Ecodan standby power consumption

[PhilT]

2 hours ago, Tom said:

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.

Presumably you mean 0013kW which would be 24 x 0.013 = 0.312kWh per day which is very low indeed compared to the Ecodan R32

[dpmiller]

2 hours ago, Tom said:

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.

And that, as well as the consumption of the compressor heater are both measured and noted in the TuV energy cert.

[JamesPa]

6 minutes ago, PhilT said:

Presumably you mean 0013kW which would be 24 x 0.013 = 0.312kWh per day which is very low indeed compared to the Ecodan R32

Never presume - it makes an ass of u and me.

 

If the units are wrong then why would you believe the statement?

[PhilT]

17 hours ago, joth said:

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. 

From this and other threads and based on my discussions with Mitsubishi techs it would seem that there is a big trade off between the "wasted" standby energy consumption in the summer months and the stunning efficiencies achieved by the pre-heated compressor in the regular use winter months. My 11.2kW Ecodan R32 heat pump energy consumption in its first full year is c. 3,300kWh which is almost unbelievable given that my (not very old and working perfectly) condensing boiler consumed 21,000kWh in its last full year. There needs to be some way of automating a controlled, damage preventing, energy saving, switch off.

[PhilT]

3 minutes ago, JamesPa said:

Never presume - it makes an ass of u and me.

 

If the units are wrong then why would you believe the statement?

thanks for your constructive and useful comment

[JamesPa]

12 minutes ago, PhilT said:

thanks for your constructive and useful comment

No offence intended, just cautious about statements made by manufacturers where they don't stack up.  Like you I would guess that 0.013kW is what was intended, but I wouldn't want to rely on this given that most people would express 0.013kW as 13W.

[JohnMo]

But they did not say 0.013kW they said 0.013kWh per day. Two different units.

[JamesPa]

3 hours ago, Tom said:

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.

 

24 minutes ago, JohnMo said:

But they did not say 0.013kW they said 0.013kWh per day. Two different units.

Er - not what Tom said - see quote.  0.013kWh per day would be truly stunning at just over half a watt!

[joth]

1 hour ago, PhilT said:

From this and other threads and based on my discussions with Mitsubishi techs it would seem that there is a big trade off between the "wasted" standby energy consumption in the summer months and the stunning efficiencies achieved by the pre-heated compressor in the regular use winter months

 

Have Mitsubishi given any explanation why some of their heatpumps have 5W background usage and others have 250W?  Until they address that I frankly don't believe a word they're saying.

The margin here is wildly beyond simple manufacturing or situational variation. 

 

 

1 hour ago, PhilT said:

My 11.2kW Ecodan R32 heat pump energy consumption in its first full year is c. 3,300kWh which is almost unbelievable given that my (not very old and working perfectly) condensing boiler consumed 21,000kWh in its last full year. There needs to be some way of automating a controlled, damage preventing, energy saving, switch off.

 

What's particularly impressive is of that 3300 kWh, approximately 2000kWh of it was wasted on keeping the compressor warm.

So it only used maybe 1,500 kWh on useful work, vs 21,000 with the old gas boiler. This is starting to sound like the discovery of cold fusion 

 

 

[PhilT]

19 minutes ago, joth said:

 

Have Mitsubishi given any explanation why some of their heatpumps have 5W background usage and others have 250W?  Until they address that I frankly don't believe a word they're saying.

The margin here is wildly beyond simple manufacturing or situational variation. 

 

 

 

What's particularly impressive is of that 3300 kWh, approximately 2000kWh of it was wasted on keeping the compressor warm.

So it only used maybe 1,500 kWh on useful work, vs 21,000 with the old gas boiler. This is starting to sound like the discovery of cold fusion 

 

 

Logical but really needs a definitive answer from a Mitsubishi designer. Till then I'll buy the idea that the c. 5kWh per day compressor preheating is doing extremely useful work in making the heat pump much more efficient during winter months, and in summer months the wasted energy drags the SCOP down to a lower figure than it should be if it were to use some kind of automated summer energy saving switch off scheme.

[Tom]

2 hours ago, JamesPa said:

 

Er - not what Tom said - see quote.  0.013kWh per day would be truly stunning at just over half a watt!

 

 

Quote from Cool Energy: "The standby power consumption of all of our inverTech range is 0.013kW/h or 312w per 24hours as per our independent TUV test data."

[SteamyTea]

2 minutes ago, Tom said:

 

 

Quote from Cool Energy: "The standby power consumption of all of our inverTech range is 0.013kW/h or 312w per 24hours as per our independent TUV test data."

They don't know what they are talking about.

 

A watt is a joule per second.

So if you divide 312 J/s by the seconds in a day (86,400 s)

0.00361 J

There are 3.6 million joules in a kWh.

To convert joules to kWh, multiple by 2.777778x10^-7 

1.0027777778x10^-9 kWh

A number so small, it is meaningless.

 

I often get messages to stop being finickity about SI units.

This is the reason I am a complete (expletive deleted) about them, to stop people getting confused.

 

Learn the units, and the derived units i.e. W, J, kWh, then you can spot nonsense quickly.

 

It is W, for watt, not Watt, that was the man, or w, that is, when italiced, often used for angular momentum.

Similarly, J is for joule, Joule was the man, lower case j is used by engineers, in mathematics (not a science) for an imaginary number, it should really be i, for imaginary.

[joth]

20 minutes ago, Tom said:

Quote from Cool Energy: "The standby power consumption of all of our inverTech range is 0.013kW/h or 312w per 24hours as per our independent TUV test data."

Wow. The main thing this tells us is Cool Energy have absolutely no idea how Energy is measured.

A constant 13W load is 312Wh per day, so let's go out on a limb and assume that's what they meant?

 

Edited May 29, 2022 by joth

[Tom]

6 minutes ago, SteamyTea said:

They don't know what they are talking about.

 

A watt is a joule per second.

So if you divide 312 J/s by the seconds in a day (86,400 s)

 

Wouldn't you multiply?

[Tom]

4 minutes ago, joth said:

Wow. The main thing this tells us is Cool Energy have absolutely no idea how Energy is measured.

A constant 13W load is 312Wh per day, so let's go out on a limb and assume that's what they meant?

Yep, that's what I assumed. Though maybe I'm an ass

[joth]

43 minutes ago, PhilT said:

Logical but really needs a definitive answer from a Mitsubishi designer. Till then I'll buy the idea that the c. 5kWh per day compressor preheating is doing extremely useful work in making the heat pump much more efficient during winter months, [...]

 

I don't buy a word of this. In January this year my 8.5kW ecodan consumed  5kWh per day *total* on heating a 151m2 house plus all DHW.

If it was spending 5kWh warming up the great outdoors with a  compressor heater it would halve the efficiency.

Edited May 29, 2022 by joth

[SteamyTea]

40 minutes ago, Tom said:

Wouldn't you multiply

I was showing that a watt, divided by an hour, kW/h, is a nonsense unit. We have the joule to describe that. J/s/s =J.

May email to them in the morning to clarify what they mean.

They could mean that that mean power was 312 W when measured over a 24 hour period.

Which gets us back to the starting point of this thread.

Edited May 29, 2022 by SteamyTea

[dpmiller]

Lifted out of the TUV certificate

[SteamyTea]

3 minutes ago, dpmiller said:

Lifted out of the TUV certificate

So a 38 W heater, and 9 W.

Total of 47 W some of the time.

Or.

That 38 W could be an average. But that would be a strange way to show it.

 

[MikeSharp01]

1 hour ago, SteamyTea said:

finickity about SI units.

Don't worry the government are about to launch a consultation about bringing back imperial units. That will mean talking about, BTU, foot pound / seconds  & horsepower (and have to deal with the fact that HP differs by country), instead of Joules, and Watts. 

[JohnMo]

Another nonsense, waste of tax payers money - more living in the past

[SteamyTea]

21 minutes ago, MikeSharp01 said:

foot pound

Don't you mean pound-foot for torque.

Force at a distance.

 

Or were you talking about Moments of an axis.

 

That Lsd we had in the early 70s, been replaced with Ritalin.

 

Will be interesting to see how this government (expletive deleted) up changing back to imperial units.

Will be using the erg before we know it.

One pound, lifted one foot is 1.356 × 10⁷ ergs.

Edited May 29, 2022 by SteamyTea

[PhilT]

1 hour ago, joth said:

 

I don't buy a word of this. In January this year my 8.5kW ecodan consumed  5kWh per day *total* on heating a 151m2 house plus all DHW.

If it was spending 5kWh warming up the great outdoors with a  compressor heater it would halve the efficiency.

Isn't your heat pump massively over-capacity based on that peak usage - that's a jaw dropper - which model number is yours? Mine is a PUHZ-W112VAA. It's all very puzzling - the mission to understand goes on...

[MikeSharp01]

8 minutes ago, SteamyTea said:

pound-foot for torque.

Force at a distance.

Nope foot-pound/seconds, to be frank I dredged it up from my far distant memory so  I could be well wrong but based on 1 kg⋅m2⋅s−3.

[SteamyTea]

3 minutes ago, MikeSharp01 said:

Nope foot-pound/seconds, to be frank I dredged it up from my far distant memory so  I could be well wrong but based on 1 kg⋅m2⋅s−3.

Ah right. Yes, thought the / second may have been angular seconds. 

 

Getting hungry, need a quarter pounder, which is 417 calories per 0.37699 lb.

Not sure if that is with cheese.