@drei your proposed radiator design looks inadequate to me. The first and second floors look OK, but a shortfall of 59% on the ground floor at 45C is too much.  

I could not work out what you use the ground floor for - apart from cooking - as you appear to have living space in the first floor.

@drei just a small detail on your table posted on the 24th. scop is seasonal coefficient of performance so you need a year  of data . What you are showing generally is monthly COP. 

Your figures are pretty bad, less than 2.0 in April is shocking 

Posted by: @old_scientist

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Posted by: @drei

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I have the 12kW Samsung gen6 ASHP, and our system volume is ~190L, comprising ~45L in the system pipework, ~95L in the radiators and a 50L volumiser (not buffer). So even with 140L native system volume, we still have a 50L volumiser. The additional volume gives higher thermal mass which should in theory help with short cycling, but most importantly in my opinion it ensures there is sufficient heat energy in the system to adequately perform system defrosts in winter. If you do not have sufficient heat in the system, it is possible to descend into a defrost spiral sucking all the heat from the system, with the heat pump then working flat out replacing it only to entering another defrost cycle...

See this thread and the YouTube video in the first post.

 

 

That's good to know, so in that case, I can turn my 50l Buffer into a volumiser, with the return pipe bypassing it and going straight back to the heat pump, so the buffer will only be using 2 pipes, well 3 if we still have to keep the orange small tank (expansion vessel?).

 

Posted by: @judith

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@drei just a small detail on your table posted on the 24th. scop is seasonal coefficient of performance so you need a year  of data . What you are showing generally is monthly COP. 

Your figures are pretty bad, less than 2.0 in April is shocking 

That's why you can just add one full year, and it will come to 2.23, so far you can just look at the total numbers over almost 2 years:

37835.6 / 16522.3 = 2.29

Or here:

Just to be clear, the SCOP is the total data, not an average of the monthly ones.

@drei do you mean running block average, so 6months before and after the date?

@drei are taking measurements from the heat pump, or do you have an independent monitor?

The reason for my question is that heat pumps are not especially good at measuring COP and SCOP.  Glyn Hudson, who developed OpenEnergyMonitor showed me some shocking comparisons for my particular heat pump and your may be the same.

Of course, your electricity bills don't lie.

Can you separate out the scop data between hot water and heating?

I.e. is the hot water more efficient than the heating?

Also did the £20,000 include the government grant?

Posted by: @andrew-j-h

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Can you separate out the scop data between hot water and heating?

I.e. is the hot water more efficient than the heating?

Also did the £20,000 include the government grant?

I can now, I done an automation in Home Assistant that records the power usage when the valve changes between Room (Space Heating) and Tank (Hot Water), so I should be able to work out the individual SCOP, however this is going to take some time.

In addition, this is Heat Geek Elite quote I received for my remedial work:

Here is the data so far, but even this is not 100% as my net sometimes drops. Still, gives an idea. I tend to have the hot water running on ECO mode, only goes to STANDARD about midday, back to ECO and then it switches OFF at 20:30 until 5:00.

@drei - there is definitely something not right, notwithstanding if your 'net sometimes drops' (not sure what happens when a person's net drops - I presume you mean internet connection), because in the day and the week data the totals are less than the sum of the parts. How are you actually getting the data?

Posted by: @cathoderay

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@drei - there is definitely something not right, notwithstanding if your 'net sometimes drops' (not sure what happens when a person's net drops - I presume you mean internet connection), because in the day and the week data the totals are less than the sum of the parts. How are you actually getting the data?

I am using Home Assistant's utility meters, so they add up the relevant data based on live readings, to make up the daily, weekly, monthly and yearly data. These will eventually get better, as right now it doesn't have a whole month worth of data, or a year.

The handicap is that it is still using the Heat Pump sensors, as it is connected to it via WiFi, and every now and then, Samsung wants HA to re-authenticate, which will cause a gap in the data, unless I can pick it up straight away.

For example, these are my readings right now over the last 168 hours:

Not 100% accurate, but it is better than we I had, and I made the power level to a maximum of 8kW and red over 6kW, no idea if the HP would even reach that but, if it is a 12kW Heat Pump, does it mean that it can draw 12kW electricity at maximum usage?

Posted by: @drei

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Not 100% accurate, but it is better than we I had, and I made the power level to a maximum of 8kW and red over 6kW, no idea if the HP would even reach that but, if it is a 12kW Heat Pump, does it mean that it can draw 12kW electricity at maximum usage?

No. 12kW is obviously the maximum heating capacity (at certain conditions, dependent on manufacturer) but the actual maximum consumption will be much lower than that. I think our 12kW max power input is around 5kW. You can get the figures for yours from the technical bulletin, data sheet etc.