Sorry yes the old data is there! great! here’s the change over:
COP jumps up from 3.98 over this first period with outside temp at ~7C:
up to 4.96 over this second period with the 8 kW unit installed:
Lower mean flow temperature delivers the results! and % carnot is a bit higher.
That’s 3 examples of just downsizing the unit resulting in pretty decent improvements in COP…
Here’s a very quick attempt at setting the oversizing factor based on compressor size of the Daikin’s , I’ve removed the daikin splits and HT models as they are another model range.
Maybe it’s just the reality that performance is dependent on so many other factors causing a wide spread of values that makes it appear like there is no trend when plotting oversizing factor vs SPF on the chart.