Variable speed pump for hybrid solar panels

[tjcooper]

I have 16k gallon pool in Northern California. I want to replace my current 1HP single speed with variable speed pump. My solar panels have a 50 foot run about 18 feet off the ground with a head pressure like 45 feet. I have been doing all the research on Pentair and Hayward. All the companies claim that a 3HP motor system will waste no extra energy powering a 1 hp system if the speed is set correctly.
1) Is there any truth to this?

2) I have an old Compool solar controller (LX-28-1) that runs solar with Compool values. I have looked at Pentair Intellicom2 and Hayward direct 12 volt relay control. It seems like nobody has a variable speed solar panel cross-over to your old system. Looks like everyone wants to sell you a new controller for $1k to do the same job of the equipment I already have. Can I just use the 3 relay connectors to the Hayward Ecostar to set my PRIME, slow-flow, booster-pump pool sweep, and no solar speeds? Anyone have experience with this?

3) I find on the Web that Pentair 3HP VS system sells for same discount price as the Hayward Ecostar (at 2.9 HP). There is a lot of "web history" saying the Pentair unit is far mor reliable than Hayward. Is this really true? Is this the CURRENT information that pool owners see? I am trying to make choice between the two and cannot find clear evidence that one is more reliable than the other. The Hayward is more efficient per Watt according to PG&E tables. Anyone feel that there is a clear reason to choose Pentair over Hayward?

4) I do almost all my own installations. Is there a clear reason to spend $400 extra to have a pool specialist install my unit to get 3 year warrantee versus doing it myself and getting a 6 month warrantee? Would it be better to hold onto that $400 to replace motor or controller down the road? Opinions?
Much thanks,
tjcooper

 

[JasonLion]

Re: Variable speed pump for hybrid solor panels

Welcome to TFP!

1) Yes, turning down the speed is just like using a smaller HP motor to begin with. However, you won't save much electricity while the solar is on (perhaps 15%). The big savings only come when the solar is off.

2) If you get an IntelliFlo you will need an IntelliComm II adapter to control it from the Compool. The EcoStar has connections included. Either way the programming is a little on the complex side, but hardly insurmountable.

3) The reliability is much more similar these days. Neither is as reliable as a conventional pump, but both are reasonable.

4) The drive failures occasionally repeat over and over, though that is quite unusual these days. We hear all the horror stories and not the "it just works" stories, so it is difficult to balance out the odds correctly to make a recommendation.

 

[tjcooper]

Re: Replacing pool pump - any recommendations?

Mark,
could you give a poor man's definition of the Curve A, B,C types? Are these basically for different head pressures? Or is
there something else that sets them apart?
tjcooper

 

[tjcooper]

Re: Replacing pool pump - any recommendations?

Mark,
forget about the Curve A, B, C definitions asked above. After I read your comments about them, then two responses later was the other thread that defined their use.

QUESTION: does anyone take apart the Variable SPeed Motors and know whether they use Hall effect sensors to control the speed, or do they use the impulse inverse voltage surges on the sets of motor poles to determine the location of the motor at any moment in time? I do a great deal of RC helicopter and propeller aircraft which use Outrunner Motors which are also variable speed motors. I have controllers and software to run my big 1 -2 HP motors that are very inexpensive (like $40 to control a 2 HP 13 pole motor). I was wondering if I could control the Pentair VS with two of my 2 HP controllers in parallel. Very good speed control with these units....and I can do it all by remote control transmitter.

tjcooper

COMMENT: I posted a new thread because when I originally saw this one it seemed like it was only comparing single and double speed motors. The new thread I posted should be moved here. It asks the same question: Which is better....Pentair or Hayward VS pump for doing solar panel systems?

Posting in someone else's topic is hijacking. Your new questions have been moved back into your existing topic, where they should have been posted originally. JasonLion

 

[mas985]

Re: Variable speed pump for hybrid solor panels

VS pump motors are driven by VFD or variable frequency drive. AC is converted to DC and then a microcontroller turns on and off the DC with a IGBT to simulate an AC waveform with PWM. A speed sensor is not required because the microcontroller directly controls the speed with the PWM. You can purchase a VFD independently from the motor and run a single phase motor with it but I would not recommend it. First the VFD price is close to the price of a small VS pump and when you add matched cables and a inverter duty motor (both are required), the cost will end up more than a VS pump.

 

[tjcooper]

Re: Variable speed pump for hybrid solor panels

Jason,
sorry for mis-posting. I am a Newbie to this group and did not know the protocol requiring new posts for all questions.

My poor little 1HP single speed motor really has to max out to prime my solar system. Once it is primed I can cut almost 50% of this wattage if I have the right kind of controller. I built the NASA induction motor phase shifter years ago to allow variable energy to the induction motors and that is how I got the 50% power rating during normal solar operation, ie, slow pumping. That controller wore out and I can't find the right components to build it again. That is why I think the variable speed should be better because it uses permanent magnets for field strength. Much better than induction motors.

QUESTION: both Pentair and Hayward reps say that a variable speed 3HP motor will not use up any extra energy when it is requested to output like 1HP of pumping action. I know there will be slight mass of impeller differences, etc, but is this basically a true statement? Should I expect about the same efficiency from a 1HP Intelliflo i1 as from a 3HP Intelliflo when both we asked to yield about 1HP of pumping activity?

I understand that Pentair is just about to release a 2HP variable speed pump. If the above question's answer is false, should I wait to get a 2HP variable speed to get more efficiency?


QUESTION2: I asked about what is the internal configuration of the permanent magnet variable speed motors in pool pumps but did not get an answer. In the attachment I have placed two images of Outrunner motors that are used in RC airplanes, helicopters, etc. This is exactly the same permanent magnet motors used in hybrid cars these days. They produce a lot of torque at relative slow rotational speed. One image shows the magnets and windings when there is no Hall-effect sensor in the motor, and the second image shows the placement of Hall probes when they are the primary control mechanism for accurate speed.

Does anyone know if the permanent magnet motors for variable speed used by Pentair and/or Hayward use the Outrunner design? Do they use Hall-sensors if they are Outrunners? This would help me decide if I should buy a used variable speed motor system without a controller and see if it might be configured with my controllers to run a pool pump. This is just academic curiosity. Much thanks.
tjcooper

 

[JasonLion]

Re: Variable speed pump for hybrid solor panels

Both of your questions are answered above. I answered the first one, and mas985 answered the second one. If those are not the answers to your questions, you are going to need to restate the questions in some way that makes clear what it is you are actually asking about.

By the by, the design challenges for an RC airplane motor and a pool water pump motor are totally unrelated. There is no reason to expect the resulting designs to have much of anything in common (beyond both being electric motors).

 

[mas985]

Re: Variable speed pump for hybrid solor panels

My poor little 1HP single speed motor really has to max out to prime my solar system.

I use a 1/2 HP pump and have no trouble priming my solar on a two story house so it could be the issue is with your plumbing and not the pump.

QUESTION: both Pentair and Hayward reps say that a variable speed 3HP motor will not use up any extra energy when it is requested to output like 1HP of pumping action. I know there will be slight mass of impeller differences, etc, but is this basically a true statement? Should I expect about the same efficiency from a 1HP Intelliflo i1 as from a 3HP Intelliflo when both we asked to yield about 1HP of pumping activity?

HP and flow rate have only a very loose relationship but in most cases, a VS is more efficient because the motors are designed with large gauge wire and efficiency does not drop much with RPM because the drive simply changes the frequency of the PWM waveform and this does not reduce efficiency. However, the drive has overhead and that does affect efficiency. On the other hand low HP pumps use motors that use smaller wire because the amp draw is less with a smaller motor.

As for the i1, at full speed, it is a little less efficient because of the impeller size. Larger impellers tend to be more efficient at lower speeds than smaller impellers at the same flow rate. This has to do with the Specific Speed (i.e. shape and RPM) of the impeller.

I understand that Pentair is just about to release a 2HP variable speed pump. If the above question's answer is false, should I wait to get a 2HP variable speed to get more efficiency?

Pentair has several lower HP VS pumps including the SuperFlo VS, Intelliflo i1 & i2 VS. They are not more efficient but the SuperFlo is certainly less expensive.

As for which design, I do not believe these motors use Hall Effect sensors since there is no need for them with a VFD as I mentioned in the last post.

 

[tjcooper]

Re: Variable speed pump for hybrid solor panels

Jason, Mas985,

thanks for your answers. I will buy my VS this week so I just want to be sure I understood Jason's answer correctly: A 3HP VS pump will have very close to the same wattage draw as a 1HP VS pump when both units are pumping the same flow rate (say 35 GPM). If this is the case then I will buy the 3HP unit to be sure I have the reserve capacity just in case I increase my number of panels (and resulting length of plumbing). The Web cost of the 3HP VS is actually less at certain suppliers than the 1HP Intelliflo i1.

Perhaps I got some bad information from the customer service representative at Pentair when I talked to last we. He said that the 3HP VS uses the same kind of electrical motors as the Hybrid Toyota car I have, and it is controlled by controllers that are of the LRK design that is used in electric aircraft these days. That is why I was asking about Hall-effect sensors, etc. It takes very special windings of the poles in an LRK motor to get the unit to spin at controlled speeds and have high efficiency (> 89% efficient). I was just wondering if anyone had taken a VS motor apart and had a photograph of what the windings and pole pieces looked like. That would tell me everything about its design.

QUESTION: how does one measure if one's solar plumbing is bad? I have a flow rate meter in the 2" lines and can measure the speed of the motor. Would that be enough to know if I had a "marginal" setup for the solar plumbing?

tjcooper

 

[mas985]

Re: Variable speed pump for hybrid solor panels

What is the filter pressure with and without solar engaged?

What is the make/model number of your current pump?

 

[tjcooper]

Re: Variable speed pump for hybrid solor panels

Was not sure from memory what all those numbers were. Today I back-flushed pool and ran all the systems.

Pool motor is Sta-rite 1 HP high efficiency pump/motor I have pictures of faceplate if that is needed (220 VAC) model P4E6E-187L at 8amps

Trition II has 35 psi when running just pump
When solar starts pressure drops to 34 psi for 2 minutes then the solar full load oscilates in 35 to 37 psi range
when I turn on polaris pool sweep booster, the pressure oscilates from 34 to 36 psi.

My flow gauge only operates with solar connection. It showed steady 75 GPM when in steady state.
hope that is enough information.

Again, does anyone have a picture of the Intelliflo motors with the cover removed where you can see the windings?
tjcooper

 

[mas985]

Re: Variable speed pump for hybrid solor panels

Trition II has 35 psi when running just pump

If correct, that is a big problem. But if the flow rate is showing 75 GPM then the pressure gauge is wrong. That pump cannot produce 75 GPM at that pressure.

Does the pressure gauge go to zero when you turn the pump off?

 

[tjcooper]

Re: Variable speed pump for hybrid solor panels

When I first put in Triton II I would routinely get 25-28 psi, but with a new pump and new return line from the skimmer, it has gone up to 32-35psi. The measurement I gave you was after a 5 minute backwash which showed a fair amount of sand coming out.

The flow meter does go to zero when I turn off the solar. But I don't trust the flow meter because it often times does not go up away from zero unless I tap on the gauge to free the slider to rise up to its full amount. I have only used it with an IR emitter-receiver to test that I have real flow coming back from the panels (it was kind of my emergency shutdown after 5 minutes of operation to tell me that the solar panels had not popped a joint).

I really don't think there is 75 GPM coming down from panels because there is a fair amount of air in the return line. I have a air bleeder value at the top of the solar run, but I don't think it works properly (replaced it last summer with a new Watts unit). Is it possible I could have installed the flow meter improperly in the 2" return solar line?
tjcooper

 

[mas985]

Re: Variable speed pump for hybrid solor panels

What is the "new pump"?

Also, sand should not come out of the filter. It could mean a broken lateral.

Check valves that fail can also cause high pressure.

If the filter pressure is correct, then you have a serious issue with your plumbing. I would suggest troubleshooting the plumbing first before thinking about any other changes. Can you post a picture of your pad equipment and plumbing?

 

[tjcooper]

Re: Variable speed pump for hybrid solor panels

mas985,
my "new pump" is the Sta-rite that I quoted....used to have 1HP single speed Hayward. I just went out and checked the flow meter gauge to be sure I was not reading the liters/minute part of gauge. Indeed, I was reading the GPM part of scale. I will try to take a short video of it powering up tomorrow so you can see the startup sequence in low res. I will prime and run solar sequence in video.

When my pool contractor installed Triton II and came back two months later to show me how it backflush and rinse the Tritton, it has always put out a small amount of sand when it does both actions. This has always been true since day one. I even showed a video of the backwash to Leslies pool people when I was worried about sending out too much sand and they said the amount (like a < quart of sand in the 1st 3 minutes) was normal. I went 8 years with the first sand install before I opened Tritton II and removed all sand and re-filled it. It was supposed to have 10.5 inches of "freeboard" and when I measured before refill I was down to like 14 inches of "freeboard". I have had like 4 groups of pool repair people come out to work on problems like air-leak, install a new return line from pool, etc. They all run the system and no one has commented that water flow or filter system was not working properly. However, all of them said I should get a new pump (which I did) and that I should consider the new 2-speed pumps and later VS pumps.

Here is a crude shot of motor and filter section. I will get a much better picture tomorrow. My check values are removeable and I have inspected them last year and they were OK (leak a little but not much, rubber O-rings in reasonable shape).

 

[tjcooper]

Re: Variable speed pump for hybrid solor panels

here are updates of stills showing the entire pump station and solar control. I re-checked the flow meter and it definitely "bottoms out" at zero when no flow and when steady-state flow, it shows 72-75 GPM. I will take the video I made of the solar startup and put it on YouTube and give you a reference here when it is available....but it clearly shows the 75 GPM. I also show the sand-run-out area when I backflush the Tritton II and the amount of sand (total for 8 years).

tjcooper

some of the images I wanted to upload exceeded my limit. Will try to include them on YouTube

 

[mas985]

Re: Variable speed pump for hybrid solor panels

What about the pressure gauge. Does it go to zero too when the pump is off?

75' of head is 32.5 PSI and that pump will only produce 55 GPM at that head loss and that doesn't even include the suction side of the plumbing. So there is still a disconnect. Either the pressure gauge is wrong or the flow gauge is wrong or perhaps both.

But if you are getting air in the solar return, then the VRV is probably not closing because there is too little pressure at the VRV. If the filter pressure is that high, then there is something wrong with the plumbing between the pressure gauge and the solar VRV. The check valve right after the filter could be the problem. I would check them all again.

Also can you post a pic of the plumbing that is above the picture?

If you have had high pressure all along, it could just be the design of your plumbing but that is pretty severe.

 

[tjcooper]

Re: Variable speed pump for hybrid solor panels

Is there a simple way to get more storage allowance for my other images to upload?
Is the VRV the air drain valve at the top of the solar plumbing? How did you get 75' of head at 32.5 psi? Just curious. BTW, is the correct measurement of the flow meter to read the bottom of the aluminum float when it rises to maximum height?

And Yes, the Tritton II pressure gauge goes to zero when pump is off.

 

[mas985]

Re: Variable speed pump for hybrid solor panels

Is there a simple way to get more storage allowance for my other images to upload?

Yes, read this:
http://www.troublefreepool.com/thre...tures-to-a-post-(full-guide-with-screenshots)

Is the VRV the air drain valve at the top of the solar plumbing?

Yes

How did you get 75' of head at 32.5 psi?

The relationship of head to pressure is 2.31' of head per PSI. So 32.5 * 2.31 ~ 75'. But again, that is only the head loss from the filter gauge forward. It does not include suction side or from the pump to the pressure gauge. All add to the total head loss so the flow rate is likely to be less than 55 GPM.


Those types of pressure gauges require long straight pipe on both sides of the gauge so they read the correct flow rates. For 2" pipe, you need 20" of straight pipe before the meter and at least 8" after. Do you have that?

Also the pilot tube can get blocked and that will affect the readings.

You read at the top of the float.

Manual: http://blue-white.com/blue-white-products/f-300-pitot-tube-acrylic/

 

[jblizzle]

Re: Variable speed pump for hybrid solor panels

Welcome to TFP!!!

To post more/larger pictures, you either need to raise your storage allotment by Becoming a TFP Supporter or follow the How To Post Pictures tutorial.