Daikin ASHP COP

[Marko]

Hi All,

 

New to ASHPs, but, just had a Daikin Altherma low temp. fitted. I kind of feel out of my depth trying to figure out if my system is preforming at it's best because it does not seem to offer much in terms of data output apart from the separate energy meters the sparky's installed which only gives total energy consumption from the outdoor unit and the control panel. 

 

I thought that I would start by trying to figure out the COP but I don't understand how I would go about determining the heat/energy that the unit has produced. All I have is the bog standard controller. Does anyone know how to do this or if I need to install a LAN adaptor to be able to log into the Daikin app to derive this kind of performance data?   

[Marvin]

Do you have a manual with it?

 

In the manual it talks about an interface on the internal unit: 

 

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.daikin.co.uk/content/dam/document-library/operation-manuals/heat/air-to-water-heat-pump-low-temperature/EHVH-CBV,%20EHBH-CBV_4PEN449973-1-2016-06_Operation%20manual_English.pdf&ved=2ahUKEwibpe-DoYT0AhV1QkEAHahuDuMQFnoECCwQAQ&usg=AOvVaw15it6mvGhTdBC9MrbQtSqM

[Marko]

Thanks Marvin. Yes, been looking and apparently there is an interface/LAN adaptor you can buy separately (roughly £200) to compliment the system. I'll have a bit more dig into the matter.

[SteamyTea]

16 hours ago, Marko said:

I thought that I would start by trying to figure out the COP but I don't understand how I would go about determining the heat/energy that the unit has produced. All I have is the bog standard controller

You can calculate it from the flow and return temperatures, but then you have to have a guess at flowrate.

[Marko]

4 hours ago, SteamyTea said:

You can calculate it from the flow and return temperatures, but then you have to have a guess at flowrate.

 

Can you? The controller does show a flowrate. What's the formula? Worthwhile having a go.

[SteamyTea]

https://en.m.wikipedia.org/wiki/Coefficient_of_performance

 

 

[MattB67]

Do we need flow rates? The Daikin units give kwh in and kwh out. 

 

I have an newly installed Daikin Altherma 3. I've been going up and down the loft ladder because the Daikin app only gives energy input, not heat output (Doh!). On the Altherma 3 indoor unit you scroll through the menus to Information > Energy data > Electricity Input to get the kwh used. Then go back a level to Information > Energy data > Heat Produced   Both of these display bar graphs which you can scroll through, and change using the left and right dials. Note that it shows Today/Yesterday, This week/Last week and This year screens. But also on the right hand side are three different symbols, a sun for heating, a shower head for hot water and a Greek thingy, which I guess is the two combined? So whatever your checking, make sure your electricity input and heat produced have the same symbol on the right, or you might be dividing the wrong figures.

 

I thought all you needed to do was divide one by the other for COP? My system is not working properly, so on 31st Oct I got 11kwh used, 28kwh produced, 28/11 gives a COP of 2.54 - which is rubbish, and what I've just joined to post about!

[SteamyTea]

3 minutes ago, MattB67 said:

on 31st Oct I got 11kwh used, 28kwh produced, 28/11 gives a COP of 2.54

It does depend on the absolute flow temperatures and the outside air temperature, and if the auxillary resistance heater kicked in.

Getting 2.5 times the energy input seems OK to me.

 

And it is kWh, not kwh.

[Marko]

4 minutes ago, MattB67 said:

Do we need flow rates? The Daikin units give kwh in and kwh out. 

 

I have an newly installed Daikin Altherma 3. I've been going up and down the loft ladder because the Daikin app only gives energy input, not heat output (Doh!). On the Altherma 3 indoor unit you scroll through the menus to Information > Energy data > Electricity Input to get the kwh used. Then go back a level to Information > Energy data > Heat Produced   Both of these display bar graphs which you can scroll through, and change using the left and right dials. Note that it shows Today/Yesterday, This week/Last week and This year screens. But also on the right hand side are three different symbols, a sun for heating, a shower head for hot water and a Greek thingy, which I guess is the two combined? So whatever your checking, make sure your electricity input and heat produced have the same symbol on the right, or you might be dividing the wrong figures.

 

I thought all you needed to do was divide one by the other for COP? My system is not working properly, so on 31st Oct I got 11kwh used, 28kwh produced, 28/11 gives a COP of 2.54 - which is rubbish, and what I've just joined to post about!

 

It sounds like you have a newer model than mine. The one I have looks like the controller hasn't been updated since circa 2013 and only displays energy used. So the Daikin app doesn't even give you any usable data? Have you registered for the Daikin Stand by Me? This apparently provides cloud monitoring, whatever that means. I haven't registered my system yet as I'm still chasing the installer for my commissioning code etc. 

[SteamyTea]

6 minutes ago, Marko said:

still chasing the installer for my commissioning code etc. 

Have a look in the user manual, they often write it down in there.

[MattB67]

13 minutes ago, Marko said:

 

It sounds like you have a newer model than mine. The one I have looks like the controller hasn't been updated since circa 2013 and only displays energy used. So the Daikin app doesn't even give you any usable data? Have you registered for the Daikin Stand by Me? This apparently provides cloud monitoring, whatever that means. I haven't registered my system yet as I'm still chasing the installer for my commissioning code etc. 

Ah, that's a shame. Yes, there is quite a lot of useful information on the new Daikin, (installed in September). I think Stand By Me is the Daikin App I have. I got it working for a day, it's quite a complicated setup, and then it refused to work the next day. It's got the ability to set flow temp and desired temp etc, but no heat output. I wonder if it would have anything more useful than what you've already got from the Daikin controller?

 

[SteamyTea]

7 minutes ago, MattB67 said:

ability to set flow temp and desired temp etc, but no heat output

What do you actually mean by 'heat'?

[MattB67]

22 minutes ago, SteamyTea said:

It does depend on the absolute flow temperatures and the outside air temperature, and if the auxillary resistance heater kicked in.

Getting 2.5 times the energy input seems OK to me.

 

And it is kWh, not kwh.

 

Well, this is a brand new install of an expensive ASHP that is supposed to return an SCOP of 3.7, room temp 20C, flow temp 45C.  According to the MCS calculations its saying I should get 12565kWh heat for 3396kWh electricity, making SCOP 3.7. We've been in a mild autumn and it's hovering around 2.5, so will get worse with the colder part of the winter, meaning the SCOP will be below 2.5, which apparently is the minimum requirement for an ASHP to be sold in the EU. Realistically I wasn't expecting 3.7, and thought anything around 3.4 would be fine. But 2.5 in a mild part of the year is not good. I posted the problems I'm having here, https://forum.buildhub.org.uk/topic/24036-advice-needed-before-i-tackle-the-installers/

 

[MattB67]

1 minute ago, SteamyTea said:

What do you actually mean by 'heat'?

kWh heat produced by the unit and put into the central heating system presumably. From the front panel of the Altherma 3 there are two lots of stats,  "Electricity Input" in kWh and "Produced Heat" in kWh. The Daikin app for some reason only shows Electricity Input.

[Marko]

22 hours ago, Marko said:

Hi All,

 

New to ASHPs, but, just had a Daikin Altherma low temp. fitted. I kind of feel out of my depth trying to figure out if my system is preforming at it's best because it does not seem to offer much in terms of data output apart from the separate energy meters the sparky's installed which only gives total energy consumption from the outdoor unit and the control panel. 

 

I thought that I would start by trying to figure out the COP but I don't understand how I would go about determining the heat/energy that the unit has produced. All I have is the bog standard controller. Does anyone know how to do this or if I need to install a LAN adaptor to be able to log into the Daikin app to derive this kind of performance data?   

 

Been doing a bit more digging on this, and in case any one else in the future wonders why the system/controller in these older models does not show energy produced; in the manual you will notice that it indicates it is possible to record energy produced, however it also notes that if glycol is present then this function is disabled. Disappointing, but there you go. 

[MattB67]

5 hours ago, Marko said:

 

Been doing a bit more digging on this, and in case any one else in the future wonders why the system/controller in these older models does not show energy produced; in the manual you will notice that it indicates it is possible to record energy produced, however it also notes that if glycol is present then this function is disabled. Disappointing, but there you go. 

ah, that's annoying. Once you have a winter's worth of bills, you might be able to get a rough estimate of COP with the energy consumed figure on your EPC. For instance, I know I use 5kWh electricity in the spring/summer per day. With eco bulbs it won't be that much more in winter. So I would subtract your daily 'background' consumption from your winter total, maybe then take something off if you run any electric heaters other than the heat pump, or have an electric shower etc. What's left is roughly being used for heating and hot water by the heat pump. You could then divide that consumption into your heat  and hot water requirement on the EPC to get a ballpark figure? 

 

Also I wonder if EPC heating requirement figures are slightly high. I'm not sure if heating requirement is the actual amount needed, or the amount they expect an average gas boiler to consume so that the householder can estimate their bills? I've asked that question on a couple of other forums and no-one seems to know for sure.

 

If an average gas boiler is 75-85% efficient maybe your heat + hw requirement should be multiplied by .75 or .85 to get the actual amount of heat needed. Divide that figure by your consumption and you'll have a very rough idea of COP. BTW, a reason I think EPC figures may be high is that last year my gas boiler broke down, so I used portable electric radiators as my main source of heating, until the Green Homes Grant came through and the heat pump went in at the end of Sept 2021. The EPC says I need 9300kWh heating, but my consumption went up by 6000kWh that year, with portable heaters that are 99% efficient. The house was a bit cold, and I lit the open fire quite often. Even so, that's quite a big difference. 

Edited November 7, 2021 by MattB67

[J1mbo]

19 hours ago, MattB67 said:

 

Well, this is a brand new install of an expensive ASHP that is supposed to return an SCOP of 3.7, room temp 20C, flow temp 45C.  According to the MCS calculations its saying I should get 12565kWh heat for 3396kWh electricity, making SCOP 3.7. We've been in a mild autumn and it's hovering around 2.5, so will get worse with the colder part of the winter, meaning the SCOP will be below 2.5, which apparently is the minimum requirement for an ASHP to be sold in the EU.

 

What controls are you using with it?