LG Therma V - how to monitor COP

[Beef]

I have a 16kW Therma V, installed in the summer. 

 

I'm happy enough with the result - house is warm, water is warm, but I can't see how I can tell/monitor what the COP is on the installation. 

 

I've looked through the control panel, and the app, but nothing stands out.

 

Is there a way to monitor the COP, or have I misunderstood a fundamental concept? 

 

Thanks in advance

[ReedRichards]

You haven't misunderstood.  The Therma V has all the data to give you a COP reading but it doesn't.  But anyway it's really the annualised figure, the Seasonal COP, that matters.  

[Beef]

I see, that's unfortunate. 

 

How do I determine the actual seasonal COP? I want to be sure I'm getting the performance quoted 

 

Thank you! 

[ReedRichards]

I'm sorry  but you can't do that either.  You can install measuring equipment that will determine your COP and thus your SCOP.  At the time my Therma V was installed it was a requirement for the heat pump to have a dedicated electricity meter so I can tell exactly how much electricity my heat pump uses - but I don't think that is done anymore.  And my EPC has a very inaccurate estimate of the heat and hot water requirements for my house so I can make an equally inaccurate estimate of my SCOP.

[JohnMo]

7 hours ago, Beef said:

How do I determine the actual seasonal COP?

You can take a guess at it, but the only real way is

 

Install a heat meter in the water pipes from or too the heat pump, this will have tappings in to the flow and return to measure water temperature. This then calculates kW and logs the data, to give kWh. You then need an electric meter or two, depending on how power is derived for the package, any external pumps and if you use an immersion. All these numbers are logged instantaneously and calculated to give kW and kWh. They will also give CoP and rolling SCoP in the software.

 

SCoP, is function of running CoP and standby CoP. More time you spend on standby, the worse the SCoP. I can get a CoP of 6 when running at 7 degs outside, but spend quite awhile on standby also, so will end of with a daily CoP nearer 4. That's running full WC, but it's also a function of heat loss rate and heat pump over/under sizing. Lots of things at play.

 

Really look to get the system performing, so it keeps the house warm first, log what's happening so you understand what the heat pump does and doesn't do. If a thermostat is switching on off in the house, your system needs to tweaked.

 

 

[Beef]

Ok, so I have data in home assistant showing the in/out water temps, plus the amount of electricity it's consuming. I have a separate meter for the heat pump (and another for the immersion), and I've confirmed that home assistant is pretty accurate with what it's recording

 

So can I somehow calculate SCOP from that? In these cold days it's running 24/7 - I only have the reused Nest acting as an over-temp cut off.

 

Interestingly, my pump gently cycles up and down during the day; it's not the defrost cycle as that looks different, but I've attached a screenshot showing what I mean. It's not causing any problems - the house is warm - so I'm figuring this is just hysteris, but would like to confirm.

 

Thank you both for your advice and help, it's really appreciated