Hydronic pumps, PSC vs ECM motors

[Daox]

I posted this in my solar pump selection thread, but also wanted to make its own thread since it extends beyond solar pumps and into hydronics heating in general as well as heat pump setups.

I've been brushing up on my hydronics lately because of the solar project and also installing hydronic floor heating in my office. I was reading John Siegenthaller's 'Modern Hydroinc Heating' and happened to be reading the chapter on pump selection. He mentioned that it is quite common to find that, going from a PSC (permanent split capacitor) motored pump to a ECM (electronically commutated motor) pump will double your efficiency! This isn't even taking into account the benefit of the variable speed advantage that the ECM motors provide.

My Grundfos UP15-100f uses a PSC type motor. With a current draw of 135W, I'd be very happy to see something in the 65-70W draw as a replacement. So, I shall be looking into what options are out there for ECM motor pumps, not only for the solar setup, but also my hydronic floor heating setup.

In the book, he continues on to show that a 85W pump operated for 3500 hours per year with an electricity cost of $.14 per kWh (a bit high) will uses almost $1400 in electricity over a 20 year life. So, reducing that number in half gives quite a bit of room for cost savings in a pump even if the new pump costs substancially more.

Does anyone know what is available for ECM pumps?

[Daox]

Some searching shows the Grundfos Alpha (and Alpha2 in Europe) circulators use an ECM motor and some fancy logic controller to optimize hydronic heating needs.

Alpha (US) pump:



Alpha (US) pump curve:





Here is a good article about an installation:

Circulator Pumps With ECM Technology Next Trend In Intelligent Hydronics Design*| Grundfos

“For example, upon installation the 1/12 HP circulator was running at 9 gallons per minute (gpm), drawing 27 watts,” explains Wolking, who now is a strong proponent of ECM circulator technology. “Two days later, the system was operating at 2 GPM and drawing 9 watts – a far cry from the constant 82 watts the original circulator required 24/7.”

Out of the box, an ECM circulator will yield the same flow rate while consuming 50 percent less energy over a traditional induction-type circulator. Some ECM circulators, such as the ALPHA, use an integrated logic board to “learn” the system’s usage patterns in order to boost the standard 50 percent energy savings into the 70-80 percent range. As the valves in the different sections open or close with rising or falling demand, the ALPHA automatically ramps up or down to meet the load.

Here is a guy in Greece who upgraded his pumps to Alpha2 (European version which seems updated from the original Alpha) pumps:

Updating my heating system using grundfos alpha 2 pumps

After a happy installation this summer from a Grundfos alpha2 pump for my solar hot water system. and dropping my energy use from 40W to a nice 5 to 7 W ( starting up is 22W for a 30 sec. and then it slowly comes down to 5 - 7 W after a 25 sec.).

The energy use is really low and it is nearly whit out noise.
So i ordered four more pumps to replace the pumps used by my underfloor heating system a setup running 3 months a year 24h a day using old fashion 60 W pumps.

...

end result the old technology pump 60 W running around 52 to 55 W. running together 160 W. the new setup running 48 W.

Here is an Alpha2:




Both cases show some pretty big energy savings from going with the ECM pumps.

[Daox]

Here is an article about the Grundfos Magna, another ECM pump, but sized for larger applications than the Alpha line.

Grundfos (and Wilo) "Smart" Circulator Pumps for Hydronic Heating | GreenSpec

Magna pump:



Magna pump curve:




The article also mentions another pump manufacturer, Wilo (apparently pronounced "veelo") that has a line of ECM pumps. They have the ECO RFC line, which seems like a smaller pump line. They also have the Stratos line which seems a little bigger.



ECO RFC



ECO RFC pump curve:




Stratos



Stratos pump curve:

[Daox]

And of course lets not forget Taco. I haven't read any articles yet on people using them, but I checked out their site and they have their Viridian pump line that features an ECM motor. It seems like this line of pump is on the larger side though.

[Mikesolar]

I use them on heating systems where there is no internal thermostat (my house). I only run the boiler on an outdoor control, the boiler keeps its pump running and the loops pump is an ECM pump.

[ecomodded]

The Alpha2 is the pump ! With the temperature sensitive flow rate and self adjusting speed it would insure the system will work according to the conditions.

Might be able to get one shipped over, a pricey but useful pump.
Grundfos Alpha2 15-60 130 Heating Pump

[Mikesolar]

Originally Posted by ecomodded

The Alpha2 is the pump ! With the temperature sensitive flow rate and self adjusting speed it would insure the system will work according to the conditions.

Might be able to get one shipped over, a pricey but useful pump.
Grundfos Alpha2 15-60 130 Heating Pump

Nice but 230V 50HZ

[AC_Hacker]

Originally Posted by Daox

Some searching shows the Grundfos Alpha (and Alpha2 in Europe) circulators use an ECM motor and some fancy logic controller to optimize hydronic heating needs.

I was checking out the alpha too, about a year ago. I found that very high efficiency radiators are being used in some installations in Europe, and they each have their own thermostat which will modulate water flow according to heat requirements. In that case, the Alpha is ideal for matching it's output curve to the changing, overall water demand.

At the time, I didn't see any Alphas that modified their flow according to water temperature.

I did see the advantage of higher power at startup and reduced power for continued running.

I also found that there seem to be a European preference for continuous water circulation, with modulating water temperature to fit conditions. In North America, there seems to be a preference for cycling on and off, the water flow.

I never came across anything that spelled out the merits of each method.

-AC

[ecomodded]

Originally Posted by Mikesolar

Nice but 230V 50HZ

It would save on electricity costs as well as hardware, well it would be the hardware expense.

It's easily adaptable with a common travelers voltage converter.

[Mikesolar]

Actually, that is not univerally true. I have a grundfos pump from a Euromarket solar system and the windings are different for the 50hz vs 60hz and Viessmann was going to use the 50hz pump as is, but did testing and it got too hot.

it may be different with the ECM pump because it is a DC motor to start with therefore the real problem is that their 230VAC is 1 hot wire and 1 neutral where ours is 2 hot wires and a neutral.

I don't think a travelers adapter will work on this unless the control was designed for multiple voltage inputs.