I am considering getting a Samsung Mono HT Quiet along with a matching EcoHub for the direct hot water. (If anyone is familiar with the EcoHub does it contain not only the main HW tank, but also the pump, valve, expansion tank, volumiser, etc.?)
I live in London in a Victorian detached house with solid brick walls so no option for cavity wall insulation. I will have double glazed box sash windows and I intend to fit aerogel (ultra thin) internal wall insulation panels and on the ground floor insulation panels between the floor joists. I also will be fitting cast iron radiators and can upsize these as required.
My main issue is that based on press comments and comments in these forums I am concerned that your typical plumber - even if they already supply and fit ASHP units are not sufficiently knowledgable about them to do it properly. I am also finding it a struggle to find a London supplier/installer for Samsung ASHP units.
Is there anyone here who can make some suggestions based on personal experience or knowledge of suppliers? Samsung themselves are useless - one of the two they suggested only did installations for business premises.
The defaults are simply the worst case (from some other
bullshit government study)
The first problem with MCS being the sole route to accessing BUS is that you’re not required to have a clue about surveying buildings or designing heating systems to be certified. An idiot from Octopus et al that can’t use a tape measure, can’t tell the difference between radiators, and can’t assess the ventilation rates of a building is perfectly entitled to be and to remain an MCS member.
The second problem with the MCS rules is that MCS don’t enforce any rules. They will not kick anybody out of the scheme until it’s long overdue and they will not pick up the pieces afterwards. Which is fine. But it is not in accordance with how they present themselves.
To be clear though the rules do not force you to completely and utterly screw up up the surveying of a building or the heat loss calculations by entering the wrong ventilation rates. That’s just something that the clowns certified by MCS do of their own willing and then lie to the customer about it being mandatory to do so in order to try cover their backsides.
I think that’s against the RECC that they notionally adhere to. Again though RECC just want that tentacled cash and would never dare do their job and suspend the rogue traders of scale unfortunately.
The premium installers won’t install bottom end of the market equipment.
Find a Heat Geek. Ask them to install what’s appropriate not what you’ve seen marketed the most heavily.
The current Samsung mono HT units are R32 (irresponsible in this day and age), noisy (vs the competition), and have relatively poor controls with regards following room temperature; particularly if you want to do setbacks.
A premium installer of the Heat Geek type is probably going to suggest a Vaillant or Viessmann unit instead; which will work better for for you.
Samsung tend to target the ECO4 end of the market - bash em in quick for cheap type clients.
Jus the latest info from DK
I believe I have found a little breakthrough in understanding why it suddenly makes reasonable CoP readings.
Th flow have not been in the high scale for some time, actually all the way down to 9,8 l/min - up to around 15-16 l/min.
Had to think a little - I changed the curve some dauys ago, + 2 degC because we had around 20 in. our living room, and that was a bit chilled. So + 2 on the Weather compensation curve and the took 1 DegC out again so total of +1 degC. After that flow went to be at around 23-28 l/min - and surprise, good CoP readings.
So just to test, I went back to chilled settings -1 degC and guess what - bad flow and CoP again.
Big thick line below the sentence: Your ASHP is to big…
So i am trying to get in touch with the dealer, and on top of it all - My Hydrounit with 260l. DHW is leaking - less than 12 month old…Damn…
Hi Arne,
I’d add one comment to Marko’s dependably wise words.
Unfortunately, there’s little we can do about the Samsung control algorithm of running at reduced compressor speed (and efficiency) when Tw2 (LWT) is within 2degC of the target set by FSVs 2011/2 and 2021/2 (“Water Law”), except to set these values as intelligently as possible (or, as you discovered, to move the weather compensation curve up/down using the +/-5degC Adjustment function).
Are you able to deselect Water Law and change to Room Temp control (p8 of MIM-E03EN User Manual)? If you can, and your room thermal inertia is high (you are very well insulated), then your compressor should cycle more slowly, and spend more of its time at full speed (hence max efficiency).
Let us know how you get on…
Sarah
Or can you take control over the circulation pump and then tell the unit to “follow me” by targeting a flow temperature and a dT whilst you dictate the flow rate?
Ideally use two flow rates; one for when compressor is running whose job it is to take away heat at an efficient power level; another for when compressor is not running whose job it is to transfer volumiser great until radiators and transfer the “currently supply and return temperature” signals to the heat pump using water as they communication channel.
Yes, I have let the pump work like that, in the beginning, but then I let it work at a fixed temp. of lets say 40degC - then I have 3 options:
I must use my Danfoss Living to control indoor temp.
I need to get a indoor sensor attached to the system
Move the MIM to my living room and use that as temp controller.
For now I have to “play” along and let the installer come with their solution model. Have to insist the unit is to large, and to my best knowledge at this point, they can not make it work at good CoP when outdoor temp is rising, then the problem just gets worse, since heat needs drops. Right now I have 7,8 degC outside - flow is around 32 deg and runs CoP around 2,18.
I do not know if a large buffer, like 300-500 liters could flatten that out?
Problably, But I have no control over anything than waterlaw, Low nad high start temp. 15/-10 and the High and low temp., so at -10 it is set to 46 degC and at 15 it is set to 26 degC - thats about it.
Anybody knows the “Mixing valve” function - 4041-4044?
Hi Marko.
Unfortunately, Samsung Mono Quiet series compressors only operate at the Best Efficiency Point (BEP) when the LWT is more than 2degC below target temp. This is normally the weather compensated LWT setting, but users can instead select room thermostat setting, though if it is, the LWT may rise even more, giving a lower CoP. Below 2degC from LWT target, the compressor successively reduces speed from 100% to 50% at target temp, when it stops. The compressor restarts when the LWT has dropped to 2degC below target.
Circulation pump flow may be fixed speed (like mine) or variable speed (I assume based on compressor speed). The user has little or no manual control of circulation rate.
My main frustration is that the above 2degC LWT hysteresis means that (apart from during initial circuit warm-up) the compressor is always running at reduced speed because it is sitting within the hysteresis band, so not at BEP. ASHP oversizing only makes this worse.
A bit more homework when I selected Samsung may have avoided this. Most folk will rely on the installer to advise about such operating constraints, but I suspect that not many do.
Sarah
If you use a third-party room thermostat to control your Samsung, you have no option but to use Water Law (weather compensator) for LWT control - you cannot set LWT manually. (This is not clear from the MIM-E03EN manual p8, but Samsung UK Tech Helpline confirmed.)
With your house being so well insulated, I think there is a case for just running your ASHP for 2-3 short periods each day, and switching it off between times. My logic: When the ASHP starts from cold, it runs at full speed and max efficiency (at any given outside temperature), so a good CoP. If you stop the ASHP (on the timer) before LWT gets near Water Law setting (when it reduces speed and efficiency), then you will still have warmed your house at good CoP and it will stay warm for a few hours because of your good insulation. Then you can repeat the cycle. (Example: try enabling your CH on its timer 06.00-08.00am, 12.00-14.00, 18.00-20.00 each day. Each period, your LWT starts cold so good CoP, but your house warms up OK and hopefully stay warm till the next period.)
FSV 4041-4044 control the differential temperature between your underfloor heating and your radiators. (See diagrams on p146 of the EHS Installer Reference Guide Book).
Why would they choose to run at an inefficient condition instead of running at best efficiency point?
Do you think they’ve adapted (bodged) air to air controls to an air to water unit perhaps? Where they’re concerned about discomfort due to cycling on air based units so instead choose to run at an inefficient operating point once demand is met?
The old fixie ground source unit I have just runs degree-minutes away from setpoint in order to decide when to start. I think the Vaillant air to water units have similar settings.
What are Samsung thinking that we’re missing? (or not thinking that we’re seeing)
I will give it a shot regarding timed start/stop - but currently at these outside temperatures I have difficulties get it to hit the high flow rate - curently at 16-18 l/min - have only seen good performance at 23-26 l/min, which also is the recommended flow rate. I will configure the timed settings in the christmas days.
Thanks Arne, and Happy Christmas to you and yours.
I’ve reduced my water flows (primary and secondary loops) and will study the effects in the New Year. I’ll keep you posted…
Sarah
And Happy New Year
Tried the scheduled settings and this will not work. After 1 hour, the temp. began to drop inside and if we really packed us in, in some warm stuff, the ASHP started after 2 hours of off time, then it ran around 15 minutes and went back into cycling. During normal operation, the cycles are around 7 minutes and 40 sec. - Turned off in 15-20 seconds, then a new cycle starts.
A cycle on 8 minutes, starts with waterpump, then powerconsumption up to 1,7 kwh and short after its down to 1,1 kwh - dropping further to 0,8 kwh and the it turns off the power and shortly after that waterpump shuts down, and so on… DeltaT in that period varies from -0,4 to 3,0 so actually only half the time I have a “Positive” Delta T - rest of the time it is less than zero (minus something…)
Outside temp is 5-6 degC and flow is between 30 and 35 degC during operation.
This means I have approximately 180 starts per 24 hour - This is insane…
are you sure about this? I’ve put a lot of effort into tuning my 16kw system. I see the compressor speed vary from about 60hz (startup) down to 17hz when running at a steady state low power level, maintaining the WC target LWT in mild conditions. So that’s a compressor turn down to less than 33%. At this power level (e.g for my system right now, and for the last 2hrs completely stable) it can be efficient (emoncms reporting 50% of carnot) and low power (800w input, 3900w output, 35C flow).
Hi Ian.
This is what Samsung Tech Support emailed me in response to several questions (my emphasis):
On 17/11/2023 17:27, Aftersales Technical Support wrote:
Hi Sarah,
Thanks for the email.
Thermo on / off hysteresis for WL flow temperature is around 2K, this combined with an anti-restart timer of around 5 minutes will dictate the off state time before the heat pump starts again.
The 405* FSV’s are for a PWM circulation pump, it’s called inverter pump in the FSV list, it’s a type of water circulation pump that can be used on the system that will modulate the flow rate slightly in heating mode. It doesn’t relate to inverter control in the heat pump sorry. The minimum turn down for your unit 4KW.
Best regards
Nick Kirwan
I guess I took his word for the 50% turndown (my ASHP is 8kW), and I don’t have any fancy monitoring equipment to verify inverter frequencies, but I believe him because I’ve never seen sustained thermal duty (as calculated from Q = m * Cp * deltaT on the circulating fluid) below about 4kW, or compressor power consumption below about 50% of the figures in the Samsung capacity tables (EHS Technical Data Book).
The one thing I would retract is my comment that at turndown the compressor has a poorer effieciency. This was based on early observations (I don’t have performance curves for the DS2BB5033FVA), but data from several subsequent test runs suggest that there is little change in efficiency across the speed range (no more than a few %).
I think 50% is the standard that customer services will always quote so they aren’t held to anything better.
there are two 8kw samsung systems on heatpumpmonitor, one HTQ (Cambridge, #22), one gen6 (Market Drayton, #71 - which is the one matt linked to). #22 appears to be setup to run in “short bursts” , has a COP over the last month of 3.5. #71 appears to be setup for longer runs and has a 30 day COP of 4.2. however both show that a steady state of 500-600w input, 2500w-3000w output is achievable.
I wonder if we are cross-purposes here, and trying to compare instantaneous compressor operation with operation over a 1-hour or 1-day period (or longer)?
If you have 15 minutes to spare, please have a look at my data from a recent test run: OEM2.xlsx (14.9 KB)
I can only get data from my ASHP controller display, and noted readings every few minutes once the LWT (column C) had more or less reached the weather compensator setpoint (column I). The lounge roomstat was set at 21.5degC which was only reached at the end of the test, so throughout the test the ASHP was just supplying room environmental loss and sensible heat.
I compared my instantaneous readings/calcs with the published Samsung data (columns K-M) to estimate compressor speed (columns O and P). Within experimental error (e.g. I only have ASHP inlet temp to the nearest degree), these did not drop below about 50%. The averages also tell a pretty consistent story (yes, I know - you can’t take averages when the time periods are different, but the principle still applies).
From this data, I think my conclusion - that the compressor really doesn’t want to go below about 50% - still stands.
Any comments? (Apart from my high weather comp setting - I’m still working the economics on that…)
