@sunandair - I am very aware that at times @jamepa and @derek-m can come across as patronising self-appointed experts who know it all, and the rest of us are but mere ants to be trodden upon by their giant feet. I'm also inclined to the view that @derek-m's alleged (by none other than himself) sense of humour may in fact be clinically rather interesting, and might even yield valuable insights if subject to suitable analysis. But such analysis can only be done in person, and so won't happen.
I also think, and have said before many times, both here and elsewhere, that all analysis must be fully visible, and comprehensible to those with sufficient interest and intellect (which I pitch at around the equivalent of attained, or would have attained, A levels). The moment you have black box modelling you are on a very slippery slope, because others can't verify the claims made by the modellers. I would even go so far as to say it is pseudo-science, because independent verification is absolutely and totally at the core of science, without verification there is no science.
When I was a young junior doctor, most doctors if they put their mind to it could understand most research papers. That meant they could question the results. Over the last couple of decades the methods have become increasingly complex, and I now often find myself totally baffled by the methods and analysis sections of published research. I am not stupid, and if it is all mumbo jumbo to me, then it will also be mumbo jumbo to most doctors. In short, it becomes black box science.
Couple black box science with arrogant and patronising scientists and you have the makings of a very toxic brew. The last time that happened on a global scale was during the covid pandemic, and look what a mess that got us into. The damaging effects of the response to the pandemic, guided by 'the science' (of course there is no such thing as 'the science') are still very much with us today, long after what was in reality mo more than just another (albeit new to a previously unexposed population, so high initial attack rates were to be expected) flu like illness has blended into the background winter respiratory tract infections.
I find this quite offensive. All the analysis I have done has been published and none of it is particularly complicated. The most recent is a very simple regression analysis of your data, and two graphs illustrating the output. The underlying spreadsheet has already been shared.
I do sometimes refer to physics, and in particular the law of conservation of energy, to comment on the data. If others wish to believe in magic then so be it, Id rather trust this law which has been tried and tested for nearly two centuries. Some people deny climate change (although presumably not on this forum).
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
I think @jamespa quoted you are thinking there is only a 5% saving when operating a setback. This obviously seems a small saving for the effort of doing a setback.
I personally don’t think I’m experiencing this in practice. And in an extreme case I recently did a huge setback for 7 days dropping down to 12c IAT. SO SAVING 7days at circa 12kwh per day X 6 and circa 24 kw on the last day when OAT dropped to -3. It took a 24 hour continuous operation at 20c to recover but that only required 40 kWh for that day.
Regarding defrost
this is where there appears to be significant energy increases and recovery time.
the last 24 hours bears this out where yesterday morning at 5c OAT resulted in 16.5kwh whereas this morning it is 2c. So I’ve compiled a few charts showing the significant DT signitures. I’ve placed the charts on a 24 hour graph to relate OAT to the time of 5e heating charts
The difference in energy signature between a soft restart of the HP compared to a post defrost restart is obviously absent in my MELCloud charts but we know they are a significantly burden.
yesturdays estimated energy usage was 16.65 with a COP4.06. I will have to wait for 12pm tonight to see what today’s energy usage will be.
@sunandair If you care to send me that data I will do some sums. I would be delighted to find a 20% saving through a modest setback (by which I mean one that lasts less than 24hrs and doesn't leave you cold in the evening), but so far haven't either a) seen any evidence of it or b) found a way to reconcile it with conservation of energy.
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
I also think, and have said before many times, both here and elsewhere, that all analysis must be fully visible, and comprehensible to those with sufficient interest and intellect (which I pitch at around the equivalent of attained, or would have attained, A levels).
Well at least that allows me to invoke conservation of energy and some basic tests for statistical significance!
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
@cathoderay thanks for that update... 20% is significant
There is a difference between what in medicine we call clinical significance and statistical significance (which is boils down to a test of how likely the results may have arisen by chance). It is possible to have either without the other: you can have something that is statistically significant (usually because the research has been done of tens of thousands of subjects) but clinically meaningless, usually because the effect is so trivial (some alcohol research for example falls into this category) (research that gets an exact answer to the wrong question also falls into this bracket); equally, you can have something that is potentially clinically (practically) significant, but hasn't (yet?) reached statistical significance. This last point tells us we don't know for sure, the apparent results may simply have arisen by chance. This is where we currently are with @jamepa's findings; and on top of this there is the intercept problem. This appears to be why we have results posted showing a 20% reduction which we are now told don't sure a 20% reduction...
Seriously though, the main problem at the moment is lack of data (more data in effect dampens down the role of chance in the results). On this we simply have to be patient: days of data take days to collect. Then we might (or might not) have clearer answers.
Midea 14kW (for now...) ASHP heating both building and DHW
This appears to be why we have results posted showing a 20% reduction which we are now told don't sure a 20% reduction...
I repeat that they do not show a 20% reduction
Here again are the graphs, separately and now overlaid. The crossover where setback gives an advantage is around 14,000 degree minutes per day (average OAT about 10C) and the advantage is only about 3% at 20,000 degree minutes (average OAT about 7C). Projecting this to 24,000 degree minutes (average OAT 4C), the maximum so far this year for which data has been provided, would give 5%. Again for the avoidance of doubt there is still uncertainty so these are not yet conclusions.
I agree its important that explanations are understandable, its equally important that those holding the conversation do not repeat things which have been challenged, unless they can disprove the challenge.
@cathoderay thanks for that update... 20% is significant
There is a difference between what in medicine we call clinical significance and statistical significance (which is boils down to a test of how likely the results may have arisen by chance). It is possible to have either without the other: you can have something that is statistically significant (usually because the research has been done of tens of thousands of subjects) but clinically meaningless, usually because the effect is so trivial (some alcohol research for example falls into this category) (research that gets an exact answer to the wrong question also falls into this bracket); equally, you can have something that is potentially clinically (practically) significant, but hasn't (yet?) reached statistical significance. This last point tells us we don't know for sure, the apparent results may simply have arisen by chance. This is where we currently are with @jamepa's findings; and on top of this there is the intercept problem. This appears to be why we have results posted showing a 20% reduction which we are now told don't sure a 20% reduction...
Seriously though, the main problem at the moment is lack of data (more data in effect dampens down the role of chance in the results). On this we simply have to be patient: days of data take days to collect. Then we might (or might not) have clearer answers.
Have you tried the medical approach to your heat pump problems?
Give it two Aspirins and tell it to call back tomorrow if it is no better. 😋
I find this quite offensive. All the analysis I have done has been published and none of it is particularly complicated. The most recent is a very simple regression analysis of your data, and two graphs illustrating the output. The underlying spreadsheet has already been shared.
No one likes being told they come across as being patronising and arrogant, all the more so if they really are that way. I wrote that earlier remark (knowing full well how it might be received) because I think there have been occasions in this thread where things have got close to that state of affairs, and it is not a pretty sight, not to mention it being a useless way to get the dumb to see the light.
If you read my post more slowly, you will notice that I moved from named individuals to more general comments. You do generally publish your methods as well as your results, which is very much to your credit. My comments were general comments about the toxic combination of black box science and arrogant 'scientists'.
And come off it, of course I 100% accept the laws of physics, and invoke no special magic in such things - such foolish delusions are merely in the minds of the readers. In medicine I am not so sure, maybe sometimes magic does happen there, but that will no doubt cause a terminal fuse to blow in @derek-m's mind, so I won't explore that one any further.
Midea 14kW (for now...) ASHP heating both building and DHW
Have you tried the medical approach to your heat pump problems?
Give it two Aspirins and tell it to call back tomorrow if it is no better. 😋
I guess the difference is that both depend on science, but the science underlying heating systems is both much simpler and much more mature than the science underlying human beings.
I hope we could all agree that, given enough data about the fabric, the heat pump and the weather, (which is not so much more than we actually have) it would be possible to create a model which faithfully reproduces the behaviour of a house in respect of heating. That's not yet remotely possible for a human being.
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
No one likes being told they come across as being patronising and arrogant, all the more so if they really are that way. I wrote that earlier remark (knowing full well how it might be received) because I think there have been occasions in this thread where things have got close to that state of affairs, and it is not a pretty sight, not to mention it being a useless way to get the dumb to see the light.
Fair comment. Sadly I've experienced this many times with the medical profession, although my current GP is actually very good in this respect. I think its also true say that no one likes being told they are wrong, all the more so if they really are wrong!
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
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