Why no heat pump?

[MeeLee]

If what they say is true, that a heatpump is more efficient than a heater, and all they need is some extra plumbing (since cars already have an AC),

Why did the fusion not get the heat pump feature?
Even if it only works down to about 20-30F, it's easy to use exhaust heat or engine coolant to melt ice on the outside condenser, and make it useable at well below 10 degrees!

[jpohlman]

Heat pumps if you've ever lived with one deliver a "cold heat", the air coming out of the duct is the temp it's set for and it can take a while to warm things up.

So in a car it's not really practical since you have nothing flowing to the radiator via the cooling system till the coolant gets up to 180º.

The Energi has a PTC electric heater as it's intended to spend most of it's life on battery.

[Sky14FFH]

Interesting.  Do you know which cars use a heat pump already?  I understand heat pumps are usually large units that are combined with geothermal (pipes installed in the ground) to deliver heat in the winter.  So can such an application be scaled down?

[MeeLee]

On 8/11/2022 at 2:31 PM, Sky14FFH said:

Interesting.  Do you know which cars use a heat pump already?  I understand heat pumps are usually large units that are combined with geothermal (pipes installed in the ground) to deliver heat in the winter.  So can such an application be scaled down?

No,

Heat pumps are modified AC units that can go in reverse. Instead of the freon be compressed and cause heat on one end, and cool on the other, the pump becomes a generator, generating electricity, as the hot side of freon is being heated by outside air, expanding the freon, which pushes the pump motor, and goes to the cold side where it shrinks as it gives off heat... thus allowing for a mild heating to happen using outside air.

 

It's one of the few devices that works at an efficiency over 100% (it generates electricity, rather than use it).

[Waldo]

On 10/9/2022 at 8:12 PM, MeeLee said:

No,

Heat pumps are modified AC units that can go in reverse. Instead of the freon be compressed and cause heat on one end, and cool on the other, the pump becomes a generator, generating electricity, as the hot side of freon is being heated by outside air, expanding the freon, which pushes the pump motor, and goes to the cold side where it shrinks as it gives off heat... thus allowing for a mild heating to happen using outside air.

 

It's one of the few devices that works at an efficiency over 100% (it generates electricity, rather than use it).

 

Your understanding of the details is a bit off.  A heat pump doesn't "generate electricity", it still consumes electricity to run the pump and it isn't really over 100% efficient when you get down to the details, but it is certainly more efficient than resistive heating elements.  It is basically an A/C system running in reverse, just pulling the air from the hot side instead of the cool side.  But the devil is always in the details, you need to carefully design the system for the conditions you expect to use it in, with respect to sizing and pressures if you want to get the efficiency gains from it.  It doesn't make a lot of sense on a hybrid that already has a heat source (the ICE), but it certainly looks like it will be the standard system going forward on EVs.

[Sky14FFH]

On 10/9/2022 at 8:12 PM, MeeLee said:

Heat pumps are modified AC units that can go in reverse.

I know this, same way with a geothermal unit,  which is why you need a warmer than ambient source for them to work efficiently.

 

On 10/9/2022 at 8:12 PM, MeeLee said:

thus allowing for a mild heating to happen using outside air.

No it doesn't. *sigh*

 

Bro that's not going to happen if the outside air is colder than the inside.  What a heatpump does is amplify the already warmer source.

On 10/9/2022 at 8:12 PM, MeeLee said:

thus allowing for a mild heating to happen using outside air.

Edited November 26, 2022 by Sky14FFH

[Waldo]

15 hours ago, Sky14FFH said:

I know this, same way with a geothermal unit,  which is why you need a warmer than ambient source for them to work efficiently.

 

No it doesn't. *sigh*

 

 

 

Actually that is exactly how it works.   It doesn't need to be colder outside than inside for your A/C to work, and it doesn't need to be hotter outside than inside for your heat pump to work.  Better go read up on this a little bit more please.