Temperature and Energy logging by: Web Energy Logger Link above. It took me a bit longer and was quite a bit of undertaking, but here is the first 7-Series on the Web Energy Logger. I am continued to be impressed by the machine. The runs unbelievable quiet. A couple time I stood right beside it and did not realize that it is on. The power draw in the graphs gives a bit of a hints how it modulates through the 12 compressor stages. A couple challenges: I still have not found a good way to monitor the stages well, since it is not a normal 24v thermostat signal. I have an on/off sensor on the circulation pump to monitor the runtime, which is obviously much more than the 2 stage heatpumps. Anyone has an idea how to monitor the stages (even WF)? On the other side I am not sure how beneficial that would be. Anything else someone could think about what would be beneficial to monitor?
It would sure be nice to know the airside CFM so as to derive a running COP. If there is aux heat, that wattage would be good to have. Looking forward to my first 7-series
[TABLE="width: 627"] [TR] [TD]Stage[/TD] [TD]CompWatts[/TD] [TD]Pump[/TD] [TD]Blower[/TD] [TD]Total[/TD] [TD]gpm[/TD] [TD]HE[/TD] [TD][/TD] [TD]COP (without circ pump)[/TD] [/TR] [TR] [TD="align: right"]1[/TD] [TD="align: right"]344[/TD] [TD="align: right"]16[/TD] [TD="align: right"]18[/TD] [TD="align: right"]378[/TD] [TD="align: right"]5.1[/TD] [TD="align: right"]4700[/TD] [TD][/TD] [TD="align: right"]4.83[/TD] [/TR] [TR] [TD="align: right"]2[/TD] [TD="align: right"]483[/TD] [TD="align: right"]23[/TD] [TD="align: right"]28[/TD] [TD="align: right"]534[/TD] [TD="align: right"]5.7[/TD] [TD="align: right"]6911[/TD] [TD][/TD] [TD="align: right"]5.00[/TD] [/TR] [TR] [TD="align: right"]3[/TD] [TD="align: right"]617[/TD] [TD="align: right"]26[/TD] [TD="align: right"]38[/TD] [TD="align: right"]681[/TD] [TD="align: right"]6.2[/TD] [TD="align: right"]8580[/TD] [TD][/TD] [TD="align: right"]4.91[/TD] [/TR] [TR] [TD="align: right"]4[/TD] [TD="align: right"]784[/TD] [TD="align: right"]33[/TD] [TD="align: right"]37[/TD] [TD="align: right"]854[/TD] [TD="align: right"]6.7[/TD] [TD="align: right"]11898[/TD] [TD][/TD] [TD="align: right"]5.27[/TD] [/TR] [TR] [TD="align: right"]6[/TD] [TD="align: right"]1133[/TD] [TD="align: right"]53[/TD] [TD="align: right"]67[/TD] [TD="align: right"]1253[/TD] [TD="align: right"]7.9[/TD] [TD="align: right"]15132[/TD] [TD][/TD] [TD="align: right"]4.74[/TD] [/TR] [TR] [TD="align: right"]9[/TD] [TD="align: right"]1718[/TD] [TD="align: right"]85[/TD] [TD="align: right"]136[/TD] [TD="align: right"]1939[/TD] [TD="align: right"]9.5[/TD] [TD="align: right"]22577[/TD] [TD][/TD] [TD="align: right"]4.67[/TD] [/TR] [TR] [TD="align: right"]12[/TD] [TD="align: right"]2453[/TD] [TD="align: right"]122[/TD] [TD="align: right"]186[/TD] [TD="align: right"]2761[/TD] [TD="align: right"]10.8[/TD] [TD="align: right"]26714[/TD] [TD][/TD] [TD="align: right"]4.04[/TD] [/TR] [/TABLE] This is the COP I measured around 37 EWT. You can see that there is probably some rounding errors. I have not much confidence to measure the COP in real time, having the temp sensors on the HDPE pipe for the heat extraction, although they are calibrated. We run HDPE all the way to the heatpump, and being 1 degrees F off with the water temp means you are 20% off with the COP calcs. You can dial in a different flowrate, I left it a bit high since it did not cost much pumping. I am surprised by the amount of DSH heat it makes.
Ground Energy Support, LLC | Track your geothermal energy resource I have been working with a company called "Ground Energy Support" which utilizes the "GxTracker" web logging system to monitor my Series 7 system. I have included the link to the "performance" page of the monitoring system. I have utilized the AID tool to manually run through all the stages to capture each modes total wattage usage. Doc, Is this installation one that you did? I am curious because I am seeing many E15 HW limit faults from the desuperheater. I have just had the new software updates installed. One for the thermostat and one for the unit which was supposedly to fix the faults. Since the update I have 10 hours of runtime with 17 E15 HW limit faults being reported. I was just curious if this is being seen on your system or something that may be unique to mine.
Dewayne, I can get the temps with P/T ports, but is this a sensor I can clip on the WEL bus? We use dry wells in tanks, but they are also more than a degree off. Again, each degree costs us about 20% accuracy. For COP I would also need flow, since the flow varies, any idea what flowmeters are there you can use with the WEL and how accurate they are?
We didn't see the flow rate vary by much at the josephparris installation (link in Comment #5). He reported the readings in the table below from of the on-board sensors (using his AID tool). My understanding is the flow center is also serving a Envision serie heat pump, so perhaps it is set up with less variable flow. For our computations, we are assuming a constant (average) flow of 11gpm (+/- 10%). [TABLE="width: 646"] [TR] [TD]Compressor Stage (Heating) [/TD] [TD] 1 [/TD] [TD] 2 [/TD] [TD] 3 [/TD] [TD] 4 [/TD] [TD] 5 [/TD] [TD] 6 [/TD] [TD] 7 [/TD] [TD] 8 [/TD] [TD] 9 [/TD] [TD] 10 [/TD] [TD] 11 [/TD] [TD] 12 [/TD] [/TR] [TR] [TD]Flow GPM [/TD] [TD]10.0 [/TD] [TD]10.3 [/TD] [TD]10.7 [/TD] [TD]11.0 [/TD] [TD]11.3 [/TD] [TD]11.7 [/TD] [TD]12.1 [/TD] [TD]12.1 [/TD] [TD]12.2 [/TD] [TD]12.2 [/TD] [TD]12.1 [/TD] [TD]12.1 [/TD] [/TR] [TR] [TD]EWT [/TD] [TD]43.1 [/TD] [TD]43.2 [/TD] [TD]43.6 [/TD] [TD]43.8 [/TD] [TD]43.6 [/TD] [TD]43.6 [/TD] [TD]43.6 [/TD] [TD]43.4 [/TD] [TD]43.2 [/TD] [TD]43.2 [/TD] [TD]43.4 [/TD] [TD]43.4 [/TD] [/TR] [TR] [TD]LWT [/TD] [TD]40.5 [/TD] [TD]40.5 [/TD] [TD]40.5 [/TD] [TD]40.5 [/TD] [TD]39.9 [/TD] [TD]39.5 [/TD] [TD]39.0 [/TD] [TD]38.6 [/TD] [TD]38.3 [/TD] [TD]37.8 [/TD] [TD]37.6 [/TD] [TD]37.4 [/TD] [/TR] [TR] [TD]MBtuh (HE) [/TD] [TD]12.74 [/TD] [TD]15.38 [/TD] [TD]17.75 [/TD] [TD]19.53 [/TD] [TD]21.89 [/TD] [TD]23.83 [/TD] [TD]27.00 [/TD] [TD]28.99 [/TD] [TD]30.18 [/TD] [TD]31.10 [/TD] [TD]32.86 [/TD] [TD]34.92 [/TD] [/TR] [TR] [TD]DeltaT [/TD] [TD]2.6 [/TD] [TD]2.7 [/TD] [TD]3.1 [/TD] [TD]3.3 [/TD] [TD]3.7 [/TD] [TD]4.1 [/TD] [TD]4.6 [/TD] [TD]4.8 [/TD] [TD]4.9 [/TD] [TD]5.4 [/TD] [TD]5.8 [/TD] [TD]6.0 [/TD] [/TR] [/TABLE] The combined operational COP (for both the Envision and Series 7 heat pumps) since March 1 is 4.25. I need to do some more data analysis to separate out the Series 7 from the Envision heat pump and will post those here in the next few days. Matt Ground Energy Support, Inc. | Track your geothermal energy resource
Doc, I don't know of a flow meter that works with the well. Dry wells are the best I have for temp on HDPE.
Yes we did. I updated the software a couple days ago, both the thermostat and the aurora board. No faults either before or after. I have another one with some fault codes, but it keeps running. I don't recall the fault code, it had something to do with the circ pump.
I had to take the pumping power down to 35% (low stage) and 65% (high stage) via the diagnostic tool. It is factory programmed to 50% low and 100% high. But that does waste some pumping power, now the Magna runs between 16-122 watts, and still with a system COP so far around 5.0. I am trying to get more consistent and accurate measures, since +/- 10% can mean a COP of 4.5, 5.0 or 5.5. I am not even sure how good the WF sensors are, since some are clipped on pipes, and are off by a degree or so. My flowrate is between 5.1 and 10.8 gpm, that way the delta T is pretty constant, but without the precise flowrate, I have no way to zoom in better on my COP. I think pumping power becomes more important, since the variable speed has much longer runtimes, about twice as long, than dual stage heatpumps, so the impact of a highly efficient circulation pump having minimal consumption to overall COP is much higher.
Nice thread and data I get the large uncertainty that arises from temperature inaccuracy on the water side since the delta-Ts are so low. Could you work it from the air side? Supposedly the ECM blower's airflow is accurate to within 5% or so of setpoint, as long as static is within range. I agree that longer runtimes call for even greater attention to pumping power. We have to beware a similar effect down here in which the longer runtimes of two stage or varible speed air source systems can worsen results if ductwork is unbalanced or leaky - the longer times lengthen periods of building pressure imbalances and periods during which ducts (in unconditioned spaces) lose more conditioned air and / or pick up more outside air on return side.
. We've looked into doing this for the ClimateMaster Tranquility Series (2 stage) which would have up to four different air flow rates (2 for heating and 2 for cooling) and potentially a fifth, depending on how the dehumidifier is set up. It would also miss the latent heat, unless humidity was factored in too. This would probably work okay for on-site commissioning, but for remote monitoring, we're inclined to stay on the source side, preferably with a flow meter. We have found that mechanical displacement meters such as the Seametrics MJR are the most accurate (1.5% of reading). The vortex shedding flow meters (e.g. Sika VVX) have the advantage of no moving parts, but are less accurate (+/- 1gpm). I agree, it would be good if WF would at least provide some information on the accuracy of their sensors (as they are unwilling provide the Modbus registry map). In terms of translating the accuracies of sensors (flow and temp) to the accuracies of BTUs produced, this is something that the ASTM subcommittee developing a heat metering standard is currently working on. If the measurement errors have a mean of zero (e.g. using average flowrate), they have a much smaller impact on BTUs than if they represent bias (e.g. on-pipe temperature sensors). So a 10% error in flow (or temp) will have a small (less than 10%) impact on calculating total BTUs, provided they are unbiased. We have also done some work on characterizing (and correcting for) the bias associated with on-pipe temperature measurements. If you are interested, send me a PM and I'd be happy to share that with you. Matt Ground Energy Support, Inc. | Track your geothermal energy resource
I hear you, as long as there is a regression around the mean, and the mean being zero error, than the influence at the long term COP is minimal, no matter what the variance is. I used to use heat transfer compound, plastic strips which got loose when the pipe contracted, believe it or not, rubber bands wrapped in heavy insulation works best so far. I am not sure if the hunt for the precise COP gets us anywhere, in a world where a dirty air filter screws everything up. The heat pumps have a very good consistent performance if fed by the right amount of water at the right temperature, so I am more interested in the balance point, EWT, flow rate, etc. Things I can improve with the next design.
That's where I'm at. I watch my balance points. If I get those right then my op cost calcs are going to be on for my customers. I'm warming up to the ecobees for this task. Stages, outdoor temp, windspeed, humidity and any other temp you want to measure are laid out on an excel spread sheet. Wind speed is handy for determining if greater air sealing or insulation might be needed as balance point would climb.
I have been watching the WEL on the Series 7 for a few weeks now. Very informative. I hope fully modulating tech becomes standard in all geo soon. I am hoping to get bids for a 3 ton for a SIP house being built this spring in the country. I have a few comments and questions though.. It seems like the desuperheater is overpumped with a 5 degreee delta-T. The only info I've seen on the net for acceptable DSH delta-T is 5 to 15 degrees. This seems like a good application for and ECM delta-T pump like the Taco BumbleBee. The BumbleBee runs full speed for 3 minutes then settles into delta-T mode at 15 degrees or so which seems like a good strategy given the periodic sampling performed by the DSH. I don't think there is a domestic BumbleBee yet however so an indirect or heat exchanger would be needed but expensive. Another option would be a multispeed pump to set the flow rate to match the piping requirements. What pump does the 036 Series 7 use? Watching the WEL, it seems like thermostat gets turned off a lot and it goes into deep setback when it's probably better just to let it keep running and modulate up and down as needed and let the DSH continue to work. When it comes out of setback it ramps up to the higher or highest stages before ramping down which is probably not as efficient as keeping a steady state inside temperature throughout the day.
Yes, the DSH is probably overpumped a bit, presumably because one size pump fits it all for the 3,4 and 5 ton (and this is a 3 ton), but what is the drawback of a 35 watts making a delta T of 5F? The pump load is static for the DSH, so variable speed does not make much sense except for efficiency. But then how much is the Taco BumbleBee? $200? So paying $150 more for a 25W saving? The thermostat appears to me at a steady temp of around 68F. What you see is high solar gain where the heatpump shuts off completely. The 7 series goes into 6th stage minimum at start up in order to circulate the oil through the compressor for a while. Then it throttles back.
