They are using an EEV - a first in heat pump laundry?
What I have just realised:
Both the LG and the Samsung appear to use an EEV - electronic expansion valve - on their new heat pump combos. LG also appears to use one on their stand alone heat pump dryer.
The GE does NOT use such a setup but only uses a capilary tube.
Short lesson on heat pumps:
To keep a pressure difference between the high pressure, warm side and the low pressure, cold side you need something the restricts the flow - a metering device.
Most domestic refrigeration systems - as they are rather small in the grand scheme of things - use capilariy tubes. That's just a very narrow tube of a certain length.
That means there's one fixed flow restriction - thus fixed flow rate of refrigerant for a given pressure difference.
The temperatures of the cold and hot side (with proper airflow) are more or less fixed to the pressure in each part aswell.
That means: You can alter the speed of the compressor (thus the flow rate through the compressor), but that will always change the temperature of your hot and cold side aswell as the restriction between those sides is fixed.
An expansion valve can however vary that restriction. That means you can ramp up the compressor speed (thus "move more heat" - move more refrigerant) but keep the temperatures on either side of the heat exchanger more or less constant.
Or in reverse: You can run a very low compressor rpms and still keep high temperature splits (low heat movement - for example towards the end of a dry cycle).
I don't know of any EU household heat pump laundry appliance that uses an EEV. Main reason is that it makes the control system more complicated, you need more sensors to feed that control system data. Further the parts are (obviously) more costly than a capilary tube.
But: You can a) squeeze that bit more of efficency out of such an appliance and/or b) speed up drying significantly without hitting pressure limits.
These circular parts in the pics are the coils that control that valve.
As far as I understand, the valve has a base position with a spring holding it there.
Depending on how much voltage is put through the coil, that moves the valve a bit.
That means there is no moving part needing to be sealed between insinde the circuit and outside.
