Hi guys, finally I was able to put all data from pump together so I can monitor how heatpump works in more details. I have some numbers though they might be not 100% precise because I use data from pump and not from external heatmeter.
Nevertheless the heat output more or less correspond to my heat loses.
This is a chart from todays run. Outside temperature was around 0C at night, around 1 - 2C during a day.
So these are all the numbers. What I don’t understand here is the COP vs Carnot COP.
When the pump starts it looks like COP and Carnot COP match perfectly and it almost 1:0. Ignore the defrost cycle at the beginning. But after 40 minutes it seems the difference between COP and simulated COP starts to be much bigger. Do you have some explanation for this ? I can see that dT at 6:50 is only 3C while target delta is 5C (don’t know why the pump reduces pump speed so slowly). Can I make it more responsive with maybe some setting in wired controller ?
The other thing I can’t understand why the pump shows such zigzag pattern for the power consumption. Why it modulates compressor speed in such harsh steps ? Don’t like this very much. The only time when I don’t see zigzag pattern is when the pump starts and then very occasionally when pump is running. Is there any setting to control this ? It’s MIM-E03CN control kit ?
At the end I would like to ask you experts what you think about this graph and how the pump is doing.
You’re probably best to be matching the “Heatpump factor” to the stable portion of the run, rather than the start. Toggling the “Show as % of carnot COP” option on and off again will do that for you. Typical value would be between 0.45 and 0.55.
Thanks, now these are screens from today run (last 6 hours) when now it’s running stable for couple of hours.
Seems like factor is 0.46 for the last 6h so looks like I’m im tolerance. My system is very easy with Type 21 radiators so maybe that’s why overal factor is lower. Not too much water in the system.
Note that I’m using just values from HP flow meter and IN/OUT temperatures reported by pump and read via modbus. So they might not be 100% accurate. In reality it can be worse or better
I’m running local version of EmonCMS but will try to connect it with cloud so you can check.
Not sure if these numbers are good, bad or average but seems quite reasonable to me. What do you think ?
Also I’m quite surprised that HP did not defrost since 6 in the morning and temps is around 1C. Must be really dry air.
So the only thing I don’t understand is this modulation and zigzag pattern. Do you guys always have it like that or is something specific to Samsung HP.
Hi there. Here is a link to a forum (its in german) but in this thread you can find many screenshots and infos, as we all are struggeling with this “zigzag” compressor pattern.
Seems to be an unsolved problem with the outdoorunit firmware
Wow, thanks this is really a huge forum thread. Will have a look with some translator help.
Yes, this zigzag pattern must be some bug I believe in mim-e03en control kit. Shame Samsung did not address this issue yet. Definitely not normal and I fear it can have negative impact on long term durability and also on overall performance. I can’t see any reason why it should manifest such crazy pattern increasing and decreasing power significantly over short period of time. Look at this screen from today. Was pretty warm ~7C on average, COP around 4 which is pretty good but that pattern is insane.
Here details from TAC4300 Modbus smart meter… What to say…Shall I send this to Samsung to fix this crap out ? It basically fluctuates in regular intervals by 400W… That’s not normal…
In the UK we have [email protected]. My contact there is Nick Kirwan.
I’ve found them very helpful to a point, but they appear to be constrained by what “Head Office” tells them. And Head Office are (understandably) a bit paranoid about compromising their competitive advantage. For example, ask them about the controller algorithms behind the economiser circuit included in some Samsung series (e.g. HTQ), and the shutters come straight down…
Thanks Sarah, maybe I will drop them an email about this horrible frequency jumps if they can say something about that. Btw, do you also have them with your unit ? You have single phase or 3 phases ?
No, I do not see rapid cycling like yours, though I run my LWT much hotter than you do (up to 50degC at 2degC ambient) and I have a 4-nozzle buffer tank with the primary circuit running at a pretty fast ~28litre/min (20% glycol), so (LWT-RWT) is only 2-3degC at 5kW heat output (compressor at ~25Hz).
I’m single phase supply.
For your interest only, here’s the raw data from a recent run as captured by the MIM-C02N, covering the first 90 minutes after startup from cold. 06H-59M-37S-EHS MONO LOWTEMP-Trend_0YDLPAFT900181M.xls (849 KB). Column R shows “Compressor current (degC)” (sic) which Samsung have confirmed is an S-NET error that should read (amps). (I’m very suspicious of this comment. When the compressor speed - column J - is over 50Hz the compressor power calculated from V.A doesn’t track heat pump duty calculated from m.Cp.dt. This I think is only possible if the compressor polytropic efficiency edit: or inverter efficiency is changing dramatically above 50Hz - something I very much doubt - and I strongly suspect that column R is reporting something different entirely. It would be interesting the compare MIM-C02N output with MIM-B19 output, but I can’t justify 200euros for the kit…)
Interestingly, the data spans a period when the economiser started (07:17 - 08:34), during which period the compressor current increased by 0.5amp or so. As Samsung won’t tell me what starts/stops the economiser I’ve been trying to reverse engineer this info myself, with only limited success to date , so any insights welcome!
I guess % Carnot depends also on outside temperature and pump efficiency or ? I’ve noticed the colder the weather the lower the Carnot heat.
Look at this chart from this night. It was around -1.5C outside and I’ve reached only 35% or so. In UK you have warmer climate and from those pumps I’ve check on heat monitor it’s barely dropping below 0C in winter co it’s hard to compare.
But this is run when there was a warmer weather and Carnot heat is much higher so really don’t know. Seems fine to me. With UHF I would probably have good over 5 but with radiators, especially Type 21 it’s rather problem to run win a lower flow temps.
Hmm, that’s a fair point. Carnot is supposed to factor in outside temperature, though I have seen that it doesn’t fit manufacturer datasheet so well at the extremes. It’s possible that the condensing and evaporating offsets need tuning for R32:
This is the last 2h run. It is still pretty cold, though humidity decreased outside so my HE outlet shows constant -3.7C. This shows much improved efficiency during a time when humidity outside was higher yesterday. Carnot heat factor is much improved almost by 0.1 since yesterday while temperature is above the same. So this seems to be very sensitive for outdoor conditions.
This is nice analysis of carnot COP. I think each pump is slightly different but at the end all pump work +/- the same no matter of brand. Then it comes only to quality of components and durability.
The zig-zag pattern seems fairly typical on Samsungs, they put it down to insufficient volume in their installation training manual, but I have at least 6x the recommended min volume and I still get it.
Yours might look worse because you are reading the flow and return through modbus, correct? On mine, the flow OEM Axioma flow meter is 10+m from my outdoor unit, so all the additional water and pipework I think will smooth the readings somewhat.
FYI my samsung flow meter under reads compared to the Axioma flow meter. The lower the flow rate, the higher the % discrepancy.
Hi Jake, interesting. So you have better numbers with axioma flow meter so at the end you are getting better COP reported by axioma than from Samsung ? I know that it takes some time when numbers are updated from modbus so there can be some discrepancies. But precision should be probably in range +/- 10%. Not sure.
Does it under read only the flow or also in/out temperatures ? Heat generated is computed from these 3 parameters so if any is underrated or not precise the incorrect values are computed.
These are reading at the exactly the same time ? Because in that case Samsung would overread heavily… The simplified formula for heat generation is as follows:
(flow temperature - return temperature) * flow_rate * 70
So in your case:
(39.3 - 34.4) * 14.8 * 70 = 5076,4W
(40.3 - 33.3) * 14.5 * 70 = 7105,4W
If this is at the same time Samsung is reporting 2KW more of heat generated than Axioma. In your case the temp difference reported by your axioma flow meter is much lower than reported by Samsung modbus…
To get the same picture you have to capture both at the very same time.
UPDATE: Sorry just read it is at the same moment… then it is pretty bad to be honest… I guess there could be some delay in values reported by modbus so then the discrepancy can be bigger but anyway it seems a bit too much for me.
I will double check another time, When I read the values (around 8:20), the temps were fairly consistent, but I might have mistyped the Samsung (homely) values, as I though they were both similar dt, but now I see one is 5 and the other is 7.
My OEM kit is 10+m from my outdoor unit (only 1m outdoor), so it could be that the temp is dropping 1 degree in each direction between them. But it is all 28mm pipework with lagging, so I suspect it wouldn’t drop this much. If this is the case, then yes, my OEM kit (while accurate for its location) will be greatly under reading COP.
Need to be careful about the order these inputs are read into emoncms. If they’re coming in the same message, then the input processing might be using a stale value for the other inputs that haven’t been read yet. It’s recommended to move the calculation to the last input to be received (usually lowest on the Inputs page), especially if the readings are oscillating.
Yeah, but with Modbus values you can’t be sure how they are coming from the pump itself so it’s an issue. You can get return temperature updated while flow is reported 10s after or vice versa. Home assistant sends all the data to emoncms mqtt server at once but problem is when they are updated in HA… So yeah without dedicated flow and temperature sensors reporting in real time this always be unprecise. To which degree I can’t tell. I’m fine with that though but what is a problem I don’t know to which direction they are unprecise. It is overestimating or underestimating ?
This is how I have it. Shall I change something ??
, so any insights welcome!
