Why does Tesla use a Resistance Heater instead of Heat Pump

[SSonnentag]

We just went through a two-week cold snap with lots of snow, wind and temps in the teens. I LOVED how quickly my Model 3 melted the ice and cleared the windows. In a gas car, I would be waiting for 10 miniutes (minimum) for the engine and coolant to heat up enough that it would START to blow warm air! The Model 3 does it instantly (OK, like 15 seconds).

If it had a heat pump, we would have to wait.

The heat pump isn't what makes it take so long for heat to appear in an ICE, it's the fact that the engine has to first heat up the engine coolant. Heat pumps produce heat or cold within a few seconds. The real reason is that defogging the windows requires the use of the AC, and you can't run both the AC and heat at the same time with a single heat pump. The AC is required to remove the moisture from the air.

ICE vehicles run both the AC and the heat at the same time when in defrost mode. The heat is not produced by blowing air through a radiator filled with hot engine coolant, but by a heat pump.

 

[Reeler]

Rumor has it that Model Y will get a heat pump and a significantly redesigned cooling system. This news comes from a Tesla technician (not I) who recently went through Model Y training. More detailed info is posted elsewhere on the forum but I don't have a link handy.

All those defending the current resistance heater design will have some back tracking if that happens. If they would add a heated steering wheel and Android Auto to the Model Y too, I would have to upgrade.

 

[arnis]

Exactly. As soon as Tesla changes something all the fans run in that same direction. Even though they smashed lots of eggs&tomatoes on "different thinkers" a moment earlier on that same...direction.
It has had already happened. It will happen again


Who else here actually has a mech.engineering degree BTW?

 

[Reeler]

Exactly. As soon as Tesla changes something all the fans run in that same direction. Even though they smashed lots of eggs&tomatoes on "different thinkers" a moment earlier on that same...direction.
It has had already happened. It will happen again

That is why I think of it as a drinking game. At some point, my level of intelligence matches the fanbois.

 

[SSonnentag]

All those defending the current resistance heater design will have some back tracking if that happens. If they would add a heated steering wheel and Android Auto to the Model Y too, I would have to upgrade.

I doubt you'd much like a heat pump design instead of resistive heat living up there in Colorado. Heat pumps don't do very well in extremely cold conditions.

 

[Reeler]

I doubt you'd much like a heat pump design instead of resistive heat living up there in Colorado. Heat pumps don't do very well in extremely cold conditions.

I have owned several EVs with heat pumps. They also have a resistance heater for very cold weather. In Denver, we get weather for a couple weeks each year where that might be used. But for the remaining 5 months of cold, a heat pump is far better. There is a reason VW, Hyundai, Kia, Nissan, and other brands offer a heat pump.

But then again, those brands all also offer a heated steering wheel. Fanbois often defend the lack of a heated steering wheel that Tesla offers in their $60K Model 3s. Wait for me to get another bottle of Teslaquila before that starts.

 

[Lon12]

It's not the pump that is noisy. It's the fans. And fan controller is not well controlled by computer. At least it shuts the fans down when driving at somewhat acceptable speed.

Also at -30 you should have noticed that fans are off. Because pump is switched off.

Keep in mind that in these topics sceptics usually get stuck at -30 weather. Like it's forever.

No. The colder it gets the noisier the heat pump gets. If I turn on the AC then the noise goes away. The beauty of an EV is that other than a bit of fan noise its can be silent when stopped. Except for the coolant pumps on high....
Where I live I can't even get the HVAC companies to install a heat pump for my house. Everyone says they don't work in this climate. So frustrating.

 

[Reeler]

Where I live I can't even get the HVAC companies to install a heat pump for my house. Everyone says they don't work in this climate. So frustrating.

Mitsubishi is making a heat pump rated down to -13 F, but that may not work for your area. It could work for Denver, but I would probably do a ground loop.

 

[arnis]

European market inverter heat pumps do work very well down to -10*C, and there are some special models (maybe 20% more expensive) that can do COP2 at around -20*C and still work at -30*C.
But if you have a huge house or really huge heating bill with really cold weather outside the only right way is to install ground heat based heat pump - underground is constantly above freezing -whatever the weather you get full blast.

No. The colder it gets the noisier the heat pump gets.

Oh you mean actually pump - well - that is hardly "very" loud. I agree that it makes sound but... well.. it's a device. Premium vehicles cocoon the pump in a massive foam shell. Audi for example did that for extreme silence. Leaf is just a very cheap vehicle. With steering wheel heating and heatpump.

I'm shocked that there are EV's on the market without steering wheel heating and/or seat heating as standard.

 

[Lon12]

Well I guess you will have to come for a ride in my Leaf. It is VERY loud. Louder than an idling ICE engine.

 

[arnis]

Well that might even be a defect, but, it's slightly offtopic now.

 

[mongo]

Well that might even be a defect, but, it's slightly offtopic now.

I wouldn't say that. Failure modes of the additional equipment seems on topic.

 

[arnis]

It is not ADDITIONAL equipment - how many times it has to be repeated?
My Leaf doesn't produce heat with heatpump system at the moment because pressure sensor gave up a week ago. But it is not HP that is not working, it's the compressor. And all Teslas already have compressor and also that sensor that failed on my Leaf.

Those who can't stand noise while HP is working might also not stand the noise while Tesla is SuperCharging. Maybe in the name of silence we should propose Tesla to start using Peltier elements for cooling.

 

[MP3Mike]

It is not ADDITIONAL equipment - how many times it has to be repeated?

How about zero, because it is wrong. Additional equipment will be required. Maybe not another actual pump, but there would need to be additional valves, pipes/hoses, etc. at a minimum.

Remember that your Leaf doesn't actively cool the battery so it doesn't have to deal with that portion of things that a Tesla does have to deal with. (And so suffers from heat soak and slow charging during trips even in cold weather.)

 

[mongo]

It is not ADDITIONAL equipment - how many times it has to be repeated?
My Leaf doesn't produce heat with heatpump system at the moment because pressure sensor gave up a week ago. But it is not HP that is not working, it's the compressor. And all Teslas already have compressor and also that sensor that failed on my Leaf.

Those who can't stand noise while HP is working might also not stand the noise while Tesla is SuperCharging. Maybe in the name of silence we should propose Tesla to start using Peltier elements for cooling.

It's all a system, if the heater makes noise in winter, or because it is failing, that is data regarding reliability and total cost. If the system is making noise because the 4 way valve is stuck, isn't that due to additional equipment?

So your heat pump system failed too? Would it have failed if it were only AC? Is the pressure sensor any different, or subjected to different operating conditions due to being dual mode?

And Peltiers need fans anyway (or a lot of surface area)

 

[arnis]

Is the pressure sensor any different, or subjected to different operating conditions due to being dual mode?

Thanks for letting me know that you know very little about those things.

But no, answer would be no.

 

[Reeler]

It is not ADDITIONAL equipment - how many times it has to be repeated?
My Leaf doesn't produce heat with heatpump system at the moment because pressure sensor gave up a week ago. But it is not HP that is not working, it's the compressor. And all Teslas already have compressor and also that sensor that failed on my Leaf.

I never noticed the noise when my LEAF's compressor was running for heat or AC. Our ludi Model X was like a freight train when supercharging though. I think if the cabin noise is loud, I would think there is a maintenance issue with the car.

 

[mongo]

Thanks for letting me know that you know very little about those things.

But no, answer would be no.

Huh, would have thought the temperature changes on the system components (especially a high side pressure sensor) would be greater when trying to generate 60C from -20C rather than 10C from 40C.

 

[arnis]

because it is wrong

Well that is very specific.

pipes

Explain, how a pipe should fail. Also not extra "VALVES" but "VALVE".
Thanks for informing me about the same thing I mentioned previously.

Remember that your Leaf doesn't actively cool the battery so it doesn't have to deal with that portion of things that a Tesla does have to deal with. (And so suffers from heat soak and slow charging during trips even in cold weather.)

1)You said it like all vehicles with heat pump capability have passive thermal management for battery.
2)Model 3 magic bottle can easily handle heat pump capable AC without any changes to glycol loop.
3) Emotions for Leaf appear to be very...deep. Right from the heart. To push a offtopic into topic called "
Why does Tesla use a Resistance Heater instead of Heat Pump"

 

[Big Earl]

It is not ADDITIONAL equipment - how many times it has to be repeated?
My Leaf doesn't produce heat with heatpump system at the moment because pressure sensor gave up a week ago. But it is not HP that is not working, it's the compressor. And all Teslas already have compressor and also that sensor that failed on my Leaf.

Those who can't stand noise while HP is working might also not stand the noise while Tesla is SuperCharging. Maybe in the name of silence we should propose Tesla to start using Peltier elements for cooling.

The compressor is the heat pump. It’s what compresses the refrigerant and transfers (pumps) heat from one side of the system (evaporator) to the other (condenser).