the solar will likely be substantially less than what you have now.

 

[tlevy]

There is another solar pv direct pump called a sunpump. I don't have any experience with these mind you.


68,000litre, IG vinyl, LorentzPS 600 Solar Pump & 1/2 HP Tristar, Sandfilter, Aquarite T-15 SWG

 

[Lou Erickson]

Your pumps are way oversized. Even with the lifts you have, you don't need those large pumps for such a small pool. Your problem is suction head. The lift to the panels is no problem. Make sure that the solar pump is able to lift water that high on its inlet.

Appropriately sized pumps might be a better option. Your flow with the solar will likely be substantially less than what you have now.

Considering what I know of the former owner, "way oversized" is probably correct. If it was possible to spend money on something they did, even when it was not a good idea. Nothing was installed properly or ever maintained, but it was all top dollar when it went in twenty five years ago.

I knew the head height could be a problem for the solar. It's one of the things on my list of questions to ask. The tradeoff of less flow but running more hours a day is one I'm not sure of. I was hoping to find someone locally who had one working.

The variable speed Pentair is the safe bet, and if there are issues with the solar, or even no one is sure if it will work, we'll go that way. I have time to research it as our old but expensive pumps are still working. I would like to get that monthly cost down. The Pentair will help a lot, but zero electrical cost would be wonderful.

If I can ever get work to be slow during the day, I'll call the local distributor and talk to them.

 

[tlevy]

My lorentz moves up to 60 gpm, and varies off that throughout the day. It also pumps from about 8 am through to about 6 pm.


68,000litre, IG vinyl, LorentzPS 600 Solar Pump & 1/2 HP Tristar, Sandfilter, Aquarite T-15 SWG

 

[Agent99]

Since you're local, you can come on by my place and I'll show you the Pentair VarSpd "bee's knees, cat's meow" pump I have running my pool. PM me. Check my equipment in my sig. I'm pumping water to the top of my house for the solar panels and I can run my pump around 2000 rpm with no problem overcoming that kind of head loss.

 

[mas985]

Our pump is set to run for six hours a day, with the booster running for two in the middle of that time. Any less and we have more algae problems than usual. The chemistry is a separate discussion which will wait until my test kit arrives.

That is a chemistry issue and not a run time issue.

 

[Lou Erickson]

That is a chemistry issue and not a run time issue.

So I believe, however that's not the advice I got from the Pool Guy. He says still water sits in the sun and the chlorine is lost during the day. This may be true. His solutions haven't changed our usage pattern any, and I'm spending time brushing and messing with it already, in addition to paying Pool Guy. If I have to do the work anyway, I want it to work!

Things are not great, but are stable right now so I'm going to leave them alone until my test kit arrives and I can take measured action. I'll be out of town from Friday until the next Sunday so it has to wait until after that. I'm reading and learning, and when I get back I'll start on the doing.

Right now, we run out of chlorine frequently, and the Pool Guy "shocks" the pool about weekly. It's usually mostly clear, but not sparkling. I've seen it sparkling once, and want that back. Taking control of it myself is how I get that, I'm sure. This trip is just inconveniently timed for that.

 

[mas985]

He says still water sits in the sun and the chlorine is lost during the day.

True but that is still a chemistry issue. With a proper CYA and FC levels, that is not an issue. Compensating incorrect levels with pump run time is never a good idea.

 

[Lou Erickson]

True but that is still a chemistry issue. With a proper CYA and FC levels, that is not an issue. Compensating incorrect levels with pump run time is never a good idea.

To his credit, the Pool Guy didn't suggest we run the pump more, he just suggested we change the time of day so that it runs when the sun is directly on the pool. That works out well for the solar heat, too, so that was not a bad suggestion.

I'll know more when my test kit arrives. Until then, I'm flying sort of blind, and am letting things stay as they are rather than flailing.

I did discover today that my Pool Guy is using test strips, which disappoints but does not surprise me. He left one by accident. It's different than the ones I would up with from the pool store.

Not making any changes till I get the test kit, then I'll ask specific questions and make informed changes.

 

[Agent99]

BTW, PG&E has a $100 rebate on the Pentair Variable Speed Pumps and other pumps. Check their website for rebates.

I just submitted for mine.

 

[Lou Erickson]

To follow up, I did find a local installer who has used the Lorentz pumps, and he says the people who have installed them have been happy with them, and that they do work as advertised in the sun we get locally. For anyone finding this in search engines later, the dealer list for Lorentz pumps on the west coast is at Western Hydro, and their web site has a list of local dealers. Once I found that I was able to find someone to talk to locally.

The Lorentz pumps are more expensive than I thought.

This changes the ROI numbers, and pushes break-even out further than I expected. I was expecting a break-even of around 18 months, and the higher cost moves it out to 27 months. That's compared to our current hugely inefficient pump.

If we run the numbers to compare to a standard mains-fed variable speed pump, the break-even for the solar gets pushed out to 61 months; a month over five years. In the lifetime of solar panels, that's usually considered acceptable but it's three years longer than I was expecting.

The break-even for the variable speed as compared to our current pump is only nine months; the savings are predicted to be quite large, and the cost of the variable speed is is significantly lower. (The savings will be even higher if it drops us down to the next billing tier, I didn't do the math at that detail.)

One of my co-workers suggested we go with the standard variable speed, then put an ordinary power generation solar system up and run the pump from that. We get solar and the less expensive pump. That's sounding like the solution we'll consider.

This is not to say I don't think the Lorentz pumps work, just that I can't justify the higher cost for us when the standard VS will save us so much and we can probably run it off solar later.

 

[tlevy]

You can't run a variable speed (AC) pump directly off solar panels - that is why the Lorentz pump is more expensive. The lorentz comes with a "controller" which is a device that tracks the sun and seeks the best voltage/amperage combo to get the most watts to run the Lorentz pump. Further more, the lorentz pump is a brushless motor DC pump, and has a voltage range of 48 - 72 V - truly a variable speed pump as its RPM changes depending in solar irradiance hitting the panels.

If you want to run your variable speed pump from solar panels, you will need an inverter to provide AC power, and a set of batteries to store the power from your solar panels to ensure a constant voltage for your AC pump, that likely will only operate b/w 200 and 240V.

This is why lotentz pumps are more expensive....


68,000litre, IG vinyl, LorentzPS 600 Solar Pump & 1/2 HP Tristar, Sandfilter, Aquarite T-15 SWG

 

[Lou Erickson]

You can't run a variable speed (AC) pump directly off solar panels - that is why the Lorentz pump is more expensive. The lorentz comes with a "controller" which is a device that tracks the sun and seeks the best voltage/amperage combo to get the most watts to run the Lorentz pump. Further more, the lorentz pump is a brushless motor DC pump, and has a voltage range of 48 - 72 V - truly a variable speed pump as its RPM changes depending in solar irradiance hitting the panels.

If you want to run your variable speed pump from solar panels, you will need an inverter to provide AC power, and a set of batteries to store the power from your solar panels to ensure a constant voltage for your AC pump, that likely will only operate b/w 200 and 240V.

This is why lotentz pumps are more expensive....


68,000litre, IG vinyl, LorentzPS 600 Solar Pump & 1/2 HP Tristar, Sandfilter, Aquarite T-15 SWG

Yep, that's completely true!

A whole-house solar system would have the inverter and (if needed) batteries. Generally they sell power back to the utility when you're generating, and then you run from the grid when you're not generating. As long as you have a net surplus of power, your power bill is zero or less. I wouldn't be running the regular VS pump straight off the solar; I'd be using solar to generate AC and then using that AC, and using line power if there wasn't enough solar available. Since I want to run my pump during the day (solar heating) I'll hopefully be generating enough AC to drive the pump without having to pull from the grid.

But, as a shortcut, it will appear as if the solar is driving the VS pump. It just won't be driving it directly.

Google's new service, Sunroof says I have plenty good rooftop for the more traditional whole-house solar.