Elevator installation and operation method therefor

An elevator installation comprising:

• a control unit;
• at least one elevator cage in a building, the building comprising a plurality of stories, the at least one elevator cage being movable among the plurality of stories;
• and
• respective elevator control units arranged on the plurality of stories, the respective elevator control units being configured to receive a travel request and transmit the travel request to the control unit, the control unit being configured in a collect mode to,
• determine a first energy consumption value of the elevator installation for a first journey from a current stopping story of the at least one elevator cage to at least one input destination story indicated by the travel request,
• determine a second energy consumption value of the elevator installation for a second journey from the current stopping story to at least one input travel request story indicated by the travel request and requiring a change in a travel direction of the elevator cage,
• determine a smallest energy consumption value out of the first energy consumption value and the second energy consumption value, and
• perform, using the elevator cage, a one of the first journey and the second journey based on the determined smallest energy consumption value.