In the case of my 7kW Panasonic at -7.1C, this was the only recent example I could find with it running at, or near 100% (without having to raise the flow temperature ) - unfortunately Panasonic only indicate compressor Hz in their controls and provide no cross reference to actual compressor duty % and max Hz varies with model depending on compressor mapping etc, so in this case (~77Hz) it’s an educated guess it’s maxed out, but there may be a little left in the tank? But its peak output is actually higher than their data sheet at around 7.4kW
Note, this is the standard/older R32 J series - the R290 L series have a similar mapping to the J, but the output is a little less at times. The M series T-Cap models maintain their output capacity down to -20C (need to test one), without back-up heaters and work down to -28C, unfortunately the smallest they offer at the moment is 9kW.
Agreed. I’d love to see a schematic diagram for each system on HPM, to help clarify the usage of e.g. buffer tanks and the placement of heat meter(s). The ability to add multiple photos of the physical installation too would be really good.
Ideally these would be on HPM rather than the Forums, perhaps as part of the existing Summary page (system/view?id=nnn) for each installation.
For example if you take air that was at 2c and high humidity and cool it to 0c (due to sun setting etc) you will likely get a different result then taking air that was at -2c and worming it to 0c.
In real life unlike test chambers the air have not been at the same temperature for many hours, and humidity is unstable when near 0c.
Late to this tread, but just to add that Samsung do publish two tables of maximum heating capacity data for their heat pumps, one for peak value and a second for integrated value. The peak values are without defrost operation in accordance with EN14511 and the integrated values represent actual capacities in an installed environment.
So the integrated values have allowances for defrost cycles, and this is confirmed by identical data for ambient temps of 7C and above, but the integrated maximum heating capacity values are lower at 2C, -2C, -7C. As temps fall below -10C, the data converges again, as presumably the air is too cold (and thus dry) to cause frosting.
For reference, the Samsung quoted integrated maximum heating capacity values are 86% at 2C, 88% at -2C, and 96% at -7C of the peak maximum heating capacities, respectively. These data seem reasonable given the experimental data presented above.
I would add to @Old_Scientist’s observation that the tabulated Samsung data appear to correspond to a compressor motor inverter frequency of 50Hz. Data from a recent test run on my 8kW nameplate HP (at ambient temp +2degC, LWT 50degC) indeed showed 8kW heat output at 50Hz (the same as the Samsung data) but ~10kW at 57Hz (the maximum during the run), and ~4.5kW at 20Hz (the minimum during the run).
So the phrase “peak value” may need to be qualified when comparing between HP makes.
I tested my Arotherm+ 55/6 at full blast at 0°C today, maximum power reached at 2500 W and maximum output power at 7500 W but only 4.6 kW average during these 2.5 hours. 99% humidity outside.
It could not even reach the desired maximum temperature of 40°, maybe because the usual temperature is low (heat curve 0.25)
House is 230sqm
. 144sqm UFH with 9 loops
. 5 1sqm radiators for the rest
It’s my first winter and each time ext temp went under 1C, it’s been foggy… Worce case scenario indeed. I’ve never seen higher defrost frequency than those 2 per hour for this test luckily
I little bit out of topic but I think your heatpump is underpowered. Is it a hybrid sustem? What is your walls insulation thickness, and what type of windows and doors you have installed?
) - unfortunately Panasonic only indicate compressor Hz in their controls and provide no cross reference to actual compressor duty % and max Hz varies with model depending on compressor mapping etc, so in this case (~77Hz) it’s an educated guess it’s maxed out, but there may be a little left in the tank? But its peak output is actually higher than their data sheet at around 7.4kW
