Traffic Simulation and Analysis

The performance of an elevator is directly related to lift simulation analysis to the population of the building, and the “arrival rate”; which is the percentage of the population arriving in the lobby to take the lift, in a time frame of 5 minutes (5AR). The other part of the equation is the capacity of the elevator system – i.e. how many passengers the elevator is able to transport from the lobby, within a certain time frame. This criterion is known as the “handling capacity”, which is also defined as a percentage of population in 5 minutes (5HC). With a well-designed lift system, the Arrival Rate and Handling Capacity are in balance during the most busy time of day (typically morning-peak or lunch-peak). However, when the Arrival Rate is higher than the Handling Capacity, the lift car will get full and some passengers will need to wait the next lift. This means that the system will saturate, and waits will increase exponentially. Similarly, when the arrival rate is significantly lower than the handling capacity, the system is overdesigned – at the expense of high costs (too many lifts) and a lift design efficiency (building core too large, too many lift shafts). The most important indicators of ‘quality of service’ in Elevators are:

 

Average Waiting Time (AWT); the average of all passenger who are using the elevator, departing from any floor in the building.Average Time To Destination (ATTD); the time it takes from the moment of arriving in the lobby until reaching the destination floor.Average Car Load Factor (ACLF); the average fill rate of the lift car

The above performance indicators can only be determined through a Traffic

 Simulation. Elevator Traffic Analysis is typically required during design stage of a new building, during a lift modernization project, and in case of traffic complaints (long waits and full cars) with existing buildings. Designing and dimensioning elevators is a careful balance between Space, Performance and Costs.

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