The HARint Plane: A Graphical Method for Visualising the Optimality of an Elevator System Design Option

Lutfi Al-Sharif, Ahmad M. Abu Alqumsan and Osama F. Abdel Aal

Thursday 27th September 2012

This paper presents a graphical methodology of visualizing the optimality of an elevator design solution. It introduces a new plane called the HARint plane, each point on which represents a solution to the elevator design problem. By visually inspecting the plane and examining the intersection of various curves on the plane, the designer can understand how far the offered solution is from the optimal solution and also whether the offered design is wasteful. The HARint plane comprises the quality of service, represented by the actual interval and the quantity of service, represented by the handling capacity. These are compared with the client/site requirements in terms of the target interval and the arrival rate. A number of curves can then be plotted on the plane based on the possible number of elevators and the car loading in passengers. In drawing the curves on the plane, the round trip time has to be known. The round trip time can either be calculated analytically or by the use of Monte Carlo simulation. however, the calculation of the round trip time is only part of the design methodology. This paper does not discuss the round trip time calculation methodology as this has been addressed in detail elsewhere. The optimality of the design is assessed by a clear step by step methodology that uses the user requirements to select an optimal design. Keywords: Elevator, lift, round trip time, interval, up peak traffic, rule base, Monte Carlo simulation, average travel time, HARint plane.

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