Heat pumps in the MG4

[Corindikev]

Not sure where you're getting your info from but as a Finn, I can tell you with confidence that there are ASHP's that work well to heat a home even at -25C temps and colder (efficiency does drop but they still work).

This is from Mitsubishi in Australia but I note there have been new developments specifically by both Misubishi and Toshiba in Finland with specially developed cold climate air sourced heat pumps with a heat coefficient of performance (COP) above 2.0 at temperatures as low as -20c and between 1.5 & 2.0 for the Mitsubishi at -30 deg C.

Coming in from the cold: Heat pump efficiency at low temperatures

So you are quite correct but I do not think this latest development will have made its way into EVs yet

 

[jiiikoo]

This is from Mitsubishi in Australia but I note there have been new developments specifically by both Misubishi and Toshiba in Finland with specially developed cold climate air sourced heat pumps with a heat coefficient of performance (COP) above 2.0 at temperatures as low as -20c and between 1.5 & 2.0 for the Mitsubishi at -30 deg C.

Coming in from the cold: Heat pump efficiency at low temperatures

So you are quite correct but I do not think this latest development will have made its way into EVs yet

Oh absolutely, no EV will be using these pumps. At least not in the foreseeable future.

 

[siteguru]

FWIW I've just watched a review (by Bobby L of the Fully Charged Show) of the BYD Seal and in there he mentions that the heat pump has an operating range of -30 to +60C ?‍

 

[Archev]

I think the range of a GSHP-equipped car might be a little limited.

What about these poor souls with water in their boots ???

 

[WonkoTheSaneUK]

What about these poor souls with water in their boots ???

If their local Boots is flooded, they should go to Superdrug instead? ?

 

[fnegroni]

I had a corsa-e which I believe used a heat pump.
In my experience it was abysmal.

 

[Corindikev]

FWIW I've just watched a review (by Bobby L of the Fully Charged Show) of the BYD Seal and in there he mentions that the heat pump has an operating range of -30 to +60C ?‍

That is an amazing claim and appears to be right at the bleeding edge of heat pump technology.

This is what their website says

"An advanced energy-saving heat pump system comes as standard. Reliably operating in a broad range of temperatures, the system is designed to highly utilise residual heat from surroundings, the powertrain, passenger compartment and even the batteries. It enhances the thermal efficiency and reduces energy loss whether heating or cooling. Therefore, the low-temperature driving range is increased."

No mention there of actual operating range.

 

[DougalDog]

They will have pre-heat, actually air source in my experience starts to struggle below 6c. Its to do with the exhaust air (usually extracted from the wet rooms) being below freezing and condensate freezes in the vains, the system then has to go into reverse to melt.

My house heat pump works very well below 6C, and -2C, manufacturer states all will work to -25C.
It heats my hot water cylinder to 60C if required, but usually 43C is hot enough.

 

[tsedge]

I had a corsa-e which I believe used a heat pump.
In my experience it was abysmal.

Car heat pumps are all about how well they are integrated. A poor integration is far worse than a PTC heater, might be more efficient but will be rubbish at heating the car in many cases.

I'd want one if I lived in a really cold climate, but not needed where I am in the UK.

 

[Rapax]

I have 77ER with heat pump. Few days ago it was 4°C in the morning, I turned on heating, in 30 seconds started to blow warm air. The same day I had 200km drive with heating on because it was 12°C. The thing I noticed, it consumed very low amount of energy. So the question for ones who know is, how much the heat pump consumes in kw? Board said 1 of 40kw used.

 

[tsedge]

I have 77ER with heat pump. Few days ago it was 4°C in the morning, I turned on heating, in 30 seconds started to blow warm air. The same day I had 200km drive with heating on because it was 12°C. The thing I noticed, it consumed very low amount of energy. So the question for ones who know is, how much the heat pump consumes in kw? Board said 1 of 40kw used.

From memory the average power with a heatpump is roughly half a PTC. I recall 750W vs 1500W but those may be misremembered. The point is although the PTC heater might be 7kW it switches in and out so this isn't the power to maintain a temperature, just the peak.

It should make a measurable range difference but I'd expect it to be perhaps 10-15 miles, not a huge increase.

With lots of short cold journeys the difference would be greater.

 

[Rapax]

I have read somewhere that ev heat pumps are most effective around 0-5°C, it is where consumption is the lowest. Idk if that is true, but every km in ev range counts ?
Winters in my area are mostly -2°C in average but it can go low as -20 so I will have to wait a few months to see if I will have problems.

 

[Lillemy]

I can say that my MG 4 use loads of extra power at -10 or below at least. Still no problem keeping the cabin hot.

Worst case last winter was getting roughly half the wltp range.

 

[tsedge]

I have read somewhere that ev heat pumps are most effective around 0-5°C, it is where consumption is the lowest. Idk if that is true, but every km in ev range counts ?
Winters in my area are mostly -2°C in average but it can go low as -20 so I will have to wait a few months to see if I will have problems.

There's certainly a peak efficiency and a curve, so they will be less effective away from the peak. So the CoP (coefficient of performance) will be less when the temperature is lower, but they should still work and should still be better than a PTC heater because of the multiplier.

Heat pumps do use a lot of electricity to run, which can surprise domestic users when they get a large electricity bill, although this should replace an even bigger gas bill.

PTC heaters are simple and cheap and easy to integrate. But they shouldn't be able to compete with a decent heat pump design.

Of course, heat pumps are only relevant if you need the extra range. If the range is enough without, they just add cost.

 

[LenEV2016]

They reckons a heat pump will add roughly 10% to the range of an EV in winter (compared to the same EV without the heat pump)

 

[Rolfe]

And different "they" say different things. I honestly don't know what to think any more.

 

[LenEV2016]

And different "they" say different things. I honestly don't know what to think any more.

To be fair what car have done some pretty good tests on the same EVs with and without a heat pump and their result are the same 9-10% more with a heat pump

 

[Rolfe]

The tests I saw found very little difference. Maybe different conditions.

 

[tsedge]

The tests I saw found very little difference. Maybe different conditions.

Maybe and maybe these were poorly integrated heat pump solutions? Tesla spent an awful lot of time and effort to make theirs work really well. They are still well ahead in the efficiency stakes (albeit behind Lucid who are the leaders).

 

[Rapax]

I will wait for Vgate dongle to arive, then I will see how much kw drains from the battery. It's simple, if it drains 2-3 times less, then it is simple math.