This is a most excellent place for technology news and articles.
Is this really an article saying heat pumps are more efficient than resistive heaters? Yes, that is why heat pumps exist.
The biggest issue is the battery itself. If it gets cold enough you can have difficulty even charging an EV outdoors. I would be a lot more concerned with whether or not my battery is well insulated and heated. Heat pumps are great and should be the default, but unless you're going really far or have a very low range EV it's not a huge issue.
Yes, resistive heat is expensive, but that's only part of what makes heat pumps in cars more effective. They don't just heat your cabin, they heat your battery so you maintain range while it's cold out. Here's an article with more details and some pretty infographics.
You still need resistive heat as heatpumps don't work below about -20C and those temperatures happen to at least some car buyers.
heatpumps don't work below about -20C
I don't think that's true? There are cold weather models that can work at COPs > 1.5 at -30C. Are we talking about a sizing constraint for the model here, perhaps?
There are, but then I think you'd have problems with the effective rang of the AC in the summer. To my knowledge this is all about at what temperature the coolant is a liquid and when it's a gas (because that's how you exchange heat).
A traditional AC only needs coolant that does this at summer temperatures. A heat pump tries to use one that will work at colder temperatures as well. A cold weather heat pump goes even further but I think there is a sacrifice in AC efficiency in the summer.
Somone please correct me if I'm wrong. But I'm not sure if a do-it-all extreme cold and extreme hot heat pump exists, and as a car manufacturer you want to put in the one that will fit most cases, as opposed to a house which only needs to operate in the range of the climate it is built in.
Im in one of those places but where im at its rare and at this point I will resist leaving the house pretty massively at those temps.
If it is rare enough and you don't have an emergency that is the right thing. Odds are the rest of your city doesn't have the ability to deal with those temperatures and so you going out will make things harder for emergency workers who must get out. If your city deals with this often then everyone will know how to deal with it and expect you to deal with it. You cannot shutdown your life for something that happens every single year, but if it is just a day or two every 5 years it isn't worth being knowing how to deal with it other than the minimum emergency needs (that is make sure your HVAC system at home can handle it)
I mean its more like we can go a winter without below zero F. Its a lot less common in the last decade and usually it does not last to long and that is really for lows. Highes below zero aren't shockers but yeah we can go some years now without them and for most folks they are doing things while the sun is up. My thing is if I grab a metal doorknob with a bare hand and it is actually painful, then its like ef this im staying inside unless someone forces me out. Even back in the early aughts I had a job that was not wfh all the time like now but did it as needed and I could easily email I was wfh do to the weather being extreme. Its actually the wfh policy outside of all the time type one I like the best. wfh anytime there is a reason to and actually that place was like do not come in if you are sick. if you came in and coughed you would get the maybe you should have stayed home today comment.
Yes, they should have both.
I know the resistive heater in my Volt can't compare to the heat put out by the ICE. Often in the winter we'll have to run the ICE to keep the cabin warm enough. It does have heated seats and wheel, but my wife is the type to set the heat to max until it gets too hot rather than just picking a temp and hitting auto to let the car manage it.
If the heat pump can put out more heat for less energy, that would be a boon. That might be the second biggest issue (next to range) that has my wife vetoing an all-electric car. She gets the next vehicle, but I want the one after that to be a full EV.
Fwiw, I’ve never had a lack of heat from my cars heat pump. It even warms up faster than a gasoline engine would. Most importantly, I can turn it on remotely to get warm before I get in the car. I never had that with a gas engine
Yeah and a lot are moving to heat pumps if they don’t already use them.
https://www.recurrentauto.com/questions/which-electric-vehicles-have-heat-pumps
There’s a list of models that have them.
If you have two cars, one EV and one ICE is a great option. I do recommend whoever is more enthusiastic about EVs get the first one, though.
I know the resistive heater in my Volt can't compare to the heat put out by the ICE.
the ICE generates an insane amount of excess waste heat as a byproduct, so you have a virtually unlimited supply. The Volt is a PHEV so resistive heating was probably not considered super important.
If the heat pump can put out more heat for less energy
There's no if about it, it is ~300% more efficient.
That might be the second biggest issue (next to range)
They are the same issue. Less energy used for heating = more range.
It defintely is a huge issue, considering resistive heaters use 3x as much energy. Most EVs have a "low range" and anything you can do increase it without adding more batteries and weight and cost, especially in winter, is a huge advantage.
The lowest range EV in the US is 114 miles. The average commute is 52 miles. Most EVs sold in the US have a range of 250 miles or more. So a resistive heater eating 10% of your range is way less of an issue than your battery not charging properly in cold weather. Again, heat pumps should be available, but they aren't going to save you if cold weather kills your battery.
The average commute is 52 miles. Most EVs sold in the US have a range of 250 miles or more.
No one cares about "average commute" when buying an electric car and considering the offered range. They're thinking about long trips.
So a resistive heater eating 10% of your range is way less of an issue than your battery not charging properly in cold weather.
Who said anything about batteries "not charging properly"? What does that even mean?
heat pumps should be available, but they aren't going to save you if cold weather kills your battery.
We're not talking about killing batteries, we're talking about electric range. Heat pumps extend your electric range and 20 miles can absolutely be the difference between making it to the next charger or not.
Actually, I'm surprised they weren't using them long before. It's basically AC with an extra valve. Thought they get priced like they're some sort of new technology.
There was never really a need in ICE vehicles since they can primarily use waste heat from the engine.
Pretty sure they meant EVs
Pretty sure @jqubed@lemmy.world meant to explain why they weren't a thing in cars in general
Vapor injection is the new technology. It's why older heat pumps were useless below 32f.
Vapor injection becomes an excuse to downsize the compressor and lowers the cost, it seems. You could easily go lower than 32 if you oversized the pump before EVI, but those were only in specific heatpumps.
I suspect the reason for that was that the pumps used in car ACs are not really very powerful. They were alright for cooling the car down, but for heating heat up in a cold environment you need a fair amount of throughput, they work if you have the throughput, but you need it to be there.
They work by pulling ambient heat out a large part of the outside and dumping it into the small inside. You need many times the contents of the interior to warm up if it's a cold day outside. Thus you need a lot of air and if you want it to happen in a reasonable time frame you need quite a powerful little motor. The ones on houses are fine because they're huge anyway.
It uses the same amount of energy to create cold as it does to create heat.
Well it's about temperature differences, those are larger in winter I guess. On the other hand there is a lot more radiative heat load in summer...
They also need to be able to get the cold side colder than the outside air so once it gets too cold they don’t really work. There can also be some problems with condensation but when they do work they’re great.
I reckon they thought seat heating and steering wheel was enough, and it kinda is for the most part
As someone in a rural state, cold weather range is one of my chief concerns. I work from home but on the weekends travel to far away backcountry areas to ski.
I'd like to get a full EV when my current lease expires(2.5 years) but the pool of cars that are affordable, have AWD, and 300 miles of range(aka 180-225 in winter) is quite limited.
You're probably a better candidate for a plug-in hybrid.
Yeah I'm coming to terms with that now lol. Debating between leasing with the hopes to get a full EV after another 3 years, or just buying a PHEV.
Check out the 2023 Q8 e-tron. There’s usually good lease deals on them and they meet that list. Wait for them to come off lease and you can get them at a steal. I’d recommend the 2022 but those had a smaller battery pack and wouldn’t meet your range.
Just leased an Ioniq 6 and been loving it. Depending on what you consider affordable, it checks your boxes! I leased mine during a major sale and with a trade in, though.
In 2.5 years, the EV market will look very different. Just the last year has shifted a lot around with the used market (such as Hertz cycling out a bunch of Teslas and offloading them cheap).
It found that those models lost 21 percent of their range on average when temperatures drop to 32° Fahrenheit.
That is a pretty significant drop.
When its that cold I use a signifcant amount of fuel more than when its warmer. I think this will improve with better battery tech. I don't think my petrol will.
Winter gas also has less energy in it than summer gas, due to the different (lighter hydrocarbon, mostly more butane) mix.
Fair, but my hybrid (not plugin) gets about the same efficiency regardless of outdoor temperature, it's usually around 45-50 mpg. While pure combustion engines likely won't improve, hybrid systems can absolutely thread that needle really well and are a great option if you need range in the winter.
We currently have a hybrid and a pure ICE car, and we're planning on replacing them with an EV and a hybrid. I'm not giving up my hybrid until EVs can go >500 miles on a single charge, because we regularly go on road trips of >800 miles in a single day, and EV charging infra is pretty spotty in those areas.
