Heat pumps in the MG4

[GrayCat]

for heating, some use PTC heaters and some heat pumps.

There is no such separate unit as "Heat pump". Effectively the thing called "HP" in electromobiles is the same compressor that is used for A/C, but with added set of valves and tubes to "invert" its action in order to transfer heat from outside to inside of the car.

 

[Rapax]

Heat pump in MG4 doesn't have linear consumption, probably it's the same for all EVs. I measured last night consumption of 300w to 1.6kw on peak.
I measured in a way that I was stationary and look at abpr consumption index.
Without any consumers, just the vehicle in ready mode consume 200w.

 

[fnegroni]

Heat pump in MG4 doesn't have linear consumption, probably it's the same for all EVs. I measured last night consumption of 300w to 1.6kw on peak.
I measured in a way that I was stationary and look at abpr consumption index.
Without any consumers, just the vehicle in ready mode consume 200w.

It’s the same for the a/c, the pts heater, the battery cooling system, etc

Using an OBD2 monitor you can see how much power is drawn from the battery.

All auxiliary demand tends to have a big upstart cost due to demand: HVAC will trigger a/c compressor and PTC heater to bring the cabin up/down to desired temperature so in the first 5 to 15 minutes of any journey that’s the most consumption.
Once temp is reached, they go into maintenance mode so consume very little in comparison.

That’s why if I only drive say 1 mile to the shops and back on a very cold day, I lower the temp in the car or completely switch off the HVAC unless the cabin is damp.

And on short journeys in town I accept the first couple journeys will consume more.

Does having a heat pump help in those scenarios? Where the ptc heater would be consuming a huge amount of energy? Would the system still use the ptc heater at that point anyway because of speed?

 

[DougalDog]

43°C is never enough for a hot water tank, it’s not enough to kill legionella bacteria. 60°C should be the minimum.

43C is more than enough by far for HWC most of the time, a legionella cycle run once a week @ 60C for a few minutes (Or 50C for a couple of hours) is more than sufficient for households, which have a high turnover of hot water.
Also, domestic heat pumps will be paired to an unvented hot water cylinder, fed from a chlorinated cold water supply.
The occurrences are so rare in domestic households as to be almost completely negligible.

From government 2016 summary

"Of the 355 confirmed cases of Legionnaires’ disease, more than half of the cases, 202 (56.9%), were considered to have been exposed to the infecting organism in the community, 147 (41.4%) cases were associated with travel abroad and 6 (1.7%) were considered to have links to a healthcare facility (nosocomial) which is half that observed in 2015. Almost three quarters of cases, 265 (74.6%), reported at least one underlying condition/risk factor; with heart conditions and smoking being the most frequently reported risk factors."

 

[DougalDog]

There is no such separate unit as "Heat pump". Effectively the thing called "HP" in electromobiles is the same compressor that is used for A/C, but with added set of valves and tubes to "invert" its action in order to transfer heat from outside to inside of the car.

And it seems the crossover valve is omitted from UK model of MG4. So no heating functionality on AC unit.

I had a look at refrigerant volume for Europe MG4 (in manual on MGiSmart App' Technical Data/ Recommended fluids) shows 580g for 'non heat pump', and 660g for 'heat pump'

When looking at the refrigerant mass for UK model, it only lists only 580g, suggesting that UK model uses resistive heating and compressor in AC for cooling only.