Heat pump vibrations and noise

[Sandro]

Yeah got it back 4 days ago with a new pump. The new pump behaves just as bad as the last one did. So I am starting to think that it should perhaps be like this?

[Vasarolli]

I have same issue, heat pump, small vibration on steering wheel (bottom area) and you can well hear the pump running. Inside and of course outside as well. Of course temp is -10 here in Finland, and pump is running all the time...

[RichR]

I wonder why I can't notice any vibration or noise at all on mine? I can hear fans but they're not really that obvious unless listening specifically for them. There's a lot more noise from the tyres for example. It's not that I've got the extra acoustic insulation in Convenience Plus is it?

Outside, yes the whole climate control system is quite noisy - mainly the radiator fan, but I can also hear the higher pitched noise from the compressor and coolant pump. No more noisy that my old Outlander PHEV though, and certainly less noisy than my wife's diesel VW

[Vasarolli]

When moving you can't hear nor feel it. When parked or at a traffic light I can. Not too bad for my ears (but hearing is not my superpower anyway)

[RichR]

Ah - I tested whilst moving last night.

[DazF05]

I can only say like RichR I have never noticed it

But I also hardly ever go above 18deg

I’ll test it next time I use the car

[Goaty]

So does the heat pump not really do anything unless a temperature of, say 23C or above, is selected? In other words, it won’t provide any noticeable benefit on range against a non-heat pump Enyaq if they’re both heated at say, 20C ? I’ll have to re-read RichR’s detailed description from last week again, to understand fully. Not that it really matters to me, as I already have my Enyaq… but still good to know.

[RichR]

Yes - it should work whenever any heat is required in the cabin. It simply works in the same way as aircon (or a fridge), by expanding a liquid refrigerant into a gas in close proximity to the hot liquid coolant from the motor and battery. That causes it to remove heat from the coolant into the refrigerant. Then that refrigerant is compressed again, which causes it to get hot (ie the heat that it gained is now released) and then outside air is passed though a radiator to transfer some of that heat into the air going into the cabin. It can work to move heat from the motor/battery to the cabin, or from the cabin to the outside (eg as aircon to cool the interior). Or a hybrid state where it can heat the battery a little whilst cooling the cabin.

The reduction in energy consumption comes from not having to use the 6kW PTC heater (like a hairdryer) once the motor and battery are hot. The same as a petrol/diesel car - waste heat from the engine cooling system is used to heat the cabin. The car will use the PTC when the motor and battery are cold, but once you've driven a few miles at a decent speed they'll warm up. Same as in a petrol car - if you just pop to the local shops at around 30mph, you won't get much heat out of the vents. But if you do 20 miles at 60mph you will. On a non-heat pump car you still have a similar 5kW compressor but it's only doing cabin air cooling and drying. So if you want warm, dry air (normal for winter) then you're running both the PTC heater and the compressor. But on a heat pump equipped car, you're just running the compressor, not the PTC heater.

I guess the vibration is probably only noticeable when the system is working really hard to raise the cabin temperature by more than 10 degrees. Once it's just maintaining a temperature, it won't be working as hard. Perhaps if it's having to move a lot of heat from the motor/battery to the cabin because a lot of heat is being lost through the windows (eg in a Finnish winter), then it'll be running at a higher speed. Whereas the amount of heat being lost from a cabin at 20C to the outside UK air of about 10C at the moment won't require it to even be on a lot of the time, just kicking in occasionally to provide a boost. The bulk of the waste heat from the motor and battery will just be lost to the air through the liquid coolant radiator, just as in non-heat pump (and indeed petrol/diesel) cars.

Question for those who feel the vibration/noise - do you have the climate control on automatic, or manual? It won't work anything like as efficiently unless it's in full automatic mode, so perhaps if you have it on manual that might partially explain why it's having to work so hard?

[DazF05]

Hello

I have just tried every combination and no vibration or unexpected noise at all

??????

[Vasarolli]

-10c outside, set to +20c inside, auto mode