Why does Tesla use a Resistance Heater instead of Heat Pump

[MP3Mike]

Explain, how a pipe should fail. Also not extra "VALVES" but "VALVE".

Who said anything about pipes failing? (Which they do occasionally, though normally with other root causes like a lose clamp that causes rubbing from vibration.)

You said no additional equipment was necessary, which is wrong. If nothing else was needed then you are saying it is just a software issue and Tesla is withholding HP ability just to spite people and make them pay more at Superchargers right?

2)Model 3 magic bottle can easily handle heat pump capable AC without any changes to glycol loop.

Isn't there only one chiller? So how is it going to heat the cabin while cooling the battery without additional pieces of equipment? (Or provide heat to both, or provide cooling to both, or provide cooling to the cabin and heat to the battery, etc.)

 

[Reeler]

If the Model Y has a heat pump like the rumors suggest, it will be funny to see the fanbois change their tune. The latest rumor is that the Model Y will be out in a couple weeks so we may know soon. There is no convincing a fanboi that Tesla did anything less than perfectly.

 

[arnis]

Isn't there only one chiller? So how is it going to heat the cabin while cooling the battery without additional pieces of equipment? (Or provide heat to both, or provide cooling to both, or provide cooling to the cabin and heat to the battery, etc.)

You tell me. First you disagree with information and then you ask questions.

Go find my topic about Model S thermal management system. Learn it. Then make a system that can do exactly that.
Stop disagreeing with everything you don't understand or like. It makes you no good.

 

[StealthP3D]

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'm not anti-heat pump at all. I own one air/air heat pump and have a condo with a heat pump water heater. Both very efficient and practical for their intended applications. But current implementations of automotive heat pumps leave a lot to be desired in cold weather. As a snow skier I appreciate the immediate and full heat output from the resistance heater (and have enough range that it's never a decision of whether to have heat or range). I just crank it on and watch it melt the ice. A well designed automotive heat pump will need to leverage the waste heat of an EV (or have a resistance heater built-in) to increase it's winter heating speed and capability. This can mitigate the reduction in cold weather performance of heat pumps.

I also have two Cybertrucks on order and I really hope they are equipped with heat pumps because that cabin is not small! But I also hope it has a supplemental resistance heater and waste heat scavenging for fast defrosting in icy conditions.

 

[Lon12]

Well that is very specific.

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


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"

Wow. I just stepped in here to say that my Leaf heat pump is way noisier than I thought it would/should be. If Tesla puts one in and it makes that much noise I will not be happy. I'm not trying to "push a off topic"!

 

[arnis]

But current implementations of automotive heat pumps leave a lot to be desired in cold weather.

Based on what data?

ALL EVs with heat pump capability use 2 heat sources simultaneously on cold start.
If Model 3 would have HP capability, heat generation would be as fast or even faster.

 

[Lon12]

Based on what data?

ALL EVs with heat pump capability use 2 heat sources simultaneously on cold start.
If Model 3 would have HP capability, heat generation would be as fast or even faster.

Oh I'll agree with that. The 2011 Leaf would go full 6 kW heating right off the bat. The 2017 barely pulls 2 or 3 kW and the cabin does NOT warm up as fast. You can add my data.

 

[SSedan]

Air to air heat pump frost up. In a house they go into AC mode to thaw the condenser. Not a big deal in a house, but in the confines of a car......
I live near Green Bay and air source heat pump is our home heat. Great technology but that doesn't mean it is perfect for everything or that it is simple to adapt.

I think people are dismissing the extra challenges. If they worked thru them all in the Y awesome.

Given the amount of trouble I have had with my 2014 S glad they didn't try and make it more complicated.

 

[arnis]

Oh I'll agree with that. The 2011 Leaf would go full 6 kW heating right off the bat. The 2017 barely pulls 2 or 3 kW and the cabin does NOT warm up as fast. You can add my data.

A feeling is not data.5-6kW 2011 Leaf is pretty much the same as 2kW on 2013+.
Also if it is cold cold, then newer leaf also draws no less than 4kW, HP+PTC. "You can add my data."
Newer Leaf can generate heat at rate above 10kW when cold starting. I've observed and recorded that for some winters.

I think people are dismissing the extra challenges.

I think that people are stupid enough to really think adding HP capability means less heat (keeping all else same).

 

[mongo]

I think that people are stupid enough to really think adding HP capability means less heat (keeping all else same).

Well there's your confusion. People really think adding the heat pump function adds cost and complexity without increasing the amount of heat.

Also, the rumor regarding the Y which brought this thread back to life is that it has no cabin PTC. That spawned the line of thought that Y uses a heat pump only (plus drive units).

 

[arnis]

If one wants 22*C inside the car then amount of heat doesn't change whatever the source.

If one states "no cabin PTC" that doesn't mean there are no resistive ways (COP 1.0) to make heat onboard the vehicle
and bring that to HVAC system.

 

[Big Earl]

Right. Just because there is no PTC in the Model Y (speculation), doesn't mean it can't do supplemental cabin heat in extremely cold weather. With the redesigned cooling system, it can likely divert motor heat to the cabin (or into the evaporator loop to increase HP effectiveness) similar to how the Model 3 diverts motor heat to the battery.

One of my buildings at work has an elaborate HP/geothermal/gas heating system. Each space is heated solely with a heat pump and the evaporator loop can harvest energy from the ground (geothermal) or by direct-fire gas boilers in extremely cold conditions.

 

[Lon12]

A feeling is not data.5-6kW 2011 Leaf is pretty much the same as 2kW on 2013+.
Also if it is cold cold, then newer leaf also draws no less than 4kW, HP+PTC. "You can add my data."
Newer Leaf can generate heat at rate above 10kW when cold starting. I've observed and recorded that for some winters.


I think that people are stupid enough to really think adding HP capability means less heat (keeping all else same).

You can't be serious.

 

[taraquin]

Using wasteheat from the coolant loop like the Tesla patent from 2012ish would be my hopes for Model Y. On long trips with supercharging the coolant often rises above 40C, that is a lot of heat that goes to waste in the S3X, if the spare heat could be used to heat cabin it will improve efficiency on long trips that uses supercharging, and it will reduce hvac consumption at very low temps where a heat pump is inefficient (-10C or colder) If you have a fast homecharger that heats the battery it can also improve efficiency if you precharge on medium-cold days.

 

[SSedan]

Relatively little travel is long distance and on superchargers though.
Now you have introduced a usually cool coolant loop to a space you want to heat.
Engineering isn't about just narrow circumstances but has to focus on the day to day and allow for the occasional circumstances.

 

[mongo]

Using wasteheat from the coolant loop like the Tesla patent from 2012ish would be my hopes for Model Y. On long trips with supercharging the coolant often rises above 40C, that is a lot of heat that goes to waste in the S3X, if the spare heat could be used to heat cabin it will improve efficiency on long trips that uses supercharging, and it will reduce hvac consumption at very low temps where a heat pump is inefficient (-10C or colder) If you have a fast homecharger that heats the battery it can also improve efficiency if you precharge on medium-cold days.

Relatively little travel is long distance and on superchargers though.
Now you have introduced a usually cool coolant loop to a space you want to heat.
Engineering isn't about just narrow circumstances but has to focus on the day to day and allow for the occasional circumstances.

If they just preheated the incoming air with the 40C coolant, that would cut energy use dramatically. 40C = 104F, not enough to handle all the heating (with realistic heat exchanger size), but it would either precondition the outside air greatly, or increase the temp of the recirculating cabin air.
Any waste heat helps with fresh air feed, any temp over 75F 20C helps with recirculation.
The coolant loop could just be in the outside air stream, then it would have no significant impact on heating requirements.Even if it were in the full cabin flow, turning off the valve isolates it, so you only have its thermal mass to additionally warm.

 

[taraquin]

Relatively little travel is long distance and on superchargers though.
Now you have introduced a usually cool coolant loop to a space you want to heat.
Engineering isn't about just narrow circumstances but has to focus on the day to day and allow for the occasional circumstances.

Not saying it's the best solution, but it's Teslas patent and maybe easier to implement than a traditional heat pump, thpugh generally not as efficient in the 10C to - 5C where a heatpump shines.

 

[SSedan]

But what percentage of the time is there actually waste heat from the battery/motor during weather that heat is needed? Talk to my fleet wide not just those of you thatl in Cali.
Valves and joints are potential failure and leakage points.

I am near Green Bay, last time I supercharged I drove about 25 miles and ran some errands first and at 30f outside car never pulled more than 40kw. Not a lot of excess heat going on.

 

[taraquin]

But what percentage of the time is there actually waste heat from the battery/motor during weather that heat is needed? Talk to my fleet wide not just those of you thatl in Cali.
Valves and joints are potential failure and leakage points.

I am near Green Bay, last time I supercharged I drove about 25 miles and ran some errands first and at 30f outside car never pulled more than 40kw. Not a lot of excess heat going on.

I live in Norway so worse off than you tempwise As I said this would mostly apply when SC or using fast home chargers, in general on longer trips when you need range the most.

 

[Big Earl]

If they just preheated the incoming air with the 40C coolant, that would cut energy use dramatically. 40C = 104F, not enough to handle all the heating (with realistic heat exchanger size), but it would either precondition the outside air greatly, or increase the temp of the recirculating cabin air.
Any waste heat helps with fresh air feed, any temp over 75F 20C helps with recirculation.
The coolant loop could just be in the outside air stream, then it would have no significant impact on heating requirements.Even if it were in the full cabin flow, turning off the valve isolates it, so you only have its thermal mass to additionally warm.

That would suck the heat out of the coolant loop very quickly.