Thread: EV general discussion

Originally Posted by DiscoMick

Can't the heater work with the air-con off?

Pretty sure all cars including Landrover now refer to air-con as Climate Control

The window down is natural. My staff stuff it up all the time. Several Reverse cycle AC at work have temp controls as does my Disco. They change the fan to manual and wonder why they cook or freeze

Originally Posted by NavyDiver

Only the ****e ones. Heat pumps are every cool or hot for very low energy. I have five big ones outside which do my hot water and hydronic heating. Almost all half decent cars and 4wds are using then now I think. Nissan can explain it better than me

oh, so its like reverse cycle aircon.

Originally Posted by Eevo

oh, so its like reverse cycle aircon.

yep

Originally Posted by NavyDiver

yep

Not sure who has written that, but I would hope that Nissan cars don't use what is written there!

Conventional air-conditioning systems used an electrical heater, but since the use of the heater directly relates to power consumption, actual driving range was significantly reduced.

Utter rubbish!

Gasoline vehicles re-use engine exhaust heat to provide the warm air for the functions of the heater.

Bollocks! Unless it has an air muff around the exhaust as in a piston engine light aircraft!

All vapour compression type air conditioners can be referred to as "heat pumps". Heat energy is being moved from one place to another, and the only place that after years of working with them, it is only the Yanks use that terminology. And the ones that I know about are just used as heaters, with what should be the evaporator buried in the ground.

I don't know about later Land Rovers, but my ancient Discovery uses a conventional type vapour compression air con system. BUT, the hot water from the engine is also continuously circulated through a separate heater matrix, or radiator type of core, along with the air con evaporator mounted in an air box. The cabin temperature is controlled by mixing the cabin air across both parts.

Reverse cycle air cons still work on the same principle, but the circuit is reversed so that internal part becomes the condenser, and the external part becomes the evaporator.

Modern engine driven car air cons now use a variable displacement compressor, that although it still runs at a speed depending on the drive ratio as in a conventional "old" type, the output, and therefore the load, is regulated to what is needed. A bit like what happens in a invertor type house air con. The end result is a more efficient system energy wise.

Much research has been done on EV cars on different types of air cons, and various systems are now in use. It should also be kept in mind that a big source of heat with a ICE car is now not there, so the cooling requirement is a lot less.

Originally Posted by Old Farang

Not sure who has written that, but I would hope that Nissan cars don't use what is written there!


Utter rubbish!



Bollocks! Unless it has an air muff around the exhaust as in a piston engine light aircraft!

All vapour compression type air conditioners can be referred to as "heat pumps". Heat energy is being moved from one place to another, and the only place that after years of working with them, it is only the Yanks use that terminology. And the ones that I know about are just used as heaters, with what should be the evaporator buried in the ground.

I don't know about later Land Rovers, but my ancient Discovery uses a conventional type vapour compression air con system. BUT, the hot water from the engine is also continuously circulated through a separate heater matrix, or radiator type of core, along with the air con evaporator mounted in an air box. The cabin temperature is controlled by mixing the cabin air across both parts.

Reverse cycle air cons still work on the same principle, but the circuit is reversed so that internal part becomes the condenser, and the external part becomes the evaporator.

Modern engine driven car air cons now use a variable displacement compressor, that although it still runs at a speed depending on the drive ratio as in a conventional "old" type, the output, and therefore the load, is regulated to what is needed. A bit like what happens in a invertor type house air con. The end result is a more efficient system energy wise.

Much research has been done on EV cars on different types of air cons, and various systems are now in use. It should also be kept in mind that a big source of heat with a ICE car is now not there, so the cooling requirement is a lot less.

Appologies. I assumed the Nissan link was ok. Heat pumps are perhaps better understood from sandan The Sanden Eco® Plus Hot Water Heat Pump System

is a highly energy-efficient replacement for your traditional electric hot water system. It absorbs heat from the air and transfers it to heat water, in a way that saves energy, saves money and reduces greenhouse gas emissions.
Sanden Hot Water Heat Pumps - Energy Efficient Hot Water Systems

they do work both ways which is way the newer some what more advanced have them.

If saden are bollocks my hot water and heating might be in trouble Have to add I can freeze water on the output of my heatpumps as a party trick

If saden are bollocks my hot water and heating might be in trouble Have to add I can freeze water on the output of my heatpumps as a party trick

Yes, all well and good. But you are talking about Co2. While Co2 is used as a refrigerant it is not the type of gas you want in a car.

To see what Co2 does just take a Co2 fire extinguisher and let some loose.

TBH I did not know about these hot water heaters. An air con "heat pump" is basically an arse about air conditioner, as I have posted. It does not use Co2, but the common Freon type refrigerants.

The problem with Co2 is the dangerous high pressures that it operates at. Discharge high side pressure up around 10MPa- 1,500 psi. Better to ask the Fridgies about this crap as it is highly specialised.

https://www.energy.gov/sites/prod/fi...amp_042414.pdf

Originally Posted by Old Farang

.....
Bollocks! Unless it has an air muff around the exhaust as in a piston engine light aircraft!

......

Or like VW and Citroen (2CV etc) did for fifty years or more. Not just light aircraft. Surely you are old enough to remember them?