Has anyone had any experience with the new Delta T circulators? I know Taco makes them, I'm sure others too.
Chris S said:I had this discussion today in th esupply house. The supplier is trying to sell me teh Grundfoss Alpha ( ecm), I am using Wilo stratos- also ecm. He claimed that he Alpha can be plugged into the wall and will run around 8 watts at idle if you will, and ramp up as zone valves open without any input or actual connection to the boiler.
I questioned running 8 watts continuous vs letting the boiler control turn the pump on & off. He answered that if a trnsformer could be eliminated the electrical usage would be equal or less with the alpha. I'll field verify this to be sure.
I do know that the Wilo circs quite often run at less than 25 watts when they're pumping, so electrical savings is potentially big. A star 16 is 88w, a Taco007 is a little more than that.
pybyr said:Chris S said:I had this discussion today in th esupply house. The supplier is trying to sell me teh Grundfoss Alpha ( ecm), I am using Wilo stratos- also ecm. He claimed that he Alpha can be plugged into the wall and will run around 8 watts at idle if you will, and ramp up as zone valves open without any input or actual connection to the boiler.
I questioned running 8 watts continuous vs letting the boiler control turn the pump on & off. He answered that if a trnsformer could be eliminated the electrical usage would be equal or less with the alpha. I'll field verify this to be sure.
I do know that the Wilo circs quite often run at less than 25 watts when they're pumping, so electrical savings is potentially big. A star 16 is 88w, a Taco007 is a little more than that.
FWIW, your supplier's claim made me curious, so I just went down cellar and connected an extra Honeywell 24 V 20VA transformer to an old appliance cord, and with an AC ammeter on it- which read 0.0 when the transformer was energized but with no load placed on the 24VAC side. I'm sure that there are some losses leading to some minor draw on the AC input, but from what I saw, it seems unlikely that it's 8 watts worth. Seems to me that smart/ ECM circs are worth a strong look, but not to the point that one leaves them running 24/7/365.
Chris S said:Gooserider,
you obviously have a EE backround, while mine is civil, maybe should've been ME. My thought though is that relays have transformers too, or are they not energized until the relay is activated?
Chris S said:Getting technical here nofossil, but what happens to that 007 under load? When you say becnh test, I'm assuming it's on the bench, not in the system. I'll be back, have to get my meter out.
nofossil said:Relays have coils that draw power when the relay is activated - typically less that a watt.
My bench tests on a Taco 007 showed 78 watts at full speed and 0' head (or as close as I can get on my test stand). Interestingly, when I connected it to my NFCS variable speed controller, the power dropped to 65 watts at full speed, with the same flow rate. Maybe it's a measurement artifact, but interesting nonetheless.
At 50% power, it drew 38 watts and delivered about 1/3 of its rated flow.
Gooserider said:pybyr said:Chris S said:I had this discussion today in th esupply house. The supplier is trying to sell me teh Grundfoss Alpha ( ecm), I am using Wilo stratos- also ecm. He claimed that he Alpha can be plugged into the wall and will run around 8 watts at idle if you will, and ramp up as zone valves open without any input or actual connection to the boiler.
I questioned running 8 watts continuous vs letting the boiler control turn the pump on & off. He answered that if a trnsformer could be eliminated the electrical usage would be equal or less with the alpha. I'll field verify this to be sure.
I do know that the Wilo circs quite often run at less than 25 watts when they're pumping, so electrical savings is potentially big. A star 16 is 88w, a Taco007 is a little more than that.
FWIW, your supplier's claim made me curious, so I just went down cellar and connected an extra Honeywell 24 V 20VA transformer to an old appliance cord, and with an AC ammeter on it- which read 0.0 when the transformer was energized but with no load placed on the 24VAC side. I'm sure that there are some losses leading to some minor draw on the AC input, but from what I saw, it seems unlikely that it's 8 watts worth. Seems to me that smart/ ECM circs are worth a strong look, but not to the point that one leaves them running 24/7/365.
I believe that if you put a load on the transformer, you will find that you have some significant energy losses in the transformer itself... Also there are some losses even just with a bare coil - notice that the transformer will get somewhat warm as it sits there, (and again, more so if it is under load) - that heat is due to power being "wasted" as it goes through the transformer.
This is why the green folks urge you to pull the plug on "wall-wart" transformers used for charging cameras, cell-phones, etc. when the thing they are nominally powering is off or not being charged....
It gets very tricky when trying to measure the power draw of either a high inductance load like a transformer, or a high capacitance load as you get a phase shift between the current and voltage that will confuse most standard instruments that are designed on the assumption that I and E are in phase...
I would tend to guess that your transformer is probably radiating around 8-10 watts worth of heat due to internal losses, so the supplier claim doesn't sound that far off... Of course, unless there is some reason not to do so, I would be inclined to run the pump through a relay of some sort so that I could turn it to ZERO when it wasn't being used, but it would sound like doing longer runs at a lower flow rate might be a good money saver during the times when you can do so...
Gooserider
pybyr said:(SNIP)
Agreed on all of the basic principles you mention above- losses in the iron core, windings, reactive power, etc., some of which are indeed present even when there's no load on the transformer output-- and the cumulative effects of "phantom load" from transformers and other power supplies that are hooked up full time even if their output is not in use -- but I'm still of the opinion, until I see some hard data otherwise, that you'd have to have a larger than usual, and less efficient than normal, 24 volt transformer to be getting 8-10 watts of AC draw under no-load conditions.
Another point, that I didn't articulate before, is that there's usually a 24 volt transformer somewhere in many/ most residential HVAC installations simply to feed the thermostat(s) in the conditioned space (and relays in whatever devices the thermostats turn on to activate heating or cooling) and that transformer would still need to be there even if you did the "plug the circulator into the wall" idea that the salesperson apparently mentioned. Once you have the transformer there, with its 24 v output available, why not also use it with relays to turn off circulators when they have no reason to be running?
Gooserider said:I think you are underestimating the power lost in that transformer - 8-10 watts is NOT a lot of power on a large scale - if you work it backwards, at 110VAC, 8-10 watts = 70-90mA which isn't a lot of current to be dropping... (I=P/E)
On the 24v transformer, you are right that it is hard to avoid having one, but the question is how big does it need to be? The fewer things you have hanging off of it, the smaller the transformer you can use... However I agree that it also makes sense to turn off circs that don't need to be running - I'd probably want to use a latching relay just on the grounds that I wouldn't want to be spending power to hold the relay in either state... The only question is if there is some reason why those circs shouldn't be turned off, or if one would spend more money on the hardware to turn them on and off, as opposed to the juice used by leaving them on....
Gooserider
pybyr said:If you're going to do a system that includes zone valves- which I expect would probably be the case if someone is using a variable-speed circ (the ability to modulate the pump does not seem to be likely to be useful if you're doing a pump-controlled primary-secondary approach rather than a valve-controlled approach) then I expect that the electrical demand of a relay or relays to shut circs off when not needed is going to be really small & inconsequential compared to the electric demand of multiple zone valves.
Gooserider said:What I'm kind of surprised is that nobody seems to have a zone valve design that only draws power when changing state... i.e. motor to open, then turns off with the valve staying open until it gets a signal to close, at which points it motors to close, and turns off until it gets a signal to open, etc. It doesn't seem to me that it would be any harder / more expensive to build than the current style which seems to require constant power to maintain it's active state, and does a spring loaded reversal if it looses power...
Gooserider
nofossil said:Gooserider said:What I'm kind of surprised is that nobody seems to have a zone valve design that only draws power when changing state... i.e. motor to open, then turns off with the valve staying open until it gets a signal to close, at which points it motors to close, and turns off until it gets a signal to open, etc. It doesn't seem to me that it would be any harder / more expensive to build than the current style which seems to require constant power to maintain it's active state, and does a spring loaded reversal if it looses power...
Gooserider
The Taco EBV does exactly what you suggest. The problem with zone valves is that the signal to close is the removal of power. With no power, how do you close the valve? Hence the spring. The Taco EBV stores enough power to close the valve after power is removed. It consumes essentially NO power, open or closed. I love them.
pybyr said:Goose-- since you seem interested in perhaps blazing new trails in both topology and technology - here's an idea I had a while back, but that I don't have the experience/ depth to run with and try out -- what if one ran valves with 'stepper motors' (with the valve shaft either direct-driven from the stepper motor or via cogged belt and pulleys); also include some sort of "position verification" (maybe an end switch so that the valve can be run to one full position, then signal to control hardware and software that it's reached that setting, and then stepped back there in repeatable increments to the desired setting. In what I'm envisioning would be that each valve would have an onboard 'driver' circuit for these purposes of running the stepper motor, and all of the valves could then be tied together & back to a main controller by some form of shared serial cable. Due to stepper motors' precise control-ability and repeatability, the valves would not be limited to "open or closed" but could be modulated in between for partial flow settings where that's useful (such as radiant floor feed or boiler return protection). Each stepper motor on each separate valve would have a way of distinctly identifying itself to a main system controller - much as one-wire temp sensors can be strung together and share one connection back to a controller. In fact, then, perhaps use the same serial "backbone cable" for connecting various sensors for thermostats and sensors for heat sources and heated zones. Use the same serial cable (or a conductor in the same bundle) to make DC available for each stepper motor's controller. Maybe also develop and include some remote AC relay-like devices that could also be controlled by the same serial bus but be located out at circulators to turn them on and off (or, better still, vary their speed as needed). Anyway, food for thought, I hope.
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