Will Model 3 get a heat pump for cabin heating?

[ratsbew]

With the smaller battery on the Model 3, it seems necessary to include a heat pump for cabin heating to reduce the drain on the battery to warm the cabin. There should be a loop that connects to the powertrain/battery to take heat from the motor and move it to the inside of the cabin. There should also be a mode that takes heat from the outside environment if it isn't too cold outside.

There would still be the need for a resistive heating element for initial heating, but once the powertrain is warm it could switch to the heat pump.

Thoughts?

 

[ItsNotAboutTheMoney]

I don't know that the powertrain generates so much heat that it'll help heat the cabin. It can help maintain battery temperature though.

A heat pump would be good to raise overall efficiency, but the big warm weather market won't care so much. And heat pumps (at least the ones you'll get in a car) won't help when it's _very_ cold, so they don't make a different to those of us in cold climates who'd be asking "How much battery do I need to get through the winter?" Also, note that people drive more in better weather, so the overall efficiency improvement might not be that great.

And of course there's a question of cost. The cost of the heat pump could be spent on other things, so as much as I'd like the option there are other important areas that could probably be improved instead.

Long-term I'd like to see consideration of integrated ethanol heaters. Ethanol burns cleanly, it's already produced in large volumes, can easily be stored, handled and refilled by owners, and has the possibility of being produced sustainably.

 

[ratsbew]

I do kind of like the idea of a fuel heater that either uses ethanol...or more likely bio-diesel. A 1 gallon tank would supply heat for many hours of driving.

From what I've heard though, it is a very simple and cheap modification to a car's regular air conditioner to turn it into a heater (reversing valve). It would work down to 20 degree weather which covers a lot of conditions even up north during the daytime. A supplemental resistive heater would be needed for very cold weather.

 

[ItsNotAboutTheMoney]

I do kind of like the idea of a fuel heater that either uses ethanol...or more likely bio-diesel. A 1 gallon tank would supply heat for many hours of driving.

From what I've heard though, it is a very simple and cheap modification to a car's regular air conditioner to turn it into a heater (reversing valve). It would work down to 20 degree weather which covers a lot of conditions even up north during the daytime. A supplemental resistive heater would be needed for very cold weather.

Biodiesel combustion isn't especially clean. It's cleaner then regular diesel, but is not a clean fuel.

Burning ethanol is _theoretically_ very clean, but isn't necessarily so. There are particular concerns about aldehyde formation. However, if BEVs are high volume, there should be able to be well-designed heating units that can keep the harmful emissions down. Combined with a use limited to heating, I think it could be a good alternative in colder locations to the cost and operational inefficiencies of additional battery capacity.

If BEV volumes increase significant we should be able to see region-appropriate solutions. People in hot climates might stick with cheap resistive heating, people in moderate climates might favor heat pumps, and people in cold climates might choose between heat pumps and combustion heaters according to range requirements.

 

[182RG]

Does anyone else find it sad that Tesla focuses so much on nonsense like Ludicrous, and fails so badly on basic blocking and tackling.

Here's a thread where people are using cheap Chinese 12V electric blankets and heating pads to keep warm in their $150K vehicles.

Model S 2017 - Behind Back Seat Open Panels - Quality Fail

A heat pump on an allegedly $35K car won't happen. Perhaps a "cold weather" upgrade can be offered, but this is such a basic problem.

Sad.

 

[JeffK]

I don't know that the powertrain generates so much heat that it'll help heat the cabin. It can help maintain battery temperature though.

Tesla seems to think it helps...

 

[Mishakim]

A heat pump on an allegedly $35K car won't happen. Perhaps a "cold weather" upgrade can be offered, but this is such a basic problem.

That's how the Leaf is heated and cooled: Heat-Pump Cabin Heater
I've had no complaints with mine in three Boston winters so far

 

[Ken7]

Does anyone else find it sad that Tesla focuses so much on nonsense like Ludicrous, and fails so badly on basic blocking and tackling.

Here's a thread where people are using cheap Chinese 12V electric blankets and heating pads to keep warm in their $150K vehicles.

Model S 2017 - Behind Back Seat Open Panels - Quality Fail

A heat pump on an allegedly $35K car won't happen. Perhaps a "cold weather" upgrade can be offered, but this is such a basic problem.

Sad.

Wow, I hope I'm misinterpreting this. Is there no standard heating system for the Model 3 for those of us that drive in cold climates? this can't possibly be, can it? That could be a rationale for some of us to cancel our preorder. There's no way I'm going to start using heating blankets and such to provide heat the car should be providing. I can just see my wife's reaction to that.

 

[EkBuZ]

No it's not. We're just speculating on what type of heater it may have. I'm hoping heat pump + resistive like the Leaf. My buddy has a late 2014 S and the heat works just fine here in MN. Granted regenerative braking doesn't work when everything's super cold (leaving work) and combine it with the heat and he uses almost 2x energy on his short commute than in the summer.

 

[shrspeedblade]

While I live in N. California, hardly a cold climate (it did snow yesterday!), I feel the cold weather package is a "must have" with an EV. On my Volt, I often only turn the defroster on for the windshield as with a heated steering wheel/seats I would forget to otherwise.

Something to keep in mind: heaters in modern cars are very, very good. I remember some of the stuff I rode in in the 80s (and before) weren't all that great: and these are vehicles managing thousands of explosions of volatile fluid just in front of you which is actually more efficient at keeping you warm than it is propelling the vehicle forward. Now I can drive around in a tank top and shorts during sub freezing temperatures and be perfectly comfortable (after the first few minutes, that is) because the ICE vehicle is so good at heating the cabin.

Just due to their nature, I don't think electric vehicles will ever get to that point, as the inherent disadvantage of burning copious amounts of said highly volatile fluid is hard to compete with. But just like at home- unless you like paying outrageous heating bills- dress appropriate to the weather and fire up that heated seat and you'll be fine!

 

[nexsuperne101]

That's how the Leaf is heated and cooled: Heat-Pump Cabin Heater
I've had no complaints with mine in three Boston winters so far

Same here. The coldest I have experienced with it in the UK was minus 5 Celcius. Heating worked great.

 

[jelloslug]

I have had EVs with and without heat pumps and I saw no noticeable difference in efficiency with one over the other.

 

[Red Sage]

Magic 8 Ball says:

NO​

 

[JeffK]

That's how the Leaf is heated and cooled: Heat-Pump Cabin Heater
I've had no complaints with mine in three Boston winters so far

Which year and model do you have exactly?

 

[McRat]

There are an awful lot of internet engineers when comes to heat pumps for cars.

So can some of the experts answer this?

Is the efficiency of an automotive heat pump when it's in AC mode just as effective as state-of-the-art automotive AC units of today?

If so, then how come all luxury cars don't come standard with them? They would heat up the car way faster. Using the ICE to heat the car takes forever, especially with diesels.

Note that the EV1 and S10 EV had heat pumps. But they were never used again on GM products regardless of cost. A $100,000 Cadillac does not have one.

 

[mtndrew1]

There are an awful lot of internet engineers when comes to heat pumps for cars.

So can some of the experts answer this?

Is the efficiency of an automotive heat pump when it's in AC mode just as effective as state-of-the-art automotive AC units of today?

If so, then how come all luxury cars don't come standard with them? They would heat up the car way faster. Using the ICE to heat the car takes forever, especially with diesels.

Note that the EV1 and S10 EV had heat pumps. But they were never used again on GM products regardless of cost. A $100,000 Cadillac does not have one.

Much of this difference is probably due to the lack of sufficient electrification. With a heat pump you want to have an extremely variable compressor so that you don't end up with big bursts of heat/cold/heat/cold. Most (all?) high-end ICE cars use a belt-driven compressor and not an electric compressor, which runs at 360V like the traction systems in an EV and has a nearly infinite number of scroll speeds.

Furthermore there is a cost component; a luxury car buyer probably won't pay an extra $1,000 for a heat pump (and the necessary electrification hardware) to speed up the cabin heating by 90 seconds where they would definitely see an equivalent-priced larger sunroof or massaging seat as a selling point.

An electrified vehicle already has a high-voltage electric A/C compressor and has minimal waste heat to spare, so the addition of a heat pump is more trivial in cost and implementation than adding one to an ICE vehicle. It also has a very measurable improvement in range loss over a resistance heater in most climates.

 

[JeffK]

There are an awful lot of internet engineers when comes to heat pumps for cars.

So can some of the experts answer this?

Is the efficiency of an automotive heat pump when it's in AC mode just as effective as state-of-the-art automotive AC units of today?

If so, then how come all luxury cars don't come standard with them? They would heat up the car way faster. Using the ICE to heat the car takes forever, especially with diesels.

Note that the EV1 and S10 EV had heat pumps. But they were never used again on GM products regardless of cost. A $100,000 Cadillac does not have one.

I don't know a whole lot about the Nissan leaf but I think it has a PTC heater supplementing the heat pump which is why it might feel hotter in the winter than the heat pump alone.

I believe people thinking that it's 100% heat pump are mistaken.

 

[N5329K]

While I live in N. California, hardly a cold climate (it did snow yesterday!), I feel the cold weather package is a "must have" with an EV. On my Volt, I often only turn the defroster on for the windshield as with a heated steering wheel/seats I would forget to otherwise.

Something to keep in mind: heaters in modern cars are very, very good. I remember some of the stuff I rode in in the 80s (and before) weren't all that great: and these are vehicles managing thousands of explosions of volatile fluid just in front of you which is actually more efficient at keeping you warm than it is propelling the vehicle forward. Now I can drive around in a tank top and shorts during sub freezing temperatures and be perfectly comfortable (after the first few minutes, that is) because the ICE vehicle is so good at heating the cabin.

Just due to their nature, I don't think electric vehicles will ever get to that point, as the inherent disadvantage of burning copious amounts of said highly volatile fluid is hard to compete with. But just like at home- unless you like paying outrageous heating bills- dress appropriate to the weather and fire up that heated seat and you'll be fine!

Internal combustion cars are just gas-powered heaters that throw off a little waste motion along the way.
Robin

 

[AustinPowers]

I know several Leaf and e-Golf owners that also have a heat pump for cabin heating, and all of them are very happy about the effectiveness of those systems, even in cold winter weather.

Our house also has a heat pump for all our central heating, and even though I was sceptical at first about efficiency, after almost nine years I can honestly say it's been perfect for us. Far cheaper than oil or gas heating while just as comfortable, even in very cold winters, of which we had a few, especially in the first years after we had had the system.

I would be very happy if the Model 3 had a heat pump. Otoh, if they use a different yet equally efficient system, I won't mind either. We will find out soon enough.

 

[JeffK]

I know several Leaf and e-Golf owners that also have a heat pump for cabin heating, and all of them are very happy about the effectiveness of those systems, even in cold winter weather.

Our house also has a heat pump for all our central heating, and even though I was sceptical at first about efficiency, after almost nine years I can honestly say it's been perfect for us.

Just keep in mind the Leaf, e Golf, and likely your house have some form of supplemental heat. The heat pump simply helps reduce energy usage of these other technologies, which is great for efficiency, but it cannot provide instant heat on its own.

Example: My house has an electric heat pump and gas for supplemental heat (it's a duel fuel heat pump). When it was below zero (F) outside this past winter the gas furnace part stopped working. The heat pump, being eletric, continued to function but although my thermostat was set to 72 it was only ever able to achieve 60 degrees and never blew air that "felt" warm. The supplemental heating system was vital to provide the extra heat.

Tesla doesn't currently use a heat pump but they do pump in heat from the drivetrain and electronics according to their patent. Supposedly once warmed up and the car has been moving, the Tesla heater only draws 1-2 kW to maintain temp which is similar to the leaf. I don't have hard measurements so maybe someone can confirm.