Real World Heat Pump Effect

[badboy1980]

Hi,

Just wanted to ask that anybody with a model y what the actual effect of the heat pump is and how it benefits or effects the range and kWh per mile. Thanks!!

 

[Watts_Up]

Hi,

Just wanted to ask that anybody with a model y what the actual effect of the heat pump is
and how it benefits or effects the range and kWh per mile. Thanks!!

I know that someone (?) cannot wait to put his hands on one of those new Model Y...

How efficient is heat pump vs PTC? Part 1

How efficient is heat pump vs PTC? Part 2​

 

[badboy1980]

I know that someone (?) cannot wait to put his hands on one of those new Model Y...

How efficient is heat pump vs PTC? Part 1

How efficient is heat pump vs PTC? Part 2​

Lol... hopefully someone will give a test on a model y. For me this is a real game changer if it really does take significantly less energy.

 

[Georgia_Y]

If it's anything like how a heat pump with aux heat works in a home, then you will see a pretty significant savings in energy.

 

[mongo]

Hi,

Just wanted to ask that anybody with a model y what the actual effect of the heat pump is and how it benefits or effects the range and kWh per mile. Thanks!!

It's going to depend on your drive cycles, but here is a mode efficiency graph from the patent.
COP of 1 is the same as current resistive heating, COP of 2 means it is only using half the energy compared to resistive.

 

[Undisclosed]

Wondering if the heat pump makes the AWD have more range than the RWD...

 

[mongo]

Wondering if the heat pump makes the AWD have more range than the RWD...

Maybe in a specific operating region. The second motor adds weight and drag. The heat pump would take advantage of the extra heat captured from the environment via the second drive unit.

So with heater on and a cool to cold day, it might outperform RWD.

 

[cgiGuy]

The second motor adds weight and drag.

Drag?

 

[Watts_Up]

It's going to depend on your drive cycles, but here is a mode efficiency graph from the patent.
COP of 1 is the same as current resistive heating,
COP of 2 means it is only using half the energy compared to resistive.

Thank you for this graph, but I'm a little puzzle understand its valuable content...
I have an Electrical Engineering degree, but my thermodynamics knowledge is very basic.

I remember Bjørn Nyland mentioning that the efficiency (CoP) of an Heat Pump has some limits when it starts to be very cold outside,
because there is not too much heat to transfer and electrical heating of a liquid and a pump can become more efficient than using a compressor.
But may be he was making reference to the stationary camping mode and not when driving?

I wonder if future Model 3 will get retrofited, at least get this option for some countries like Canada or Europe.

 

[mongo]

Drag?

Mechanical losses due to half shafts, gearbox, and bearings spinning.

 

[mongo]

View attachment 523633
Thank you for this graph, but I'm a little puzzle understand its valuable content...
I have an Electrical Engineering degree, but my thermodynamics knowledge is very basic.

I remember Bjørn Nyland mentioning that the efficiency (CoP) of an Heat Pump has some limits when it starts to be very cold outside,
because there is not too much heat to transfer and electrical heating of a liquid and a pump can become more efficient than using a compressor.
But may be he was making reference to the stationary camping mode and not when driving?

I wonder if future Model 3 will get retrofited, at least get this option for some countries like Canada or Europe.

Yeah, it's a bit atypical and I go into the details more in the resistive vs heat pump thread.
Basically, in the simplest version of the system, they do not have an ambient air evaporator to draw heat from the surrounding environment.
The refrigerant system is not set up for typical heat pump cold weather operation. Rather, the heat sources are the pack/ drive unit coolant loop, the cabin evaporator, and the compressor motor (via mechanical work and also inefficient drive waveforms like the drive units on the 3 for pack heating).

Due to this, the normal ideal thermal engine efficiency curve does not apply, but they also do not need to worry about frosting over the evaporator.
I think there is too much that needs replaced to cost effectively retrofit existing 3s, but I could see new ones being built with this system.

Patent link: US20190070924A1 - Optimal source electric vehicle heat pump with extreme temperature heating capability and efficient thermal preconditioning - Google Patents

Simple version:

 

[J1mbo]

Looking at the patents, Tesla seem to have gone all-in on their(?) innvoation of running things in "inefficent mode" to generate heat. Even the cabin heater blower has an inefficent mode!

 

[mongo]

Looking at the patents, Tesla seem to have gone all-in on their(?) innvoation of running things in "inefficent mode" to generate heat. Even the cabin heater blower has an inefficent mode!

Yeah, though it is low voltage so only 400 watts or so.

 

[badboy1980]

Hoping someone can tell us in the real world how much this benefits not losing so much range.

 

[Saghost]

Hoping someone can tell us in the real world how much this benefits not losing so much range.

Too many variables mixed together for a clear answer. Every Y has the heat pump, so efficiency differences between the Y and other cars will be mixed in - and the efficiency gain of the heat pump is going to be variable with temperature and humidity as well.

 

[mongo]

Too many variables mixed together for a clear answer. Every Y has the heat pump, so efficiency differences between the Y and other cars will be mixed in - and the efficiency gain of the heat pump is going to be variable with temperature and humidity as well.

True, however the more data minded drivers out there could log their energy usage on their commute over the year along with temp and humidity. Then we could look at seasonal variation.

 

[Saghost]

True, however the more data minded drivers out there could log their energy usage on their commute over the year along with temp and humidity. Then we could look at seasonal variation.

Services like TeslaFI will do that automatically, I think including the temperature (not sure about humidity.)

We just need a mass of Y data (and 3 or X data) to wade through.

 

[mongo]

Services like TeslaFI will do that automatically, I think including the temperature (not sure about humidity.)

We just need a mass of Y data (and 3 or X data) to wade through.

Indeed.

 

[Watts_Up]

I have the Scan My Tesla OBD2, I wonder what additional information will be display?

 

[badboy1980]

is there a model y owner who has had a Tesla previously that can may state how they found the heat pump compared to previous heating system?