It’s been mentioned in other threads that certain devices have a dirty/noisy power signature and prevent sense from accurately identifying other devices. Plasma TVs have been mentioned as well as GeoThermal pumps. Are there other types of devices that create these noisy signatures?
Yes indeed, and Sense engineering says that they can’t do anything meaningful with my home because the Franklin Electric constant pressure pump (its signature varies dynamically depending on how much water is being used) is so “noisy”. The pump is a synchronous motor and the controlled generates variable frequency power for the pump, in addition to variable power draw. So it’s a jittery line with lots of wobble riding on a variable magnitude base.
Visually it’s absolutely clear and identifiable, their chief architect picked it out immediately, but the algorithms aren’t designed for such behavior.
And, since it’s both my domestic water source and my 500’ deep geothermal well water source (which provides for heating and cooling, as well as domestic hot water), the well runs frequently enough to pretty much obscure my entire home.
Good info, thank you Andy. You’re the person I was referring to with the geothermal pump. I’d like to identify all categories of noisy power signatures if possible so people speaking out about their experiences is helpful. I’m curious if all variable pumps are considered noisy since they have dynamic signatures. Hopefully others speak up about their “noisy” devices so we can compile this information.
I want to be sure that the “geothermal” isn’t causing any confusion. This is a domestic well pump. Actually, this pump only incidentally provides water to my geothermal. Its primary function is domestic water.
That’s because we implemented a “standing column” (one deep well, instead of 2/3) geothermal, where the very same well provides domestic water and the geothermal heat pump water. Anyone with this kind of pump, regardless of geothermal, would have the same issues with Sense.
The manufacturer for our pump is Franklin Electric and the model is SubDrive 745. We love it, because it maintains the water pressure within about 2PSI and we don’t get any fluctuation at faucets, showerheads, etc, like most other well water systems. I don’t know if other manufacturers of constant pressure pumps would have the same kind of controller signature.
With assistance of the Sense data scientists, we determined that whenever our constant pressure pump is running, there is a 2.5-3 second ramp up, to 250 watt consumption at low flow rates and up to 750 watt at 15 GPM (which is what our geothermal needs), and sub second saw tooth oscillation in power consumption. That’s seriously confusing their analytics.
Visually, both on the Sense power monitoring and on my oscilloscope when connected to my WelServer, it’s pretty neat looking, particularly when you watch while adjusting water flow. Very distinctive to a human, disaster for Sense algorithms.
For purposes of this discussion, we might also want to adopt slightly different nomenclature:
- signature = 500msec or so on and off signatures recognized by current Sense algorithms
- SIGNATURE = full power envelope of a device from on-event through to off-event.
I would imagine that noisy devices have SIGNATUREs with the following characteristics.
- On for a significant % of the time - obscuring other devices
- Substantial power peaks - 500W or more, that would obscure other devices
- Continued variability in both time and amplitude domain - no real steady state constant power consumption.
Though I would think that devices with some what predictable amplitude / time cycles would eventually be recognized and cancelled in the future, as Sense works on longer window (SIGNATURE) identification.
I have very variable power draw from two devices. The first is my desktop computer that has a range of power draws that can change by 80 watts (140 to 220) in a few seconds that depend on the tasks the cpu and graphics have to accomplish. There is essentially no pattern to the variable power level I can detect. The second device is the washing machine with it’s direct drive motor. Every movement of the direct drive creates a different power demand and while the pattern is repeatable, the power draws vary depending on the load and where the wash cycle is. I doubt either of these devices will be detected anytime soon. Fortunately, they are not always on and Sense has been successful at identifying many devices.
I tracked down noise on my line yesterday after turning off breakers and watching the power meter. It turns out to be my work laptop (newer dell) which is on a docking station and power supply (older unit). It seems like very small changes in load become spikes on the power meter. I’m going to see if I can get a new power supply that is less noisy.
I’ve just had to replace my “noisy” Franklin Electric variable frequency pump (due to “lightening strike” the dealer says) that Sense support says has adversely effected all my device detection. So my question is does anyone have the replacement pump controller working successfully with Sense?
It’s a PENTEK Intellidrive PID20. I have my fingers crossed that this device, which I was told is “far better quality” and includes EMI/RFI filtering might work with Sense.
I assume your controller was also Franklin Electric?
I have the PID10, open loop geothermal, not detected by Sense. I don’t think the Pentek controllers are very good with EMI/RFI, I can ‘hear’ my well turn on through some old florescent fixtures and it’ll flicker some smart dimmers when turning on. Maybe it’s ‘normal’ for VFD’s…
Thanks. So it sounds like the PID is no more likely to be detected than the Franklin Electric was…sigh. Has the PID interfered with other Sense detection or is Sense working well for you? Emergency replacing the pump and controller was a HUGE cost, and I’d like to get something out of it ((-;), besides mere domestic water.
According to Sense engineering (spent some time on the phone with a woman I believe is their CTO, looking at waveforms), the Franklin Electric noise has been blocking detection of most other devices…after two years I only have about a dozen, and some of those not reliably.
Correct, I have large doubts it’ll be detected. My heat pump started tracking my well pump on the heat pumps power meter. While this gives me hope about variable devices, it’s incorrect and I was told directly from Sense that they have no intention of separating devices that run with each other. In our case, our well is used for other things other than HVAC, but they claim that if it runs every time the heat pump runs it’ll be lumped into one.
I have a hard time believing that beings my circulation pump that runs every time the heat pump runs is detected separately.
To address your question, I believe any VFD will have a hard time being detected by Sense and will hinder other device detection and accuracy. I don’t believe its because of literal electrical noise or RF, but rather the fact that the wattage is flying everywhere every time the heat pump runs (as you know that can be quite a bit.) Now that mine runs less, detection accuracy of has improved again…
Question: Is your pump itself 3 phase or single phase with a capacitor? (Controller has settings and provisions for both) A true 3 phase pump and a controller in 3 phase mode is supposed to be quieter in the literal sense, but still would have the variable wattage issue.
Thanks…I was kind of expecting that.
Well pump is three phase, which is all the Franklin Electric system could handle. Both well pump and controller blew (contractor says “major power surge, probably lightening”) and they replaced the pump first, then they discovered the controller was also shot. So the PID had to be set up for the already installed replacement pump.
My well also does multiple duty, same as yours. It provides geothermal energy for the heat pump (it’s what’s called a “standing column”…pioneered in this part of the world by http://northeastgeo.com), but also provides all our normal domestic water, plus things like irrigation, car washes, etc. This time of the year the geothermal use goes WAY down and remains so until summer cooling season…neither soon nor for very long up here in the mountains of NH. So, most of the well pump use is for other uses. Also, cooling is “down hill” (well temp much lower than room temp), so summer heat pump use is correspondingly lower than winter, even when it does run.
Additionally, while our heat pump requires a constant 15 GPM, domestic use is way lower and very variable. So the waveform is still “noisy” but it’s much lower amplitude. Because of the way these systems work, both frequency and wattage vary with water flow, something Sense detection doesn’t seem able to cope with.
@andy, have you given any thought to just removing the well circuit from the Sense readings entirely? You’ll lose the ability to track the pump usage as part of your overall numbers, but you’ll also remove it as a source of randomness in your usage signature and theoretically improve your detection performance.
If you have a traditional single-panel setup, you could run your pump circuit conductors through the Sense CTs alongside your main panel feeders, but in the opposite direction. This way, the current flow associated with the pump will cancel out as seen by the CTs. If your pump circuit conductors are small enough, this should work well.
Alternatively, depending on your panel configuration, you could locate your pump circuit upstream of the Sense CTs.
Hmmm, I had not, but it’s an interesting idea. I’ll give that some thought. Thanks also for the instructions…seems simple enough, and I may try it out to see what happens. If I do, I’ll post results for others having similar problems.
I purchased Sense primarily to monitor my major power users, and the geothermal system is definitely the biggest. It runs during 9 months of the year and 50-60% of the time during the harsher months of winter. Since the heat pump depends on the well (470 feet deep and 15 GPM), that consumption has to be a significant part of my electric bill. So, giving up on monitoring that, even if it enables finding and accurately monitoring other far less consumption devices, severely reduces the value.