GodFollower said:
If the heat pump is used in the mixed operation, the shutoff valves with the numbers 17, 20 and 21 are
open. The shutoff valve with the number 18 is closed as there should be no reverse flow. This results in a division of the hot, high-pressure refrigerant. On the one hand, cooling of the high-voltage battery unit and dehumidification of the passenger compartment can be realized by the cooling at the evaporator, on the other hand, the divided heat transported with the refrigerant is used for the heat pump heat exchanger.
Basically, it still uses the A/C compressor to chill the evaporator, but uses the heat formed by that evaporation to heat the coolant in the resistive heater circuit. So, it is still using the same resistive heater circuit; but generating the heat with the heat pump rather than from the resistive heater.
Clever!
Thanks for posting the explanation! However, I think your restatement of the heating function is not accurate in that evaporation doesn't generate heat that warms the coolant in the resistive heater circuit. The hot compressed liquid refrigerant is split into two streams. As you stated, one stream is fed into the evaporator where its conversion from a liquid to a gas takes heat from the surroundings (i.e., it lowers the temperature of the cabin air which dehumidifies it). The other hot compressed liquid refrigerant stream is passed through a heat exchanger that transfers heat from the hot refrigerant to the coolant in the resistive heater circuit which then warms the dehumidified cabin air.
It seems like pretty clever technology to make it all work under varying conditions. The hot liquid refrigerant in the dehumidifier stream won't evaporate in the evaporator if its temperature is too low or its pressure is too high, so the compressor speed and how the refrigerant is split into two streams are probably critical. The heating stream seems less critical since its heat is just being transferred to the resistive heater circuit coolant with no phase change occurring (i.e., the refrigerant remains a liquid). How these two streams are recombined for another pass through the compressor probably involves some clever engineering.