[tom66]

Air con is a heat pump. It's moving heat from a cooler area (the cabin, once it's cooled down) to a higher temperature area (the outside air). So cooling the inside air and dumping the heat outside - exactly like a fridge. A "heat pump" in common parlance is the exact same process, but cooling outside air and dumping the heat into the cabin to warm it up. Usually achieved just by adding some diverter valves and other bits and pieces and charging a nice mark-up for it. There's no additional/separate compressor or refrigerant circuit.

Worth noting that most true heat pumps (those that can heat and cool) use different refrigerants. R32, R410A and R290 are common in home units. R290 is otherwise known as propane - the same stuff you use in your barbeque. Due to flammability (for R290) and F-gas regulations (for R32/R410A) these are not used in cars. Cars tend to use R134a on older models, and the ID.3 non-heatpump systems use R1234yf. These refrigerants don't work that well for heating functions as they need to be able to provide heating when the condenser temperature is e.g. at -20C. So the ID.3 uses R744 instead - which is CO2 to you and me. This works well providing both heat and cooling functions. The problem with CO2 refrigeration is it needs a very high pressure, which requires much uprated components, valves, radiators and compressor. In fact, the R744 system in the ID.3 isn't even made by VW, but bought from a British manufacturer who specialise in heatpumps.

So it is most definitely is not just as simple as adding a few valves here and there (I blame the Technology Connections video for making this claim, but it's just not quite as simple as he claims.)

 

[tom66]

Well OK, I was simplifying a bit. But the reality is the the manufacturers of car that have a "heat pump" option are using the same HVAC kit regardless of whether you buy the HP option or not. The Niro EV heat pump option is literally a little bit of extra piping and valves, all the other kit is the same, that'll be £1,200 please kind sir. Kerching!

But that's not true. For instance, the Kia/Hyundai heatpump uses an additional 200g of refrigerant, which implies a much higher system pressure, probably at least 2x. It does use R1234yf, which is not ideal, so they probably have poor COP below -5C.

And as stated the VW system uses a very high pressure CO2 system, we're talking about something around 1300 psi! That's around 6x higher pressure than a conventional air conditioning only system.

Also both systems additionally need a refrigerant dryer, and a conventional PTC heater to provide startup assistance in very cold temperatures.

 

[tom66]

But does the VW system without "heat pump" use the same refrigerant and system? If so, the additional retail cost of the "heat pump" is vastly inflated.

No, it uses R1234yf.

 

[tom66]

I'm pretty sure that response was a ChatGPT one....
Hope you get it fixed soon.

I was thinking the same thing, it's so weird how you can almost pick out how it responds to things.
I notice now there's a hidden link, so it's definitely spam.

 

[tom66]

That's cute. You should have asked for the VW sausages!

https://en.wikipedia.org/wiki/Volkswagen_currywurst

VW part number: 199 398 500 A