Reverse cycle air con for the car

[mik]

Just talking to my brother the other day , dunno how it come up but apparently some of these electric cars have reverse cycle heating/air conditioning, for reasons .....ala no internal combustion engine with a cooling system to bypass hot water to a heater core.
my brother seems to think with a bit of plumbing and valving it wouldn't be too hard to do.
now when my brother says things like this we must be wary......hes a bit different, he gets an idea in head and most others would say get outa town (me included), but he usually does what he says......eventually.
Now if a bloke was looking at dash out job i`m thinking this might be an alternative as all the work would (i think ???) need to be done in the engine bay.
so do we have any one been down this path or do we have any aircon guys that can comment on this to say yay it could be a worthwhile thing or forget it.

[Watto_Cobra]

I'd guess a pure electric car would be forced to use reverse-cycle A/C. A heating element would be even worse on the battery pack than running a compressor.

I think it would be pointless and far less efficient to run reverse-cycle A/C in an internal combustion engine car, where you already have a water pump running the coolant system and only need a fan to get heat from the vents.

A heater core is basically free heat because the internal combustion engine is going to produce heaps of heat no matter what. Instead of all that wasted heat being dissipated via the radiator, you're redirecting some into the cabin.

A fan would use much less than a compressor+fan (reverse-cycle) which, in turn, would use much less than a heating element+fan.

[SumoDog68]

From memory Mitsubishi I Miev electric car uses electrically driven a/c compressor for a/c (cooling) and heating elements with coolant ( liquid) piped into cabin for heating .
Hybrids like Prius and Volt use conventional heater core combined with electrcally driven compressors for a/c.
If you want reverse cycle a/c for heating and cooling you will have to decide how to drive the compressor - mechanically or electrically. Pretty sure large automotive companies looked into this and decided it is not an efficiant option.
Heating is pretty much free byproduct of combustion engine so why drive a compressor to acheive the same result.

[ea90gl]

A reverse cycle air conditioner on heating basically works the same way as it does on cooling except the flow of refrigerant is reversed and the condensor and evaporater exchange roles, not a complicated procedure. Without going into the nuts and bolts the main difference between a domestic air con and car air con is the addition of a 4 way valve with additional control that allows the refrigerant to reverse its path in the system and of course the different type of refrigerant used between systems. I couldnt say off the top of my head Whats required to make a car air con reverse cycle but with a bit of design and the right parts I could see it being done if the manufacturers really wanted to

[Yellow_Festiva]

Don't know why, but this came to mind:

[ea90gl]

lol too funny seen that one before

[mik]

Originally Posted by ea90gl

A reverse cycle air conditioner on heating basically works the same way as it does on cooling except the flow of refrigerant is reversed and the condensor and evaporater exchange roles, not a complicated procedure. Without going into the nuts and bolts the main difference between a domestic air con and car air con is the addition of a 4 way valve with additional control that allows the refrigerant to reverse its path in the system and of course the different type of refrigerant used between systems. I couldnt say off the top of my head Whats required to make a car air con reverse cycle but with a bit of design and the right parts I could see it being done if the manufacturers really wanted to

My brother is going to do this, he reckons it does have some good points over the conventional car heating/ac system, for a start getting rid of heater core and hoses, that's one less place to worry about cooling system malfunction, I can't blame him for that one , its no fun pulling dashes out ,
The other thing is the reverse cycle ac warms up quicker(he thinks), to him or , I for that matter ,we run our ac nearly all the time anyway so that part wouldn't be a bother.
I have to say when he mentioned this I thought it was probably a lot of trouble to go to but some air con mech might have done it before for a bit of fun, it looks like my bro might be a hot rodding pioneer in this area.: ).