However, disagree with the statement that a climate control system is not meant to be operated while idle. That is an old myth that I expect came from back when there was fewer electrical components in the car so not turning the ac /off/ before turning the vehicle off would risk damaging the cars electrical.
that’s not actually a myth. The car is functionally not designed to be left on idle for extended periods. (Note, I’m saying extended periods. Warming/cooling your car at idle is normal. idling at a stop light is normal. Five minutes while waiting to pick some one up is normal. Leaving it to stay cool for 2 hours is outside that design window.)
When an engine is idling, it’s turning at a lower RPM than when moving. of particular note here is that the alternator and AC compressor are both driven by the serpetine belt directly connected to the crankshaft. The lower RPM makes both less efficient. For the compressor, what this means is that the AC system is turning more slowly than it normally would, reducing the total amount of cooling. For the alternator; it produces less electricity and may cause the battery to be discharging. Depends on some things, including how hard the AC is having to work, etc.
Further, because the car is not moving, there is less air moving around the engine compartment (or wherever the radiator for the engine and the AC is located.) This equates to higher operating temperatures for the engine, as well as yet more reduced ability for the AC system to remove excess heat from the cabin.
just because an AC can be run at idle for extended periods doesn’t mean it’s designed to, and doing so, especially on old or poorly maintained systems, in excessive heat, is likely to cause it to crap out where it wouldn’t have normally. Is it a particularly high probability? Not really. Is it still too high considering it’s a life-safety system? fucking absolutely.
brygphilomena@lemmy.dbzer0.com 1 day ago
This very much depends on the car.
Most modern computer controlled cars will not discharge the battery at idle unless you have a powerful sound system or an alternator that’s already on its way out. And they can adjust idle anyway if needed, most will increase idle when AC is turned on now to compensate the increased load on the engine. Driving the AC compressor is such a light load compared to the moving a 2 ton vehicle.
Also, many newer cars may even run an electric compressor instead of one driven off the motor. Think hybrid vehicles, it wouldn’t be feasible to have an AC system that turns off half the time if it’s running on the electric motors.
What you might deal with is heat soak if the fans can’t move enough air over the condenser core. But modern vehicles are immensely more efficient than even 10 year old vehicles.
FuglyDuck@lemmy.world 1 day ago
You’re point?
They’re not designed to idle for extended periods, and doing so puts strain on the systems. that the cars are “more efficient” doesn’t change that.
the AC compressor isn’t a significant load, no. But it’ expects a certain engine RPM coming into it, and it’s designed at that. It’s significantly less when the engine is idling because that’s below it’s designed range. There’s a reason the manufacturers tell you not to idle your car for extended periods (mine says more than 10 minutes, my last one said 5.) and this is part of it.
the increase in RPM modern cars do isn’t for the AC system. it’s to keep the engine from stalling and running smoothly… the compressor is still not designed to operate at that RPM.
Malfeasant@lemmy.world 13 hours ago
You’re still ignoring the argument that a hybrid doesn’t have a typical vehicle alternator, it has a charging system that’s whole job is to generate electricity from the engine, and do that efficiently and reliably, and it has an electric a/c compressor.
LustyArgonianMana@lemmy.world 1 day ago
And she had a hybrid vehicle btw