Will Model 3 get a heat pump for cabin heating?

[arnolddeleon]

On the first generation models from 1997 to 2003 wikipedia says:



but I can't actually find hard evidence from Toyota either way. It looks like only around 1500 were ever produced between those years and very few were sold to consumers (328), most were fleet vehicles for California (with California weather). We do know for sure that all gen II models of the RAV 4 EV do have a PTC heater with the heat pump so either way the first gen wasn't adequate.

I was one of those 328, drove one for over 120,000 miles. It's possible my memory is faulty on the absence of a PTC heater. If it had one it must have been extremely tiny or the car practically never used it since there was no way to get fast heat out of car. It had heated seats so that saved the day (or rather the bottom). The car had a pre-climate option which was useful when it still plugged in. I don't recall the climate control pulling more power than I can attribute to a heat pump. I gave my service manuals away so I can't look things up. BTW high voltage heated windshield is very efficient both at defogging and amount of energy consumed. Main downside is expensive to replace.

The second generation (arguably a different generation because the drive train is practically all Tesla) most definitely has only PTC heating, no heat pump. A 2012 model is my daily driver.

arnold

 

[Sonny Daze]

Looks like the I-Pace will have one.

Jaguar says all-electric I-Pace’s thermal management system adds up to 30 miles of range

 

[TSMCReader]

Just a couple thoughts on heat pumps in general, not specifically regarding use in auto applications.
- A few comments were made about low temp efficacy. Mitsubishi's H2i and Fujitsu's Halcyon systems maintain pretty good efficiency (like 80%) down to temps around -12F to -15F (-25C).
- Use of a heat pump system doesn't preclude use of resistive heat for the extremes
- This is a bit of an over simplification but, heat pumps are just air conditioners with a refrigerant reversing valve. That is, they just switch directions so that instead of moving heat energy out of the living space they flip and move heat energy into the living space (car's cabin).
- Belt driven compressors in ICE applications are often of the variable displacement variety not just clutch activated binary on/off units.

 

[Peter Egan]

Tesla seems to think it helps...

I think it better to have a common reservoir as per the attached Glycol loop diagram. Every circuit will have a pair of electronically controlled valves and a pump to match fluid flow to circumstances. Also, if a leak is detected in a loop, the thermal management system needs to close it off.

The battery should be fully insulated, due to its size, and fluid pumped around to maintain it between 15C and 30C degrees for best range.

The cabin refrigeration system would also exchange energy with the reservoir. A refrigeration circuit can pump heat into a reservoir that is up to 40 C degrees hotter than the space it is trying to cool. Humans generally prefer 23 C which is in the middle of the range preferred by the battery.

If the battery is insulated, it may only take a trickle current of 50 W to keep in in the right temperature range and ready to go.

 

[JeffK]

I think it better to have a common reservoir as per the attached Glycol loop diagram. Every circuit will have a pair of electronically controlled valves and a pump to match fluid flow to circumstances. Also, if a leak is detected in a loop, the thermal management system needs to close it off.

The battery should be fully insulated, due to its size, and fluid pumped around to maintain it between 15C and 30C degrees for best range.

The cabin refrigeration system would also exchange energy with the reservoir. A refrigeration circuit can pump heat into a reservoir that is up to 40 C degrees hotter than the space it is trying to cool. Humans generally prefer 23 C which is in the middle of the range preferred by the battery.

If the battery is insulated, it may only take a trickle current of 50 W to keep in in the right temperature range and ready to go.

That puts a lot of eggs in one basket...

 

[Saghost]

I think it better to have a common reservoir as per the attached Glycol loop diagram. Every circuit will have a pair of electronically controlled valves and a pump to match fluid flow to circumstances. Also, if a leak is detected in a loop, the thermal management system needs to close it off.

The battery should be fully insulated, due to its size, and fluid pumped around to maintain it between 15C and 30C degrees for best range.

The cabin refrigeration system would also exchange energy with the reservoir. A refrigeration circuit can pump heat into a reservoir that is up to 40 C degrees hotter than the space it is trying to cool. Humans generally prefer 23 C which is in the middle of the range preferred by the battery.

If the battery is insulated, it may only take a trickle current of 50 W to keep in in the right temperature range and ready to go.

The reason you don't see the single system approach you're suggesting is that all the systems want to be at different temperatures sometimes.

GM uses for independent cooling systems on the Volt, plus a heater core that can be tied in to the ICE coolant or independent.

We've never seen a system that's even as integrated as the Tesla patent you cited in an actual car - and while it's common practice in building HVAC, I've never seen a car that uses liquid coolant to cool the air.

 

[IhateOPEC]

Seriously. Why not?

 

[Thomas Edison]

Seriously. Why not?

Will Model 3 get a heat pump for cabin heating?

/end thread

 

[IhateOPEC]

Electric-Car Battery Energy: Why Waste It On Cabin Heating? (Video)

/resart thread

 

[Cosmacelf]

Why not? Cost and reliability I imagine. Tesla apparently does not think it important enough to give winter weather customers longer range with a heat pump instead of resistance heating. Also, how well does a heat pump work when you need it the most anyways? Efficiency goes down a lot when it is really cold out.

 

[Thomas Edison]

Electric-Car Battery Energy: Why Waste It On Cabin Heating? (Video)

/resart thread

I said end thread because there's already a long active thread on this. It makes people repeat the same stuff over and over again. Please post on the thread I linked

/end thread

 

[Thomas Edison]

Bump for the new guy.



Heat pump

 

[IhateOPEC]

Bump for the new guy.



Heat pump

^^^
Yay!

I think Tesla is making a mistake here.

When "civilians" start getting stranded between Omaha and KC, out in the cold because 20% of their range evaporated it will make the news.

It's a valve. That's it more or less. The plumbing is already there. If they need to use the same glycol to cool the engine, add another valve and use the heat from the pack to momentarily heat the cabin.


This car will be bought by large numbers of non engineering types in cold weather climates, and heat pumps bump up the range significanly from pure resistive heat.

 

[Sudre]

I had originally assumed in 2013 when I purchased my S that Tesla used heat pumps. As TSMCReader had posted. New heat pump systems work efficiently down to some pretty chilly temps. My heat pump at home works efficiently down to -5F at which point below it still works just not as efficient. These systems are pretty advanced tho and rather costly. I am guessing Tesla doesn't want to spend research money in the direction of heating and would rather focus on more powerful batteries.

I don't think some understand that a heat pump for low temps is a high speed, high pressure system. The cost is much higher than a standard cooling system. Twice as much at least. It's not a matter of just throwing in another valve or two. If you want a system that works efficiently down to around 40F then just throw in a valve and reverse a standard A/C. If you want a system that heats in temps down to -5F then you need a bigger compressor and higher pressures.

Would cold weather drivers pay a $5K upgrade to gain 40 miles of range?
Remember for $9k you can gain 90 miles of range with a bigger battery.

Look at it this way.


From my experience driving my S60 my 220 ideal miles of full charged range on a 9 degree or colder day gets me about an actual 130-140 miles. That's with the system Tesla uses now.

I am guessing based on the energy usage of my high efficient heat pump at home that Tesla could save 40 of those miles but it won't be cheap. I am guessing at least $5K just looking at the cost difference when pricing the home heat pump I have. So for an extra $5k you get 170-180 miles in some really cold weather with an upgraded heating system.

OR

Just spend $9K extra and get a 310 mile car with a cold weather range of 220-230 miles. That will make any supercharger I know of.

I think that's why Tesla is focusing on battery over heat pump.... but what do I know. That's just all guessing anyway.

 

[ratsbew]

Do we know if the Model S uses waste heat from the powertrain to heat the cabin? If so, using the coolant loops to move that heat to the cabin would be very efficient. You cold preheat the cabin using a resistive heater (maybe 1kWh) and then keep it up to temp with waste heat.

 

[JeffK]

Do we know if the Model S uses waste heat from the powertrain to heat the cabin? If so, using the coolant loops to move that heat to the cabin would be very efficient. You cold preheat the cabin using a resistive heater (maybe 1kWh) and then keep it up to temp with waste heat.

Waste heat from the motors is used to help heat the battery. The patent allowed heat from the motors and battery to be used for cabin heating but according to in-car diagrams it appears not to be the case.

This was posted a while back by Kman measuring usage over the course of an hour (hence kWh)

Baseline (vehicle at rest but powered up): 247 Wh = .74 mph
Defroster (rear window & side mirror heaters): 285 Wh = .86 mph
Steering Wheel Heater: 95 Wh = .29 mph
Heated Wipers & Nozzles: 95Wh = .29 mph
1 Seat Heater: 57 Wh = .17 mph
2 Seat Heaters: 133 Wh = .40 mph
3 Seat Heaters: 171 Wh = .51 mph
4 Seat Heaters: 209 Wh = .63 mph
5 Seat Heaters: 247 Wh = .74 mph
HVAC at ‘HI’ or 82F (28C): 6.4 kWh = ~18-20 mph
HVAC at 74F (23C): 342 Wh = 1.03 mph

Energy Consumption Of Various Tesla Heating Features

If you preheat your car while plugged in and use the normal HVAC, combined with the seat heaters, you'd be in pretty good shape.

 

[IhateOPEC]

I had originally assumed in 2013 when I purchased my S that Tesla used heat pumps. As TSMCReader had posted. New heat pump systems work efficiently down to some pretty chilly temps. My heat pump at home works efficiently down to -5F at which point below it still works just not as efficient. These systems are pretty advanced tho and rather costly. I am guessing Tesla doesn't want to spend research money in the direction of heating and would rather focus on more powerful batteries.

I don't think some understand that a heat pump for low temps is a high speed, high pressure system. The cost is much higher than a standard cooling system. Twice as much at least. It's not a matter of just throwing in another valve or two. If you want a system that works efficiently down to around 40F then just throw in a valve and reverse a standard A/C. If you want a system that heats in temps down to -5F then you need a bigger compressor and higher pressures.

Would cold weather drivers pay a $5K upgrade to gain 40 miles of range?
Remember for $9k you can gain 90 miles of range with a bigger battery.

Look at it this way.


From my experience driving my S60 my 220 ideal miles of full charged range on a 9 degree or colder day gets me about an actual 130-140 miles. That's with the system Tesla uses now.

I am guessing based on the energy usage of my high efficient heat pump at home that Tesla could save 40 of those miles but it won't be cheap. I am guessing at least $5K just looking at the cost difference when pricing the home heat pump I have. So for an extra $5k you get 170-180 miles in some really cold weather with an upgraded heating system.

OR

Just spend $9K extra and get a 310 mile car with a cold weather range of 220-230 miles. That will make any supercharger I know of.

I think that's why Tesla is focusing on battery over heat pump.... but what do I know. That's just all guessing anyway.

I get that high efficiency cold temp pumps would be expensive, but why not ad the valve for temps down to 40? Most cities even in the upper midwest would still see huge benefits as temps aren't always 20 degrees and below. With a glass roof even just "chilly" temps will require a heater.

 

[David99]

I think this video makes a compelling argument for the heat pump.

 

[insaneoctane]

I think this video makes a compelling argument for the heat pump.

So the Kia beats the Tesla...seems like someone ought to tweet the video to Elon and ask him what's up with Kia beating the Tesla!

 

[Joell]

So the Kia beats the Tesla...seems like someone ought to tweet the video to Elon and ask him what's up with Kia beating the Tesla!

I was thinking the same thing, maybe Elon has some ideas on what settings could improve the efficiency for this type of test.