Heat pumps

Busman Paddy Lasty

Busman Paddy Lasty wrote: »

Burnt the face off me but I wanted to test it out of curiosity!

krissovo

Busman Paddy Lasty wrote: »

What type of car is it if you don't mind the question?
I did a 23 degrees mild weather test this morning with PTC and it was 10% of total energy used.

Its a I3

How can you calculate heater usage in an i3 ?

Busman Paddy Lasty

krissovo wrote: »

Its a I3

Nice. Good i3 forums out there talking about HP energy savings dating back to 2014. Anecdotally 30% ish probably over 50% by now. HP as standard for i3's sold in Sweden apparently. No idea how they measured this or what they have to back up these claims.

Busman Paddy Lasty

Busman Paddy Lasty wrote: »

Nice. Good i3 forums out there talking about HP energy savings dating back to 2014. Anecdotally 30% ish probably over 50% by now. HP as standard for i3's sold in Sweden apparently. No idea how they measured this or what they have to back up these claims.

A lot of guess work to be honest, unless they have dedicated tools to measure the current directly taken from the heating system from a car with and without HP, otherwise it's meaningless.

Busman Paddy Lasty

[Deleted User] wrote: »

A lot of guess work to be honest, unless they have dedicated tools to measure the current directly taken from the heating system from a car with and without HP, otherwise it's meaningless.

Meaningless then :-(

liamog

Busman Paddy Lasty wrote: »

Meaningless then :-(

So far we have in agreement with the Korean Ministry of the Environment, Volkswagen, Tesla, and a BMW owners club. But yes, all meaningless :rolleyes:

Busman Paddy Lasty

liamog wrote: »

So far we have in agreement with the Korean Ministry of the Environment, Volkswagen, Tesla, and a BMW owners club. But yes, all meaningless :rolleyes:

Whoa, was only referring to the guesswork of a few posters on an i3 forum in 2014! How their estimations had no backup on that forum.

Kramer

There's an algorithm guys...........

If:
a. The initial cost of the heat pump
b. The extra range benefit derived, by having a heat pump
c. The financial savings accrued, by having a heat pump
d. The environmental benefits, of significantly more efficient heating

If b+c+d ≥ a, get a heat pump equipped car.
Elon used this very same algorithm when deciding to add a heat pump in the Model Y.

.

Busman Paddy Lasty

Busman Paddy Lasty wrote: »

Whoa, was only referring to the guesswork of a few posters on an i3 forum in 2014! How their estimations had no backup on that forum.

Is that a fact ?

liamog

Kramer wrote: »

If:
a. The initial cost of the heat pump
b. The extra range benefit derived, by having a heat pump
c. The financial savings accrued, by having a heat pump
d. The environmental benefits, of significantly more efficient heating

I only care about a and b, for me it's the consistency factor, each person will have different preferences, I'm glad the Mini SE comes with a heat pump as standard.

the_amazing_raisin

I feel there's one example that's been ignored so far, the Gen1 Nissan Leaf. Before 2013 it was fitted with a resistive heater, afterwards they added a heat pump. It seemed to make the difference for winter range for some people.

My view is that it's a lot more up to personal habits than whether the heat pump is installed or not.

If you pre-heat the cabin then that takes a lot of the initial heating load off the battery.
If you set the heating to 19C it'll save more battery than 23C
Longer journeys probably see less impact from heating than short ones, since once the cabin is up to temperature the load on the heater is low

Personally, if all other things were equal I'd go for the heat pump simply because there's an efficiency gain with the heat pump. I think the Irish climate is suited for hat pumps since it doesn't get too cold here and if you can set the cabin temp a bit lower so the resistive heater doesn't kick in then you'll save more energy.

I was disappointed to learn the VW ID models don't include a Heat pump in Ireland and I'd be looking to add one after purchase, assuming I get one

KCross

liamog wrote: »

I only care about a and b, for me it's the consistency factor, each person will have different preferences, I'm glad the Mini SE comes with a heat pump as standard.

+1

Financial savings are relatively speaking miniscule as are the environmental aspects. Its about price, convenience, range and whether it affects you at all.

KCross

cruisey1987 wrote: »

I was disappointed to learn the VW ID models don't include a Heat pump in Ireland and I'd be looking to add one after purchase, assuming I get one

How are you going to do that?

This is an expensive, complicated piece of equipment that has to be tied into lots of car systems.

the_amazing_raisin

KCross wrote: »

How are you going to do that?

This is an expensive, complicated piece of equipment that has to be tied into lots of car systems.

How expensive and how complicated? My understanding is that the MEB is based on modular toolkits, the heat pump would just be another kit. What would make it complicated would be if other parts need to be removed or moved around


I said I'd look into it, it all depends on expense and complexity. We won't know either of those until VW release the ID3 parts list and service manuals

KCross

cruisey1987 wrote: »

How expensive and how complicated? My understanding is that the MEB is based on modular toolkits, the heat pump would just be another kit. What would make it complicated would be if other parts need to be removed or moved around


I said I'd look into it, it all depends on expense and complexity. We won't know either of those until VW release the ID3 parts list and service manuals

You can bet your bottom dollar that if you are buying/installing the OEM parts from VW and getting it added after purchase by VW that it will cost more than having it factory fitted.

Getting your local indy to do it is highly unlikely in the medium term and is also unlikely to be financially viable. Your money would be better spent getting the longer range variant than any potential range issues in winter from not having the HP.

Busman Paddy Lasty

Busman Paddy Lasty wrote: »

Whoa, was only referring to the guesswork of a few posters on an i3 forum in 2014! How their estimations had no backup on that forum.

Deleted User wrote: »

Is that a fact ?

Sorry, mis read what you said there hadn't got my coffee.

I think 30 percent is a gross overestimate because if People are preheating off the battery then this is going to use the resistive heating and not the heat pump.

liamog

Deleted User wrote: »

I think 30 percent is a gross overestimate because if People are preheating off the battery then this is going to use the resistive heating and not the heat pump.

It's backed up by numerous sources at this point. I'm not sure there is a big heat pump conspiracy designed to hoodwink motorists out of the money. Why would preheating only use the resistive and not the heat pump?

liamog

liamog wrote: »

It's backed up by numerous sources at this point. I'm not sure there is a big heat pump conspiracy designed to hoodwink motorists out of the money. Why would preheating only use the resistive and not the heat pump?

Well unless things have changed with newer electric cars the HP only works when the High Voltage system is energised, so if preheating a lot off the mains the HP isn't going to be 30% more efficient than the resistive heating.

I'm not saying the HP isn't more efficient but they are more important for lower range electrics. If it's free I'll take it but I wouldn't pay 1K more for one in a 300+ Km range EV considering the amount of times I need that kind of range.

liamog

Deleted User wrote: »

Well unless things have changed with newer electric cars the HP only works when the High Voltage system is energised

Is your info based on the original Leaf implementation? I've not found any details either way re whether the heat pump is used on other cars during pre-heating. The Hyundai/Kia and Tesla systems, will be less efficient during pre heating, because they also scavenge heat from the other vehicle systems.

I saw Munro's teardown of the octovalve in the Model Y, that's an impressive piece of engineering.

KCross

Who knows what VW have implemented but an important part of air based heat pumps is to have a large air flow over the coils to capture the heat. Thats easy to do when you are moving in the car. To make it happen on a car that is stationery outside your house would require you to spin up a fan. Think of the fan noise that you hear from some cars when they are DC charging!

I'd imagine alot of people would not want to have that spinning up outside their door/neighbourhood every morning. Air based heat pumps are not quiet.

In contrast a PTC heater just needs to pull juice from your charge point and run a small fan to circulate heat around the cabin.... very quiet and the designers dont have to worry about efficiency as the power is not coming from the HV battery... hence PTC over HP for pre-conditioning.

Lets see what VW bring to the table. They might have a different design philosophy or maybe this new heat pump is so good it doesnt need much air flow.... we just dont know yet.... not long now though!

liamog

liamog wrote: »

Is your info based on the original Leaf implementation? I've not found any details either way re whether the heat pump is used on other cars during pre-heating. The Hyundai/Kia and Tesla systems, will be less efficient during pre heating, because they also scavenge heat from the other vehicle systems.

I saw Munro's teardown of the octovalve in the Model Y, that's an impressive piece of engineering.

It's easy to know if the HP comes on during pre heat, if the radiator fan comes on then it's likely it does if not then it doesn't. You'll also hear the compressor.

Ionised

Deleted User wrote:

It's easy to know if the HP comes on during pre heat, if the radiator fan comes on then it's likely it does if not then it doesn't. You'll also hear the compressor.

I have no idea what it is, but my Mini does make a fair noise when preheating. Sounds more pump than fan though.

Ionised

Ionised wrote: »

I have no idea what it is, but my Mini does make a fair noise when preheating. Sounds more pump than fan though.

All you have to do is listen for the radiator fan at the front bumper and it should be obvious if it's on.

liamog

If as KCross says the heat pump requires airflow, why wouldn't you engineer it to use the radiator fan to provide that airflow, the ducts will need to be there anyway for operation while driving.

liamog

liamog wrote: »

If as KCross says the heat pump requires airflow, why wouldn't you engineer it to use the radiator fan to provide that airflow, the ducts will need to be there anyway for operation while driving.

They do, or at least the Leaf I did for when the car was stationary or driving slow. But not for pre-heating, no fan I assume no HP because it needs quite a lot of air.

liamog

Ok, so the rad fan being on, means the Mini SE could be using it's HP to pre-heat. I can't remember what the Ioniq does, as we don't tend to pre-heat it due to the plugged in requirement and no app

liamog

liamog wrote: »

Ok, so the rad fan being on, means the Mini SE could be using it's HP to pre-heat. I can't remember what the Ioniq does, as we don't tend to pre-heat it due to the plugged in requirement and no app

If the radiator fan is on when the car is pre-heating with the car turned off then there is a good chance the hp is running because I see no other reason it should be running, if the fan is off then there's no hp being used for pre-heat.

Ionised

I'd better have a proper listen next time I'm preheating. This heat pump business seems awfully controversial reading through this thread.