Actually, I’m surprised they weren’t using them long before. It’s basically AC with an extra valve. Thought they get priced like they’re some sort of new technology.
Vapor injection becomes an excuse to downsize the compressor and lowers the cost, it seems. You could easily go lower than 32 if you oversized the pump before EVI, but those were only in specific heatpumps.
I suspect the reason for that was that the pumps used in car ACs are not really very powerful. They were alright for cooling the car down, but for heating heat up in a cold environment you need a fair amount of throughput, they work if you have the throughput, but you need it to be there.
They work by pulling ambient heat out a large part of the outside and dumping it into the small inside. You need many times the contents of the interior to warm up if it’s a cold day outside. Thus you need a lot of air and if you want it to happen in a reasonable time frame you need quite a powerful little motor. The ones on houses are fine because they’re huge anyway.
They also need to be able to get the cold side colder than the outside air so once it gets too cold they don’t really work. There can also be some problems with condensation but when they do work they’re great.
Actually, I’m surprised they weren’t using them long before. It’s basically AC with an extra valve. Thought they get priced like they’re some sort of new technology.
There was never really a need in ICE vehicles since they can primarily use waste heat from the engine.
Pretty sure they meant EVs
Pretty sure @jqubed@lemmy.world meant to explain why they weren’t a thing in cars in general
Yes that was my point.
Vapor injection is the new technology. It’s why older heat pumps were useless below 32f.
Vapor injection becomes an excuse to downsize the compressor and lowers the cost, it seems. You could easily go lower than 32 if you oversized the pump before EVI, but those were only in specific heatpumps.
I reckon they thought seat heating and steering wheel was enough, and it kinda is for the most part
I suspect the reason for that was that the pumps used in car ACs are not really very powerful. They were alright for cooling the car down, but for heating heat up in a cold environment you need a fair amount of throughput, they work if you have the throughput, but you need it to be there.
They work by pulling ambient heat out a large part of the outside and dumping it into the small inside. You need many times the contents of the interior to warm up if it’s a cold day outside. Thus you need a lot of air and if you want it to happen in a reasonable time frame you need quite a powerful little motor. The ones on houses are fine because they’re huge anyway.
It uses the same amount of energy to create cold as it does to create heat.
Heart pumps don’t create heat, they move it.
Well it’s about temperature differences, those are larger in winter I guess. On the other hand there is a lot more radiative heat load in summer…
There’s a “sweet spot” for temperatures, so if a compressor and heating agent works well in summer, it won’t work well in winter.
They also need to be able to get the cold side colder than the outside air so once it gets too cold they don’t really work. There can also be some problems with condensation but when they do work they’re great.