Will Model Y finally get a heat pump???

[ratsbew]

Tesla NEEDS to start putting heat pumps in their cars to improve winter driving range. I realize that heat pumps don't work well below about 0C, but there are plenty of times when the temps are above 0C and you still want to use heat.

My understanding of the tech is that it's trivial to implement and the costs would be very low per car.

My only guess is that they can't use the heat pump to simultaneously heat the cabin and cool the battery (aggressive driving during winter).

 

[RDoc]

An onboard diesel heater would work better, be more efficient, and produce less CO2.

 

[ratsbew]

While I agree 100%, I don't think a Tesla will ever have a fossil fuel tank.

 

[mongo]

My understanding of the tech is that it's trivial to implement and the costs would be very low per car.

There is a huge thread on this, but from my POV:

A single point of use system is fairly simple, 4 way valve and dual TXVs.

Cars are more complicated:
Defrost needs cold for dehumidification and heat for melt.

Pack heat demands do not always line up with cabin heat demands.
Sun is shining on you, but pack is cold.
You're cold, but pack is heating from supercharging.

Evaporator and condenser sizing is impacted along with cooling efficency.

An onboard diesel heater would work better, be more efficient, and produce less CO2.

Not less that hydro, solar, or wind sourced electrons though, yeah?

 

[RDoc]

<snip>
Not less that hydro, solar, or wind sourced electrons though, yeah?

Hydro is 7% of US power production
Wind is 6.6%
Solar is 1.6%

 

[kayak1]

Hydro is 7% of US power production
Wind is 6.6%
Solar is 1.6%

The mix is changing. My house has 24KW of panels installed... I rather a heap pump than diesel...

 

[burrMcD]

Tesla NEEDS to start putting heat pumps in their cars to improve winter driving range. I realize that heat pumps don't work well below about 0C, but there are plenty of times when the temps are above 0C and you still want to use heat.

My understanding of the tech is that it's trivial to implement and the costs would be very low per car.

My only guess is that they can't use the heat pump to simultaneously heat the cabin and cool the battery (aggressive driving during winter).

I would like that too living near Boston.

 

[Daniel in SD]

The diesel idea is pretty funny. Automotive diesel heaters are only about $200 and 2 gallons of diesel is 80kWh of heat energy.

 

[ricksastro]

It has a heat pump! Confirmed in the manual

 

[THX723]

It has a heat pump! Confirmed in the manual

Got a link?

 

[SSedan]

Thing is RANGE is not really affected at modest temps where a heat pump would work well. One of you mentioned 0C, that is not even cold.

When I say RANGE I am differentiating between the morning commute where the initial cabin heating sucks down a big chunk right away from the long distance drives where once the cabin is warm consumption drops dramatically.

I want to know how they are handling the defrosting of the condenser, I have air source heat pump at my home near Green Bay very happy but defrost cycles run AC for a few minutes. A car will need this more often due to road spray. I presume they will use resistance heat from the battery which will reduce the gains.

I think a big part of why folks are fixated on this is pretending the big efficiency hit on your daily commute due to cold translate to long drives, it doesn't. In cold weather if I don't preheat I can see energy use well over double, but my 242mile range S still has no problem making the 183mile trek to the next westbound supercharger at single digit temps, because once the cabin is warm demands decrease dramatically.

I hope they have something sorted out that works well, but you guys are making way too big a deal about this because again you are confusing short trip efficiency with RANGE and it isn't the same thing.

 

[ArcticStation]

An onboard diesel heater would work better, be more efficient, and produce less CO2.

When I was a kid, we had a Corvair with a gasoline heater. Worked great until it didn't--because it set the car on fire!

 

[MP3Mike]

Got a link?

https://www.tesla.com/sites/default/files/model_y_owners_manual_north_america_en.pdf

Item number 2:

Model Y uses a heat pump to maximize
efficiency; therefore, your air conditioning
compressor and external fan may run and
make noise even when the outside
temperature is cold and your vehicle is
heating or supercharging.

 

[Daniel in SD]

Thing is RANGE is not really affected at modest temps where a heat pump would work well. One of you mentioned 0C, that is not even cold.

When I say RANGE I am differentiating between the morning commute where the initial cabin heating sucks down a big chunk right away from the long distance drives where once the cabin is warm consumption drops dramatically.

I want to know how they are handling the defrosting of the condenser, I have air source heat pump at my home near Green Bay very happy but defrost cycles run AC for a few minutes. A car will need this more often due to road spray. I presume they will use resistance heat from the battery which will reduce the gains.

I think a big part of why folks are fixated on this is pretending the big efficiency hit on your daily commute due to cold translate to long drives, it doesn't. In cold weather if I don't preheat I can see energy use well over double, but my 242mile range S still has no problem making the 183mile trek to the next westbound supercharger at single digit temps, because once the cabin is warm demands decrease dramatically.

I hope they have something sorted out that works well, but you guys are making way too big a deal about this because again you are confusing short trip efficiency with RANGE and it isn't the same thing.

Yep. The high speed highway range for the Model Y will be much worse than the Model 3. The relative overall efficiency in regular day to day suburban driving will likely be similar to what the MPGe suggests.

 

[THX723]

https://www.tesla.com/sites/default/files/model_y_owners_manual_north_america_en.pdf

Item number 2:

View attachment 521405

Super!

 

[neezer]

Yep. The high speed highway range for the Model Y will be much worse than the Model 3.

Why?

 

[SSedan]

Aerodynamics, faster you go the bigger a factor.

 

[Daniel in SD]

Why?

Because in the actual EPA highway test the Model Y did significantly worse than the Model 3. Manufacturers are allowed to use a different scale factor of the 2 cycle test (which is antiquated for ICE but for some reason still allowed for EVs) if it would do better in the 5 cycle test (which includes cold weather testing).
It's explained here: Model y battery upgrade?

 

[Shayne]

With a heat pump these may get better range than the M3 in cold temps on the highway? Should have an effect on the optimum speed at least. Harnessing dumped heat should not hurt one would think.

 

[SSedan]

Heat pump isn't necessarily harnessing waste heat, it might bit I doubt there is much waste heat if cold enough to need heat.

Heat pump moves heat usually from outdoors to in even if it is colder outdoors. When it is humid or there is most in the air the cooling of the outdoor coil results in frosting that needs to be periodically thawed.

In a house with a big volume of air it will run the AC a little and take some inside heat to do this, in a car the air volume is too low to do this, would freeze you out.

Again as I keep saying what freaks people out about heat use in EVs is the admittedly big hit to efficiency in normal day to day use, warming the cabin takes a lot. Long duration cruise range is not affected anywhere near as badly because the cabin gets heated once for 150miles rather than reheated every 20miles.

Since the Y has a taller profile and therefore worse aerodynamics it is going to consume more energy on the highway unless Tesla found some other sources of efficiency. The heat pump may help in dry cool to moderately cold conditions but I doubt anywhere near enough to offset the aero disadvantage. If it is wet out and frosting a concern I don't think it is going to help all that much.