Heat pump vs non heat pump. What is the difference in efficiency

[Zardoz]

I have an apple's to oranges comparison, but it might help....

I went from a 2023.5 MME CR1 to a 2024 Lightning Pro (heat pump). I am on the Olympic Peninsula in the NW corner of NW Washington, across the Strait from Victoria Canada. We have had a few cool mornings already so plenty of chances to use the Lightning heat. I had CarScanner set up in the MME and now on the Lightning to watch the heater and air conditioner usage.

The Lightning has to have a resistive heater for really cold weather. Is there a way to turn that on if you want immediate heat?

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[Murse-In-Airy]

I live in the cold. Just south of Ontario in NY on the south bank of the St Lawrence. I have heat pumps / minisplits for my house. When it’s cold out, 15°F and under, my heat pumps, which are specially certified for the cold I live in, quit working. They spend more electricity cycling a defrost mode, during which the house is getting colder and colder, than they do warming up the house. So I have to kick the propane forced air furnace on.
So take my heat pumps, and add the cooling effect of airflow from driving… nah, I’m good. I’ll keep my resistive heater. Sure it costs range. A heat pump might be more efficient above 32°F, but once it’s below freezing, it’s going to work less and less until it just can’t keep up. At some point it will be using just as much range, only without producing any actual heat.

I’ll keep my resistive electric heat.

 

[B177y]

The Lightning has to have a resistive heater for really cold weather. Is there a way to turn that on if you want immediate heat?

There is no way to choose heat pump or resistance, it's controlled by the FM (Ford Magic) ?

 

[Mache_Nor]

Don’t know what kind of heat pumps you have in America, but in Norway - a land that is cold, 80% of houses has heat pumps. Many of them are rated to work down to -30C (celcius, 0 is when water freeze), even though they get less effective when you get down to the double digits minus temperature.

my latest heat pump gives roughly 6 to 7 times the amount of heat for the same amount of electricity a heat element would give down to around 0C. Then it goes down to “only 3-4) until close to double digits, before it eventually is a 1-1 at minus 25.

Whether heat pumps or not, look at Tesla (not their leader), and look how much range it loses compared to ideal vs worst conditions, then do same for our car. Heck, on a -12 trip last year I could not get warm and around half the energy was used for heating. That is not great.

 

[Norcolboulder]

Yes getting back to the question- a 2023 or 2024 for the Heat pump? I believe 2023 ,s with a build date after 7/23 on the door has the new heat pump

 

[Mache_Nor]

Yes getting back to the question- a 2023 or 2024 for the Heat pump? I believe 2023 ,s with a build date after 7/23 on the door has the new heat pump

Don't think so. I went through the configuration now of all specs, no places are there mention of a heat pump.

 

[ARK]

I have an apple's to oranges comparison, but it might help....

I went from a 2023.5 MME CR1 to a 2024 Lightning Pro (heat pump). I am on the Olympic Peninsula in the NW corner of NW Washington, across the Strait from Victoria Canada. We have had a few cool mornings already so plenty of chances to use the Lightning heat. I had CarScanner set up in the MME and now on the Lightning to watch the heater and air conditioner usage.

The MME would use up to 8kW on the heater when I called for it. The MME heated up very quickly, turn the heat up and it got warm in the cabin, no hesitation. I kept the MME temp pretty consistently at 68 deg F and it was always comfortable. The efficiency hit was obvious while driving as my normal was around 3.2 MPK and if using heat would quickly go into the mid-high 2.x MPK, even lower if it was really cold.

The Lightning doesn't warm up nearly as fast. The heater generally bounces between 0-4 kW and the "air conditioner" (heat pump) spools up and down, but tops at about 9 amps total (it only shows amps in CarScanner for the AC, not sure if it's off the 12 volt or the HVB. If 12 volt, then it's about 110 watts (per @Snakebitten it's 240 volt so that's about 2200 watts)). I adjust the Lightning cabin temperature anywhere from 68 to 76, and usually keep it around 72 to get comfortable. The heat is much slower to come no matter where I adjust it. Efficiency wise, my normal in the Lightning is 2.4 MPK. With the heat blasting, it goes to about 1.8. In normal cruising with it set to 72, I get about 2.2 MPK in cool weather.

Yesterday the kids and I got hit with a cold driving rain that turned into a windy thunderstorm during their soccer practice. After the thunder hit we cancelled practice and got into to Lightning, all cold and wet. I cranked the heat to max, it very slowly got warm. The outside temp showed 46 F. I wish I had the instant MME heat... The Lightning was much more like an ICE vehicle, I had to wait a while for it to heat up. CarScanner showed my air conditioner at 9 amps pretty consistently, and the heater was late to the game, and cycled on and off from 0-4. We waited about 5 minutes while we warmed up and waited for the window fog to clear. I was at "Auto 3 (high)" and heat to "MAX" with the seat heaters on high.

All of this to say that the heat pump is not a godsend, but it's not terrible. I think it is more efficient than the resistance only heater, but not nearly as quick to heat. The lowest outdoor temp that I have driven in so far is 40 deg F, so no real world comparison in really cold temps yet.

That's interesting, thanks for sharing. In my mind, I had always sort of thought of the PNW as prime heat pump territory - long stretches of cool but not extremely cold weather. I guess even there it is slower than the resistive heater to warm the cabin.

I do like that about the Mach-E's resistive heater, the way you get instant heat compared to an ICE. If the Mach-E ever got a heat pump, I'd like to keep the option of using the resistive heater. Sometimes I feel like automotive discussions around EVs are bit too dominated by maximizing range and charging speed to the detriment of everything else.

It's not so obvious to me that a heat pump would be a net positive for me. Factor in the extra cost of building in a heat pump into the vehicle, if it was a standalone option, I probably would pass.

 

[CTZ]

I'm sure that every vehicle with a heat pump also has a resistance heater since there's always a temperature where a heat pump won't work, even if it's extreme cold. I should note that every car has a heat pump, anyway, so it's not really an extra addition. Air conditioning is a one-way heat pump.

Also, preconditioning the cabin on plug will make the heat pump versus resistance heater a moot point for shorter drives, anyway.

 

[tuminatr]

I had forgotten about that! That is a benefit. I hope the motors aren't warm enough to heat the battery and cabin to comfortable temperatures in sub-zero temperatures, but every little bit helps.

Do new Mach E's harvest some of that motor heat?
https://www.macheforum.com/site/threads/heat-pump-in-new-models.33047/

The Mach e has uses the same system to heat the cabin as the battery so heat created from driving helps warm the car too.

 

[Alan]

My first EV was a BMW i3. It had a single compressor that powered two heat pumps. One managed the cabin, and the other managed temps in the battery/motor/inverter. Also, rather than having a heat exchanger that transferred the hot or cold refrigerate to a water loop that circulated through the battery, it ran the refrigerant straight through the battery. And then, for even another gram of efficiency, there was no trap in the dryer as is normal. All very efficient with excellent temperature management for the cabin and drivetrain. Except…

A year out of warranty, the compressor self-destructed, sending shrapnel through the entire system (no trap to prevent this) taking out both heat pumps and requiring battery disassembly. The over $23K repair estimate was $5K over book value. BMW didn’t see fit to take any responsibility and forever lost this customer. I’m fine with no heat pump in my Mach-E!!!!

 

[Womps]

Yes getting back to the question- a 2023 or 2024 for the Heat pump? I believe 2023 ,s with a build date after 7/23 on the door has the new heat pump

The 2024 model does not have a heat pump. If it did Ford would be making a huge deal about it.

 

[Norcolboulder]

Later model 2023's had "heater" improvement ( buying a used 2023 look at the build date )

https://www.macheforum.com/site/thr...-redesign-and-larger-7-kw-heater.34305/page-2



and -
The 2024 Ford Mustang Mach-E has a new thermal control module that monitors component temperatures in real time and adjusts the vehicle's derating based on temperature. This is an improvement over previous models, which would assume all conditions were extreme and derate based on worst-case scenarios.


so improvements over time

 

[grein002]

My first EV was a BMW i3. It had a single compressor that powered two heat pumps. One managed the cabin, and the other managed temps in the battery/motor/inverter. Also, rather than having a heat exchanger that transferred the hot or cold refrigerate to a water loop that circulated through the battery, it ran the refrigerant straight through the battery. And then, for even another gram of efficiency, there was no trap in the dryer as is normal. All very efficient with excellent temperature management for the cabin and drivetrain. Except…

A year out of warranty, the compressor self-destructed, sending shrapnel through the entire system (no trap to prevent this) taking out both heat pumps and requiring battery disassembly. The over $23K repair estimate was $5K over book value. BMW didn’t see fit to take any responsibility and forever lost this customer. I’m fine with no heat pump in my Mach-E!!!!

Except that wasn't a "heat pump" issue, it was a "stupid BMW sends refrigerent directly through battery pack and uses crappy compressor w/o drier" issue. The same would have happened even if they only used the compressor to cool the battery.

Most systems use AC/heat pump to chill/heat a water/coolant loop that then provide heat/cool for cabin, battery pack, motors, etc.

 

[Dear_OP]

There is a geeky nerdy video regarding Tesla's proprietary heat pump system (it may now be open sourced). The video described the incredible methods this device scavenge heat and move it between the cabin and the battery. The device looks like a mechanical octopus. I know it's all very sci-fi but what do you expect, it's the same subsidiary family that also managed to grab hold of a falling rocket.

Ioniq6 and the latest Model 3 both have modern heat pumps and are the efficiency kings of affordable EVs.

 

[Oxford]

I have an apple's to oranges comparison, but it might help....

I went from a 2023.5 MME CR1 to a 2024 Lightning Pro (heat pump). I am on the Olympic Peninsula in the NW corner of NW Washington, across the Strait from Victoria Canada. We have had a few cool mornings already so plenty of chances to use the Lightning heat. I had CarScanner set up in the MME and now on the Lightning to watch the heater and air conditioner usage.

The MME would use up to 8kW on the heater when I called for it. The MME heated up very quickly, turn the heat up and it got warm in the cabin, no hesitation. I kept the MME temp pretty consistently at 68 deg F and it was always comfortable. The efficiency hit was obvious while driving as my normal was around 3.2 MPK and if using heat would quickly go into the mid-high 2.x MPK, even lower if it was really cold.

The Lightning doesn't warm up nearly as fast. The heater generally bounces between 0-4 kW and the "air conditioner" (heat pump) spools up and down, but tops at about 9 amps total (it only shows amps in CarScanner for the AC, not sure if it's off the 12 volt or the HVB. If 12 volt, then it's about 110 watts (per @Snakebitten it's 240 volt so that's about 2200 watts)). I adjust the Lightning cabin temperature anywhere from 68 to 76, and usually keep it around 72 to get comfortable. The heat is much slower to come no matter where I adjust it. Efficiency wise, my normal in the Lightning is 2.4 MPK. With the heat blasting, it goes to about 1.8. In normal cruising with it set to 72, I get about 2.2 MPK in cool weather.

Yesterday the kids and I got hit with a cold driving rain that turned into a windy thunderstorm during their soccer practice. After the thunder hit we cancelled practice and got into to Lightning, all cold and wet. I cranked the heat to max, it very slowly got warm. The outside temp showed 46 F. I wish I had the instant MME heat... The Lightning was much more like an ICE vehicle, I had to wait a while for it to heat up. CarScanner showed my air conditioner at 9 amps pretty consistently, and the heater was late to the game, and cycled on and off from 0-4. We waited about 5 minutes while we warmed up and waited for the window fog to clear. I was at "Auto 3 (high)" and heat to "MAX" with the seat heaters on high.

All of this to say that the heat pump is not a godsend, but it's not terrible. I think it is more efficient than the resistance only heater, but not nearly as quick to heat. The lowest outdoor temp that I have driven in so far is 40 deg F, so no real world comparison in really cold temps yet.

That is impressive. I think I am getting an idea what you are saying. Each has its advantages. I believe that a long trip in a temperature that is not artic would favour the heat pump. Short trips seem to favour the resistive heater set up, which makes a lot of sense.since instant heat is the byproduct. Short trips in turn mean charging at home is cheaper.
Thanks a bunch!

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