2. Set to auto my ICE GK3 starts heating as soon as it is started in contrast with the good old days when you could shiver for at least 5 minutes before getting a bit of heat. That led me to think it was using reverse cycle aircon rather than engine heat.
3. You can set the temperature and the system will either heat or cool to maintain it very precisely. That sort of seamless and precise control is very common in automatic air conditioner systems fitted in buildings but using engine heat would maybe be harder to implement? Maybe not though. Perhaps fan speed would be sufficient?
Maybe because auto electric heating components are now more widely available they incorporated one in the GK3, at least in some markets.
Conventional I.C.E heating uses a combination of a valve that controls the rate of flow of hot water into the heater matrix (a small radiator) and fan speed blowing air through the hot matrix. The hybrid could easily incorporate such a system although I dont know if it does.
There seems to be a whole range of heaters and coolers controlling engine, electric motor and battery temperatures .
For HV battery temperature I think the Jazz uses the simplest system described in the Hella web site. Ie it uses the relatively warm or cool air from the cabin to regulate battery temperature.
I think I recall from a dealers hand over video that there are two locations for topping up coolant. One for the I.C.E and one for the electric motors and stuff. Possibly some integration between both systems.
Another interesting thing from the Hella site (or I might have seen it elsewhere) is that some EV's have a cold sink . Part of the air con system can freeze solid so that cold air can be produced even when the car is idle. I dont know if the Jazz has one.
