Giant high-quality refrigerator with tiny energy consumption

We have since last weekend now as a huge refrigerator from Bosch; the KGE39AI40; fashionable design, about 2m high and it should consume little power crazy.
Our old fridge (installation variant combi) Whirlpool (IKEA) has about 500KWh "wasted" year in energy. Cooling performance was so-so in the fridge and a couple of drawers and pull-outs were begun. Even the rear wall in the refrigerator had a cross plan. Age approx 12-15Jahre.

So it was clear: The old man has to go.

The newly consumed (measured !!) about 0,44kwh in 24 hours; which is about only 1/3 of the old refrigerator. Thus we seem to mind. To save on energy 100 a year ?!
And a bonus from the electricity provider Lichtblick there are also, if you consume at least 10% less total power a year ....

Now my mustard and my suspicions it; I can not wait for your comments:

How does a refrigerator or engineers; save as much electricity?

1.
Insulation thicker compressor smaller and less power (simple)

. 2
The compressor is supplied with AC230V 40-150hz of a Wechselumrichter. This allows you to vary the power (lt. My meter display of approximately 30-90 watts)

. 3
The refrigerator has two (two-way?) - Valves in the cooling circuit and can control separately so probably the two areas (fridge and Gefierraum). Moreover, it seems so that the compressor can pump from "freezer evaporator" in the "cooling-evaporator" and simply "bypass" of the condenser coolant (low energy consumption and noise with the "gurgling") and thus lower temperatures on the frozen can be transported in refrigerated area. This fits well with the phenomenon that most of the freezer is much colder than the set desired temperature.
For this theory fits well that one only the temperature is no longer capable of setting in the freezer at the even newer and more expensive refrigerators from B + S from the refrigerator compartment and.

. 4
Fan in refrigerator; Spread the cold better and more evenly in the refrigerator.

5. In addition, there is a control electronics, which probably can adaptively adjust to user behavior and also the ambient temperature.

The last point is only a "suspicion".

This whole control technology caused by the valves and pressure changes many Klacker- and hissing noises.
But the hammer is the "Bach noise"; that is, when it once again behind the refrigerator "loud" gurgles and gurgles.

The compressor itself can be heard as no longer so good. It is at least as quiet as our
Old of Whirpool ...

Images from the new Bosch:
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One thing that is a little surprising: Was hoping to do with the purchase of the Bosch equipment for our "support you locals, buy local" and I therefore decided to LG, SAMSUNG, Pansaonic, OK, and Haier Indesit and Co. ; But power is built in Turkey.