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BlueMach

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Heat pumps lose efficiency as the temperature drops. If you research them, you'll find they are recommended for heating at temps above freezing. If it's below around 30°F it is recommended that they be supplemented with some other form of heat. It isn't that they don't run ... it's that they don't offer much heat for all the energy you put into running them.
Go tell automotive HVAC suppliers, their tests show their heat pumps working down to -30C (-22F).

For example, the VW ID.3's R744 (CO2) heat pump supplier shows their VW system working with higher efficiency at -30F than a resistive heater like the Mach-E.

1609804811547.png


To be fair they do note that a Tesla-style R1234yf heat pump only has full operation down to -20C (-4F).

There's a big reason some of us want one so much:

1609805001773.png
 

All Hat No Cattle

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6 Heat heats the heated heat to be heated
LOL, I said that the schematic was simplified. But that is funny. They should have put the reversing valve in the graphic, then it would have been hilarious.

For example, the VW ID.3's R744 (CO2) heat pump supplier shows their VW system working with higher efficiency at -30F than a resistive heater like the Mach-E.
Excellent info. I was going to ask what refrigerant the BEV's are using, but I thought it would be getting into the weeds a bit much.

R744 is a new one for me, (I'm retired!), but the lower the boiling point of the refrigerant the more efficient a heat pump becomes.

The lower the refrigerant temp in the outside coil, the more BTU's that the refrigerant will absorb from the air going over it.

And you can see how much colder the outside coil is with CO2 refrigerant compared to 134A. But the pressures in the CO2 system are out there. The static (not running) pressure in a R744 system is about 900 PSI at 75° F. Yikes!

Fact check me, please!

Main characteristics of R744 (CO2 carbon dioxide)
PROPERTIESR744R134a
Boiling Point-78°C-26°C
Critical Point31°C102°C
 

BlueMach

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LOL, I said that the schematic was simplified. But that is funny. They should have put the reversing valve in the graphic, then it would have been hilarious.



Excellent info. I was going to ask what refrigerant the BEV's are using, but I thought it would be getting into the weeds a bit much.

R744 is a new one for me, (I'm retired!), but the lower the boiling point of the refrigerant the more efficient a heat pump becomes.

The lower the refrigerant temp in the outside coil, the more BTU's that the refrigerant will absorb from the air going over it.

And you can see how much colder the outside coil is with CO2 refrigerant compared to 134A. But the pressures in the CO2 system are out there. The static (not running) pressure in a R744 system is about 900 PSI at 75° F. Yikes!

Fact check me, please!
R744 definitely has to operate at significantly higher pressure as you note. That's probably one of the reasons it's taken so long to get mainstream adoption of R744 systems.
 

TheVirtualTim

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Go tell automotive HVAC suppliers, their tests show their heat pumps working down to -30C (-22F).

For example, the VW ID.3's R744 (CO2) heat pump supplier shows their VW system working with higher efficiency at -30F than a resistive heater like the Mach-E.

1609804811547.png


To be fair they do note that a Tesla-style R1234yf heat pump only has full operation down to -20C (-4F).

There's a big reason some of us want one so much:

1609805001773.png
If Ford had put a heat-pump in the car... I probably wouldn't have bought the car.

Heat pumps are WELL understood and they don't work below the freezing point. Not for homes. Not for cars. (and it's a lot easier to do this for a home) Tesla put them in their Model Y and their later builds of Model 3 ... and they are plagued with failures.

I am not trying to suggest that they cannot be made to work ... but they don't have a track record for being reliable at this time.

The physics involved are simple. Compress a gas and it will become warmer. Decompress a gas and it will become cooler. But this shift in "warmer" vs. "cooler" is relative. So when it's 40° outside and the heat pump can raise the temp by up to 40° additional degrees... great! But when it's 10° out and the delta 40° increase means the new best temp is 50° ... not so great. You'd need something that can cause a swing of a greater range of temps. This is why supplementing a heat-pump with something else is recommended when you have very cold temps.

I have not seen a track-record for reliable heat pumps in very cold temps ... but will be totally on-board when that happens. Until then ... I'll shy away.
 

BlueMach

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If Ford had put a heat-pump in the car... I probably wouldn't have bought the car.

Heat pumps are WELL understood and they don't work below the freezing point. Not for homes. Not for cars. (and it's a lot easier to do this for a home) Tesla put them in their Model Y and their later builds of Model 3 ... and they are plagued with failures.

I am not trying to suggest that they cannot be made to work ... but they don't have a track record for being reliable at this time.

The physics involved are simple. Compress a gas and it will become warmer. Decompress a gas and it will become cooler. But this shift in "warmer" vs. "cooler" is relative. So when it's 40° outside and the heat pump can raise the temp by up to 40° additional degrees... great! But when it's 10° out and the delta 40° increase means the new best temp is 50° ... not so great. You'd need something that can cause a swing of a greater range of temps. This is why supplementing a heat-pump with something else is recommended when you have very cold temps.

I have not seen a track-record for reliable heat pumps in very cold temps ... but will be totally on-board when that happens. Until then ... I'll shy away.
You said they didn't work, they work.

Tesla has reliability problems, due to a faulty sensor (same kind of sensors non-heat pump vehicles use), that's true.

But that's fine, you can not want one on your car, but don't pretend they don't work . All those Kia, Hyundai, VW, Nissan, Renault (etc.) owners in Norway would probably have noticed by now if they didn't have heat in the winter.

Automotive HVAC is so far beyond the performance of residential it isn't even funny. They work, period. They work down to -20ishC at least, period.

I'd pay significantly more for a heat pump.
 

TheVirtualTim

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You said they didn't work, they work.

Tesla has reliability problems, due to a faulty sensor (same kind of sensors non-heat pump vehicles use), that's true.

But that's fine, you can not want one on your car, but don't pretend they don't work . All those Kia, Hyundai, VW, Nissan, Renault (etc.) owners in Norway would probably have noticed by now if they didn't have heat in the winter.

Automotive HVAC is so far beyond the performance of residential it isn't even funny. They work, period. They work down to -20ishC at least, period.

I'd pay significantly more for a heat pump.
I"m a science geek. I understand the "physics" of how and why they work. I follow the best available information at the time. When there is new information that is better than the old information ... I am completely comfortable updating my position.

With that said.... home heat-pump systems don't work below freezing .

You have suggested that some cars with heat pumps work reliably ... I am intrigued. Tell me more.

Tesla's system is the first I've heard of for cars ... and sadly that botched system is garbage. It's not a few isolated problems... it's a sufficient number of cars with problems that the repair centers in northern climates are having problems keeping up with repairs. As I am a person who lives in a climate where a noticeable part of the year is spent below the freezing point ... I would not enjoy that customer experience.
 

jlauro

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With that said.... home heat-pump systems don't work below freezing .
What kind? Your statement is true for the cheap air to air single stage ones. However, that is not the only kind of heat pump.

Air to air above ground? or ground source? or water source?
Single stage or Multistage?
Variable speed or not?

There are plenty of heat pumps that work below freezing, but it is true not all do.
 

All Hat No Cattle

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With that said.... home heat-pump systems don't work below freezing .
Hmm, these guys on a Professional HVAC Forum are obviously delusional. :)

Some of the high end units shut off when it gets cold. Nortek's IQ Drive shuts off at 14. Others in the 0-10 range. Carrier's 18 SEER, which is a 5 step rotary like the IQ Drive says minimum of 10. The scroll model goes to -15. Rheem's inverter scroll says provides heat down to 7.

my hp is too large for my house so I have it where my auxiliary heat can not come on. Now with that said my heat pump heats down to -17 so far. This was 1 year ago January.

Trane/Am Std heat pumps will work down below "0" but don't do much like BaldLoonie said. They do have a high end model that uses a variable speed compressor that will run up to 140% of rated speed so it will produce an adequate amount of heat even at the lower temperatures
 

BK2EV

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A bit late but....


As an enthusiast - Congrats to all those that got and are getting delivery of their cars...

As a Ford stock holder - Congrats to everyone at Ford for meeting their goal(s) and Great Job!!......

As a day-1 reservation holder - Excitement is getting closer....




BK2EV
 

TheSeg

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I don't know if this a 2020 chart and just not updated since the actual cars were "sold" until the last week of the year
No need to panic, it's just not updated! Not even the third quarter sales numbers are up.

Remember: The deprecation doesn't start until two quarters after the quarter where 200,000 units are made.
 

dliunatic

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According to my dealer, that red Mach-E Premium wasn't at their dealership location. They only got the CA Route 1 and the First Edition.

Also apparently won't have shipping updates until Wednesday for some reason...
 

ClaudeMach-E

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I"m a science geek. I understand the "physics" of how and why they work. I follow the best available information at the time. When there is new information that is better than the old information ... I am completely comfortable updating my position.

With that said.... home heat-pump systems don't work below freezing .

You have suggested that some cars with heat pumps work reliably ... I am intrigued. Tell me more.

Tesla's system is the first I've heard of for cars ... and sadly that botched system is garbage. It's not a few isolated problems... it's a sufficient number of cars with problems that the repair centers in northern climates are having problems keeping up with repairs. As I am a person who lives in a climate where a noticeable part of the year is spent below the freezing point ... I would not enjoy that customer experience.
Like I have pointed out before in the thread, car heat pumps systems are more complex then home systems has they are also recuperating heat from the circulating liquid in the cooling system of the main battery and motors helping out in maintaining a confort cabin temp. They don't only rely on air exchange and so far I have not heard of any Kia Niro EV owner here in Canada complaining about their heat pump system in winter which is not optional on the top trim. But I agree that it should only be an option if not needed which is the case with the Niro EV in the US I believe.
https://blog.greenenergyconsumers.o...-overlap-between-heat-pumps-and-electric-cars
 



 









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