Ecodan standby power consumption

[ReedRichards]

We never established if the problem was confined to split stage Ecodans (and possibly other makes).  There was some suggestion that it was.  We don't know what type @joth's friend has or @JamesPais thinking of getting and this could be rather important.    

[JamesPa]

3 hours ago, ReedRichards said:

We never established if the problem was confined to split stage Ecodans (and possibly other makes).  There was some suggestion that it was.  We don't know what type @joth's friend has or @JamesPais thinking of getting and this could be rather important.    

In answer to the above Im thinking of the 11kW monobloc.

[joth]

5 hours ago, JamesPa said:

In answer to the above Im thinking of the 11kW monobloc.

That's exactly what my friend has. Basically same as me (same installer, even the same Oso geocoil UVC) just one size up ASHP.

[ReedRichards]

My LG Therma V monobloc consumed 60 Wh in 7 hours overnight, according to its dedicated meter.  It should have been on "standby" the whole time.

[Radian]

2 hours ago, ReedRichards said:

My LG Therma V monobloc consumed 60 Wh in 7 hours overnight, according to its dedicated meter.  It should have been on "standby" the whole time.

~£75p.a. @ 30p/unit - still, for comparison, a single Echo Dot or Google assistant would cost ~£26p.a.

[SteamyTea]

60 ÷ 7 = 8.6 

Seems reasonable.

[Radian]

50 minutes ago, SteamyTea said:

60 ÷ 7 = 8.6 

Seems reasonable.

 

Yes indeed.

 

So WTF did I calculate in my previous our post... Oh, the same 8.6Watts divided by 1000 to make into kWh then times 24*365 to get 75kWh p.a. Should have multiplied that by 30p/unit and come up with the proper answer £22.50 p.a. I accidentallly skipped that bit 🙄 same for smart speakers - more like £8 p.a. to run.

[SteamyTea]

19 minutes ago, Radian said:

 

So WTF did I calculate in my previous our post

Should really be just the standby usage.

So multiply by the fraction it is not producing.

[markocosic]

sCOP calc description:

 

https://studylib.net/doc/6625073/calculation-of-scop-for-heat-pumps-according-to-en-14825

 

This should include standby

[PhilT]

I have an Ecodan 11.2kW. I switched off my main consumer unit leaving just the dedicated supply for the Ecodan pump and control system running at 24W background idle, agreeing with previous posts. Must be the control system. Whatever the standby consumtion may be, all I know is that in its first full year it has produced absolutely stunning results - 3,600kWh of electricity consumption for the year compared to 21,000kWh worth of gas the previous year. I'm having trouble believing the figures but if real that's certainly one way to help solve the energy crisis!!!

[PhilT]

On 09/05/2022 at 15:30, PhilT said:

I have an Ecodan 11.2kW. I switched off my main consumer unit leaving just the dedicated supply for the Ecodan pump and control system running at 24W background idle, agreeing with previous posts. Must be the control system. Whatever the standby consumtion may be, all I know is that in its first full year it has produced absolutely stunning results - 3,600kWh of electricity consumption for the year compared to 21,000kWh worth of gas the previous year. I'm having trouble believing the figures but if real that's certainly one way to help solve the energy crisis!!!

Seems I was completely wrong about this I must have taken a measurement when the compressor heating was at that moment not required. The compressor temperature is maintained while idle and my heat pump uses between 4 and 6 kWh per day when switched on but not heating either radiators or DHW. Mitsubishi tech support say although the manual specifies a 12 hour wait between switching on and use this can in fact be as little as 4 hours without any problem. TBH I can't see why it should take 12 or even 4 hours to simply heat up the compressor - anyone know why it has to be such a long wait?

[ProDave]

Just to add by way of comparison with other makes. My LG Therma V in the last few weeks has metered precisely 0 kWh when idle (i.e. any time it is not  heating DHW) as there is no space heating use at present.  This confirms the only metered use when idle is when it invokes it's anti frost water circulation function when it's very cold outside.   And it's only averaging 3.5kWh per day heating DHW.

[SteamyTea]

2 hours ago, PhilT said:

my heat pump uses between 4 and 6 kWh per day when switched on but not heating

That is about what I use a day this time of year.

 

[joth]

4 hours ago, PhilT said:

The compressor temperature is maintained while idle and my heat pump uses between 4 and 6 kWh per day when switched on but not heating either radiators or DHW.

That's insane. That's 45 times more than my ecodan 8.5kW is using on standby.

If it's true you need to get it fixed. Having a 250W heater permanently heating the compressor sounds both unbelievable and criminal.

 

[ProDave]

47 minutes ago, joth said:

That's insane. That's 45 times more than my ecodan 8.5kW is using on standby.

If it's true you need to get it fixed. Having a 250W heater permanently heating the compressor sounds both unbelievable and criminal.

 

Agreed.  6kWh per day of "wasted" energy is almost as much in a year as my ASHP consumes doing something useful with it like heating the house or the hot water.

[LA3222]

5 hours ago, PhilT said:

Seems I was completely wrong about this I must have taken a measurement when the compressor heating was at that moment not required. The compressor temperature is maintained while idle and my heat pump uses between 4 and 6 kWh per day when switched on but not heating either radiators or DHW. Mitsubishi tech support say although the manual specifies a 12 hour wait between switching on and use this can in fact be as little as 4 hours without any problem. TBH I can't see why it should take 12 or even 4 hours to simply heat up the compressor - anyone know why it has to be such a long wait?

That tallies up with my figures. I removed the monitoring system I have from all but the ASHP supply and used the main ct clamp which goes on the incomer to make sure it is true power or whatever being measured. Still seems to show 200W plus being used constantly. I'm away for a couple of days soon and intend to kote the main meter readings before and after (turning the fuses off for as much stuff as I can) as a final confirmation of this constant power drain. 

 

I find it odd that some ecodan uses have identified this drain, discussed with tech support who confirm its normal but then others with the same model claim they don't see the same power drain. Strange.

[MikeSharp01]

It is odd given that you could use something like the EPS32 mini in a light sleep to watch over it and that would cost about 3p per year to run and be ready for action on reciept of a prod via wifi, Bluetooth, it's RTC or one of its pins.

[SteamyTea]

1 minute ago, MikeSharp01 said:

It is odd given that you could use something like the EPS32 mini in a light sleep to watch over it and that would cost about 3p per year to run and be ready for action on reciept of a prod via wifi, Bluetooth, it's RTC or one of its pins.

It may still take a few hours to warm the compressor up.

It is the compressor design/shortcomings that seem to be the problem.

It is probably built down to a price, and to keep the warrantee/reliability it has to be constantly warm. 

[JohnMo]

Wow - Is that £400+ to be in standby for a year?

 

Just found this article on the subject from 2013, they should certainly drop the eco from the name.

 

https://heatpumps.co.uk/2013/08/13/stand-by-power-and-air-source-heat-pumps/

[MikeSharp01]

34 minutes ago, JohnMo said:

https://heatpumps.co.uk/2013/08/13/stand-by-power-and-air-source-heat-pumps/

Looks like nothing much has changed in 9 years then - this is close to obscene in the sense that we are all being encouraged to fit these devices for 'eco' reasons and yet the devices themselves are not so eco as all that. Looks like the scroll compressor driven units do not exhibit this effect so that's the way to go + asking what the standby current is for a unit you want to start instantly.

[JohnMo]

I think it depends more on how the bearing and compressor are lubricated.  The compressor can run dry with bearing away from the refrigerant gas or be lubricated with compressor flooded with oil, the same oil lubricates the bearings.  Sounds like the ecodan compressor is a flooded compressor, the lube oil works fine while the compressor gas is in the gaseous phase, but when it turns to the liquid state; on compressor cool down, the lube oil no longer lubricates.  So a typical start up would be, heat oil within the compressor, flash off refrigerant to gas phase start compressor.  Possibly a 15 to 20 minutes delay in startup.

 

So during the heating season the operation of the heat pump, would be, lowest temperature for central heating possible run 24/7 (weather compensation) except for when doing DHW heating.  At least that way your standby losses are confined to none heating periods.

[ProDave]

I guess the message from this thread is ask the manufacturer before you order an ASHP, what is the standby power consumption in kWh per day.  And then if you measure more than they quoted, then complain.

[joth]

5 hours ago, ProDave said:

Agreed.  6kWh per day of "wasted" energy is almost as much in a year as my ASHP consumes doing something useful with it like heating the house or the hot water.

We use about 0.5kWh on DHW per day (for about 1.5kWh of heat delivered into the tank).

So is we were one of those taking 6kWh just on ASHP standby, we'd save about £250 per year shutting of the ASHP completely for 6 months over summer and exclusively using the immersion heater instead. 

[Tom]

Apologies if this might already have been posted, but heard from Cool Energy yesterday (from the MD, about 30 mins after emailing - which I guess is quite impressive) that their 9kw inverTech unit consumes 0.013kWh on standby.

[SteamyTea]

2 hours ago, Tom said:

0.013kWh on standby

Over how long?

An hour, day, week, month, year, decade?