What's your monthly SCOP

NedS

Reed_Richards said:

michaels said:

I find it annoying that our LG has no night time 'set back' which out previous Viessman gas boiler had on weather comp mode.  We don't really want to switch it off overnight and actually don't currently have the controls to do so.  Being such a newbie I would actually like it to get much colder so we can see how it performs against more of a challenge....

I can confirm that later models are no better.  You can use the control panel to set back the target temperature but you would have to set an alarm, get out of bed and then manually set it back to normal, if you want it to be warm enough by the time you get up again at your regular hour.  There is no way to program this that I have ever found.  
  

My Samsung is no different - I can easily adjust the WC set point (LWT) up or down by 5C, so could knock my flow temps back from 35C to 32C overnight for example, but there is no way to programme this.

For finer control I use my 3rd party wireless programmable room stat where I can set up to 3 daily schedules to turn on/off at different room temps. So I could set a daytime temp of 20C, evening temp of 21C and an overnight setback of 18C, and the room stat will simply call for heat as required with the ASHP operating to it's WC settings as determined by the outside ambient temp. If I were on a SVR as opposed to Agile, this is exactly how I would run the system as we like it a bit warmer in the evening and cooler overnight for sleeping.

Actually, our system seems to have been designed extremely well, as when all rads are fully opened, and the main living space is heated to 20C, the bedrooms are around 18C so no set back is required as those rooms are cooler by design anyway (MCS recommends 21C for living spaces, 23C for bathrooms and 18C for bedrooms)

matelodave

Interestingly my 14 year old Daikin has the ability to shift the w/c slope by +/- 5 degrees in one degree steps, either manually or under control of the schedule timer.

So thats what I do, it automatically shifts down by -4 degrees at 21:30 and comes back up to it normal setting at 07:00. If I do tweak it a bit, it always reverts to normal at the next change. I can set up to five settings/times per day.

It doesn't have a posh graphical interface - it uses a multitude of codes to select the functions to change parameters so I produced a table of codes and settings (based on the default settings in the commissioning manual) and then when I tweaked them I recorded the changed settings in extra columns so I could see what I did and what effect it had (it also enabled me to step back if I totally cods it up).  I haven changed it now since 2012.

I cant actually work out the SCOP but based on my EPC, the MCS certificate and the amount of energy that I estimate that it uses (based on the difference between my summer and winter electricity consumption) I guess I'm getting around three.

Exiled_Tyke

matelodave said:

Interestingly my 14 year old Daikin has the ability to shift the w/c slope by +/- 5 degrees in one degree steps, either manually or under control of the schedule timer.

So thats what I do, it automatically shifts down by -4 degrees at 21:30 and comes back up to it normal setting at 07:00. If I do tweak it a bit, it always reverts to normal at the next change. I can set up to five settings/times per day.

It doesn't have a posh graphical interface - it uses a multitude of codes to select the functions to change parameters so I produced a table of codes and settings (based on the default settings in the commissioning manual) and then when I tweaked them I recorded the changed settings in extra columns so I could see what I did and what effect it had (it also enabled me to step back if I totally cods it up).  I haven changed it now since 2012.

I cant actually work out the SCOP but based on my EPC, the MCS certificate and the amount of energy that I estimate that it uses (based on the difference between my summer and winter electricity consumption) I guess I'm getting around three.

This is helpful. Thanks.  Where is the WD slope shift setting? I'm sure I've seen it but it would be helpful to go straight to it.  

As someone else has pointed out to me (who I should really be crediting) you can get  energy input and output readings from the MMI.  For (I think) on a day, month or all time basis. So you can calculate changes in COP but only by taking regular readings and doing the maths yourself. 

matelodave

I dont know about your controller but mine is 14 years old and is probably nothing like yours - have a look in your operating or commissioning document to see how to do it or even have a shufti on t'interweb. There are usually lots of Youtube videos on how to adjust and set up the controllers or you can download the appropriate documents. 

Tells what you've got an possibly someone on here could help if yours does actually have that function.

Mine is pretty basic, it doesn't do any calculations or estimations, it's just a basic controller to set the operating parameters and set time/temp schedules for heating, hot water

this is my controller (the video is pretty rubbish, but it gives you an idea of how it is programmed) - https://www.bing.com/videos/riverview/relatedvideo?q=daikin heat pump controller manual&mid=D2FB93603C125225B1A7D2FB93603C125225B1A7&ajaxhist=0 You'll note that he doesn't tell you how to programme in weather compensation parameters as these are in the engineers menu however you can programme the weather compensation offset just like he show you

As I said you really need to study all your documentation to find out how to programme yours. Most controllers have an engineers and/or commissioning mode which has to be accessed to enable some of the more in depth tweaking which avoids the un-initiated from making random adjustments and upsetting the system.

michaels

So I am trying to do a back of the envelope COP calculation.

Between 10AM and 11AM my heat pump drew 1.21kwh.

For 45 minutes it circulated the water at flow 43, return 37 at a rate of 0.85m3 per hour  (I have a heat meter but the flow and return temp probes are not giving accurate readings but I can measure the flow).  For the other 15 minutes it slept and the flow and return were equal (this is of course a simplification as it went off and back on so had a cooling and warming period but I think these probably cancel out).

By my calcs this is a transfer of 4.45kwh of heat into the house.

4.45 / 1.21 give a COP of 3.68.  Which I think sounds ballpark for air temp 6C and flow temp 43C?

Heat pump is a 12kw LG U32 model which I think means at last 6 years old.

Spies

The manual method is to take your litres per minute, divide it by 60 to get kg/s, then do the following

4200 (assuming plain water) x kg/s x delta T = heat output in watts

then take the heat output and divide it by your instantaneous power usage and it gives you your live COP

michaels

Spies said:

The manual method is to take your litres per minute, divide it by 60 to get kg/s, then do the following

4200 (assuming plain water) x kg/s x delta T = heat output in watts

then take the heat output and divide it by your instantaneous power usage and it gives you your live COP

Thanks, seems to be the same calculation and gives the same answer.

michaels

How are the current temps impacting cop? We probably averaged zero outdoors for the last 24 hours and our cop is probably only about 2.75. Shame that you need the most output when the cop is lowest! 

matt_drummer

Mine is 4.5 including dhw at 1c average outside today.

No defrost so far this year.

michaels

matt_drummer said:

Mine is 4.5 including dhw at 1c average outside today.

No defrost so far this year.

That sounds very good indeed, what does your heat pump documentation claim for that outside temp and your flow temp?