Electric vehicle heat pumps

[Job]

It seems some already have them like the Leaf and some Hyundai and Kia models. I didn't realize the big difference in energy used to produce heat in a car. Surprised the Prius Prime has one.

How does the heat pump work in a Toyota Prius Prime plug-in hybrid?

The challenge of reducing the energy used by traditional heating systems in battery-electric and plug-in hybrid cars is one automakers still grapple with today. Reduced battery range in cold temperatures, combined with batteries working overtime to heat the cabin, can produce drastic declines in...

www.greencarreports.com

Hyundai and Kia Turn Up EV Efficiency with New Heat Pump Technology

www.hyundai.news

 

[Propflux01]

Impressive

 

[Cujet]

It’s interesting that a 100W light bulb is very efficient at producing heat, the one thing it really should not do. Same goes for an internal combustion engine. The difference is that the heat is not always wasted, we use the heat from the engine half the year. It’s funny how EV marketing claims never include the heat energy required when comparing to a combustion powered car.

EV’s can heat up before you drive, using the house power, so it can help extend battery range.

 

[pezzy84]

My E-Golf unfortunately does not have heat pump (SEL has heat pump) and that is one thing I regret not waiting to find an SEL. On a recent mild morning in the high 40's low 50's the strip heat with HVAC set to 70 will immediately chop about 6-7 miles off the range, I have the lower range 83 mile edition so its a solid 10% reduction. I didn't live with the car during the depths of last winter so I am curious to see how range is when we are regularly in the 30's.

Reading some of the E-Golf forums it appears some just get cabin warm enough to be bearable then shut system down to preserve range. Fortunately windshield is heated so you can get all the frost melted before you head out and not have to blast the heat to defrost the windshield - not a huge penalty using it either (~1 mile range hit when in operation). Heated seats are only ~1 mile penalty too.

 

[Danno]

I take it the range hit would be substantial in the - 30C we see here quite often.

 

[Job]

I am surprised the Chevy Bolt and Teslas don't have heat pumps. I would wager they will on coming models, they already say the Y will have it. This turned me off to the Bolt. Such a good deal right now on them. Local dealer is discounting them 14,400, plus any energy rebates which in my case is 4,800 directly back. But no heat pump apparently. I have to say Kia/Hyundai is an aggressive company to compete with.

 

[nthach]

In the 2nd gen Prius, Toyota incorporated PTC elements into the heater core to help keeping the cabin warm but the engine needs to be running to sustain heat - the PTCs and coolant heat storage/exhaust heat recovery system can only offer so much. The newest xEV buses I see are using some kind of hot water heating.

Heat pumps are nothing new to stationary HVAC - but it’s new to cars. Denso is Toyota’s HVAC supplier of choice, while Hyundai-Kia got theirs from a buyout of Visteon. The other automakers will get it - more so Tesla who buys from Denso and Ford given the Visteon(Hanon) connection. PTCs aren’t efficient and for a ZEV, it makes no sense to add a fuel-fired heater.

 

[CR94]

How do automotive heat pumps deal with potential ice formation on the outside heat exchanger (evaporator in heating mode)?

 

[Cujet]

How do automotive heat pumps deal with potential ice formation on the outside heat exchanger (evaporator in heating mode)?

I believe they have backup resistance heating for when the system loses function or if it’s really cold out.

 

[Oildudeny]

The old take power to make power.

 

[kschachn]

How do automotive heat pumps deal with potential ice formation on the outside heat exchanger (evaporator in heating mode)?

One would guess it is similar to how an A/C evaporator is regulated to prevent ice formation. Cars have long had "heat pumps" installed of course, this one just operates in reverse.

 

[JeffKeryk]

I am surprised the Chevy Bolt and Teslas don't have heat pumps. I would wager they will on coming models, they already say the Y will have it.

Good point. The Model Y uses the heat pump and the Model 3s being produced now have been improved to use it.
I was just reading about this yesterday.

 

[kschachn]

Good point. The Model Y uses the heat pump and the Model 3s being produced now have been improved to use it.
I was just reading about this yesterday.

Unless it is scavenging some previously unused source of waste heat then simple resistance heating would be more efficient.

 

[JeffKeryk]

The Model 3 “Passenger Face Vent” mode allows the vehicle to detect if there is someone in passenger seat. If the passenger sear it empty, it will automatically turn off the air conditioning to save energy.

The Model 3 is constantly improving based on lessons learned. The Model Y and cars built in Shanghai already have these improvements.
Apparantly the Berlin plant will be the most high tech of all.

 

[Andrew1972]

I don't own an electric car. Can you simple click a button or app and have the car heat/cool itself up in your garage or wherever it is plugged in?

 

[OVERKILL]

I don't own an electric car. Can you simple click a button or app and have the car heat/cool itself up in your garage or wherever it is plugged in?

Yes.

 

[JeffKeryk]

I don't own an electric car. Can you simple click a button or app and have the car heat/cool itself up in your garage or wherever it is plugged in?

Your cell phone has an app and is your key as well.
Here is a terrible pic of the climate screen and the main app menu.

.

 

[CR94]

One would guess it is similar to how an A/C evaporator is regulated to prevent ice formation. Cars have long had "heat pumps" installed of course, this one just operates in reverse.

I'd imagine avoiding ice formation is far easier when air enters the evaporator at 70°-110°F than when it enters at 0°---or at 35° with high humidity.

 

[CR94]

. [Duplicate deleted]

 

[pezzy84]

One would guess it is similar to how an A/C evaporator is regulated to prevent ice formation. Cars have long had "heat pumps" installed of course, this one just operates in reverse.

I'd imagine avoiding ice formation is far easier when air enters the evaporator at 70°-110°F than when it enters at 0°---or at 35° with high humidity.

This is a wild guess since these seem to be nothing more than a scaled down version of a home heat pump. I imagine they probably have a similar defrost cycle which clicks it back over to A/C mode to heat up the condenser - even home heat pumps that are nearly solid block of ice melt real fast once the defrost kicks in.

If you have not seen it happen in real life on a home HVAC the steam show can be pretty impressive especially once the condenser fan kicks back on once defrost is done.