Tesla Model Y - The Only Tesla With A Heat Pump

TheSteelRider

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Jason from Engineering Explained did a dive on the Tesla Model Y's heat pump. Very educational!

Tesla Model Y - The Only Tesla With A Heat Pump
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TheCats

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As of January 2021 (the introduction of the refreshed Model S and Model X, and the final sales of the old versions) all Teslas now have heat pumps.

This is a significant efficiency improvement in cool and cold weather, although it has only a minor benefit in extreme cold.
 

kltye

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So silly question, but this is only a large improvement in winter if you heat the cabin, correct? Does this also have a large efficiency improvement if you don't use cabin heat? (Maybe to heat the batteries?)
 

TheCats

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So silly question, but this is only a large improvement in winter if you heat the cabin, correct? Does this also have a large efficiency improvement if you don't use cabin heat? (Maybe to heat the batteries?)
Yes, the heat pump is used to heat the batteries. The battery always kept above the minimum storage temperature, warmed before and during charging in cold weather, warmed more when driving in cold weather, and pre-heated to about 30C when navigating to a supercharger.

The heat pump isn't going to help much for maintaining the minimum storage temperature. It is going to help efficiency when it's needed to warm the battery to accept a charge. Pre-heating when heading to DCFC stations is arguably a negative for efficiency, although that is mitigated by slightly more efficient charging at the optimal temperature. (Voltage efficiency, coulomb efficiency remains about the same.)
 

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Ford, we also need heat pumps.
 

TruWrecks

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As long as it's optional, the way BMW has it as a standalone option for the i3. Basically deadweight for much of the Sun Belt.
Heat-pumps can also cool. They can be used for both purposes and are more efficient then a dedicated heater or AC. They are not as fast in temperature change but they work very well.

I have a heat-pump for my house that works from 19F-130F with no issues. It keeps my house between 68-75 all year. If it gets colder than 19F the heater turns on.

I would gladly trade the heater and AC in my Mach-E for a dual purpose heat-pump.
 

QuRace

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Ford, we also need heat pumps.
Well, I'm not so sure.

I kind of get what the intent of a heat pump in a BEV is, although I have yet to see a precise technical description of the workings of such a device (and sales people have no clue anyways).

A heat pump doesn't come for free (and I don't mean that financially). It WILL use up energy all by itself, just by running, and before I believe that efficiency/range argument, I need to see some actual numbers, acquired in the wild, before I believe any of those claims.

In Germany, Volkswagen initially promised a range increase of up to 30% in their ID.3/ID.4 models when ordering a heat pump (which is an expensive extra). Guess what, they do not make such bold claims anymore, and they had to give a partial refund to all buyers of that extra b/c their claims WRT efficiency gains were nowhere near to what was empirically observed by people driving cars equipped w/ a heat pump (which was an effect close to zero).

And the fact that Tesla now plans to use them is, IMHO, an argument for exactly nothing.


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ARK

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Heat-pumps can also cool. They can be used for both purposes and are more efficient then a dedicated heater or AC. They are not as fast in temperature change but they work very well.

I have a heat-pump for my house that works from 19F-130F with no issues. It keeps my house between 68-75 all year. If it gets colder than 19F the heater turns on.

I would gladly trade the heater and AC in my Mach-E for a dual purpose heat-pump.
Don’t air conditioners already work like heat pumps for purposes of cooling? I’d actually be curious as to why heat pumps have only been used for heating, not cooling, in BEVs so far, but I thought the general principle of how they worked was similar.
 

TheCats

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As long as it's optional, the way BMW has it as a standalone option for the i3. Basically deadweight for much of the Sun Belt.
The heat pump is exactly like a home heat pump: it's also the air conditioning system. The additional weight and complexity is a valve system that (simplified) swaps the position of the evaporator and condenser.

For an EV using a heat pump with an all-positions cooling loop valve can reduce the overall weight. For instance it allows eliminating the HV PTC heater.

The reason not to use one is design effort. Using existing HVAC units and design experience is easier.
 

Jimrpa

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As long as it's optional, the way BMW has it as a standalone option for the i3. Basically deadweight for much of the Sun Belt.
Heat pumps are also useless for most of the northeast winter. I have a highly efficient heat pump at my home and, as is typical for heat pumps, count on auxiliary heat (I.e. electric) to kick in below 30-25).
 

sotek2345

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Ford, we also need heat pumps.
Won't be nearly as effective on the Mach-e. Tesla's have induction motors to harvest heat from. the Perm magnet motors in the Mach-e don't generate as much heat so there is less to scavenge.
 

prdude

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Won't be nearly as effective on the Mach-e. Tesla's have induction motors to harvest heat from. the Perm magnet motors in the Mach-e don't generate as much heat so there is less to scavenge.
the main point of the heat pump system is not really to scavenge heat generated by the motors but rather to scavenge heat from the ambient air
 
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